[500962] Test a working incremental execution of a property change

26 files changed, 1079 insertions, 780 deletions

diff --git a/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/qvti/java/QVTiCG2JavaVisitor.java b/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/qvti/java/QVTiCG2JavaVisitor.java
index cf9d6028e..fc769dff3 100644
--- a/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/qvti/java/QVTiCG2JavaVisitor.java
+++ b/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/qvti/java/QVTiCG2JavaVisitor.java
@@ -131,6 +131,7 @@ import org.eclipse.qvtd.runtime.evaluation.TransformationExecutor;
 import org.eclipse.qvtd.runtime.evaluation.Transformer;
 import org.eclipse.qvtd.runtime.internal.evaluation.AbstractComputationConstructor;
 import org.eclipse.qvtd.runtime.internal.evaluation.AbstractInvocationConstructor;
+import org.eclipse.qvtd.runtime.internal.evaluation.AbstractTransformerInternal.Model;
 
 import com.google.common.collect.Iterables;
 
@@ -139,6 +140,49 @@ import com.google.common.collect.Iterables;
  */
 public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerator> implements QVTiCGModelVisitor<@NonNull Boolean>
 {
+	protected static class AllInstancesAnalysis
+	{
+		protected final @NonNull Set<org.eclipse.ocl.pivot.@NonNull Class> allInstancesClasses;
+		protected final @NonNull Map<org.eclipse.ocl.pivot.@NonNull Class, @Nullable List<org.eclipse.ocl.pivot.@NonNull Class>> instancesClassAnalysis;
+		protected final @NonNull Map<org.eclipse.ocl.pivot.@NonNull Class, @NonNull Integer> instancesClass2index;
+		protected final @NonNull List<org.eclipse.ocl.pivot.@NonNull Class> sortedList;
+		private @NonNull String @Nullable [] names = null;
+
+		public AllInstancesAnalysis(@NonNull QVTiTransformationAnalysis transformationAnalysis, @NonNull Set<org.eclipse.ocl.pivot.@NonNull Class> allInstancesClasses) {
+			this.allInstancesClasses = allInstancesClasses;
+			this.instancesClassAnalysis = transformationAnalysis.getInstancesClassAnalysis(allInstancesClasses);
+			//
+			// Populate a mapping from instancesClass to linear index.
+			//
+			this.instancesClass2index = new HashMap<>(instancesClassAnalysis.size());
+			this.sortedList = new ArrayList<>(instancesClassAnalysis.keySet());
+			Collections.sort(sortedList, NameUtil.NameableComparator.INSTANCE);
+			for (int i = 0; i < sortedList.size(); i++) {
+				instancesClass2index.put(sortedList.get(i), i);
+			}
+		}
+
+		protected @NonNull Map<org.eclipse.ocl.pivot.@NonNull Class, @NonNull Integer> getInstancesClass2index() {
+			return instancesClass2index;
+		}
+
+		protected @NonNull Map<org.eclipse.ocl.pivot.@NonNull Class, @Nullable List<org.eclipse.ocl.pivot.@NonNull Class>> getInstancesClassAnalysis() {
+			return instancesClassAnalysis;
+		}
+
+		protected @NonNull String @NonNull [] getNames() {
+			return ClassUtil.nonNullState(names);
+		}
+
+		protected @NonNull List<org.eclipse.ocl.pivot.@NonNull Class> getSortedList() {
+			return sortedList;
+		}
+
+		public void setNames(@NonNull String[] names) {
+			this.names = names;
+		}
+	}
+
 	/**
 	 * The run-time API version.
 	 *
@@ -226,49 +270,6 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 		}
 	}
 
-	protected static class AllInstancesAnalysis
-	{
-		protected final @NonNull Set<org.eclipse.ocl.pivot.@NonNull Class> allInstancesClasses;
-		protected final @NonNull Map<org.eclipse.ocl.pivot.@NonNull Class, @Nullable List<org.eclipse.ocl.pivot.@NonNull Class>> instancesClassAnalysis;
-		protected final @NonNull Map<org.eclipse.ocl.pivot.@NonNull Class, @NonNull Integer> instancesClass2index;
-		protected final @NonNull List<org.eclipse.ocl.pivot.@NonNull Class> sortedList;
-		private @NonNull String @Nullable [] names = null;
-
-		public AllInstancesAnalysis(@NonNull QVTiTransformationAnalysis transformationAnalysis, @NonNull Set<org.eclipse.ocl.pivot.@NonNull Class> allInstancesClasses) {
-			this.allInstancesClasses = allInstancesClasses;
-			this.instancesClassAnalysis = transformationAnalysis.getInstancesClassAnalysis(allInstancesClasses);
-			//
-			// Populate a mapping from instancesClass to linear index.
-			//
-			this.instancesClass2index = new HashMap<>(instancesClassAnalysis.size());
-			this.sortedList = new ArrayList<>(instancesClassAnalysis.keySet());
-			Collections.sort(sortedList, NameUtil.NameableComparator.INSTANCE);
-			for (int i = 0; i < sortedList.size(); i++) {
-				instancesClass2index.put(sortedList.get(i), i);
-			}
-		}
-
-		protected @NonNull Map<org.eclipse.ocl.pivot.@NonNull Class, @NonNull Integer> getInstancesClass2index() {
-			return instancesClass2index;
-		}
-
-		protected @NonNull Map<org.eclipse.ocl.pivot.@NonNull Class, @Nullable List<org.eclipse.ocl.pivot.@NonNull Class>> getInstancesClassAnalysis() {
-			return instancesClassAnalysis;
-		}
-
-		protected @NonNull String @NonNull [] getNames() {
-			return ClassUtil.nonNullState(names);
-		}
-
-		protected @NonNull List<org.eclipse.ocl.pivot.@NonNull Class> getSortedList() {
-			return sortedList;
-		}
-
-		public void setNames(@NonNull String[] names) {
-			this.names = names;
-		}
-	}
-
 	protected @Nullable AllInstancesAnalysis doAllInstances(@NonNull QVTiTransformationAnalysis transformationAnalysis) {
 		Set<org.eclipse.ocl.pivot.@NonNull Class> allInstancesClasses = transformationAnalysis.getAllInstancesClasses();
 		if (allInstancesClasses.size() > 0) {
@@ -382,9 +383,9 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 	}
 
 	protected void doAssigned(@NonNull CGEcoreContainerAssignment cgPropertyAssignment) {
-		EStructuralFeature eStructuralFeature = ClassUtil.nonNullModel(cgPropertyAssignment.getEStructuralFeature());
-		CGValuedElement cgSlot = getExpression(cgPropertyAssignment.getOwnedSlotValue());
-		CGValuedElement cgInit = getExpression(cgPropertyAssignment.getOwnedInitValue());
+		EStructuralFeature eStructuralFeature = QVTiCGUtil.getEStructuralFeature(cgPropertyAssignment);
+		CGValuedElement cgSlot = getExpression(QVTiCGUtil.getOwnedSlotValue(cgPropertyAssignment));
+		CGValuedElement cgInit = getExpression(QVTiCGUtil.getOwnedInitValue(cgPropertyAssignment));
 		EPackage ePackage = ClassUtil.nonNullModel(eStructuralFeature.getEContainingClass().getEPackage());
 		if (isIncremental || ((SetStatement)cgPropertyAssignment.getAst()).isIsNotify()) {
 			js.append("objectManager.assigned(");
@@ -404,9 +405,9 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 	}
 
 	protected void doAssigned(@NonNull CGEcorePropertyAssignment cgPropertyAssignment) {
-		EStructuralFeature eStructuralFeature = ClassUtil.nonNullModel(cgPropertyAssignment.getEStructuralFeature());
-		CGValuedElement cgSlot = getExpression(cgPropertyAssignment.getOwnedSlotValue());
-		CGValuedElement cgInit = getExpression(cgPropertyAssignment.getOwnedInitValue());
+		EStructuralFeature eStructuralFeature = QVTiCGUtil.getEStructuralFeature(cgPropertyAssignment);
+		CGValuedElement cgSlot = getExpression(QVTiCGUtil.getOwnedSlotValue(cgPropertyAssignment));
+		CGValuedElement cgInit = getExpression(QVTiCGUtil.getOwnedInitValue(cgPropertyAssignment));
 		EPackage ePackage = ClassUtil.nonNullModel(eStructuralFeature.getEContainingClass().getEPackage());
 		if (isIncremental || ((SetStatement)cgPropertyAssignment.getAst()).isIsNotify()) {
 			js.append("objectManager.assigned(");
@@ -504,6 +505,36 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 		js.append("}\n");
 	} */
 
+	protected void doCreateRealizedVariable(@NonNull CGRealizedVariable cgRealizedVariable) {
+		if (isIncremental) {
+			js.appendClassReference(null, cgRealizedVariable);
+			js.append(" ");
+			js.appendValueName(cgRealizedVariable);
+			js.append(" = this.");
+			js.appendValueName(cgRealizedVariable);
+			js.append(";\n");
+			js.append("if (");
+			js.appendValueName(cgRealizedVariable);
+			js.append(" == null) {\n");
+			js.pushIndentation(null);
+		}
+		cgRealizedVariable.accept(this);
+		doAddRealization(cgRealizedVariable);
+		//
+		if (isIncremental) {
+			js.append("assert ");
+			js.appendValueName(cgRealizedVariable);
+			js.append(" != null;\n");
+			js.append("this.");
+			js.appendValueName(cgRealizedVariable);
+			js.append(" = ");
+			js.appendValueName(cgRealizedVariable);
+			js.append(";\n");
+			js.popIndentation();
+			js.append("}\n");
+		}
+	}
+
 	protected boolean doEcoreCreateClass(@NonNull CGValuedElement cgElement, @NonNull EClass eClass) {
 		String createMethodName = "create" + eClass.getName();
 		boolean doSetNonNull = false;
@@ -528,7 +559,16 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 			javaClass = null;
 		}
 		//
-		js.appendDeclaration(cgElement);
+		CGMapping cgMapping = QVTiCGUtil.basicGetContainingCGMapping(cgElement);
+		if ((cgMapping == null) || !useClass(cgMapping) || !isIncremental) {
+			js.append("final ");
+			if (!doSetNonNull) {
+				js.appendSuppressWarningsNull(false);
+			}
+			js.appendClassReference(true, cgElement);
+			js.append(" ");
+		}
+		js.appendValueName(cgElement);
 		js.append(" = ");
 		js.appendClassReference(javaClass);
 		js.append(".eINSTANCE.");
@@ -649,7 +689,7 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 			}
 			else if (asTypeId instanceof CollectionTypeId) {			// FIXME Fudge for body-less functions
 				if (js.isUseNullAnnotations()) {
-					js.append("@SuppressWarnings(\"null\")");
+					js.appendSuppressWarningsNull(false);
 					js.appendIsRequired(true);
 					js.append(" ");
 				}
@@ -701,7 +741,7 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 			}
 			else if (asTypeId instanceof CollectionTypeId) {			// FIXME Fudge for body-less functions
 				if (js.isUseNullAnnotations()) {
-					js.append("@SuppressWarnings(\"null\")");
+					js.appendSuppressWarningsNull(false);
 					js.appendIsRequired(true);
 					js.append(" ");
 				}
@@ -854,9 +894,9 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 
 	protected void doFunctionConstructor(@NonNull CGFunction cgFunction, @NonNull CGShadowExp cgShadowExp, @NonNull String instanceName) {
 		//		List<@NonNull CGParameter> cgParameters = ClassUtil.nullFree(cgFunction.getParameters());
-		if (js.isUseNullAnnotations()) {
-			js.append("@SuppressWarnings(\"null\")\n");		// Accurate casts are too hard
-		}
+		//		if (js.isUseNullAnnotations()) {
+		//			js.append("@SuppressWarnings(\"null\")\n");		// Accurate casts are too hard
+		//		}
 		js.append("public ");
 		js.append(getFunctionName(cgFunction));
 		js.append("(/*Nullable*/ Object ");
@@ -1122,9 +1162,8 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 
 	public @NonNull Boolean doMappingCall_Class(@NonNull CGMappingCall cgMappingCall) {
 		js.append("invocationManager.flush();\n");
-		MappingCall pMappingCall = (MappingCall) cgMappingCall.getAst();
-		Mapping pReferredMapping = pMappingCall.getReferredMapping();
-		assert pReferredMapping != null;
+		MappingCall pMappingCall = QVTiCGUtil.getAST(cgMappingCall);
+		Mapping pReferredMapping = QVTimperativeUtil.getReferredMapping(pMappingCall);
 		CGMapping cgReferredMapping = analyzer.getMapping(pReferredMapping);
 		assert cgReferredMapping != null;
 		Iterable<@NonNull CGMappingCallBinding> cgMappingCallBindings = QVTiCGUtil.getOwnedMappingCallBindings(cgMappingCall);
@@ -1132,20 +1171,21 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 		//	Set loopVariable non-null if it needs to be type-checked and cast to a narrower type.
 		//
 		for (@NonNull CGMappingCallBinding cgMappingCallBinding : cgMappingCallBindings) {
+			CGValuedElement ownedValue = cgMappingCallBinding.getOwnedValue();
 			TypeDescriptor checkedType = needsTypeCheck(cgMappingCallBinding);
 			if (checkedType != null) {
 				js.append("if (");
-				js.appendValueName(cgMappingCallBinding.getOwnedValue());
+				js.appendValueName(ownedValue);
 				js.append(" instanceof ");
 				js.appendClassReference(checkedType);
 				js.append(") {\n");
 				js.pushIndentation(null);
 			}
-			else if (!cgMappingCallBinding.isNonNull()) {
+			else if (!ownedValue.isNonNull()) {
 				Element asMappingParameterBinding = cgMappingCallBinding.getAst();
 				if (!(asMappingParameterBinding instanceof GuardParameterBinding)) {		// FIXME this should be part of isNonNull
 					js.append("if (");
-					js.appendValueName(cgMappingCallBinding.getOwnedValue());
+					js.appendValueName(ownedValue);
 					js.append(" != null) {\n");
 					js.pushIndentation(null);
 				}
@@ -1195,7 +1235,7 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 				js.popIndentation();
 				js.append("}\n");
 			}
-			else if (!cgMappingCallBinding.isNonNull()) {
+			else if (!cgMappingCallBinding.getOwnedValue().isNonNull()) {
 				Element asMappingParameterBinding = cgMappingCallBinding.getAst();
 				if (!(asMappingParameterBinding instanceof GuardParameterBinding)) {		// FIXME this should be part of isNonNull
 					js.popIndentation();
@@ -1208,16 +1248,15 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 	}
 
 	public @NonNull Boolean doMappingCall_Function(@NonNull CGMappingCall cgMappingCall) {
-		MappingCall pMappingCall = (MappingCall) cgMappingCall.getAst();
-		Mapping pReferredMapping = pMappingCall.getReferredMapping();
-		assert pReferredMapping != null;
+		MappingCall pMappingCall = QVTiCGUtil.getAST(cgMappingCall);
+		Mapping pReferredMapping = QVTimperativeUtil.getReferredMapping(pMappingCall);
 		CGMapping cgReferredMapping = analyzer.getMapping(pReferredMapping);
 		assert cgReferredMapping != null;
-		List<CGMappingCallBinding> cgMappingCallBindings = cgMappingCall.getOwnedMappingCallBindings();
+		Iterable<@NonNull CGMappingCallBinding> cgMappingCallBindings = QVTiCGUtil.getOwnedMappingCallBindings(cgMappingCall);
 		//
 		//	Set loopVariable non-null if it needs to be type-checked and cast to a narrower type.
 		//
-		for (@SuppressWarnings("null")@NonNull CGMappingCallBinding cgMappingCallBinding : cgMappingCallBindings) {
+		for (@NonNull CGMappingCallBinding cgMappingCallBinding : cgMappingCallBindings) {
 			MappingParameterBinding asMappingParameterBinding = (MappingParameterBinding)cgMappingCallBinding.getAst();
 			if (asMappingParameterBinding instanceof AppendParameterBinding) {
 			}
@@ -1258,7 +1297,7 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 		//
 		js.append(getMappingName(cgReferredMapping) + "(");
 		boolean isFirst = true;
-		for (@SuppressWarnings("null")@NonNull CGMappingCallBinding cgMappingCallBinding : cgMappingCallBindings) {
+		for (@NonNull CGMappingCallBinding cgMappingCallBinding : cgMappingCallBindings) {
 			if (!isFirst) {
 				js.append(", ");
 			}
@@ -1281,7 +1320,7 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 		//
 		//	End the type check.
 		//
-		for (@SuppressWarnings("null")@NonNull CGMappingCallBinding cgMappingCallBinding : cgMappingCallBindings) {
+		for (@NonNull CGMappingCallBinding cgMappingCallBinding : cgMappingCallBindings) {
 			MappingParameterBinding asMappingParameterBinding = (MappingParameterBinding)cgMappingCallBinding.getAst();
 			if (asMappingParameterBinding instanceof AppendParameterBinding) {
 			}
@@ -1371,7 +1410,7 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 				js.append("(invocationManager, ");
 				js.appendString(QVTiCGUtil.getName(cgMapping));
 				js.append(", ");
-				js.appendBooleanString(((Mapping)cgMapping.getAst()).isIsStrict());
+				js.appendBooleanString(QVTiCGUtil.getAST(cgMapping).isIsStrict());
 				js.append(")\n");
 				js.append("{\n");
 				js.pushIndentation(null);
@@ -1399,16 +1438,63 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 		}
 	}
 
-	/*	protected void doMappingConstructorInitializers(@NonNull CGTransformation cgTransformation) {
-		String className = cgTransformation.getName();
-		for (@NonNull CGMapping cgMapping : ClassUtil.nullFree(cgTransformation.getMappings())) {
-			if (useClass(cgMapping) && (cgMapping.getFreeVariables().size() > 0)) {
-				js.append(getMappingCtorName(cgMapping) + " = ");
-				js.appendClassReference(ClassUtil.class);
-				js.append(".nonNullState(" + getMappingName(cgMapping) + ".class.getConstructor(" + className + ".class, Object[].class));\n");
+	protected boolean doMappingFields(@NonNull CGMapping cgMapping) {
+		boolean needsNewLine = false;
+		for (@NonNull CGGuardVariable cgVariable : ClassUtil.nullFree(cgMapping.getOwnedGuardVariables())) {
+			js.append("protected ");
+			doMappingConnectionVariable(cgVariable);
+			js.append(";\n");
+			needsNewLine = true;
+		}
+		if (isIncremental) {
+			for (@NonNull CGRealizedVariable cgVariable : QVTiCGUtil.getOwnedRealizedVariables(cgMapping)) {
+				js.append("protected ");
+				js.appendClassReference(false, cgVariable);
+				js.append(" ");
+				js.appendValueName(cgVariable);
+				if (isIncremental) {
+					js.append(" = null");
+				}
+				js.append(";\n");
+				needsNewLine = true;
 			}
 		}
-	} */
+		return needsNewLine;
+	}
+
+	protected void doMappingRevokeInvocation(@NonNull CGMapping cgMapping) {
+		js.append("@Override\n");
+		js.append("public void revokeInvocation() {\n");
+		js.pushIndentation(null);
+		js.append("super.revokeInvocation();\n");
+		for (@NonNull CGRealizedVariable cgRealizedVariable : QVTiCGUtil.getOwnedRealizedVariables(cgMapping)) {
+			CGTypedModel cgTypedModel = cgRealizedVariable.getTypedModel();
+			//
+			js.appendClassReference(null, cgRealizedVariable);
+			js.append(" ");
+			js.appendValueName(cgRealizedVariable);
+			js.append(" = this.");
+			js.appendValueName(cgRealizedVariable);
+			js.append(";\n");
+			js.append("if (");
+			js.appendValueName(cgRealizedVariable);
+			js.append(" != null) {\n");
+			js.pushIndentation(null);
+			js.append("((");
+			js.appendClassReference(Model.Incremental.class);
+			js.append(")");
+			js.append(QVTiGlobalContext.MODELS_NAME);
+			js.append("[");
+			appendModelIndex(cgTypedModel);
+			js.append("]).remove(");
+			js.appendValueName(cgRealizedVariable);
+			js.append(");\n");
+			js.popIndentation();
+			js.append("}\n");
+		}
+		js.popIndentation();
+		js.append("}\n");
+	}
 
 	protected void doOppositeCaches(@NonNull QVTiTransformationAnalysis transformationAnalysis) {
 		Map<@NonNull Property, @NonNull Integer> opposites = transformationAnalysis.getCaches();
@@ -1725,8 +1811,7 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 
 	@Override
 	public @NonNull Boolean visitCGConnectionAssignment(@NonNull CGConnectionAssignment cgConnectionAssignment) {
-		CGValuedElement initValue = cgConnectionAssignment.getOwnedInitValue();
-		assert initValue != null;
+		CGValuedElement initValue = QVTiCGUtil.getOwnedInitValue(cgConnectionAssignment);
 		if (!js.appendLocalStatements(initValue)) {
 			return false;
 		}
@@ -1737,7 +1822,7 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 		BoxedDescriptor abstractBoxedDescriptor = concreteBoxedDescriptor;
 		if (!(initValue.getASTypeId() instanceof CollectionTypeId)) {
 			js.appendReferenceTo(cgConnectionAssignment.getConnectionVariable());
-			js.append(".append(");
+			js.append(".appendElement(");
 			js.appendValueName(initValue);
 			js.append(");\n");
 		}
@@ -1793,9 +1878,9 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 		//		Property pivotProperty = cgPropertyCallExp.getReferredProperty();
 		//		CGTypeId cgTypeId = analyzer.getTypeId(pivotProperty.getOwningType().getTypeId());
 		//		JavaTypeDescriptor requiredTypeDescriptor = context.getJavaTypeDescriptor(cgTypeId, false);
-		EStructuralFeature eStructuralFeature = ClassUtil.nonNullModel(cgPropertyAssignment.getEStructuralFeature());
-		CGValuedElement cgSlot = getExpression(cgPropertyAssignment.getOwnedSlotValue());
-		CGValuedElement cgInit = getExpression(cgPropertyAssignment.getOwnedInitValue());
+		EStructuralFeature eStructuralFeature = QVTiCGUtil.getEStructuralFeature(cgPropertyAssignment);
+		CGValuedElement cgSlot = getExpression(QVTiCGUtil.getOwnedSlotValue(cgPropertyAssignment));
+		CGValuedElement cgInit = getExpression(QVTiCGUtil.getOwnedInitValue(cgPropertyAssignment));
 		//		Class<?> requiredJavaClass = requiredTypeDescriptor.getJavaClass();
 		//		Method leastDerivedMethod = requiredJavaClass != null ? getLeastDerivedMethod(requiredJavaClass, getAccessor) : null;
 		//		Class<?> unboxedSourceClass = leastDerivedMethod != null ? leastDerivedMethod.getDeclaringClass() : requiredJavaClass;
@@ -1836,9 +1921,9 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 		//		Property pivotProperty = cgPropertyCallExp.getReferredProperty();
 		//		CGTypeId cgTypeId = analyzer.getTypeId(pivotProperty.getOwningType().getTypeId());
 		//		JavaTypeDescriptor requiredTypeDescriptor = context.getJavaTypeDescriptor(cgTypeId, false);
-		EStructuralFeature eStructuralFeature = ClassUtil.nonNullModel(cgPropertyAssignment.getEStructuralFeature());
-		CGValuedElement cgSlot = getExpression(cgPropertyAssignment.getOwnedSlotValue());
-		CGValuedElement cgInit = getExpression(cgPropertyAssignment.getOwnedInitValue());
+		EStructuralFeature eStructuralFeature = QVTiCGUtil.getEStructuralFeature(cgPropertyAssignment);
+		CGValuedElement cgSlot = getExpression(QVTiCGUtil.getOwnedSlotValue(cgPropertyAssignment));
+		CGValuedElement cgInit = getExpression(QVTiCGUtil.getOwnedInitValue(cgPropertyAssignment));
 		//		Class<?> requiredJavaClass = requiredTypeDescriptor.getJavaClass();
 		//		Method leastDerivedMethod = requiredJavaClass != null ? getLeastDerivedMethod(requiredJavaClass, getAccessor) : null;
 		//		Class<?> unboxedSourceClass = leastDerivedMethod != null ? leastDerivedMethod.getDeclaringClass() : requiredJavaClass;
@@ -1861,7 +1946,7 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 		if (!js.appendLocalStatements(source)) {
 			return false;
 		}
-		EStructuralFeature eStructuralFeature = ClassUtil.nonNullState(cgPropertyCallExp.getEStructuralFeature());
+		EStructuralFeature eStructuralFeature = QVTiCGUtil.getEStructuralFeature(cgPropertyCallExp);
 		doGetting(cgPropertyCallExp, eStructuralFeature, false);
 		Boolean status = appendCGEcorePropertyCallExp(cgPropertyCallExp, source);
 		if (status != ValueUtil.TRUE_VALUE) {
@@ -1877,12 +1962,6 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 		if (doEcoreCreateClass(cgRealizedVariable, (EClass)eClassifier)) {
 			cgRealizedVariable.setNonNull();
 		}
-		//
-		js.append("assert ");
-		js.appendValueName(cgRealizedVariable);
-		js.append(" != null;\n");
-		//
-		doAddRealization(cgRealizedVariable);
 		return true;
 	}
 
@@ -2085,13 +2164,7 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 					js.append(" extends ");
 					js.appendClassReference(isIncremental ? AbstractInvocation.Incremental.class : AbstractInvocation.class);
 					js.pushClassBody(mappingName);
-					boolean needsNewLine = false;
-					for (@NonNull CGGuardVariable cgFreeVariable : cgFreeVariables) {
-						js.append("protected ");
-						doMappingConnectionVariable(cgFreeVariable);
-						js.append(";\n");
-						needsNewLine = true;
-					}
+					boolean needsNewLine = doMappingFields(cgMapping);
 					if (needsNewLine) {
 						js.append("\n");
 					}
@@ -2102,6 +2175,10 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 					doMappingBody(cgMapping, true);
 					js.append("\n");
 					doIsEqual(cgFreeVariables);
+					if (isIncremental && !Iterables.isEmpty(QVTiCGUtil.getOwnedRealizedVariables(cgMapping))) {
+						js.append("\n");
+						doMappingRevokeInvocation(cgMapping);
+					}
 					js.popClassBody(false);
 				}
 				else {
@@ -2117,7 +2194,6 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 					js.append(") ");
 
 					doMappingBody(cgMapping, false);
-
 				}
 			}
 			finally {
@@ -2129,11 +2205,8 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 
 	@Override
 	public @NonNull Boolean visitCGMappingCall(@NonNull CGMappingCall cgMappingCall) {
-		MappingCall pMappingCall = (MappingCall) cgMappingCall.getAst();
-		Mapping pReferredMapping = pMappingCall.getReferredMapping();
-		if (pReferredMapping == null) {
-			return true;
-		}
+		MappingCall pMappingCall = QVTiCGUtil.getAST(cgMappingCall);
+		Mapping pReferredMapping = QVTimperativeUtil.getReferredMapping(pMappingCall);
 		CGMapping cgReferredMapping = analyzer.getMapping(pReferredMapping);
 		if (cgReferredMapping == null) {
 			return true;
@@ -2163,9 +2236,9 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 	@Override
 	public @NonNull Boolean visitCGMappingExp(@NonNull CGMappingExp cgMappingExp) {
 		//		assert cgMappingExp.getPredicates().isEmpty();		// Get rewritten during JavaPre pass
-		CGMapping cgMapping = ClassUtil.nonNullState(QVTiCGUtil.getContainingCGMapping(cgMappingExp));
-		List<@NonNull CGAccumulator> cgAccumulators = ClassUtil.nullFree(cgMappingExp.getOwnedAccumulators());
-		if (cgAccumulators.size() > 0) {
+		CGMapping cgMapping = QVTiCGUtil.getContainingCGMapping(cgMappingExp);
+		Iterable<@NonNull CGAccumulator> cgAccumulators = QVTiCGUtil.getOwnedAccumulators(cgMappingExp);
+		if (!Iterables.isEmpty(cgAccumulators)) {
 			js.append("// connection variables\n");
 			for (@NonNull CGAccumulator cgAccumulator : cgAccumulators) {
 				Element ast = cgAccumulator.getAst();
@@ -2219,7 +2292,7 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 					js.append(") {\n");
 					js.pushIndentation(null);
 					js.appendReferenceTo(cgAccumulator);
-					js.append(".append(");
+					js.append(".appendElement(");
 					js.append(iteratorName);
 					js.append(");\n");
 					js.popIndentation();
@@ -2227,22 +2300,22 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 				}
 			}
 		}
-		List<@NonNull CGRealizedVariable> cgRealizedVariables = ClassUtil.nullFree(cgMapping.getOwnedRealizedVariables());
-		if (cgRealizedVariables.size() > 0) {
+		Iterable<@NonNull CGRealizedVariable> cgRealizedVariables = QVTiCGUtil.getOwnedRealizedVariables(cgMapping);
+		if (!Iterables.isEmpty(cgRealizedVariables)) {
 			js.append("// creations\n");
 			for (@NonNull CGRealizedVariable cgRealizedVariable : cgRealizedVariables) {
-				cgRealizedVariable.accept(this);
+				doCreateRealizedVariable(cgRealizedVariable);
 			}
 		}
-		List<@NonNull CGPropertyAssignment> cgPropertyAssignments = ClassUtil.nullFree(cgMapping.getOwnedAssignments());
-		if (cgPropertyAssignments.size() > 0) {
+		Iterable<@NonNull CGPropertyAssignment> cgPropertyAssignments = QVTiCGUtil.getOwnedAssignments(cgMapping);
+		if (!Iterables.isEmpty(cgPropertyAssignments)) {
 			js.append("// property assignments\n");
 			for (@NonNull CGPropertyAssignment cgAssignment : cgPropertyAssignments) {
 				cgAssignment.accept(this);
 			}
 		}
-		List<@NonNull CGConnectionAssignment> cgConnectionAssignments = ClassUtil.nullFree(cgMapping.getOwnedConnectionAssignments());
-		if (cgConnectionAssignments.size() > 0) {
+		Iterable<@NonNull CGConnectionAssignment> cgConnectionAssignments = QVTiCGUtil.getOwnedConnectionAssignments(cgMapping);
+		if (!Iterables.isEmpty(cgConnectionAssignments)) {
 			js.append("// connection assignments\n");
 			for (@NonNull CGConnectionAssignment cgConnectionAssignment : cgConnectionAssignments) {
 				cgConnectionAssignment.accept(this);
@@ -2309,14 +2382,12 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 		for (EObject eObject : new TreeIterable(body, false)) {
 			if (eObject instanceof CGMappingCall) {
 				CGMappingCall cgMappingCall = (CGMappingCall)eObject;
-				MappingCall asMappingCall = (MappingCall) cgMappingCall.getAst();
-				Mapping pReferredMapping = asMappingCall.getReferredMapping();
-				if (pReferredMapping != null) {
-					CGMapping cgReferredMapping = analyzer.getMapping(pReferredMapping);
-					if ((cgReferredMapping != null) && useClass(cgReferredMapping)) {
-						needsFlush = true;
-						break;
-					}
+				MappingCall asMappingCall = QVTiCGUtil.getAST(cgMappingCall);
+				Mapping pReferredMapping = QVTimperativeUtil.getReferredMapping(asMappingCall);
+				CGMapping cgReferredMapping = analyzer.getMapping(pReferredMapping);
+				if ((cgReferredMapping != null) && useClass(cgReferredMapping)) {
+					needsFlush = true;
+					break;
 				}
 			}
 		}
@@ -2328,22 +2399,20 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 
 	@Override
 	public @NonNull Boolean visitCGMiddlePropertyAssignment(@NonNull CGMiddlePropertyAssignment cgMiddlePropertyAssignment) {
-		Property pReferredProperty = ClassUtil.nonNullModel(cgMiddlePropertyAssignment.getReferredProperty());
+		Property pReferredProperty = QVTiCGUtil.getReferredProperty(cgMiddlePropertyAssignment);
 		assert !pReferredProperty.isIsImplicit();
-		CGValuedElement slotValue = cgMiddlePropertyAssignment.getOwnedSlotValue();
-		CGValuedElement initValue = cgMiddlePropertyAssignment.getOwnedInitValue();
-		if ((slotValue != null) && (initValue != null)) {
-			Map<@NonNull Property, @NonNull String> oppositeProperties = getGlobalContext().getOppositeProperties();
-			if (oppositeProperties != null) {
-				String cacheName = oppositeProperties.get(pReferredProperty);
-				if (cacheName != null) {
-					js.append(cacheName);
-					js.append(".put(");
-					js.appendValueName(initValue);
-					js.append(", ");
-					js.appendValueName(slotValue);
-					js.append(");\n");
-				}
+		CGValuedElement slotValue = QVTiCGUtil.getOwnedSlotValue(cgMiddlePropertyAssignment);
+		CGValuedElement initValue = QVTiCGUtil.getOwnedInitValue(cgMiddlePropertyAssignment);
+		Map<@NonNull Property, @NonNull String> oppositeProperties = getGlobalContext().getOppositeProperties();
+		if (oppositeProperties != null) {
+			String cacheName = oppositeProperties.get(pReferredProperty);
+			if (cacheName != null) {
+				js.append(cacheName);
+				js.append(".put(");
+				js.appendValueName(initValue);
+				js.append(", ");
+				js.appendValueName(slotValue);
+				js.append(");\n");
 			}
 		}
 		return visitCGEcorePropertyAssignment(cgMiddlePropertyAssignment);
@@ -2390,22 +2459,20 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 	@Override
 	public @NonNull Boolean visitCGPropertyAssignment(@NonNull CGPropertyAssignment cgPropertyAssignment) {
 		CGExecutorProperty cgExecutorProperty = cgPropertyAssignment.getExecutorProperty();
-		CGValuedElement slotValue = cgPropertyAssignment.getOwnedSlotValue();
-		CGValuedElement initValue = cgPropertyAssignment.getOwnedInitValue();
-		if ((slotValue != null) && (initValue != null)) {
-			if (!js.appendLocalStatements(slotValue)) {
-				return false;
-			}
-			if (!js.appendLocalStatements(initValue)) {
-				return false;
-			}
-			js.appendReferenceTo(cgExecutorProperty);
-			js.append(".initValue(");
-			js.appendValueName(slotValue);
-			js.append(", ");
-			js.appendValueName(initValue);
-			js.append(");\n");
+		CGValuedElement slotValue = QVTiCGUtil.getOwnedSlotValue(cgPropertyAssignment);
+		CGValuedElement initValue = QVTiCGUtil.getOwnedInitValue(cgPropertyAssignment);
+		if (!js.appendLocalStatements(slotValue)) {
+			return false;
+		}
+		if (!js.appendLocalStatements(initValue)) {
+			return false;
 		}
+		js.appendReferenceTo(cgExecutorProperty);
+		js.append(".initValue(");
+		js.appendValueName(slotValue);
+		js.append(", ");
+		js.appendValueName(initValue);
+		js.append(");\n");
 		return true;
 	}
 
@@ -2413,13 +2480,17 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 	public @NonNull Boolean visitCGRealizedVariable(@NonNull CGRealizedVariable cgRealizedVariable) {
 		TypeId typeId = cgRealizedVariable.getASTypeId();
 		if (typeId != null) {
-			js.appendDeclaration(cgRealizedVariable);
+			CGMapping cgMapping = QVTiCGUtil.getOwningMapping(cgRealizedVariable);
+			if (useClass(cgMapping)) {
+				js.appendValueName(cgRealizedVariable);
+			}
+			else {
+				js.appendDeclaration(cgRealizedVariable);
+			}
 			js.append(" = ");
 			js.appendReferenceTo(cgRealizedVariable.getExecutorType());
 			js.append(".createInstance();\n");
 		}
-		//
-		doAddRealization(cgRealizedVariable);
 		return true;
 	}
 
@@ -2466,7 +2537,7 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 		js.append(" * <br>\n");
 		js.append(" * Extract each output model with {@link getRootObjects(String)}\n");
 		js.append(" */\n");
-		js.append("@SuppressWarnings(\"nls\")\n");
+		js.append("@SuppressWarnings({\"nls\",\"unused\"})\n");
 		js.append("public class " + className + " extends ");
 		js.appendClassReference(getAbstractTransformationExecutorClass());
 		js.pushClassBody(className);
diff --git a/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/utilities/QVTiCGUtil.java b/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/utilities/QVTiCGUtil.java
index 042a4f0ad..260da702d 100644
--- a/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/utilities/QVTiCGUtil.java
+++ b/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/utilities/QVTiCGUtil.java
@@ -17,16 +17,22 @@ import org.eclipse.jdt.annotation.Nullable;
 import org.eclipse.ocl.examples.codegen.cgmodel.CGAccumulator;
 import org.eclipse.ocl.examples.codegen.cgmodel.CGEcorePropertyCallExp;
 import org.eclipse.ocl.examples.codegen.cgmodel.CGElement;
+import org.eclipse.ocl.examples.codegen.cgmodel.CGValuedElement;
 import org.eclipse.ocl.examples.codegen.utilities.CGUtil;
 import org.eclipse.ocl.pivot.VariableDeclaration;
+import org.eclipse.ocl.pivot.Property;
 import org.eclipse.ocl.pivot.utilities.ClassUtil;
 import org.eclipse.ocl.pivot.utilities.NameUtil;
+import org.eclipse.qvtd.codegen.qvticgmodel.CGConnectionAssignment;
 import org.eclipse.qvtd.codegen.qvticgmodel.CGEcoreContainerAssignment;
 import org.eclipse.qvtd.codegen.qvticgmodel.CGEcorePropertyAssignment;
 import org.eclipse.qvtd.codegen.qvticgmodel.CGGuardVariable;
 import org.eclipse.qvtd.codegen.qvticgmodel.CGMapping;
 import org.eclipse.qvtd.codegen.qvticgmodel.CGMappingCall;
 import org.eclipse.qvtd.codegen.qvticgmodel.CGMappingCallBinding;
+import org.eclipse.qvtd.codegen.qvticgmodel.CGMappingExp;
+import org.eclipse.qvtd.codegen.qvticgmodel.CGPropertyAssignment;
+import org.eclipse.qvtd.codegen.qvticgmodel.CGRealizedVariable;
 import org.eclipse.qvtd.codegen.qvticgmodel.CGTransformation;
 import org.eclipse.qvtd.codegen.qvticgmodel.CGTypedModel;
 import org.eclipse.qvtd.pivot.qvtimperative.GuardParameter;
@@ -85,12 +91,36 @@ public class QVTiCGUtil extends CGUtil
 		return ClassUtil.nonNullState(cgPropertyCallExp.getEStructuralFeature());
 	}
 
+	public static @NonNull String getName(@NonNull CGAccumulator cgAccumulator) {
+		return ClassUtil.nonNullState(cgAccumulator.getName());
+	}
+
 	public static @NonNull String getName(@NonNull CGMapping cgMapping) {
 		return ClassUtil.nonNullState(cgMapping.getName());
 	}
 
-	public static @NonNull String getName(@NonNull CGAccumulator cgAccumulator) {
-		return ClassUtil.nonNullState(cgAccumulator.getName());
+	public static @NonNull Iterable<@NonNull CGAccumulator> getOwnedAccumulators(@NonNull CGMappingExp cgMappingExp) {
+		return ClassUtil.nullFree(cgMappingExp.getOwnedAccumulators());
+	}
+
+	public static @NonNull Iterable<@NonNull CGPropertyAssignment> getOwnedAssignments(@NonNull CGMapping cgMapping) {
+		return ClassUtil.nullFree(cgMapping.getOwnedAssignments());
+	}
+
+	public static @NonNull Iterable<@NonNull CGConnectionAssignment> getOwnedConnectionAssignments(@NonNull CGMapping cgMapping) {
+		return ClassUtil.nullFree(cgMapping.getOwnedConnectionAssignments());
+	}
+
+	public static @NonNull Iterable<@NonNull CGGuardVariable> getOwnedGuardVariables(@NonNull CGMapping cgRootMapping) {
+		return ClassUtil.nullFree(cgRootMapping.getOwnedGuardVariables());
+	}
+
+	public static @NonNull CGValuedElement getOwnedInitValue(@NonNull CGConnectionAssignment cgConnectionAssignment) {
+		return ClassUtil.nonNullState(cgConnectionAssignment.getOwnedInitValue());
+	}
+
+	public static @NonNull CGValuedElement getOwnedInitValue(@NonNull CGPropertyAssignment cgPropertyAssignment) {
+		return ClassUtil.nonNullState(cgPropertyAssignment.getOwnedInitValue());
 	}
 
 	public static @NonNull Iterable<@NonNull CGMappingCallBinding> getOwnedMappingCallBindings(@NonNull CGMappingCall cgMappingCall) {
@@ -101,6 +131,31 @@ public class QVTiCGUtil extends CGUtil
 		return ClassUtil.nullFree(cgTransformation.getOwnedMappings());
 	}
 
+	public static @NonNull Iterable<@NonNull CGRealizedVariable> getOwnedRealizedVariables(@NonNull CGMapping cgMapping) {
+		return ClassUtil.nullFree(cgMapping.getOwnedRealizedVariables());
+	}
+
+	public static @NonNull CGValuedElement getOwnedSlotValue(@NonNull CGPropertyAssignment cgPropertyAssignment) {
+		return ClassUtil.nonNullState(cgPropertyAssignment.getOwnedSlotValue());
+	}
+
+	public static @NonNull Iterable<@NonNull CGTypedModel> getOwnedTypedModels(@NonNull CGTransformation cgTransformation) {
+		return ClassUtil.nullFree(cgTransformation.getOwnedTypedModels());
+	}
+
+	public static @NonNull CGMapping getOwningMapping(@NonNull CGRealizedVariable cgRealizedVariable) {
+		return ClassUtil.nonNullState(cgRealizedVariable.getOwningMapping());
+	}
+
+	public static @NonNull CGTransformation getOwningTransformation(@NonNull CGMapping cgMapping) {
+		return ClassUtil.nonNullState(cgMapping.getOwningTransformation());
+
+	}
+
+	public static @NonNull Property getReferredProperty(@NonNull CGPropertyAssignment cgPropertyAssignment) {
+		return ClassUtil.nonNullState(cgPropertyAssignment.getReferredProperty());
+	}
+
 	public static @NonNull CGMapping getRootMapping(@NonNull CGTransformation cgTransformation) {
 		CGMapping cgRootMapping = NameUtil.getNameable(cgTransformation.getOwnedMappings(), QVTimperativeUtil.ROOT_MAPPING_NAME);	// Obsolete relic
 		for (@NonNull CGMapping cgMapping : getOwnedMappings(cgTransformation)) {
@@ -130,17 +185,4 @@ public class QVTiCGUtil extends CGUtil
 		}
 		return cgRootMapping;
 	}
-
-	public static @NonNull Iterable<@NonNull CGGuardVariable> getOwnedGuardVariables(@NonNull CGMapping cgRootMapping) {
-		return ClassUtil.nullFree(cgRootMapping.getOwnedGuardVariables());
-	}
-
-	public static @NonNull Iterable<@NonNull CGTypedModel> getOwnedTypedModels(@NonNull CGTransformation cgTransformation) {
-		return ClassUtil.nullFree(cgTransformation.getOwnedTypedModels());
-	}
-
-	public static @NonNull CGTransformation getOwningTransformation(@NonNull CGMapping cgMapping) {
-		return ClassUtil.nonNullState(cgMapping.getOwningTransformation());
-
-	}
 }
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/BasicQVTiExecutor.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/BasicQVTiExecutor.java
index 3465732fb..7b3783d8a 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/BasicQVTiExecutor.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/BasicQVTiExecutor.java
@@ -400,7 +400,7 @@ public abstract class BasicQVTiExecutor extends AbstractExecutor implements QVTi
 					Connection connection = rootInterval.createConnection(QVTimperativeUtil.getName(mappingParameter), type.getTypeId(), false);
 					Iterable<@NonNull ? extends Object> objectsOfKind = modelInstance.getObjectsOfKind(type);
 					for (@NonNull Object object : objectsOfKind) {
-						connection.append(object);
+						connection.appendElement(object);
 					}
 					getEvaluationEnvironment().add(mappingParameter, connection);
 				}
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiEvaluationVisitor.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiEvaluationVisitor.java
index c388c7280..6b6051245 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiEvaluationVisitor.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiEvaluationVisitor.java
@@ -101,7 +101,7 @@ public class QVTiEvaluationVisitor extends BasicEvaluationVisitor implements IQV
 			//				}
 			//			}
 			//			else {
-			connectionCollection.append(values);
+			connectionCollection.appendElement(values);
 			//			}
 			return connectionCollection;
 		}
@@ -306,7 +306,7 @@ public class QVTiEvaluationVisitor extends BasicEvaluationVisitor implements IQV
 			if (initValue != null) {
 				for (Object value : (Iterable<?>)initValue) {
 					assert value != null;
-					connection.append(value);
+					connection.appendElement(value);
 				}
 			}
 		}
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeUtil.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeUtil.java
index 33c49f484..3d4769c9c 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeUtil.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeUtil.java
@@ -308,6 +308,10 @@ public class QVTimperativeUtil extends QVTbaseUtil
 		return (@NonNull Iterable<@NonNull ImperativeTypedModel>)modelParameter;
 	}
 
+	public static @NonNull Mapping getReferredMapping(MappingCall asMappingCall) {
+		return ClassUtil.nonNullState(asMappingCall.getReferredMapping());
+	}
+
 	public static @NonNull Mapping getRootMapping(@NonNull ImperativeTransformation asTransformation) {
 		Mapping asRootMapping = NameUtil.getNameable(getOwnedMappings(asTransformation), QVTimperativeUtil.ROOT_MAPPING_NAME);	// Obsolete relic
 		for (@NonNull Mapping asMapping : getOwnedMappings(asTransformation)) {
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractComputation.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractComputation.java
index 801e2ad5e..eb3395025 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractComputation.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractComputation.java
@@ -41,6 +41,18 @@ public abstract class AbstractComputation implements Computation
 		public @NonNull Iterable<@NonNull Object> getCreatedObjects() {
 			return /*createdObjects != null ? createdObjects :*/ EMPTY_OBJECT_LIST;
 		}
+
+		@Override
+		public void revokeExecution() {
+			// TODO Auto-generated method stub
+
+		}
+
+		@Override
+		public void revokeInvocation() {
+			// TODO Auto-generated method stub
+
+		}
 	}
 
 	@Override
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractInvocation.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractInvocation.java
index e391c45a5..307f916d7 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractInvocation.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractInvocation.java
@@ -99,6 +99,26 @@ public abstract class AbstractInvocation extends AbstractInvocationInternal
 		}
 
 		@Override
+		public void revokeExecution() {
+			if (writeSlots != null) {
+				for (SlotState.@NonNull Incremental writeSlot : writeSlots) {
+					writeSlot.revokeAssigned();
+				}
+			}
+			interval.queue(this);
+		}
+
+		@Override
+		public void revokeInvocation() {
+			if (writeSlots != null) {
+				for (SlotState.@NonNull Incremental writeSlot : writeSlots) {
+					writeSlot.revokeAssigned();
+				}
+			}
+			interval.queue(this);
+		}
+
+		@Override
 		public @NonNull String toString() {
 			return getName();
 		}
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractSlotState.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractSlotState.java
index 33ed9e9a5..8668c73e1 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractSlotState.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractSlotState.java
@@ -58,6 +58,12 @@ public abstract class AbstractSlotState implements SlotState
 		public @NonNull Iterable<Execution.@NonNull Incremental> getTargets() {
 			return targets != null ? targets : EMPTY_EXECUTIONS_LIST;
 		}
+
+		protected void revokeTargets() {
+			for (Execution.@NonNull Incremental target : getTargets()) {
+				target.revokeExecution();
+			}
+		}
 	}
 
 	@Override
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/Connection.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/Connection.java
index ba36c8104..2133f0555 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/Connection.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/Connection.java
@@ -41,6 +41,16 @@ public interface Connection extends ExecutionVisitable, Nameable
 		@NonNull Iterable<@NonNull InvocationConstructor> getAppenders();
 
 		/**
+		 * Remove, inverse append, the old anElement.
+		 *
+		 * If the old value is a multiple value in a unique value connection, the multi-value count is decremented.
+		 *
+		 * Otherwise the old value is removed, its consumingInvocations are revoked
+		 * so that their appends are also revoked.
+		 */
+		void removeElement(@NonNull Object anElement);
+
+		/**
 		 * Replace the old value at connectionKey by newValue.
 		 *
 		 * If the old value is a multiple value in a unique value connection, the multi-value count is decremented
@@ -67,12 +77,12 @@ public interface Connection extends ExecutionVisitable, Nameable
 	boolean addConsumer(@NonNull InvocationConstructor consumingInvoker);
 
 	/**
-	 * Append aValue to the contents, enforcing uniqueness if necessary, and waking up the overall
+	 * Append anElement to the contents, enforcing uniqueness if necessary, and waking up the overall
 	 * connection manager to schedule a propagate() to consumers when convenient.
 	 *
 	 * Return the new entry.
 	 */
-	@NonNull Object append(@NonNull Object aValue);
+	@NonNull Object appendElement(@NonNull Object anElement);
 
 	int getCapacity();
 
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/Execution.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/Execution.java
index 413b5b772..4263778af 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/Execution.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/Execution.java
@@ -15,7 +15,7 @@ import org.eclipse.ocl.pivot.utilities.Nameable;
 
 /**
  * An Execution identifies a unique execution and the objects/values that it uses.
- * Derived EXecutions support Mapping Invocations and unique Function Computations
+ * Derived Executions support Mapping Invocations and unique Function Computations
  *
  * @noimplement clients should derive from AbstractInvocation
  */
@@ -25,7 +25,20 @@ public interface Execution extends ExecutionVisitable, Nameable
 	{
 		void addReadSlot(SlotState.@NonNull Incremental readSlot);
 		@NonNull Iterable<@NonNull Object> getCreatedObjects();
-		@Override
-		@NonNull String getName();
+
+		/**
+		 * Revoke the consequences of a previous execution in preparation for a new execution.
+		 * This reverts all assigned slot states back to REASSIGNABLE.
+		 */
+		void revokeExecution();
+
+		/**
+		 * Revoke the consequences of a previous execution that will not be re-executed.
+		 * All created objects are revoked.
+		 */
+		void revokeInvocation();
 	}
+
+	@Override
+	@NonNull String getName();
 }
\ No newline at end of file
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/SlotState.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/SlotState.java
index 7668dca99..b6af059d3 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/SlotState.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/SlotState.java
@@ -49,5 +49,6 @@ public interface SlotState extends ExecutionVisitable
 		@Nullable Object getValue();
 		@NonNull Iterable<Invocation.@NonNull Incremental> getSources();
 		@NonNull Iterable<Execution.@NonNull Incremental> getTargets();
+		void revokeAssigned();
 	}
 }
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/StrictIncrementalConnection.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/StrictIncrementalConnection.java
index 9b2eafd17..ca62a88c9 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/StrictIncrementalConnection.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/StrictIncrementalConnection.java
@@ -10,6 +10,8 @@
  *******************************************************************************/
 package org.eclipse.qvtd.runtime.evaluation;
 
+import java.util.List;
+
 import org.eclipse.jdt.annotation.NonNull;
 import org.eclipse.ocl.pivot.ids.TypeId;
 import org.eclipse.qvtd.runtime.internal.evaluation.StrictIncrementalConnectionInternal;
@@ -28,4 +30,31 @@ public class StrictIncrementalConnection extends StrictIncrementalConnectionInte
 	public StrictIncrementalConnection(@NonNull Interval interval, @NonNull String name, @NonNull TypeId typeId) {
 		super(interval, name, typeId);
 	}
+
+	/**
+	 * Remove, inverse append, the old anElement. The old value is removed,
+	 * its consumingInvocations are revoked so that their appends are also revoked.
+	 */
+	@Override
+	public synchronized void removeElement(@NonNull Object anElement) {
+		for (int i = 0; i < listOfValueAndConsumingInvocations.size(); i++) {
+			List<@NonNull Object> valueAndConsumingInvocations = listOfValueAndConsumingInvocations.get(i);
+			if ((valueAndConsumingInvocations != null) && (valueAndConsumingInvocations.get(VALUE_INDEX) == anElement)) {
+				Integer count = (Integer) valueAndConsumingInvocations.get(COUNT_INDEX);
+				assert count != null;
+				if (count <= 0) {
+					listOfValueAndConsumingInvocations.set(i, null);
+					int jMax = valueAndConsumingInvocations.size();
+					for (int j = INDEX_INDEX+1; j < jMax; j++) {
+						AbstractInvocation.Incremental consumingInvocation = (AbstractInvocation.Incremental) valueAndConsumingInvocations.get(j);
+						consumingInvocation.revokeExecution();
+					}
+				}
+				else {
+					valueAndConsumingInvocations.set(COUNT_INDEX, count-1);
+				}
+				break;
+			}
+		}
+	}
 }
\ No newline at end of file
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractConnectionInternal.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractConnectionInternal.java
index ac67c953c..514c509e8 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractConnectionInternal.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractConnectionInternal.java
@@ -45,17 +45,17 @@ public abstract class AbstractConnectionInternal extends AbstractConnection
 	public void addAppender(@NonNull InvocationConstructor appendingInvoker) {}
 
 	/**
-	 * Append aValue to the contents, and waking up the overall
+	 * Append anElement to the contents, and waking up the overall
 	 * connection manager to schedule a propagate() to consumers when convenient.
 	 */
 	@Override
-	public synchronized @NonNull Object append(@NonNull Object aValue) {
+	public synchronized @NonNull Object appendElement(@NonNull Object anElement) {
 		if (debugAppends) {
-			AbstractTransformer.APPENDS.println(this + " <= " + LabelUtil.getLabel(aValue));
+			AbstractTransformer.APPENDS.println(this + " <= " + LabelUtil.getLabel(anElement));
 		}
-		values.add(aValue);
+		values.add(anElement);
 		queue();
-		return aValue;
+		return anElement;
 	}
 
 	@Override
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractInvocationInternal.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractInvocationInternal.java
index 6ac99e2ad..1dbb171cb 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractInvocationInternal.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractInvocationInternal.java
@@ -54,10 +54,6 @@ public abstract class AbstractInvocationInternal implements Invocation
 		next = this;
 	}
 
-	public void revoke() {
-		throw new UnsupportedOperationException();
-	}
-
 	@Override
 	public String toString() {
 		return getClass().getSimpleName() + "@" + Integer.toHexString(System.identityHashCode(this));
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractTransformerInternal.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractTransformerInternal.java
index 64bdaf9ea..a025651cf 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractTransformerInternal.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractTransformerInternal.java
@@ -67,6 +67,11 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 		}
 
 		@Override
+		protected @NonNull Connection createConnection(@NonNull String name, @NonNull TypeId typeId, boolean isStrict) {
+			return invocationManager.getRootInterval().createIncrementalConnection(name, typeId, isStrict);
+		}
+
+		@Override
 		protected @NonNull InvocationManager createInvocationManager() {
 			return new IncrementalInvocationManager(executor);
 		}
@@ -74,7 +79,7 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 		@Override
 		protected @NonNull Model createModel(@NonNull String modelName, @NonNull PropertyId @Nullable [] propertyIndex2propertyId,
 				@NonNull ClassId @NonNull [] classIndex2classId, int @Nullable [] @NonNull [] classIndex2allClassIndexes) {
-			return new Model(modelName, propertyIndex2propertyId, classIndex2classId, classIndex2allClassIndexes);
+			return new Model.Incremental(this, modelName, propertyIndex2propertyId, classIndex2classId, classIndex2allClassIndexes);
 		}
 
 		@Override
@@ -86,13 +91,13 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 	private static final @NonNull List<@NonNull Integer> EMPTY_INDEX_LIST = Collections.emptyList();
 	private static final @NonNull List<@NonNull Object> EMPTY_EOBJECT_LIST = Collections.emptyList();
 
-	protected class Model extends AbstractTypedModelInstance
+	public static class Model extends AbstractTypedModelInstance
 	{
-		protected class Incremental extends Model
+		public static class Incremental extends Model
 		{
-			public Incremental(@NonNull String name, @NonNull PropertyId @Nullable [] propertyIndex2propertyId,
+			public Incremental(@NonNull AbstractTransformerInternal transformer, @NonNull String name, @NonNull PropertyId @Nullable [] propertyIndex2propertyId,
 					@NonNull ClassId @NonNull [] classIndex2classId, int @Nullable [] @NonNull [] classIndex2allClassIndexes) {
-				super(name, propertyIndex2propertyId, classIndex2classId, classIndex2allClassIndexes);
+				super(transformer, name, propertyIndex2propertyId, classIndex2classId, classIndex2allClassIndexes);
 			}
 
 			public void remove(@NonNull EObject eObject) {
@@ -122,12 +127,12 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 			private void unaccumulateEObject(@Nullable Map<@NonNull EClass, @NonNull Set<@NonNull Integer>> eClass2allClassIndexes,
 					@Nullable Map<@NonNull EClass, @NonNull List<@NonNull Integer>> eClass2allPropertyIndexes, @Nullable Map<@NonNull EReference, @NonNull Integer> eReference2propertyIndex,
 					@NonNull Object eObject) {
-				EClass eClass = eClass(eObject);
+				EClass eClass = transformer.eClass(eObject);
 				if (eClass2allClassIndexes != null) {
 					Set<@NonNull Integer> allClassIndexes = eClass2allClassIndexes.get(eClass);
 					if (allClassIndexes != null) {
 						for (@NonNull Integer classIndex : allClassIndexes) {
-							((Connection.Incremental)classIndex2connection[classIndex]).revoke(eObject);
+							((Connection.Incremental)classIndex2connection[classIndex]).removeElement(eObject);
 						}
 					}
 				}
@@ -136,14 +141,14 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 					assert eReference2propertyIndex2 != null;
 					List<@NonNull Integer> allPropertyIndexes = eClass2allPropertyIndexes.get(eClass);
 					if (allPropertyIndexes != null) {
-						Map<@NonNull Object, @NonNull Object>[] object2oppositeObject2 = object2oppositeObject;
+						Map<@NonNull Object, @NonNull Object>[] object2oppositeObject2 = transformer.object2oppositeObject;
 						assert object2oppositeObject2 != null;
 						for (@NonNull Integer propertyIndex : allPropertyIndexes) {
-							EReference @Nullable [] propertyIndex2eReference2 = propertyIndex2eReference;
+							EReference @Nullable [] propertyIndex2eReference2 = transformer.propertyIndex2eReference;
 							assert propertyIndex2eReference2 != null;
 							EReference eReference = propertyIndex2eReference2[propertyIndex];
 							if (eReference != null) {
-								Object object = eGet(eObject, eReference);
+								Object object = transformer.eGet(eObject, eReference);
 								assert object != null;
 								object2oppositeObject2[propertyIndex].remove(object);
 							}
@@ -153,18 +158,20 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 			}
 		}
 
+		protected final @NonNull AbstractTransformerInternal transformer;
 		protected final @NonNull String name;
-		private @Nullable List<@NonNull Object> allEObjects = null;
+		protected @Nullable List<@NonNull Object> allEObjects = null;
 		private @Nullable List<@NonNull Object> rootEObjects = null;
-		private final @NonNull Map<@NonNull EClass, @NonNull Set<@NonNull Integer>> eClass2allClassIndexes = new HashMap<>();
+		protected final @NonNull Map<@NonNull EClass, @NonNull Set<@NonNull Integer>> eClass2allClassIndexes = new HashMap<>();
 
 		/**
 		 * All possible allInstances() returns indexed by the ClassIndex of the ClassId for which allInstances() may be invoked.
 		 */
-		private final @NonNull Connection [] classIndex2connection;
+		protected final @NonNull Connection [] classIndex2connection;
 
-		public Model(@NonNull String name, @NonNull PropertyId @Nullable [] propertyIndex2propertyId,
+		public Model(@NonNull AbstractTransformerInternal transformer, @NonNull String name, @NonNull PropertyId @Nullable [] propertyIndex2propertyId,
 				@NonNull ClassId @NonNull [] classIndex2classId, int @Nullable [] @NonNull [] classIndex2allClassIndexes) {
+			this.transformer = transformer;
 			this.name = name;
 			//
 			//	Prepare the allInstances() fields
@@ -174,7 +181,7 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 			for (int i = 0; i < classIds; i++) {
 				@NonNull
 				ClassId classId = classIndex2classId[i];
-				classIndex2connection[i] = createConnection(name + "-" + classId, classId, false);
+				classIndex2connection[i] = transformer.createConnection(name + "-" + classId, classId, false);
 			}
 		}
 
@@ -185,11 +192,11 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 		private void accumulateEObject1(@NonNull Object eObject, @NonNull EClass eClass) {
 			Set<@NonNull Integer> allClassIndexes = eClass2allClassIndexes.get(eClass);
 			if (allClassIndexes == null) {
-				allClassIndexes = getClassIndexes(eClass);
+				allClassIndexes = transformer.getClassIndexes(eClass);
 				eClass2allClassIndexes.put(eClass, allClassIndexes);
 			}
 			for (@NonNull Integer classIndex : allClassIndexes) {
-				classIndex2connection[classIndex].append(eObject);
+				classIndex2connection[classIndex].appendElement(eObject);
 			}
 		}
 
@@ -206,24 +213,24 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 			assert eReference2propertyIndex2 != null;
 			List<@NonNull Integer> allPropertyIndexes = eClass2allPropertyIndexes.get(eClass);
 			if (allPropertyIndexes == null) {
-				allPropertyIndexes = getOppositePropertyIndexes(eReference2propertyIndex2, eClass);
+				allPropertyIndexes = transformer.getOppositePropertyIndexes(eReference2propertyIndex2, eClass);
 				eClass2allPropertyIndexes.put(eClass, allPropertyIndexes);
 			}
-			Map<@NonNull Object, @NonNull Object>[] object2oppositeObject2 = object2oppositeObject;
+			Map<@NonNull Object, @NonNull Object>[] object2oppositeObject2 = transformer.object2oppositeObject;
 			assert object2oppositeObject2 != null;
 			for (@NonNull Integer propertyIndex : allPropertyIndexes) {
-				EReference @Nullable [] propertyIndex2eReference2 = propertyIndex2eReference;
+				EReference @Nullable [] propertyIndex2eReference2 = transformer.propertyIndex2eReference;
 				assert propertyIndex2eReference2 != null;
 				EReference eReference = propertyIndex2eReference2[propertyIndex];
 				if (eReference == null) {
-					PropertyId @Nullable [] propertyIndex2propertyId2 = propertyIndex2propertyId;
+					PropertyId @Nullable [] propertyIndex2propertyId2 = transformer.propertyIndex2propertyId;
 					assert propertyIndex2propertyId2 != null;
 					PropertyId propertyId = propertyIndex2propertyId2[propertyIndex];
 					assert propertyId != null;
 					eReference = (EReference) NameUtil.getENamedElement(eClass.getEAllStructuralFeatures(), propertyId.getName());
 					assert eReference != null;
 				}
-				Object object = eGet(eObject, eReference);
+				Object object = transformer.eGet(eObject, eReference);
 				assert object != null;
 				object2oppositeObject2[propertyIndex].put(object, eObject);
 			}
@@ -237,7 +244,7 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 			rootEObjects = null;
 			assert !allEObjects2.contains(eObject);
 			allEObjects2.add(eObject);
-			EClass eClass = eClass(eObject);
+			EClass eClass = transformer.eClass(eObject);
 			accumulateEObject1(eObject, eClass);
 		}
 
@@ -252,7 +259,7 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 			allEObjects = null;
 			Map<@NonNull EClass, @NonNull List<@NonNull Integer>> eClass2allPropertyIndexes = null;
 			Map<@NonNull EReference, @NonNull Integer> eReference2propertyIndex = null;
-			if (propertyIndex2propertyId != null) {
+			if (transformer.propertyIndex2propertyId != null) {
 				eClass2allPropertyIndexes = new HashMap<>();
 				eReference2propertyIndex = new HashMap<>();
 			}
@@ -264,15 +271,15 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 				//
 				//	Accumulate the root object and all its child objects in the allInstances() returns
 				//
-				EClass eRootClass = eClass(eRootObject);
+				EClass eRootClass = transformer.eClass(eRootObject);
 				accumulateEObject1(eRootObject, eRootClass);
 				if (eClass2allPropertyIndexes != null) {
 					accumulateEObject2(eRootObject, eRootClass, eClass2allPropertyIndexes, eReference2propertyIndex);
 				}
-				for (TreeIterator<? extends Object> tit = eAllContents(eRootObject); tit.hasNext(); ) {
+				for (TreeIterator<? extends Object> tit = transformer.eAllContents(eRootObject); tit.hasNext(); ) {
 					Object eObject = tit.next();
 					if (eObject != null) {
-						EClass eClass = eClass(eObject);
+						EClass eClass = transformer.eClass(eObject);
 						accumulateEObject1(eObject, eClass);
 						if (eClass2allPropertyIndexes != null) {
 							accumulateEObject2(eObject, eClass, eClass2allPropertyIndexes, eReference2propertyIndex);
@@ -292,7 +299,7 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 					for (@NonNull Object eRootObject : rootEObjects2) {
 						assert !allEObjects2.contains(eRootObject);
 						allEObjects2.add(eRootObject);
-						for (TreeIterator<? extends Object> tit = eAllContents(eRootObject); tit.hasNext(); ) {
+						for (TreeIterator<? extends Object> tit = transformer.eAllContents(eRootObject); tit.hasNext(); ) {
 							Object eObject = tit.next();
 							if (eObject != null) {
 								assert !allEObjects2.contains(eObject);
@@ -312,7 +319,7 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 		@Override
 		public @NonNull Iterable<@NonNull Object> getObjectsOfKind(org.eclipse.ocl.pivot.@NonNull Class type) {
 			TypeId classId = type.getTypeId();
-			Integer classIndex = classId2classIndex.get(classId);
+			Integer classIndex = transformer.classId2classIndex.get(classId);
 			if (classIndex != null) {
 				Iterable<@NonNull Object> typedIterable = classIndex2connection[classIndex].typedIterable(Object.class);
 				//				List<@NonNull Object> collection =  new ArrayList<>();
@@ -360,7 +367,7 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 				List<@NonNull Object> allEObjects2 = allEObjects;
 				if (allEObjects2 != null) {
 					for (@NonNull Object eObject : allEObjects2) {
-						if (eContainer(eObject) == null) {
+						if (transformer.eContainer(eObject) == null) {
 							rootEObjects2.add(eObject);
 						}
 					}
@@ -383,7 +390,7 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 
 		public <@NonNull T> Iterable<T> typedIterable(Class<T> javaClass, org.eclipse.ocl.pivot.@NonNull Class pivotType) {
 			TypeId typeId = pivotType.getTypeId();
-			Integer classIndex = classId2classIndex.get(typeId);
+			Integer classIndex = transformer.classId2classIndex.get(typeId);
 			if (classIndex != null) {
 				Connection connection = classIndex2connection[classIndex];
 				return connection.typedIterable(javaClass);
@@ -559,7 +566,7 @@ public abstract class AbstractTransformerInternal /*extends AbstractModelManager
 
 	protected @NonNull Model createModel(@NonNull String modelName, @NonNull PropertyId @Nullable [] propertyIndex2propertyId,
 			@NonNull ClassId @NonNull [] classIndex2classId, int @Nullable [] @NonNull [] classIndex2allClassIndexes) {
-		return new Model(modelName, propertyIndex2propertyId, classIndex2classId, classIndex2allClassIndexes);
+		return new Model(this, modelName, propertyIndex2propertyId, classIndex2classId, classIndex2allClassIndexes);
 	}
 
 	@Deprecated // Use createConnection
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/IncrementalConnectionInternal.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/IncrementalConnectionInternal.java
index b847fd50f..aaad51458 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/IncrementalConnectionInternal.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/IncrementalConnectionInternal.java
@@ -37,16 +37,16 @@ public class IncrementalConnectionInternal extends AbstractIncrementalConnection
 	}
 
 	/**
-	 * Append aValue to the contents, and waking up the overall
+	 * Append anElement to the contents, and waking up the overall
 	 * connection manager to schedule a propagate() to consumers when convenient.
 	 */
 	@Override
-	public synchronized @NonNull Object append(@NonNull Object aValue) {
+	public synchronized @NonNull Object appendElement(@NonNull Object anElement) {
 		if (debugAppends) {
-			AbstractTransformer.APPENDS.println(this + " <= " + LabelUtil.getLabel(aValue));
+			AbstractTransformer.APPENDS.println(this + " <= " + LabelUtil.getLabel(anElement));
 		}
 		List<@NonNull Object> valueAndConsumingInvocations = new ArrayList<>();
-		valueAndConsumingInvocations.add(aValue);										// VALUE_INDEX
+		valueAndConsumingInvocations.add(anElement);									// VALUE_INDEX
 		valueAndConsumingInvocations.add(listOfValueAndConsumingInvocations.size());	// INDEX_INDEX
 		listOfValueAndConsumingInvocations.add(valueAndConsumingInvocations);
 		queue();
@@ -64,6 +64,26 @@ public class IncrementalConnectionInternal extends AbstractIncrementalConnection
 	}
 
 	/**
+	 * Remove, inverse append, the old anElement. The old value is removed,
+	 * its consumingInvocations are revoked so that their appends are also revoked.
+	 */
+	@Override
+	public synchronized void removeElement(@NonNull Object anElement) {
+		for (int i = 0; i < listOfValueAndConsumingInvocations.size(); i++) {
+			List<@NonNull Object> valueAndConsumingInvocations = listOfValueAndConsumingInvocations.get(i);
+			if ((valueAndConsumingInvocations != null) && (valueAndConsumingInvocations.get(VALUE_INDEX) == anElement)) {
+				listOfValueAndConsumingInvocations.set(i, null);
+				int jMax = valueAndConsumingInvocations.size();
+				for (int j = INDEX_INDEX+1; j < jMax; j++) {
+					AbstractInvocation.Incremental consumingInvocation = (AbstractInvocation.Incremental) valueAndConsumingInvocations.get(j);
+					consumingInvocation.revokeExecution();
+				}
+				break;
+			}
+		}
+	}
+
+	/**
 	 * Replace the old value at connectionKey by newValue.The old value is removed,
 	 * its consumingInvocations are invalidated so that they recompute with the newValue which replaces the old.
 	 */
@@ -93,8 +113,8 @@ public class IncrementalConnectionInternal extends AbstractIncrementalConnection
 		listOfValueAndConsumingInvocations.set(valueIndex, null);			// Do not disrupt index equivalence.
 		int iMax = valueAndConsumingInvocations.size();
 		for (int i = INDEX_INDEX+1; i < iMax; i++) {
-			AbstractInvocation consumingInvocation = (AbstractInvocation) valueAndConsumingInvocations.get(i);
-			consumingInvocation.revoke();
+			AbstractInvocation.Incremental consumingInvocation = (AbstractInvocation.Incremental) valueAndConsumingInvocations.get(i);
+			consumingInvocation.revokeExecution();
 		}
 	}
 }
\ No newline at end of file
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/IncrementalObjectManager.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/IncrementalObjectManager.java
index cbcd0dedd..f4a43b0e5 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/IncrementalObjectManager.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/IncrementalObjectManager.java
@@ -41,7 +41,8 @@ public class IncrementalObjectManager extends AbstractObjectManager
 	{
 		public enum SlotMode {
 			ASSIGNABLE,		// No assignment has been performed, object reads are blocked (collections reads may be unblocked)
-			ASSIGNED		// Last assignment has been performed, reads are unblocked
+			ASSIGNED,		// Last assignment has been performed, reads are unblocked
+			REASSIGNABLE,	// No assignment has been performed by a re-execution, object reads are blocked (collections reads may be unblocked)
 		}
 
 		protected final @NonNull Object eObject;
@@ -69,12 +70,20 @@ public class IncrementalObjectManager extends AbstractObjectManager
 				case ASSIGNABLE:
 					mode = SlotMode.ASSIGNED;
 					unblock(objectManager);
+					this.value = ecoreValue;
 					break;
 				case ASSIGNED:
 					System.out.println("Re-assignment of " + eFeature.getEContainingClass().getName() + "::" + eFeature.getName() + " for " + eObject + " with " + ecoreValue);
 					break;
+				case REASSIGNABLE:
+					mode = SlotMode.ASSIGNED;
+					if (this.value != ecoreValue) {		// FIXME equals() ??
+						this.value = ecoreValue;
+						revokeTargets();
+					}
+					unblock(objectManager);
+					break;
 			}
-			this.value = ecoreValue;
 		}
 
 		@Override
@@ -115,6 +124,7 @@ public class IncrementalObjectManager extends AbstractObjectManager
 		public synchronized void getting( @NonNull Object eObject, @NonNull EStructuralFeature eFeature) {
 			switch (mode) {
 				case ASSIGNABLE:
+				case REASSIGNABLE:
 					throw new InvocationFailedException(this);
 				case ASSIGNED:
 					break;
@@ -126,6 +136,12 @@ public class IncrementalObjectManager extends AbstractObjectManager
 		}
 
 		@Override
+		public void revokeAssigned() {
+			assert isAssigned();
+			mode = SlotMode.REASSIGNABLE;
+		}
+
+		@Override
 		public String toString() {
 			return getClass().getSimpleName() + "@" + Integer.toHexString(System.identityHashCode(this)) + "[" + eFeature.getEContainingClass().getName() + "::" + eFeature.getName() + " for " + eObject + "]";
 		}
@@ -416,6 +432,7 @@ public class IncrementalObjectManager extends AbstractObjectManager
 			//			super.assigned(objectManager, eContainer, eReference, eObject);
 			switch (mode) {
 				case ASSIGNABLE:
+				case REASSIGNABLE:
 					mode = SlotMode.ASSIGNED;
 					unblock(IncrementalObjectManager.this);
 					break;
@@ -428,6 +445,7 @@ public class IncrementalObjectManager extends AbstractObjectManager
 		public synchronized void getting(@NonNull Object eObject, @NonNull EStructuralFeature eFeature) {
 			switch (mode) {
 				case ASSIGNABLE:
+				case REASSIGNABLE:
 					mode = SlotMode.ASSIGNED;
 					unblock(IncrementalObjectManager.this);
 					break;
@@ -836,4 +854,11 @@ public class IncrementalObjectManager extends AbstractObjectManager
 		BasicSlotState slotState = getSlotState(eObject, eFeature);
 		execution.addReadSlot(slotState);
 	}
+
+	public void modified(@NonNull Object eObject, @NonNull EStructuralFeature eFeature) {
+		BasicSlotState slotState = getSlotState(eObject, eFeature);
+		for (Execution.@NonNull Incremental execution : slotState.getTargets()) {
+			execution.revokeExecution();
+		}
+	}
 }
\ No newline at end of file
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/ModificationMonitor.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/ModificationMonitor.java
new file mode 100644
index 000000000..7b0274c3e
--- /dev/null
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/ModificationMonitor.java
@@ -0,0 +1,104 @@
+package org.eclipse.qvtd.runtime.internal.evaluation;
+
+import java.util.List;
+
+import org.eclipse.emf.common.notify.Adapter;
+import org.eclipse.emf.common.notify.Notification;
+import org.eclipse.emf.common.notify.Notifier;
+import org.eclipse.emf.ecore.EObject;
+import org.eclipse.emf.ecore.EStructuralFeature;
+import org.eclipse.emf.ecore.resource.Resource;
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
+import org.eclipse.ocl.pivot.utilities.TreeIterable;
+import org.eclipse.qvtd.runtime.evaluation.TransformationExecutor;
+
+/**
+ * An adapter implementation for tracking resource modification.
+ */
+public class ModificationMonitor implements Adapter
+{
+	public static @Nullable ModificationMonitor basicGetModificationMonitor(@NonNull Resource resource, @NonNull TransformationExecutor executor) {
+		for (Adapter eAdapter : resource.eAdapters()) {
+			if (eAdapter instanceof ModificationMonitor) {
+				ModificationMonitor monitor = (ModificationMonitor)eAdapter;
+				if (monitor.getExecutor() == executor) {
+					return monitor;
+				}
+			}
+		}
+		return null;
+	}
+
+	public static @NonNull ModificationMonitor getModificationMonitor(@NonNull Resource resource, @NonNull TransformationExecutor executor) {
+		List<Adapter> eAdapters = resource.eAdapters();
+		for (Adapter eAdapter : eAdapters) {
+			if (eAdapter instanceof ModificationMonitor) {
+				ModificationMonitor monitor = (ModificationMonitor)eAdapter;
+				if (monitor.getExecutor() == executor) {
+					return monitor;
+				}
+			}
+		}
+		ModificationMonitor monitor = new ModificationMonitor(resource, executor);
+		for (@NonNull EObject eObject : new TreeIterable(resource)) {
+			eObject.eAdapters().add(monitor);
+		}
+		eAdapters.add(monitor);
+		return monitor;
+	}
+
+	private @NonNull Resource resource;
+	private @NonNull TransformationExecutor executor;
+
+	public ModificationMonitor(@NonNull Resource resource, @NonNull TransformationExecutor executor) {
+		this.resource = resource;
+		this.executor = executor;
+	}
+
+	public @NonNull TransformationExecutor getExecutor() {
+		return executor;
+	}
+
+	@Override
+	public @NonNull Resource getTarget() {
+		return resource;
+	}
+
+	@Override
+	public boolean isAdapterForType(Object type) {
+		return type == ModificationMonitor.class;
+	}
+
+	@Override
+	public void notifyChanged(Notification notification)
+	{
+		if (!notification.isTouch())
+		{
+			Object notifier = notification.getNotifier();
+			assert notifier != null;
+			IncrementalObjectManager objectManager = (IncrementalObjectManager) executor.getTransformer().getObjectManager();
+			switch (notification.getEventType()) {
+				case Notification.ADD:
+				case Notification.REMOVE: {
+					break;
+				}
+				case Notification.ADD_MANY:
+				case Notification.REMOVE_MANY: {
+					break;
+				}
+				case Notification.SET:
+				case Notification.UNSET: {
+					Object feature = notification.getFeature();
+					if (feature instanceof EStructuralFeature) {
+						objectManager.modified(notifier, (EStructuralFeature)feature);
+					}
+					break;
+				}
+			}
+		}
+	}
+
+	@Override
+	public void setTarget(Notifier newTarget) {}
+}
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictConnectionInternal.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictConnectionInternal.java
index 131889241..19ed2944d 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictConnectionInternal.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictConnectionInternal.java
@@ -42,28 +42,28 @@ public abstract class StrictConnectionInternal extends AbstractConnectionInterna
 	 * connection manager to schedule a propagate() to consumers when convenient.
 	 */
 	@Override
-	public synchronized @NonNull Object append(@NonNull Object aValue) {
+	public synchronized @NonNull Object appendElement(@NonNull Object anElement) {
 		if (debugAppends) {
-			AbstractTransformer.APPENDS.println(this + " <= " + LabelUtil.getLabel(aValue));
+			AbstractTransformer.APPENDS.println(this + " <= " + LabelUtil.getLabel(anElement));
 		}
 		if (uniqueValues != null) {
-			if (!uniqueValues.add(aValue)) {
-				return aValue;
+			if (!uniqueValues.add(anElement)) {
+				return anElement;
 			}
 		}
 		else if (values.size() < 10) {
 			for (@NonNull Object value : values) {
-				if (value.equals(aValue)) {			// FIXME ==/oclEquals
-					return aValue;
+				if (value.equals(anElement)) {			// FIXME ==/oclEquals
+					return anElement;
 				}
 			}
 		}
-		else if (!createUniqueValues().add(aValue)) {
-			return aValue;
+		else if (!createUniqueValues().add(anElement)) {
+			return anElement;
 		}
-		values.add(aValue);
+		values.add(anElement);
 		queue();
-		return aValue;
+		return anElement;
 	}
 
 	private @NonNull Set<@NonNull Object> createUniqueValues() {
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictIncrementalConnectionInternal.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictIncrementalConnectionInternal.java
index 9eb2eef62..98ea08109 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictIncrementalConnectionInternal.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictIncrementalConnectionInternal.java
@@ -42,22 +42,22 @@ public abstract class StrictIncrementalConnectionInternal extends AbstractIncrem
 	}
 
 	/**
-	 * Append aValue to the contents, enforcing uniqueness if necessary, and waking up the overall
+	 * Append anElement to the contents, enforcing uniqueness if necessary, and waking up the overall
 	 * connection manager to schedule a propagate() to consumers when convenient.
 	 */
 	@Override
-	public synchronized @NonNull Object append(@NonNull Object aValue) {
+	public synchronized @NonNull Object appendElement(@NonNull Object anElement) {
 		if (debugAppends) {
-			AbstractTransformer.APPENDS.println(this + " <= " + LabelUtil.getLabel(aValue));
+			AbstractTransformer.APPENDS.println(this + " <= " + LabelUtil.getLabel(anElement));
 		}
-		List<@NonNull Object> valueAndConsumingInvocations = uniqueValues2valueAndConsumingInvocations.get(aValue);
+		List<@NonNull Object> valueAndConsumingInvocations = uniqueValues2valueAndConsumingInvocations.get(anElement);
 		if (valueAndConsumingInvocations == null) {
 			valueAndConsumingInvocations = new ArrayList<>();
-			valueAndConsumingInvocations.add(aValue);										// VALUE_INDEX
+			valueAndConsumingInvocations.add(anElement);									// VALUE_INDEX
 			valueAndConsumingInvocations.add(listOfValueAndConsumingInvocations.size());	// INDEX_INDEX
 			valueAndConsumingInvocations.add(1);											// COUNT_INDEX
 			listOfValueAndConsumingInvocations.add(valueAndConsumingInvocations);
-			uniqueValues2valueAndConsumingInvocations.put(aValue, valueAndConsumingInvocations);
+			uniqueValues2valueAndConsumingInvocations.put(anElement, valueAndConsumingInvocations);
 			queue();
 		}
 		else {
@@ -95,7 +95,7 @@ public abstract class StrictIncrementalConnectionInternal extends AbstractIncrem
 			Integer count = (Integer) valueAndConsumingInvocations.get(COUNT_INDEX);
 			if (count > 1) {
 				valueAndConsumingInvocations.set(COUNT_INDEX, count-1);
-				return append(newValue);
+				return appendElement(newValue);
 			}
 			valueAndConsumingInvocations.set(VALUE_INDEX, newValue);
 			int iMax = valueAndConsumingInvocations.size();
@@ -127,8 +127,8 @@ public abstract class StrictIncrementalConnectionInternal extends AbstractIncrem
 		listOfValueAndConsumingInvocations.set(valueIndex, null);			// Do not disrupt index equivalence.
 		int iMax = valueAndConsumingInvocations.size();
 		for (int i = COUNT_INDEX+1; i < iMax; i++) {
-			AbstractInvocation consumingInvocation = (AbstractInvocation) valueAndConsumingInvocations.get(i);
-			consumingInvocation.revoke();
+			AbstractInvocation.Incremental consumingInvocation = (AbstractInvocation.Incremental) valueAndConsumingInvocations.get(i);
+			consumingInvocation.revokeExecution();
 		}
 	}
 }
\ No newline at end of file
diff --git a/tests/org.eclipse.qvtd.compiler.tests/src/org/eclipse/qvtd/compiler/tests/RuntimeConnectionTests.java b/tests/org.eclipse.qvtd.compiler.tests/src/org/eclipse/qvtd/compiler/tests/RuntimeConnectionTests.java
index 245d97e49..0e2d45160 100644
--- a/tests/org.eclipse.qvtd.compiler.tests/src/org/eclipse/qvtd/compiler/tests/RuntimeConnectionTests.java
+++ b/tests/org.eclipse.qvtd.compiler.tests/src/org/eclipse/qvtd/compiler/tests/RuntimeConnectionTests.java
@@ -208,7 +208,7 @@ public class RuntimeConnectionTests extends TestCase
 		}
 
 		public void append() {
-			append(counter++);
+			appendElement(counter++);
 		}
 	}
 
diff --git a/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/QVTiCompilerTests.java b/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/QVTiCompilerTests.java
index 4f5579cff..91c95a62b 100644
--- a/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/QVTiCompilerTests.java
+++ b/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/QVTiCompilerTests.java
@@ -17,6 +17,8 @@ import java.util.Map;
 import org.eclipse.emf.codegen.ecore.genmodel.GenModel;
 import org.eclipse.emf.codegen.ecore.genmodel.GenModelPackage;
 import org.eclipse.emf.common.util.URI;
+import org.eclipse.emf.ecore.EAttribute;
+import org.eclipse.emf.ecore.EClass;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.resource.Resource;
 import org.eclipse.emf.ecore.resource.ResourceSet;
@@ -31,6 +33,7 @@ import org.eclipse.ocl.pivot.oclstdlib.OCLstdlibTables;
 import org.eclipse.ocl.pivot.resource.ASResource;
 import org.eclipse.ocl.pivot.resource.ProjectManager;
 import org.eclipse.ocl.pivot.utilities.ClassUtil;
+import org.eclipse.ocl.pivot.utilities.TreeIterable;
 import org.eclipse.ocl.pivot.validation.ComposedEValidator;
 import org.eclipse.ocl.xtext.base.services.BaseLinkingService;
 import org.eclipse.ocl.xtext.base.utilities.BaseCSResource;
@@ -45,15 +48,15 @@ import org.eclipse.qvtd.pivot.qvtimperative.QVTimperativePackage;
 import org.eclipse.qvtd.pivot.qvtimperative.evaluation.Execution2GraphVisitor;
 import org.eclipse.qvtd.pivot.qvtimperative.evaluation.QVTiEnvironmentFactory;
 import org.eclipse.qvtd.pivot.qvtimperative.evaluation.QVTiTransformationExecutor;
+import org.eclipse.qvtd.runtime.evaluation.TransformationExecutor;
 import org.eclipse.qvtd.runtime.evaluation.Transformer;
+import org.eclipse.qvtd.runtime.internal.evaluation.ModificationMonitor;
 import org.eclipse.qvtd.xtext.qvtbase.tests.LoadTestCase;
 import org.eclipse.qvtd.xtext.qvtbase.tests.ModelNormalizer;
 import org.eclipse.qvtd.xtext.qvtbase.tests.utilities.TestsXMLUtil;
 import org.eclipse.qvtd.xtext.qvtimperative.tests.ManualUML2RDBMS.ManualRDBMSNormalizer;
 import org.eclipse.qvtd.xtext.qvtimperative.tests.SimpleUML2RDBMS.SimpleRDBMSNormalizer;
-import org.eclipse.qvtd.xtext.qvtimperative.tests.Tree2TallTree.Tree2TallTreeInstallManual;
 
-import cg_qvtimperative_tests._hsv2hls.hsv2hls;
 import junit.framework.TestCase;
 
 /**
@@ -142,9 +145,10 @@ public class QVTiCompilerTests extends LoadTestCase
 			return (QVTiEnvironmentFactory) super.getEnvironmentFactory();
 		}
 
-		public void loadInput(@NonNull Transformer tx, @NonNull String inputModelName, URI inputModelURI) {
+		public @NonNull Resource loadInput(@NonNull Transformer tx, @NonNull String inputModelName, URI inputModelURI) {
 			Resource inputResource = getResourceSet().getResource(inputModelURI, true);
 			tx.addRootObjects(inputModelName, ClassUtil.nonNullState(inputResource.getContents()));
+			return inputResource;
 		}
 
 		public @NonNull Transformation loadTransformation(@NonNull URI transformURI, @NonNull URI genModelURI) throws Exception {
@@ -233,7 +237,7 @@ public class QVTiCompilerTests extends LoadTestCase
 		myQVT.dispose();
 	}
 
-	public void testCG_HSV2HLS_qvti2() throws Exception {
+	/*	public void testCG_HSV2HLS_qvti2() throws Exception {
 		MyQVT myQVT = createQVT();
 		URI inputModelURI = getProjectFileURI("HSV2HLS/HSVNode.xmi");
 		URI outputModelURI = getProjectFileURI("HSV2HLS/HLSNode.xmi");
@@ -243,7 +247,7 @@ public class QVTiCompilerTests extends LoadTestCase
 		tx.run();
 		myQVT.saveOutput(tx, "hls", outputModelURI, referenceModelURI, null);
 		myQVT.dispose();
-	}
+	} */
 
 	public void testCG_ClassesCS2AS_qvti() throws Exception {
 		MyQVT myQVT = createQVT();
@@ -327,52 +331,88 @@ public class QVTiCompilerTests extends LoadTestCase
 		URI transformURI = getProjectFileURI("Tree2TallTree/Tree2TallTree.qvti");
 		URI inputModelURI = getProjectFileURI("Tree2TallTree/Tree.xmi");
 		URI outputModelURI = getProjectFileURI("Tree2TallTree/Tree2TallTree.xmi");
+		URI outputModelURI2 = getProjectFileURI("Tree2TallTree/Tree2TallTree2.xmi");
 		URI referenceModelURI = getProjectFileURI("Tree2TallTree/TallTreeValidate.xmi");
+		URI referenceModelURI2 = getProjectFileURI("Tree2TallTree/TallTreeValidate2.xmi");
 		Transformation asTransformation = myQVT.loadTransformation(transformURI, genModelURI);
 		Class<? extends Transformer> txClass = myQVT.generateCode(asTransformation, true);
 		Transformer tx = myQVT.createTransformer(txClass);
-		myQVT.loadInput(tx, "tree", inputModelURI);
+		Resource inputResource = myQVT.loadInput(tx, "tree", inputModelURI);
 		tx.run();
+		Execution2GraphVisitor.writeGraphMLfile(tx, getProjectFileURI("Tree2TallTree/Tree2TallTree-inc.graphml"));
 		myQVT.saveOutput(tx, "talltree", outputModelURI, referenceModelURI, null);
+		TransformationExecutor executor = tx.getExecutor();
+		@SuppressWarnings("unused") ModificationMonitor monitor = ModificationMonitor.getModificationMonitor(inputResource, executor);
+		int gotOne = 0;
+		for (EObject eObject : new TreeIterable(inputResource)) {
+			EClass eClass = eObject.eClass();
+			if ("Node".equals(eClass.getName())) {
+				EAttribute nameAttribute = (EAttribute) eClass.getEStructuralFeature("name");
+				Object name = eObject.eGet(nameAttribute);
+				if ("n1.1".equals(name)) {
+					gotOne++;
+					eObject.eSet(nameAttribute, "x1.1");
+				}
+			}
+		}
+		assert gotOne == 1;
+		executor.getTransformer().getInvocationManager().flush();
+		Execution2GraphVisitor.writeGraphMLfile(tx, getProjectFileURI("Tree2TallTree/Tree2TallTree-inc2.graphml"));
+		myQVT.saveOutput(tx, "talltree", outputModelURI2, referenceModelURI2, null);
 		myQVT.dispose();
 	}
 
-	public void testCG_Tree2TallTreeInstall_qvti() throws Exception {
+	/*	public void testCG_Tree2TallTree_Incremental_qvti2() throws Exception {
 		//		AbstractTransformer.INVOCATIONS.setState(true);
 		MyQVT myQVT = createQVT();
 		URI genModelURI = getProjectFileURI("Tree2TallTree/Tree2TallTree.genmodel");
-		URI transformURI = getProjectFileURI("Tree2TallTree/Tree2TallTreeInstall.qvti");
-
+		URI transformURI = getProjectFileURI("Tree2TallTree/Tree2TallTree.qvti");
 		URI inputModelURI = getProjectFileURI("Tree2TallTree/Tree.xmi");
 		URI outputModelURI = getProjectFileURI("Tree2TallTree/Tree2TallTree.xmi");
+		URI outputModelURI2 = getProjectFileURI("Tree2TallTree/Tree2TallTree2.xmi");
 		URI referenceModelURI = getProjectFileURI("Tree2TallTree/TallTreeValidate.xmi");
-		Transformation asTransformation = myQVT.loadTransformation(transformURI, genModelURI);
-		Class<? extends Transformer> txClass = myQVT.generateCode(asTransformation, true);
+		URI referenceModelURI2 = getProjectFileURI("Tree2TallTree/TallTreeValidate2.xmi");
+		Class<? extends Transformer> txClass = Tree2TallTree.class;
 		Transformer tx = myQVT.createTransformer(txClass);
-		myQVT.loadInput(tx, "tree", inputModelURI);
+		Resource inputResource = myQVT.loadInput(tx, "tree", inputModelURI);
 		tx.run();
+		Execution2GraphVisitor.writeGraphMLfile(tx, getProjectFileURI("Tree2TallTree/Tree2TallTree-inc.graphml"));
 		myQVT.saveOutput(tx, "talltree", outputModelURI, referenceModelURI, null);
+		TransformationExecutor executor = tx.getExecutor();
+		ModificationMonitor monitor = ModificationMonitor.getModificationMonitor(inputResource, executor);
+		int gotOne = 0;
+		for (EObject eObject : new TreeIterable(inputResource)) {
+			EClass eClass = eObject.eClass();
+			if ("Node".equals(eClass.getName())) {
+				EAttribute nameAttribute = (EAttribute) eClass.getEStructuralFeature("name");
+				Object name = eObject.eGet(nameAttribute);
+				if ("n1.1".equals(name)) {
+					gotOne++;
+					eObject.eSet(nameAttribute, "x1.1");
+				}
+			}
+		}
+		assert gotOne == 1;
+		executor.getTransformer().getInvocationManager().flush();
+		Execution2GraphVisitor.writeGraphMLfile(tx, getProjectFileURI("Tree2TallTree/Tree2TallTree-inc2.graphml"));
+		myQVT.saveOutput(tx, "talltree", outputModelURI2, referenceModelURI2, null);
 		myQVT.dispose();
-	}
+	} */
 
-	public void testCG_Tree2TallTreeInstallManual_qvti() throws Exception {
-		//		AbstractTransformer.APPENDS.setState(true);
-		//		AbstractTransformer.CONSUMES.setState(true);
-		//		AbstractTransformer.EXCEPTIONS.setState(true);
+	public void testCG_Tree2TallTreeInstall_qvti() throws Exception {
 		//		AbstractTransformer.INVOCATIONS.setState(true);
 		MyQVT myQVT = createQVT();
-		//		URI genModelURI = getProjectFileURI("Tree2TallTree/Tree2TallTree.genmodel");
-		//		URI transformURI = getProjectFileURI("Tree2TallTree/Tree2TallTreeInstall.qvti");
+		URI genModelURI = getProjectFileURI("Tree2TallTree/Tree2TallTree.genmodel");
+		URI transformURI = getProjectFileURI("Tree2TallTree/Tree2TallTreeInstall.qvti");
 
 		URI inputModelURI = getProjectFileURI("Tree2TallTree/Tree.xmi");
 		URI outputModelURI = getProjectFileURI("Tree2TallTree/Tree2TallTree.xmi");
 		URI referenceModelURI = getProjectFileURI("Tree2TallTree/TallTreeValidate.xmi");
-		//		Transformation asTransformation = myQVT.loadTransformation(transformURI, genModelURI);
-		Class<? extends Transformer> txClass = Tree2TallTreeInstallManual.class;
+		Transformation asTransformation = myQVT.loadTransformation(transformURI, genModelURI);
+		Class<? extends Transformer> txClass = myQVT.generateCode(asTransformation, true);
 		Transformer tx = myQVT.createTransformer(txClass);
 		myQVT.loadInput(tx, "tree", inputModelURI);
 		tx.run();
-		Execution2GraphVisitor.writeGraphMLfile(tx, getProjectFileURI("Tree2TallTree/Tree2TallTreeInstallManual-execution.graphml"));
 		myQVT.saveOutput(tx, "talltree", outputModelURI, referenceModelURI, null);
 		myQVT.dispose();
 	}
diff --git a/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/RuntimeConnectionTests.java b/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/RuntimeConnectionTests.java
new file mode 100644
index 000000000..11aa0c7ab
--- /dev/null
+++ b/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/RuntimeConnectionTests.java
@@ -0,0 +1,385 @@
+/*******************************************************************************
+ * Copyright (c) 2016 Willink Transformations and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     E.D.Willink - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.qvtd.xtext.qvtimperative.tests;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
+import org.eclipse.ocl.pivot.evaluation.Executor;
+import org.eclipse.ocl.pivot.evaluation.ModelManager;
+import org.eclipse.ocl.pivot.ids.TypeId;
+import org.eclipse.ocl.pivot.internal.evaluation.AbstractExecutor;
+import org.eclipse.ocl.pivot.internal.utilities.EnvironmentFactoryInternal.EnvironmentFactoryInternalExtension;
+import org.eclipse.ocl.pivot.utilities.EnvironmentFactory;
+import org.eclipse.ocl.pivot.utilities.OCL;
+import org.eclipse.qvtd.pivot.qvtimperative.evaluation.AbstractInterpretedInvocation;
+import org.eclipse.qvtd.runtime.evaluation.Interval;
+import org.eclipse.qvtd.runtime.evaluation.Invocation;
+import org.eclipse.qvtd.runtime.evaluation.InvocationFailedException;
+import org.eclipse.qvtd.runtime.evaluation.InvocationManager;
+import org.eclipse.qvtd.runtime.evaluation.SimpleConnection;
+import org.eclipse.qvtd.runtime.internal.evaluation.AbstractInvocationConstructor;
+import org.eclipse.qvtd.runtime.internal.evaluation.AbstractInvocationManagerInternal;
+import org.junit.Test;
+
+import junit.framework.TestCase;
+
+
+public class RuntimeConnectionTests extends TestCase
+{
+	public static final class Tester
+	{
+		protected final @NonNull OCL ocl;
+		protected final @NonNull TestExecutor executor;
+		protected final @NonNull TestInvocationManager invocationManager;
+		protected final @NonNull TestInvocationConstructor invocationConstructor;
+		protected final @NonNull List<@NonNull TestConnection> testConnections = new ArrayList<>();
+
+		public Tester() {
+			ocl = OCL.newInstance();
+			executor = new TestExecutor(ocl.getEnvironmentFactory());
+			invocationManager = new TestInvocationManager(executor);
+			invocationConstructor = new TestInvocationConstructor(invocationManager, "name", false);
+		}
+
+		public void addConsumedConnection(@NonNull TestConnection testConnection) {
+			invocationConstructor.addConsumedConnection(testConnection);
+			testConnections.add(testConnection);
+		}
+
+		public void check() {
+			StringBuilder s = new StringBuilder();
+			check(0, "9", s);
+			check(s.toString());
+		}
+
+		private void check(int connectionIndex, @NonNull String partialString, @NonNull StringBuilder s) {
+			if (connectionIndex < testConnections.size()) {
+				for (int i = 0; i < testConnections.get(connectionIndex).counter; i++) {
+					check(connectionIndex+1, partialString + i, s);
+				}
+			}
+			else {
+				if (s.length() > 0) {
+					s.append(",");
+				}
+				s.append(partialString);
+			}
+		}
+
+		public void check(@Nullable String stringValue) {
+			invocationManager.flush();
+			if (stringValue != null) {
+				assertEquals(stringValue, invocationConstructor.stringValue());
+			}
+			int product = 1;
+			for (@NonNull TestConnection testConnection : testConnections) {
+				product *= testConnection.counter;
+			}
+			TestCase.assertEquals(product, invocationConstructor.allValues.size());
+			@NonNull Object[] values = new @NonNull Object[testConnections.size()];
+			invocationConstructor.check(0, values, testConnections);
+		}
+
+		public @NonNull TestConnection createConsumedConnection() {
+			String name = "connection" + testConnections.size();
+			TestConnection testConnection = new TestConnection(invocationManager.getRootInterval(), name, TypeId.INTEGER);
+			addConsumedConnection(testConnection);
+			return testConnection;
+		}
+
+		public void dispose() {
+			ocl.dispose();
+		}
+
+		public @NonNull TestInvocationConstructor getInvocationConstructor() {
+			return invocationConstructor;
+		}
+	}
+
+	public static final class TestExecutor extends AbstractExecutor
+	{
+		public TestExecutor(@NonNull EnvironmentFactory environmentFactory) {
+			super((@NonNull EnvironmentFactoryInternalExtension) environmentFactory);
+		}
+
+		@Override
+		public @NonNull ModelManager getModelManager() {
+			throw new UnsupportedOperationException();
+		}
+	}
+
+	public static final class TestInvocationManager extends AbstractInvocationManagerInternal
+	{
+		public TestInvocationManager(@NonNull Executor executor) {
+			super(executor);
+		}
+	}
+
+	public static final class TestInvocationConstructor extends AbstractInvocationConstructor
+	{
+		protected final @NonNull Set<@NonNull Integer> allValues = new HashSet<>();
+
+		public TestInvocationConstructor(@NonNull InvocationManager invocationManager, @NonNull String name, boolean isStrict) {
+			super(invocationManager, name, isStrict);
+		}
+
+		public void executed(@NonNull Object @NonNull [] values) {
+			int intValue = compositeValue(values);
+			boolean wasAdded = allValues.add(intValue);
+			TestCase.assertTrue(wasAdded);
+		}
+
+		public void check(int consumerIndex, @NonNull Object @NonNull [] values, @NonNull List<@NonNull TestConnection> testConnections) {
+			if (consumerIndex >= testConnections.size()) {
+				int intValue = compositeValue(values);
+				TestCase.assertTrue(allValues.contains(intValue));
+			}
+			else {
+				for (int i = 0; i < testConnections.get(consumerIndex).counter; i++) {
+					values[consumerIndex] = i;
+					check(consumerIndex+1, values, testConnections);
+				}
+			}
+		}
+
+		private int compositeValue(@NonNull Object @NonNull [] values) {
+			int intValue = 9;
+			for (@NonNull Object value : values) {
+				intValue = 10 * intValue + ((Integer)value).intValue();
+			}
+			return intValue;
+		}
+
+		@Override
+		public @NonNull Invocation newInstance(@NonNull Object @NonNull [] values) {
+			return new TestInvocation(this, values);
+		}
+
+		public @NonNull String stringValue() {
+			List<@NonNull Integer> intValues = new ArrayList<>(allValues);
+			Collections.sort(intValues);
+			StringBuilder s = new StringBuilder();
+			for (int i = 0; i < intValues.size(); i++) {
+				if (i != 0) {
+					s.append(",");
+				}
+				s.append(intValues.get(i));
+			}
+			return s.toString();
+		}
+	}
+
+	public static final class TestInvocation extends AbstractInterpretedInvocation
+	{
+		protected final @NonNull TestInvocationConstructor invocationConstructor;
+
+		public TestInvocation(@NonNull TestInvocationConstructor invocationConstructor, @NonNull Object @NonNull [] values) {
+			super(invocationConstructor, values);
+			this.invocationConstructor = invocationConstructor;
+		}
+
+		@Override
+		public boolean execute() throws InvocationFailedException {
+			invocationConstructor.executed(values);
+			return false;
+		}
+	}
+
+	public static final class TestConnection extends SimpleConnection
+	{
+		private Integer counter = 0;
+
+		public TestConnection(@NonNull Interval interval, @NonNull String name, @NonNull TypeId typeId) {
+			super(interval, name, typeId);
+		}
+
+		public void append() {
+			appendElement(counter++);
+		}
+	}
+
+	@Test
+	public void testRuntime_DoubleSimpleConnection() {
+		Tester tester = new Tester();
+		TestConnection connection0  = tester.createConsumedConnection();
+		TestConnection connection1  = tester.createConsumedConnection();
+		//
+		tester.check("");
+		//
+		tester.check("");
+		//
+		connection0.append();
+		tester.check("");
+		//
+		connection1.append();
+		tester.check("900");
+		//
+		tester.check("900");
+		//
+		connection1.append();
+		tester.check("900,901");
+		//
+		connection1.append();
+		tester.check("900,901,902");
+		//
+		connection0.append();
+		tester.check("900,901,902,910,911,912");
+		//
+		connection1.append();
+		tester.check("900,901,902,903,910,911,912,913");
+		//
+		connection0.append();
+		connection0.append();
+		connection0.append();
+		tester.check();
+		//
+		connection1.append();
+		connection1.append();
+		tester.check();
+		//
+		tester.check();
+		//
+		tester.dispose();
+	}
+
+	@Test
+	public void testRuntime_RedundantDoubleSimpleConnection() {
+		Tester tester = new Tester();
+		TestConnection connection0  = tester.createConsumedConnection();
+		tester.addConsumedConnection(connection0);
+		//
+		tester.check("");
+		//
+		tester.check("");
+		//
+		connection0.append();
+		tester.check("900");
+		//
+		tester.check("900");
+		//
+		connection0.append();
+		tester.check("900,901,910,911");
+		//
+		connection0.append();
+		tester.check("900,901,902,910,911,912,920,921,922");
+		//
+		connection0.append();
+		tester.check();
+		//
+		connection0.append();
+		tester.check();
+		//
+		connection0.append();
+		connection0.append();
+		connection0.append();
+		tester.check();
+		//
+		connection0.append();
+		connection0.append();
+		tester.check();
+		//
+		tester.check();
+		//
+		tester.dispose();
+	}
+
+	@Test
+	public void testRuntime_SingleSimpleConnection() {
+		Tester tester = new Tester();
+		TestConnection connection0  = tester.createConsumedConnection();
+		//
+		tester.check("");
+		//
+		tester.check("");
+		//
+		connection0.append();
+		tester.check("90");
+		//
+		tester.check("90");
+		//
+		connection0.append();
+		connection0.append();
+		tester.check("90,91,92");
+		//
+		connection0.append();
+		tester.check("90,91,92,93");
+		//
+		connection0.append();
+		connection0.append();
+		connection0.append();
+		tester.check("90,91,92,93,94,95,96");
+		//
+		tester.check();
+		//
+		tester.dispose();
+	}
+
+	@Test
+	public void testRuntime_TripleSimpleConnection() {
+		Tester tester = new Tester();
+		TestConnection connection0  = tester.createConsumedConnection();
+		TestConnection connection1  = tester.createConsumedConnection();
+		TestConnection connection2  = tester.createConsumedConnection();
+		//
+		tester.check("");
+		//
+		tester.check("");
+		//
+		connection0.append();
+		tester.check("");
+		//
+		connection1.append();
+		tester.check("");
+		//
+		connection2.append();
+		tester.check("9000");
+		//
+		tester.check("9000");
+		//
+		connection1.append();
+		tester.check("9000,9010");
+		//
+		connection1.append();
+		tester.check("9000,9010,9020");
+		//
+		connection0.append();
+		tester.check("9000,9010,9020,9100,9110,9120");
+		//
+		connection2.append();
+		tester.check("9000,9001,9010,9011,9020,9021,9100,9101,9110,9111,9120,9121");
+		//
+		connection0.append();
+		connection1.append();
+		connection0.append();
+		tester.check();
+		//
+		connection1.append();
+		connection1.append();
+		tester.check();
+		//
+		connection2.append();
+		connection2.append();
+		tester.check();
+		//
+		connection0.append();
+		tester.check();
+		//
+		tester.check();
+		//
+		tester.dispose();
+	}
+}
diff --git a/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/Tree2TallTree/TallTreeValidate2.xmi b/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/Tree2TallTree/TallTreeValidate2.xmi
new file mode 100644
index 000000000..8f3351492
--- /dev/null
+++ b/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/Tree2TallTree/TallTreeValidate2.xmi
@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="ASCII"?>

+<talltree:TallNode

+	xmi:version="2.0"

+	xmlns:xmi="http://www.omg.org/XMI"

+	xmlns:talltree="http://www.eclipse.org/qvt/examples/0.1/TallTree"

+    xsi:schemaLocation="http://www.eclipse.org/qvt/examples/0.1/TallTree TallTree.ecore"

+	height="2"

+	name="n1">

+  <children

+	height="1"

+      name="x1.1">

+    <children

+	height="0"

+        name="n1.1.1"/>

+  </children>

+</talltree:TallNode>

diff --git a/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/Tree2TallTree/Tree2TallTree.qvti b/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/Tree2TallTree/Tree2TallTree.qvti
index 62ef003b6..e9e043b25 100644
--- a/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/Tree2TallTree/Tree2TallTree.qvti
+++ b/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/Tree2TallTree/Tree2TallTree.qvti
@@ -9,7 +9,8 @@ transformation Tree2TallTree {
 }
 
 map __root__ in Tree2TallTree {
-    buffer nodes := tree.objectsOfKind(Node)->sortedBy(name);
+--    buffer nodes := tree.objectsOfKind(Node)->sortedBy(name);
+    buffer nodes := tree.objectsOfKind(Node);
     for node : tree::Node in nodes {
         call Node2MiddleNode {
             node iterates node;
@@ -20,7 +21,8 @@ map __root__ in Tree2TallTree {
             node iterates node;
         } 
     } 
-    for node2tallNode : tree2talltree::Node2TallNode in tree2talltree.objectsOfKind(Node2TallNode)->sortedBy(name) {
+--    for node2tallNode : tree2talltree::Node2TallNode in tree2talltree.objectsOfKind(Node2TallNode)->sortedBy(name) {
+    for node2tallNode : tree2talltree::Node2TallNode in tree2talltree.objectsOfKind(Node2TallNode) {
         call MiddleNode2TallNode {
             node2tallNode iterates node2tallNode;	
         } 
diff --git a/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/Tree2TallTree/Tree2TallTreeInstallManual.java b/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/Tree2TallTree/Tree2TallTreeInstallManual.java
deleted file mode 100644
index 576b59e54..000000000
--- a/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/Tree2TallTree/Tree2TallTreeInstallManual.java
+++ /dev/null
@@ -1,504 +0,0 @@
-/*******************************************************************************
- * «codeGenHelper.getCopyright(' * ')»
- *
- * This code is 100% auto-generated
- * using: org.eclipse.qvtd.codegen.qvti.java.QVTiCodeGenerator
- *
- * Do not edit it.
- ********************************************************************************/
-
-package org.eclipse.qvtd.xtext.qvtimperative.tests.Tree2TallTree;
-
-import java.util.HashMap;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
-
-import org.eclipse.emf.ecore.EcorePackage;
-import org.eclipse.jdt.annotation.NonNull;
-import org.eclipse.jdt.annotation.Nullable;
-import org.eclipse.ocl.pivot.StandardLibrary;
-import org.eclipse.ocl.pivot.evaluation.Executor;
-import org.eclipse.ocl.pivot.ids.ClassId;
-import org.eclipse.ocl.pivot.ids.CollectionTypeId;
-import org.eclipse.ocl.pivot.ids.DataTypeId;
-import org.eclipse.ocl.pivot.ids.IdManager;
-import org.eclipse.ocl.pivot.ids.IdResolver;
-import org.eclipse.ocl.pivot.ids.NsURIPackageId;
-import org.eclipse.ocl.pivot.ids.RootPackageId;
-import org.eclipse.ocl.pivot.ids.TypeId;
-import org.eclipse.ocl.pivot.internal.library.executor.ExecutorSingleIterationManager;
-import org.eclipse.ocl.pivot.library.AbstractBinaryOperation;
-import org.eclipse.ocl.pivot.library.LibraryIteration;
-import org.eclipse.ocl.pivot.library.collection.CollectionAsSetOperation;
-import org.eclipse.ocl.pivot.library.collection.CollectionExcludingOperation;
-import org.eclipse.ocl.pivot.library.collection.CollectionMaxOperation;
-import org.eclipse.ocl.pivot.library.collection.CollectionNotEmptyOperation;
-import org.eclipse.ocl.pivot.library.numeric.NumericPlusOperation;
-import org.eclipse.ocl.pivot.oclstdlib.OCLstdlibTables;
-import org.eclipse.ocl.pivot.utilities.ClassUtil;
-import org.eclipse.ocl.pivot.utilities.ValueUtil;
-import org.eclipse.ocl.pivot.values.BagValue;
-import org.eclipse.ocl.pivot.values.IntegerValue;
-import org.eclipse.ocl.pivot.values.InvalidValueException;
-import org.eclipse.ocl.pivot.values.OrderedSetValue;
-import org.eclipse.ocl.pivot.values.SetValue;
-import org.eclipse.qvtd.runtime.evaluation.AbstractInvocation;
-import org.eclipse.qvtd.runtime.evaluation.AbstractTransformer;
-import org.eclipse.qvtd.runtime.evaluation.Connection;
-import org.eclipse.qvtd.runtime.evaluation.InvocationConstructor;
-import org.eclipse.qvtd.runtime.evaluation.InvocationManager;
-import org.eclipse.qvtd.runtime.evaluation.ObjectManager;
-import org.eclipse.qvtd.runtime.evaluation.TransformationExecutor;
-import org.eclipse.qvtd.runtime.internal.evaluation.AbstractInvocationConstructor;
-import org.eclipse.qvtd.runtime.internal.evaluation.IncrementalInvocationManager;
-import org.eclipse.qvtd.runtime.internal.evaluation.IncrementalObjectManager;
-import org.eclipse.qvtd.runtime.library.model.ModelObjectsOfKindOperation;
-
-import tree2talltree.talltree.TallNode;
-import tree2talltree.talltree.TalltreeFactory;
-import tree2talltree.talltree.TalltreePackage;
-import tree2talltree.tree.Node;
-import tree2talltree.tree.TreePackage;
-import tree2talltree.tree2talltree.Node2TallNode;
-import tree2talltree.tree2talltree.Tree2talltreeFactory;
-import tree2talltree.tree2talltree.Tree2talltreePackage;
-
-/**
- * The Tree2TallTreeInstall transformation:
- * <p>
- * Construct with an evaluator
- * <br>
- * Populate each input model with {@link addRootObjects(String,List)}
- * <br>
- * {@link run()}
- * <br>
- * Extract each output model with {@link getRootObjects(String)}
- */
-@SuppressWarnings("nls")
-public class Tree2TallTreeInstallManual extends AbstractTransformer
-{
-	public static final /*@NonInvalid*/ @NonNull RootPackageId PACKid_$metamodel$ = IdManager.getRootPackageId("$metamodel$");
-	public static final /*@NonInvalid*/ @NonNull NsURIPackageId PACKid_http_c_s_s_www_eclipse_org_s_emf_s_2002_s_Ecore = IdManager.getNsURIPackageId("http://www.eclipse.org/emf/2002/Ecore", null, EcorePackage.eINSTANCE);
-	public static final /*@NonInvalid*/ @NonNull NsURIPackageId PACKid_http_c_s_s_www_eclipse_org_s_qvt_s_2015_s_QVTbaseLibrary = IdManager.getNsURIPackageId("http://www.eclipse.org/qvt/2015/QVTbaseLibrary", "qvtbaselib", null);
-	public static final /*@NonInvalid*/ @NonNull NsURIPackageId PACKid_http_c_s_s_www_eclipse_org_s_qvt_s_examples_s_0_1_s_List2List = IdManager.getNsURIPackageId("http://www.eclipse.org/qvt/examples/0.1/List2List", null, Tree2talltreePackage.eINSTANCE);
-	public static final /*@NonInvalid*/ @NonNull NsURIPackageId PACKid_http_c_s_s_www_eclipse_org_s_qvt_s_examples_s_0_1_s_TallTree = IdManager.getNsURIPackageId("http://www.eclipse.org/qvt/examples/0.1/TallTree", null, TalltreePackage.eINSTANCE);
-	public static final /*@NonInvalid*/ @NonNull NsURIPackageId PACKid_http_c_s_s_www_eclipse_org_s_qvt_s_examples_s_0_1_s_Tree = IdManager.getNsURIPackageId("http://www.eclipse.org/qvt/examples/0.1/Tree", null, TreePackage.eINSTANCE);
-	public static final /*@NonInvalid*/ @NonNull ClassId CLSSid_Class = PACKid_$metamodel$.getClassId("Class", 0);
-	public static final /*@NonInvalid*/ @NonNull ClassId CLSSid_Model = PACKid_http_c_s_s_www_eclipse_org_s_qvt_s_2015_s_QVTbaseLibrary.getClassId("Model", 0);
-	public static final /*@NonInvalid*/ @NonNull ClassId CLSSid_Node = PACKid_http_c_s_s_www_eclipse_org_s_qvt_s_examples_s_0_1_s_Tree.getClassId("Node", 0);
-	public static final /*@NonInvalid*/ @NonNull ClassId CLSSid_Node2TallNode = PACKid_http_c_s_s_www_eclipse_org_s_qvt_s_examples_s_0_1_s_List2List.getClassId("Node2TallNode", 0);
-	public static final /*@NonInvalid*/ @NonNull ClassId CLSSid_TallNode = PACKid_http_c_s_s_www_eclipse_org_s_qvt_s_examples_s_0_1_s_TallTree.getClassId("TallNode", 0);
-	public static final /*@NonInvalid*/ @NonNull DataTypeId DATAid_EInt = PACKid_http_c_s_s_www_eclipse_org_s_emf_s_2002_s_Ecore.getDataTypeId("EInt", 0);
-	public static final /*@NonInvalid*/ @NonNull IntegerValue INT_0 = ValueUtil.integerValueOf("0");
-	public static final /*@NonInvalid*/ @NonNull IntegerValue INT_1 = ValueUtil.integerValueOf("1");
-	public static final /*@NonInvalid*/ @NonNull CollectionTypeId BAG_CLSSid_TallNode = TypeId.BAG.getSpecializedId(CLSSid_TallNode);
-	public static final /*@NonInvalid*/ @NonNull CollectionTypeId BAG_DATAid_EInt = TypeId.BAG.getSpecializedId(DATAid_EInt);
-	public static final /*@NonInvalid*/ @NonNull CollectionTypeId ORD_CLSSid_Node = TypeId.ORDERED_SET.getSpecializedId(CLSSid_Node);
-	public static final /*@NonInvalid*/ @NonNull CollectionTypeId SEQ_CLSSid_Node2TallNode = TypeId.SEQUENCE.getSpecializedId(CLSSid_Node2TallNode);
-	public static final /*@NonInvalid*/ @NonNull CollectionTypeId SET_CLSSid_Node = TypeId.SET.getSpecializedId(CLSSid_Node);
-	public static final /*@NonInvalid*/ @NonNull CollectionTypeId SET_CLSSid_Node2TallNode = TypeId.SET.getSpecializedId(CLSSid_Node2TallNode);
-	public static final /*@NonInvalid*/ @NonNull CollectionTypeId SET_CLSSid_TallNode = TypeId.SET.getSpecializedId(CLSSid_TallNode);
-
-	/*
-	 * Property-source to Property-target unnavigable navigation caches
-	 */
-	protected final @NonNull Map<Node,Node2TallNode> OPPOSITE_OF_Node2TallNode_node = new HashMap<Node,Node2TallNode>();
-
-	/*
-	 * Array of the ClassIds of each class for which allInstances() may be invoked. Array index is the ClassIndex.
-	 */
-	private static final @NonNull ClassId[] classIndex2classId = new @NonNull ClassId[]{
-		CLSSid_Node                     // 0 => Node
-	};
-
-	/*
-	 * Mapping from each ClassIndex to all the ClassIndexes to which an object of the outer index
-	 * may contribute results to an allInstances() invocation.
-	 * Non trivial inner arrays arise when one ClassId is a derivation of another and so an
-	 * instance of the derived classId contributes to derived and inherited ClassIndexes.
-	 */
-	private final static int @NonNull [] @NonNull [] classIndex2allClassIndexes = new int @NonNull [] @NonNull [] {
-		{0}                     // 0 : Node -> {Node}
-	};
-
-	protected final AbstractInvocationConstructor.@NonNull Incremental CTOR_Root = new AbstractInvocationConstructor.Incremental(invocationManager, "__root__", false)
-	{
-		@Override
-		public @NonNull MAP___root__ newInstance(@NonNull Object @NonNull [] values) {
-			return new MAP___root__(this, values);
-		}
-	};
-
-	protected final AbstractInvocationConstructor.@NonNull Incremental CTOR_Node2MiddleNode = new AbstractInvocationConstructor.Incremental(invocationManager, "Node2MiddleNode", false)
-	{
-		@Override
-		public @NonNull MAP_Node2MiddleNode newInstance(@NonNull Object @NonNull [] values) {
-			return new MAP_Node2MiddleNode(this, values);
-		}
-	};
-
-	protected final AbstractInvocationConstructor.@NonNull Incremental CTOR_Edge2MiddleEdge = new AbstractInvocationConstructor.Incremental(invocationManager, "Edge2MiddleEdge", false)
-	{
-		@Override
-		public @NonNull MAP_Edge2MiddleEdge newInstance(@NonNull Object @NonNull [] values) {
-			return new MAP_Edge2MiddleEdge(this, values);
-		}
-	};
-
-	protected final AbstractInvocationConstructor.@NonNull Incremental CTOR_MiddleNode2TallNode = new AbstractInvocationConstructor.Incremental(invocationManager, "MiddleNode2TallNode", false)
-	{
-		@Override
-		public @NonNull MAP_MiddleNode2TallNode newInstance(@NonNull Object @NonNull [] values) {
-			return new MAP_MiddleNode2TallNode(this, values);
-		}
-	};
-
-	public Tree2TallTreeInstallManual(final @NonNull TransformationExecutor executor) {
-		super(executor, new @NonNull String[] {"tree", "talltree", "tree2talltree"}, null, classIndex2classId, classIndex2allClassIndexes);
-	}
-
-	@Override
-	protected @NonNull InvocationManager createInvocationManager() {
-		return new IncrementalInvocationManager(executor);
-	}
-
-	@Override
-	protected @NonNull ObjectManager createObjectManager() {
-		return new IncrementalObjectManager((IncrementalInvocationManager)invocationManager);
-	}
-
-	@Override
-	public boolean run() {
-		//		CTOR_Root.connect(null, null);
-		CTOR_Root.invoke();
-		//		invocationManager.setWorkToDoAt(0);
-		return invocationManager.flush();
-	}
-
-	/**
-	 *
-	 * map __root__ in Tree2TallTreeInstall {
-	 *
-	 *   nodes : OrderedSet(tree::Node)node2tallNodes : Sequence(tree2talltree::Node2TallNode)install Node2MiddleNode {
-	 * node consumes nodes : OrderedSet(tree::Node);
-	 * node2tallNodes appendsTo node2tallNodes;
-	 * }
-	 *   install Edge2MiddleEdge {
-	 * node consumes nodes : OrderedSet(tree::Node);
-	 * }
-	 *   install MiddleNode2TallNode {
-	 * node2tallNode consumes node2tallNodes : Sequence(tree2talltree::Node2TallNode);
-	 * }
-	 */
-	protected class MAP___root__ extends AbstractInvocation.Incremental
-	{
-		public MAP___root__(InvocationConstructor.@NonNull Incremental constructor, @NonNull Object @NonNull [] boundValues) {
-			super(constructor);
-		}
-
-		@Override
-		public boolean execute()  {
-			try {
-				final /*@NonInvalid*/ @NonNull IdResolver idResolver = executor.getIdResolver();
-				final /*@NonInvalid*/ org.eclipse.ocl.pivot.@NonNull Class TYP_tree_c_c_Node_0 = idResolver.getClass(CLSSid_Node, null);
-				final /*@NonInvalid*/ @NonNull StandardLibrary standardLibrary = idResolver.getStandardLibrary();
-				// connection variables
-				final @NonNull Connection nodes = createConnection("nodes", ORD_CLSSid_Node, false);
-				final /*@NonInvalid*/ @NonNull SetValue objectsOfKind = ModelObjectsOfKindOperation.INSTANCE.evaluate(executor, SET_CLSSid_Node, models[0/*tree*/], TYP_tree_c_c_Node_0);
-				final org.eclipse.ocl.pivot.@NonNull Class TYPE_sortedBy_0 = executor.getStaticTypeOf(objectsOfKind);
-				final LibraryIteration.@NonNull LibraryIterationExtension IMPL_sortedBy_0 = (LibraryIteration.LibraryIterationExtension)TYPE_sortedBy_0.lookupImplementation(standardLibrary, OCLstdlibTables.Operations._Set__sortedBy);
-				final @NonNull Object ACC_sortedBy_0 = IMPL_sortedBy_0.createAccumulatorValue(executor, ORD_CLSSid_Node, TypeId.STRING);
-				/**
-				 * Implementation of the iterator body.
-				 */
-				final @NonNull AbstractBinaryOperation BODY_sortedBy_0 = new AbstractBinaryOperation()
-				{
-					/**
-					 * name
-					 */
-					@Override
-					public @Nullable Object evaluate(final @NonNull Executor executor, final @NonNull TypeId typeId, final @Nullable Object objectsOfKind, final /*@NonInvalid*/ @Nullable Object _1) {
-						final /*@NonInvalid*/ @Nullable Node symbol_4 = (Node)_1;
-						if (symbol_4 == null) {
-							throw new InvalidValueException("Null source for \'\'http://www.eclipse.org/qvt/examples/0.1/Tree\'::Node::name\'");
-						}
-						@SuppressWarnings("null")
-						final /*@Thrown*/ @NonNull String name = symbol_4.getName();
-						objectManager.got(MAP___root__.this, symbol_4, TreePackage.Literals.NODE__NAME, name);
-						return name;
-					}
-				};
-				final @NonNull  ExecutorSingleIterationManager MGR_sortedBy_0 = new ExecutorSingleIterationManager(executor, ORD_CLSSid_Node, BODY_sortedBy_0, objectsOfKind, ACC_sortedBy_0);
-				final /*@Thrown*/ @NonNull OrderedSetValue sortedBy = ClassUtil.nonNullState((OrderedSetValue)IMPL_sortedBy_0.evaluateIteration(MGR_sortedBy_0));
-				for (@NonNull Node iterator : ValueUtil.typedIterable(Node.class, sortedBy)) {
-					nodes.append(iterator);
-				}
-				final Connection.@NonNull Incremental node2tallNodes_1 = createIncrementalConnection("node2tallNodes_1", SEQ_CLSSid_Node2TallNode, false);
-				// mapping statements
-				CTOR_Node2MiddleNode.addConsumedConnection(nodes);
-				CTOR_Node2MiddleNode.addAppendedConnection(node2tallNodes_1);
-				CTOR_Edge2MiddleEdge.addConsumedConnection(nodes);
-				CTOR_MiddleNode2TallNode.addConsumedConnection(node2tallNodes_1);
-				final /*@Thrown*/ @Nullable Boolean __root__ = ValueUtil.TRUE_VALUE;
-				return __root__;
-			} catch (Throwable e) {
-				return handleExecutionFailure("MAP___root__", e);
-			}
-		}
-
-		@Override
-		public boolean isEqual(@NonNull IdResolver idResolver, @NonNull Object @NonNull [] thoseValues) {
-			return true;
-		}
-	}
-
-	/**
-	 *
-	 * map Node2MiddleNode in Tree2TallTreeInstall {
-	 * guard:tree node  : tree::Node[?];
-	 * append node2tallNodes  : Sequence(tree2talltree::Node2TallNode);
-	 * new:tree2talltree node2tallNode : tree2talltree::Node2TallNode[?];
-	 * set node2tallNode.node := node;
-	 * set node2tallNode.name := node.name;
-	 * add node2tallNodes += node2tallNode;
-	 *
-	 */
-	protected class MAP_Node2MiddleNode extends AbstractInvocation.Incremental
-	{
-		protected final /*@NonInvalid*/ @NonNull Node node;
-		protected final @NonNull Connection node2tallNodes;
-
-		public MAP_Node2MiddleNode(InvocationConstructor.@NonNull Incremental constructor, @NonNull Object @NonNull [] boundValues) {
-			super(constructor);
-			node = (Node)boundValues[0];
-			node2tallNodes = (Connection)boundValues[1];
-		}
-
-		@Override
-		public boolean execute()  {
-			try {
-				// creations
-				final /*@Thrown*/ @Nullable Node2TallNode node2tallNode_0 = Tree2talltreeFactory.eINSTANCE.createNode2TallNode();
-				assert node2tallNode_0 != null;
-				models[2/*tree2talltree*/].add(node2tallNode_0);
-				objectManager.created(this, node2tallNode_0);
-				// mapping statements
-				OPPOSITE_OF_Node2TallNode_node.put(node, node2tallNode_0);
-				node2tallNode_0.setNode(node);
-				objectManager.assigned(this, node2tallNode_0, Tree2talltreePackage.Literals.NODE2_TALL_NODE__NODE, node, null);
-				@SuppressWarnings("null")
-				final /*@Thrown*/ @NonNull String name = node.getName();
-				objectManager.got(this, node, TreePackage.Literals.NODE__NAME, name);
-				node2tallNode_0.setName(name);
-				objectManager.assigned(this, node2tallNode_0, Tree2talltreePackage.Literals.NODE2_TALL_NODE__NAME, name, null);
-				node2tallNodes.append(node2tallNode_0);
-				final /*@Thrown*/ @Nullable Boolean Node2MiddleNode = ValueUtil.TRUE_VALUE;
-				return Node2MiddleNode;
-			} catch (Throwable e) {
-				return handleExecutionFailure("MAP_Node2MiddleNode", e);
-			}
-		}
-
-		@Override
-		public boolean isEqual(@NonNull IdResolver idResolver, @NonNull Object @NonNull [] thoseValues) {
-			return idResolver.oclEquals(node, thoseValues[0])
-					&& idResolver.oclEquals(node2tallNodes, thoseValues[1]);
-		}
-	}
-
-	/**
-	 *
-	 * map Edge2MiddleEdge in Tree2TallTreeInstall {
-	 * guard:tree node  : tree::Node[?];
-	 * var node2tallNode : tree2talltree::Node2TallNode[?] := node.Node2TallNode;
-	 * check node.parent <> null;
-	 * notify set node2tallNode.parent := node.parent.Node2TallNode;
-	 *
-	 */
-	protected class MAP_Edge2MiddleEdge extends AbstractInvocation.Incremental
-	{
-		protected final /*@NonInvalid*/ @NonNull Node node_0;
-
-		public MAP_Edge2MiddleEdge(InvocationConstructor.@NonNull Incremental constructor, @NonNull Object @NonNull [] boundValues) {
-			super(constructor);
-			node_0 = (Node)boundValues[0];
-		}
-
-		@Override
-		public boolean execute()  {
-			try {
-				final /*@Thrown*/ @NonNull Node2TallNode Node2TallNode = ClassUtil.nonNullState (OPPOSITE_OF_Node2TallNode_node.get(node_0));
-				objectManager.got(this, node_0, Tree2talltreePackage.Literals.NODE2_TALL_NODE__NODE, Node2TallNode);
-				final /*@Thrown*/ @Nullable Node parent = node_0.getParent();
-				objectManager.got(this, node_0, TreePackage.Literals.NODE__PARENT, parent);
-				final /*@Thrown*/ boolean ne = parent != null;
-				/*@Thrown*/ @Nullable Boolean symbol_2;
-				if (ne) {
-					// mapping statements
-					if (parent == null) {
-						throw new InvalidValueException("Null source for \'\'http://www.eclipse.org/qvt/examples/0.1/Tree\'::Node::Node2TallNode\'");
-					}
-					final /*@Thrown*/ @NonNull Node2TallNode Node2TallNode_0 = ClassUtil.nonNullState (OPPOSITE_OF_Node2TallNode_node.get(parent));
-					objectManager.got(this, parent, Tree2talltreePackage.Literals.NODE2_TALL_NODE__NODE, Node2TallNode_0);
-					Node2TallNode.setParent(Node2TallNode_0);
-					objectManager.assigned(this, Node2TallNode, Tree2talltreePackage.Literals.NODE2_TALL_NODE__PARENT, Node2TallNode_0, null);
-					final /*@Thrown*/ @Nullable Boolean Edge2MiddleEdge = ValueUtil.TRUE_VALUE;
-					symbol_2 = Edge2MiddleEdge;
-				}
-				else {
-					symbol_2 = ValueUtil.FALSE_VALUE;
-				}
-				return symbol_2;
-			} catch (Throwable e) {
-				return handleExecutionFailure("MAP_Edge2MiddleEdge", e);
-			}
-		}
-
-		@Override
-		public boolean isEqual(@NonNull IdResolver idResolver, @NonNull Object @NonNull [] thoseValues) {
-			return idResolver.oclEquals(node_0, thoseValues[0]);
-		}
-	}
-
-	/**
-	 *
-	 * map MiddleNode2TallNode in Tree2TallTreeInstall {
-	 *
-	 *   guard:tree2talltree node2tallNode  : tree2talltree::Node2TallNode[?];
-	 * var tallNode_name : String[?] := node2tallNode.name;
-	 * var tallNode_children : Set(talltree::TallNode) := node2tallNode.children?.tallNode->asSet()
-	 *   ;
-	 * var tallNode_height : Integer[?] := if node2tallNode.children->notEmpty()
-	 *   then node2tallNode.children.tallNode.height->max() + 1
-	 *   else 0
-	 *   endif;
-	 * new:talltree tallNode : talltree::TallNode[?];
-	 * notify set node2tallNode.tallNode := tallNode;
-	 * set tallNode.name := tallNode_name;
-	 * set tallNode.children := tallNode_children;
-	 * notify set tallNode.height := tallNode_height;
-	 *
-	 */
-	protected class MAP_MiddleNode2TallNode extends AbstractInvocation.Incremental
-	{
-		protected final /*@NonInvalid*/ @NonNull Node2TallNode node2tallNode;
-
-		public MAP_MiddleNode2TallNode(InvocationConstructor.@NonNull Incremental constructor, @NonNull Object @NonNull [] boundValues) {
-			super(constructor);
-			node2tallNode = (Node2TallNode)boundValues[0];
-		}
-
-		@Override
-		public boolean execute()  {
-			try {
-				final /*@NonInvalid*/ @NonNull IdResolver idResolver = executor.getIdResolver();
-				@SuppressWarnings("null")
-				final /*@Thrown*/ @NonNull String name = node2tallNode.getName();
-				objectManager.got(this, node2tallNode, Tree2talltreePackage.Literals.NODE2_TALL_NODE__NAME, name);
-				objectManager.getting(node2tallNode, Tree2talltreePackage.Literals.NODE2_TALL_NODE__CHILDREN, false);
-				@SuppressWarnings("null")
-				final /*@Thrown*/ @NonNull List<Node2TallNode> children_0 = node2tallNode.getChildren();
-				objectManager.got(this, node2tallNode, Tree2talltreePackage.Literals.NODE2_TALL_NODE__CHILDREN, children_0);
-				final /*@Thrown*/ @NonNull SetValue BOXED_children_0 = idResolver.createSetOfAll(SET_CLSSid_Node2TallNode, children_0);
-				final /*@Thrown*/ @NonNull SetValue safe_collect_sources = (SetValue)CollectionExcludingOperation.INSTANCE.evaluate(BOXED_children_0, (Object)null);
-				/*@Thrown*/ BagValue.@NonNull Accumulator accumulator = ValueUtil.createBagAccumulatorValue(BAG_CLSSid_TallNode);
-				@NonNull Iterator<Object> ITERATOR__1 = safe_collect_sources.iterator();
-				/*@Thrown*/ @NonNull BagValue collect;
-				while (true) {
-					if (!ITERATOR__1.hasNext()) {
-						collect = accumulator;
-						break;
-					}
-					@SuppressWarnings("null")
-					/*@NonInvalid*/ @NonNull Node2TallNode _1 = (Node2TallNode)ITERATOR__1.next();
-					/**
-					 * tallNode
-					 */
-					objectManager.getting(_1, Tree2talltreePackage.Literals.NODE2_TALL_NODE__TALL_NODE, false);
-					@SuppressWarnings("null")
-					final /*@Thrown*/ @NonNull TallNode tallNode_0 = _1.getTallNode();
-					objectManager.got(this, _1, Tree2talltreePackage.Literals.NODE2_TALL_NODE__TALL_NODE, tallNode_0);
-					//
-					accumulator.add(tallNode_0);
-				}
-				final /*@Thrown*/ @NonNull SetValue asSet = CollectionAsSetOperation.INSTANCE.evaluate(collect);
-				final /*@Thrown*/ boolean notEmpty = CollectionNotEmptyOperation.INSTANCE.evaluate(BOXED_children_0).booleanValue();
-				/*@Thrown*/ @NonNull IntegerValue symbol_0;
-				if (notEmpty) {
-					/*@Thrown*/ BagValue.@NonNull Accumulator accumulator_0 = ValueUtil.createBagAccumulatorValue(BAG_CLSSid_TallNode);
-					@NonNull Iterator<Object> ITERATOR__1_0 = BOXED_children_0.iterator();
-					/*@Thrown*/ @NonNull BagValue collect_1;
-					while (true) {
-						if (!ITERATOR__1_0.hasNext()) {
-							collect_1 = accumulator_0;
-							break;
-						}
-						@SuppressWarnings("null")
-						/*@NonInvalid*/ @NonNull Node2TallNode _1_0 = (Node2TallNode)ITERATOR__1_0.next();
-						/**
-						 * tallNode
-						 */
-						objectManager.getting(_1_0, Tree2talltreePackage.Literals.NODE2_TALL_NODE__TALL_NODE, false);
-						@SuppressWarnings("null")
-						final /*@Thrown*/ @NonNull TallNode tallNode_1 = _1_0.getTallNode();
-						objectManager.got(this, _1_0, Tree2talltreePackage.Literals.NODE2_TALL_NODE__TALL_NODE, tallNode_1);
-						//
-						accumulator_0.add(tallNode_1);
-					}
-					/*@Thrown*/ BagValue.@NonNull Accumulator accumulator_1 = ValueUtil.createBagAccumulatorValue(BAG_DATAid_EInt);
-					@NonNull Iterator<Object> ITERATOR__1_1 = collect_1.iterator();
-					/*@Thrown*/ @NonNull BagValue collect_0;
-					while (true) {
-						if (!ITERATOR__1_1.hasNext()) {
-							collect_0 = accumulator_1;
-							break;
-						}
-						@SuppressWarnings("null")
-						/*@NonInvalid*/ @NonNull TallNode _1_1 = (TallNode)ITERATOR__1_1.next();
-						/**
-						 * height
-						 */
-						objectManager.getting(_1_1, TalltreePackage.Literals.TALL_NODE__HEIGHT, false);
-						final /*@Thrown*/ int height = _1_1.getHeight();
-						objectManager.got(this, _1_1, TalltreePackage.Literals.TALL_NODE__HEIGHT, height);
-						final /*@Thrown*/ @NonNull IntegerValue BOXED_height = ValueUtil.integerValueOf(height);
-						//
-						accumulator_1.add(BOXED_height);
-					}
-					final /*@Thrown*/ @NonNull IntegerValue max = (IntegerValue)CollectionMaxOperation.INSTANCE.evaluate(collect_0);
-					final /*@Thrown*/ @NonNull IntegerValue sum = (IntegerValue)NumericPlusOperation.INSTANCE.evaluate(max, INT_1);
-					symbol_0 = sum;
-				}
-				else {
-					symbol_0 = INT_0;
-				}
-				// creations
-				final /*@Thrown*/ @Nullable TallNode tallNode = TalltreeFactory.eINSTANCE.createTallNode();
-				assert tallNode != null;
-				models[1/*talltree*/].add(tallNode);
-				objectManager.created(this, tallNode);
-				// mapping statements
-				node2tallNode.setTallNode(tallNode);
-				objectManager.assigned(this, node2tallNode, Tree2talltreePackage.Literals.NODE2_TALL_NODE__TALL_NODE, tallNode, null);
-				tallNode.setName(name);
-				objectManager.assigned(this, tallNode, TalltreePackage.Literals.TALL_NODE__NAME, name, null);
-				final /*@Thrown*/ @NonNull List<TallNode> ECORE_asSet = ((IdResolver.IdResolverExtension)idResolver).ecoreValueOfAll(TallNode.class, asSet);
-				tallNode.getChildren().addAll(ECORE_asSet);
-				objectManager.assigned(this, tallNode, TalltreePackage.Literals.TALL_NODE__CHILDREN, ECORE_asSet, null);
-				final int ECORE_symbol_0 = ValueUtil.intValueOf(symbol_0);
-				tallNode.setHeight(ECORE_symbol_0);
-				objectManager.assigned(this, tallNode, TalltreePackage.Literals.TALL_NODE__HEIGHT, ECORE_symbol_0, null);
-				final /*@Thrown*/ @Nullable Boolean MiddleNode2TallNode = ValueUtil.TRUE_VALUE;
-				return MiddleNode2TallNode;
-			} catch (Throwable e) {
-				return handleExecutionFailure("MAP_MiddleNode2TallNode", e);
-			}
-		}
-
-		@Override
-		public boolean isEqual(@NonNull IdResolver idResolver, @NonNull Object @NonNull [] thoseValues) {
-			return idResolver.oclEquals(node2tallNode, thoseValues[0]);
-		}
-	}
-}