[482528] Refactor EEPageImpl

Refactor EEPageImpl using utilities extracted from EEFViewImpl into the
new Util class.

Bug: 482528
Change-Id: I351e7b55b6a566749b69f4dc4350971451dd02bb
Signed-off-by: Pierre-Charles David <pierre-charles.david@obeo.fr>

3 files changed, 95 insertions, 59 deletions

diff --git a/plugins/org.eclipse.eef.core/src/org/eclipse/eef/core/internal/EEFPageImpl.java b/plugins/org.eclipse.eef.core/src/org/eclipse/eef/core/internal/EEFPageImpl.java
index 70fe6f9d6..fdeb12430 100644
--- a/plugins/org.eclipse.eef.core/src/org/eclipse/eef/core/internal/EEFPageImpl.java
+++ b/plugins/org.eclipse.eef.core/src/org/eclipse/eef/core/internal/EEFPageImpl.java
@@ -19,6 +19,7 @@ import org.eclipse.eef.core.api.EEFExpressionUtils;
 import org.eclipse.eef.core.api.EEFGroup;
 import org.eclipse.eef.core.api.EEFPage;
 import org.eclipse.eef.core.api.EEFView;
+import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.transaction.TransactionalEditingDomain;
 import org.eclipse.sirius.common.interpreter.api.IEvaluationResult;
 import org.eclipse.sirius.common.interpreter.api.IInterpreter;
@@ -87,34 +88,16 @@ public class EEFPageImpl implements EEFPage {
 	 * Initialize the variables of the EEFPage.
 	 */
 	public void initialize() {
-		List<EEFGroupDescription> eefGroupDescriptions = this.eefPageDescription.getGroups();
-		for (EEFGroupDescription eefGroupDescription : eefGroupDescriptions) {
-			String semanticCandidatesExpression = eefGroupDescription.getSemanticCandidateExpression();
-			if (semanticCandidatesExpression != null && semanticCandidatesExpression.trim().length() > 0) {
-				IEvaluationResult evaluationResult = this.interpreter.evaluateExpression(this.getVariableManager().getVariables(),
-						semanticCandidatesExpression);
-				if (evaluationResult.getValue() instanceof Iterable<?>) {
-					@SuppressWarnings("unchecked")
-					Iterable<Object> groupSemanticCandidates = (Iterable<Object>) evaluationResult.getValue();
-					for (Object groupSemanticCandidate : groupSemanticCandidates) {
-						IVariableManager childVariableManager = this.getVariableManager().createChild();
-						childVariableManager.put(EEFExpressionUtils.SELF, groupSemanticCandidate);
-						EEFGroupImpl eefGroupImpl = new EEFGroupImpl(this, eefGroupDescription, childVariableManager, this.interpreter,
-								this.editingDomain);
-						eefGroups.add(eefGroupImpl);
-					}
-				} else {
-					Object groupSemanticCandidate = evaluationResult.getValue();
+		for (EEFGroupDescription eefGroupDescription : eefPageDescription.getGroups()) {
+			String semanticCandidatesExpression = Util.firstNonBlank(eefGroupDescription.getSemanticCandidateExpression(), "var:self"); //$NON-NLS-1$
+			IEvaluationResult result = interpreter.evaluateExpression(this.getVariableManager().getVariables(), semanticCandidatesExpression);
+			if (result.success()) {
+				for (EObject groupSemanticCandidate : result.asEObjects()) {
 					IVariableManager childVariableManager = this.getVariableManager().createChild();
 					childVariableManager.put(EEFExpressionUtils.SELF, groupSemanticCandidate);
-					EEFGroupImpl eefGroupImpl = new EEFGroupImpl(this, eefGroupDescription, childVariableManager, this.interpreter,
-							this.editingDomain);
+					EEFGroupImpl eefGroupImpl = new EEFGroupImpl(this, eefGroupDescription, childVariableManager, interpreter, editingDomain);
 					eefGroups.add(eefGroupImpl);
 				}
-			} else {
-				IVariableManager childVariableManager = this.getVariableManager().createChild();
-				EEFGroupImpl eefGroupImpl = new EEFGroupImpl(this, eefGroupDescription, childVariableManager, this.interpreter, this.editingDomain);
-				eefGroups.add(eefGroupImpl);
 			}
 		}
 	}
@@ -129,8 +112,8 @@ public class EEFPageImpl implements EEFPage {
 		String labelExpression = this.eefPageDescription.getLabelExpression();
 		if (labelExpression != null) {
 			IEvaluationResult evaluationResult = this.interpreter.evaluateExpression(this.getVariableManager().getVariables(), labelExpression);
-			if (evaluationResult.getValue() != null) {
-				return evaluationResult.getValue().toString();
+			if (evaluationResult.success()) {
+				return evaluationResult.asString();
 			}
 		}
 		return labelExpression;
@@ -156,6 +139,11 @@ public class EEFPageImpl implements EEFPage {
 		return this.eefPageDescription;
 	}
 
+	/**
+	 * {@inheritDoc}
+	 *
+	 * @see org.eclipse.eef.core.api.EEFPage#getView()
+	 */
 	@Override
 	public EEFView getView() {
 		return this.eefView;
diff --git a/plugins/org.eclipse.eef.core/src/org/eclipse/eef/core/internal/EEFViewImpl.java b/plugins/org.eclipse.eef.core/src/org/eclipse/eef/core/internal/EEFViewImpl.java
index 109e453fc..01dc7cd50 100644
--- a/plugins/org.eclipse.eef.core/src/org/eclipse/eef/core/internal/EEFViewImpl.java
+++ b/plugins/org.eclipse.eef.core/src/org/eclipse/eef/core/internal/EEFViewImpl.java
@@ -118,7 +118,7 @@ public class EEFViewImpl implements EEFView {
 	 * @return an actual {@link EEFPage} setup according to the description.
 	 */
 	private EEFPageImpl createPage(EEFPageDescription description) {
-		Object candidate = computeCandidate(this.variableManager, description.getSemanticCandidateExpression());
+		Object candidate = Util.computeCandidate(this.interpreter, this.variableManager, description.getSemanticCandidateExpression());
 		IVariableManager childVariableManager = this.variableManager.createChild();
 		if (candidate != null) {
 			childVariableManager.put(EEFExpressionUtils.SELF, candidate);
@@ -141,7 +141,7 @@ public class EEFViewImpl implements EEFView {
 
 			for (EEFPage eefPage : this.eefPages) {
 				String pageSemanticCandidateExpression = eefPage.getDescription().getSemanticCandidateExpression();
-				if (!isBlank(pageSemanticCandidateExpression)) {
+				if (!Util.isBlank(pageSemanticCandidateExpression)) {
 					IEvaluationResult evaluationResult = this.interpreter.evaluateExpression(this.variableManager.getVariables(),
 							pageSemanticCandidateExpression);
 					if (evaluationResult.success()) {
@@ -154,7 +154,7 @@ public class EEFViewImpl implements EEFView {
 				List<EEFGroup> groups = eefPage.getGroups();
 				for (EEFGroup eefGroup : groups) {
 					String groupSemanticCandidateExpression = eefGroup.getDescription().getSemanticCandidateExpression();
-					if (!isBlank(groupSemanticCandidateExpression)) {
+					if (!Util.isBlank(groupSemanticCandidateExpression)) {
 						IEvaluationResult evaluationResult = this.interpreter.evaluateExpression(eefPage.getVariableManager().getVariables(),
 								groupSemanticCandidateExpression);
 						if (evaluationResult.success()) {
@@ -188,34 +188,4 @@ public class EEFViewImpl implements EEFView {
 		return this.eefViewDescription;
 	}
 
-	/**
-	 * Helper to evaluate a SemanticCandidateExpression.
-	 *
-	 * @param context
-	 *            the evaluation context (variables).
-	 * @param expression
-	 *            the expression to evaluate.
-	 * @return the result, or <code>null</code> if the evaluation failed.
-	 */
-	private Object computeCandidate(IVariableManager context, String expression) {
-		if (!isBlank(expression)) {
-			IEvaluationResult evaluationResult = interpreter.evaluateExpression(context.getVariables(), expression);
-			if (evaluationResult.success()) {
-				return evaluationResult.getValue();
-			}
-		}
-		return null;
-	}
-
-	/**
-	 * Tests if a string is blank (i.e. null, empty, or containing only whitespace).
-	 *
-	 * @param s
-	 *            the string to test.
-	 * @return <code>true</code> if and only if the string is blank.
-	 */
-	private boolean isBlank(String s) {
-		return s == null || s.trim().length() == 0;
-	}
-
 }
diff --git a/plugins/org.eclipse.eef.core/src/org/eclipse/eef/core/internal/Util.java b/plugins/org.eclipse.eef.core/src/org/eclipse/eef/core/internal/Util.java
new file mode 100644
index 000000000..b7a8198db
--- /dev/null
+++ b/plugins/org.eclipse.eef.core/src/org/eclipse/eef/core/internal/Util.java
@@ -0,0 +1,78 @@
+/*******************************************************************************
+ * Copyright (c) 2016 Obeo.
+ * 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:
+ *    Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.eef.core.internal;
+
+import org.eclipse.sirius.common.interpreter.api.IEvaluationResult;
+import org.eclipse.sirius.common.interpreter.api.IInterpreter;
+import org.eclipse.sirius.common.interpreter.api.IVariableManager;
+
+/**
+ * Shared utility methods.
+ *
+ * @author Pierre-Charles David <pierre-charles.david@obeo.fr>
+ */
+public final class Util {
+	/**
+	 * Prevent instantiation.
+	 */
+	private Util() {
+		// Prevent instantiation.
+	}
+
+	/**
+	 * Helper to evaluate a SemanticCandidateExpression.
+	 *
+	 * @param itp
+	 *            the interpreter to use.
+	 * @param context
+	 *            the evaluation context (variables).
+	 * @param expression
+	 *            the expression to evaluate.
+	 * @return the result, or <code>null</code> if the evaluation failed.
+	 */
+	public static Object computeCandidate(IInterpreter itp, IVariableManager context, String expression) {
+		if (!isBlank(expression)) {
+			IEvaluationResult evaluationResult = itp.evaluateExpression(context.getVariables(), expression);
+			if (evaluationResult.success()) {
+				return evaluationResult.getValue();
+			}
+		}
+		return null;
+	}
+
+	/**
+	 * Returns the first of a series of alternative string values which is not {@link Util#blank blank}.
+	 *
+	 * @param alternatives
+	 *            the alernative strings, in order of preference.
+	 * @return the first non-blank alternative, or <code>null</code> if they are all blank.
+	 */
+	public static String firstNonBlank(String... alternatives) {
+		for (String s : alternatives) {
+			if (!isBlank(s)) {
+				return s;
+			}
+		}
+		return null;
+	}
+
+	/**
+	 * Tests if a string is blank (i.e. null, empty, or containing only whitespace).
+	 *
+	 * @param s
+	 *            the string to test.
+	 * @return <code>true</code> if and only if the string is blank.
+	 */
+	public static boolean isBlank(String s) {
+		return s == null || s.trim().length() == 0;
+	}
+
+}