add: 'right-to-left' (backtrack?) capability and differentiate CA for crossref depending on if its linked or not linked

7 files changed, 532 insertions, 316 deletions

diff --git a/devtools/org.eclipse.xtext.reference.ui/src-gen/org/eclipse/xtext/reference/ReferenceGrammarGenProposalProvider.java b/devtools/org.eclipse.xtext.reference.ui/src-gen/org/eclipse/xtext/reference/ReferenceGrammarGenProposalProvider.java
index 571d996..bc840df 100644
--- a/devtools/org.eclipse.xtext.reference.ui/src-gen/org/eclipse/xtext/reference/ReferenceGrammarGenProposalProvider.java
+++ b/devtools/org.eclipse.xtext.reference.ui/src-gen/org/eclipse/xtext/reference/ReferenceGrammarGenProposalProvider.java
@@ -52,7 +52,7 @@ public class ReferenceGrammarGenProposalProvider  extends AbstractProposalProvid
 					+ assignment.getTerminal() + "' cardinality '" + assignment.getCardinality() + "' and prefix '"
 					+ prefix.trim() + "'");
 		}
-		return Collections.singletonList(createCompletionProposal("1", offset));		
+		return Collections.singletonList(createCompletionProposal(assignment,model,"1", offset));		
 	}
 	
 	public List<? extends ICompletionProposal> completeSpielplatzBeschreibung(Assignment assignment, EObject model, String prefix, IDocument doc,int offset) {
@@ -61,7 +61,7 @@ public class ReferenceGrammarGenProposalProvider  extends AbstractProposalProvid
 					+ assignment.getTerminal() + "' cardinality '" + assignment.getCardinality() + "' and prefix '"
 					+ prefix.trim() + "'");
 		}
-		return Collections.singletonList(createCompletionProposal("\"SpielplatzBeschreibung\"", offset));		
+		return Collections.singletonList(createCompletionProposal(assignment,model,"\"SpielplatzBeschreibung\"", offset));		
 	}
 	
 	public List<? extends ICompletionProposal> completeSpielplatzKinder(Assignment assignment, EObject model, String prefix, IDocument doc,int offset) {
@@ -115,7 +115,7 @@ public class ReferenceGrammarGenProposalProvider  extends AbstractProposalProvid
 					+ assignment.getTerminal() + "' cardinality '" + assignment.getCardinality() + "' and prefix '"
 					+ prefix.trim() + "'");
 		}
-		return Collections.singletonList(createCompletionProposal("KindName", offset));
+		return Collections.singletonList(createCompletionProposal(assignment,model,"KindName", offset));
 	}
 	
 	public List<? extends ICompletionProposal> completeKindAge(Assignment assignment, EObject model, String prefix, IDocument doc,int offset) {
@@ -124,7 +124,7 @@ public class ReferenceGrammarGenProposalProvider  extends AbstractProposalProvid
 					+ assignment.getTerminal() + "' cardinality '" + assignment.getCardinality() + "' and prefix '"
 					+ prefix.trim() + "'");
 		}
-		return Collections.singletonList(createCompletionProposal("1", offset));		
+		return Collections.singletonList(createCompletionProposal(assignment,model,"1", offset));		
 	}
 	
 	public List<? extends ICompletionProposal> completeErwachsenerName(Assignment assignment, EObject model, String prefix, IDocument doc,int offset) {
@@ -133,7 +133,7 @@ public class ReferenceGrammarGenProposalProvider  extends AbstractProposalProvid
 					+ assignment.getTerminal() + "' cardinality '" + assignment.getCardinality() + "' and prefix '"
 					+ prefix.trim() + "'");
 		}
-		return Collections.singletonList(createCompletionProposal("ErwachsenerName", offset));
+		return Collections.singletonList(createCompletionProposal(assignment,model,"ErwachsenerName", offset));
 	}
 	
 	public List<? extends ICompletionProposal> completeErwachsenerAge(Assignment assignment, EObject model, String prefix, IDocument doc,int offset) {
@@ -142,7 +142,7 @@ public class ReferenceGrammarGenProposalProvider  extends AbstractProposalProvid
 					+ assignment.getTerminal() + "' cardinality '" + assignment.getCardinality() + "' and prefix '"
 					+ prefix.trim() + "'");
 		}
-		return Collections.singletonList(createCompletionProposal("1", offset));		
+		return Collections.singletonList(createCompletionProposal(assignment,model,"1", offset));		
 	}
 	
 	public List<? extends ICompletionProposal> completeSpielzeugName(Assignment assignment, EObject model, String prefix, IDocument doc,int offset) {
@@ -151,7 +151,7 @@ public class ReferenceGrammarGenProposalProvider  extends AbstractProposalProvid
 					+ assignment.getTerminal() + "' cardinality '" + assignment.getCardinality() + "' and prefix '"
 					+ prefix.trim() + "'");
 		}
-		return Collections.singletonList(createCompletionProposal("SpielzeugName", offset));
+		return Collections.singletonList(createCompletionProposal(assignment,model,"SpielzeugName", offset));
 	}
 	
 	public List<? extends ICompletionProposal> completeSpielzeugFarbe(Assignment assignment, EObject model, String prefix, IDocument doc,int offset) {
@@ -215,7 +215,7 @@ public class ReferenceGrammarGenProposalProvider  extends AbstractProposalProvid
 					+ assignment.getTerminal() + "' cardinality '" + assignment.getCardinality() + "' and prefix '"
 					+ prefix.trim() + "'");
 		}
-		return Collections.singletonList(createCompletionProposal("CustomTypeParserRuleName", offset));
+		return Collections.singletonList(createCompletionProposal(assignment,model,"CustomTypeParserRuleName", offset));
 	}
     
     
diff --git a/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/AbstractProposalProvider.java b/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/AbstractProposalProvider.java
index 0eda0d4..ec42692 100644
--- a/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/AbstractProposalProvider.java
+++ b/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/AbstractProposalProvider.java
@@ -13,6 +13,7 @@ import org.eclipse.emf.ecore.EObject;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.text.contentassist.ICompletionProposal;
 import org.eclipse.jface.viewers.StyledString;
+import org.eclipse.xtext.AbstractElement;
 import org.eclipse.xtext.AbstractRule;
 import org.eclipse.xtext.Assignment;
 import org.eclipse.xtext.CrossReference;
@@ -58,9 +59,9 @@ public abstract class AbstractProposalProvider implements IProposalProvider {
 					+ prefix.trim() + "'");
 		}
 		String text = keyword.getValue().length() == 1 ? keyword.getValue() : keyword.getValue() + " ";
-		return Collections.singletonList(createCompletionProposal(text, offset));
+		return Collections.singletonList(createCompletionProposal(keyword, model, text, offset));
 	}
-	
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.eclipse.xtext.ui.common.editor.codecompletion.IProposalProvider#completeRuleCall(org.eclipse.xtext.RuleCall, org.eclipse.emf.ecore.EObject, java.lang.String, org.eclipse.jface.text.IDocument, int)
@@ -71,119 +72,78 @@ public abstract class AbstractProposalProvider implements IProposalProvider {
 			logger.debug("completeRuleCall '" + ruleCall.getName() + "' cardinality '" + ruleCall.getCardinality()
 					+ "' for model '" + model + "' and prefix '" + prefix.trim() + "'");
 		}
-		
+
 		AbstractRule calledRule = GrammarUtil.calledRule(ruleCall);
-		
+
 		if (calledRule instanceof LexerRule) {
-			return doCompleteLexerRuleRuleCall((LexerRule) calledRule, ruleCall, offset);
-		} 
-		
+			return doCompleteLexerRuleRuleCall((LexerRule) calledRule, ruleCall, model, offset);
+		}
+
 		return Collections.emptyList();
 	}
-	
+
 	/*
 	 * (non-Javadoc)
-	 * @see org.eclipse.xtext.ui.common.editor.codecompletion.IProposalProvider#sortAndFilter(java.util.List, org.eclipse.emf.ecore.EObject, java.lang.String)
+	 * @see org.eclipse.xtext.ui.common.editor.codecompletion.IProposalProvider#sortAndFilter(java.util.List, org.eclipse.emf.ecore.EObject, java.lang.String, org.eclipse.jface.text.IDocument, int)
 	 */
 	public List<? extends ICompletionProposal> sortAndFilter(
-			List<? extends ICompletionProposal> completionProposalList, EObject model, String prefix) {
-		return doSortAndFilter(completionProposalList,model,prefix);
+			List<? extends ICompletionProposal> completionProposalList, EObject model, String prefix,
+			IDocument document, int offset) {
+		return doSortAndFilter(completionProposalList, model, prefix, document, offset);
 	}
-	
-	/**
-	 * Concrete subclasses can override this for custom sort and filter
-	 * behavior. Gets called after all completion proposals have been collected.
-	 * 
-	 * The default behavior of this implementation is to sort duplicates and to trim 
-	 * matching <code>ICompletionProposal#displayString</code> with matching prefix values.
-	 * 
-	 * @param completionProposalList matching {@link ICompletionProposal} to sort and filter
-	 * @param model - the most specific model element under the cursor. 
-	 * @param prefix - the prefix under the cursor or null if there is no prefix
-	 * @return the sorted and filtered <code>ICompletionProposal</code> list.
-	 * 
-	 */
-	protected List<? extends ICompletionProposal> doSortAndFilter(
-			List<? extends ICompletionProposal> completionProposalList,EObject model,String prefix) {
-		
-		if (model instanceof LeafNode) {
-			
-			LeafNode leafNode = (LeafNode) model;
-			
-			Map<String,ICompletionProposal> displayString2ICompletionProposalMap = new HashMap<String,ICompletionProposal>();
-			
-			for (Iterator<? extends ICompletionProposal> iterator = completionProposalList.iterator(); iterator.hasNext();) {
 
-				ICompletionProposal completionProposal = iterator.next();
-				
-				// filter duplicate displayString
-				if (!displayString2ICompletionProposalMap.containsKey(completionProposal.getDisplayString())) {
-				
-					displayString2ICompletionProposalMap.put(completionProposal.getDisplayString(), completionProposal);
-					
-					// trim displayString
-					if (leafNode.isHidden() && !"".equals(leafNode.getText().trim()) ) {
-						
-						if (completionProposal.getDisplayString().startsWith(leafNode.getText()) && 
-								completionProposal instanceof XtextCompletionProposal) {
-							
-							XtextCompletionProposal xtextCompletionProposal = (XtextCompletionProposal) completionProposal;
-							
-							xtextCompletionProposal.setText(xtextCompletionProposal.getText().replaceFirst(leafNode.getText(), ""));
-						}  else {
-							iterator.remove();
-						}
-					}
-				} else {
-					iterator.remove();
-				}
-			}
-		} 
-		
-		return completionProposalList;
-	}
-	
 	/**
-	 * Concrete subclasses can override this to provide a more meaningful and sophisticated behaviour
-	 * whenever a list of ICompletionProposal's should be computed for simple <code>LexerRule</code> call's.
+	 * Concrete subclasses can override this to provide a more meaningful and
+	 * sophisticated behaviour whenever a list of ICompletionProposal's should
+	 * be computed for simple <code>LexerRule</code> call's.
 	 * 
-	 * This implementation returns one <code>ICompletionProposal</code> with a displayString composed
-	 * of the name of the containing rule plus the featurename of an optional assignment and at the end the name 
-	 * of the given LexerRule (e.i. ParserRuleName+AssignmentFeatureName+LexerRuleName) or {@link #getDefaultIntegerValue()} 
-	 * if its <i>INT</i> based LexerRule.
+	 * This implementation returns one <code>ICompletionProposal</code> with a
+	 * displayString composed of the name of the containing rule plus the
+	 * featurename of an optional assignment and at the end the name of the
+	 * given LexerRule (e.i. ParserRuleName+AssignmentFeatureName+LexerRuleName)
+	 * or {@link #getDefaultIntegerValue()} if its <i>INT</i> based LexerRule.
 	 * 
-	 * @param lexerRule the 'called' LexerRule instance
-	 * @param ruleCall the ruleCall for the provided lexerRule
-	 * @param offset an offset within the document for which completions should be computed
-	 * @return a computed list of <code>ICompletionProposal</code> for the given <code>LexerRule</code>
+	 * @param lexerRule
+	 *            the 'called' LexerRule instance
+	 * @param ruleCall
+	 *            the ruleCall for the provided lexerRule
+	 * @param offset
+	 *            an offset within the document for which completions should be
+	 *            computed
+	 * @return a computed list of <code>ICompletionProposal</code> for the given
+	 *         <code>LexerRule</code>
 	 */
-	protected List<? extends ICompletionProposal> doCompleteLexerRuleRuleCall(LexerRule lexerRule,RuleCall ruleCall, int offset) {
+	protected List<? extends ICompletionProposal> doCompleteLexerRuleRuleCall(LexerRule lexerRule, RuleCall ruleCall,
+			EObject model, int offset) {
 		ParserRule containingParserRule = GrammarUtil.containingParserRule(ruleCall);
 		Assignment containingAssignment = GrammarUtil.containingAssignment(ruleCall);
-		
-		String defaultDisplayString = containingParserRule.getName() + 
-			(null != containingAssignment ? firstLetterCapitalized(containingAssignment.getFeature()) : "") + lexerRule.getName();
-		
+
+		String defaultDisplayString = containingParserRule.getName()
+				+ (null != containingAssignment ? firstLetterCapitalized(containingAssignment.getFeature()) : "")
+				+ lexerRule.getName();
+
 		if (LEXER_RULE_INT.equalsIgnoreCase(lexerRule.getName())) {
-			defaultDisplayString=String.valueOf(getDefaultIntegerValue());
-		} else if (LEXER_RULE_STRING.equalsIgnoreCase(lexerRule.getName())) {
-			defaultDisplayString="\""+defaultDisplayString+"\"";
-		} 
-		
-		return Collections.singletonList(createCompletionProposal(defaultDisplayString, offset));
+			defaultDisplayString = String.valueOf(getDefaultIntegerValue());
+		}
+		else if (LEXER_RULE_STRING.equalsIgnoreCase(lexerRule.getName())) {
+			defaultDisplayString = "\"" + defaultDisplayString + "\"";
+		}
+
+		return Collections.singletonList(createCompletionProposal(containingAssignment, model, defaultDisplayString,
+				offset));
 	}
-	
+
 	/**
 	 * @return the default integer value for ecore::EInt <code>RuleCall<>
 	 */
 	protected int getDefaultIntegerValue() {
 		return 0;
 	}
-	
+
 	/**
 	 * 
-	 * @return the id of the plug-in containing the image files;
-	 *         <code>null</code> is returned if the plug-in does not exist
+	 * @return the id of the plug-in containing the image files; <code>null
+	 *         </code> is returned if the plug-in does not exist
 	 */
 	protected abstract String getPluginId();
 
@@ -209,14 +169,17 @@ public abstract class AbstractProposalProvider implements IProposalProvider {
 	 */
 	protected List<? extends ICompletionProposal> lookupCrossReference(CrossReference crossReference, EObject model,
 			String prefix, int offset) {
-		
+
 		List<ICompletionProposal> completionProposalList = new ArrayList<ICompletionProposal>();
 
 		if (linkingService != null) {
-			EObject semanticModel = model instanceof AbstractNode?NodeUtil.getNearestSemanticObject((AbstractNode) model):model;
-			List<Pair<String, URI>> candidates = linkingService.getLinkCandidates(semanticModel, crossReference, prefix);
+			EObject semanticModel = model instanceof AbstractNode ? NodeUtil
+					.getNearestSemanticObject((AbstractNode) model) : model;
+			List<Pair<String, URI>> candidates = linkingService
+					.getLinkCandidates(semanticModel, crossReference, prefix);
 			for (Pair<String, URI> candidate : candidates) {
-				completionProposalList.add(createCompletionProposal(candidate.getFirstElement(), offset));
+				completionProposalList.add(createCompletionProposal(crossReference, model, candidate.getFirstElement(),
+						offset));
 			}
 		}
 
@@ -227,13 +190,103 @@ public abstract class AbstractProposalProvider implements IProposalProvider {
 	 * @return a new <code>XtextCompletionProposal</code> for the given text and
 	 *         offset.
 	 */
-	protected final XtextCompletionProposal createCompletionProposal(String text, int offset) {
-		return new XtextCompletionProposal(text, new StyledString(text), text, getDefaultImageFilePath(),
-				getPluginId(), offset);
+	protected final XtextCompletionProposal createCompletionProposal(AbstractElement abstractElement, EObject model,
+			String text, int offset) {
+		return new XtextCompletionProposal(abstractElement, model, text, new StyledString(text), text,
+				getDefaultImageFilePath(), getPluginId(), offset);
+	}
+	
+	/**
+	 * Concrete subclasses can override this for custom sort and filter
+	 * behavior. Gets called after all completion proposals have been collected.
+	 * 
+	 * The default behavior of this implementation is to sort duplicates and to
+	 * trim matching <code>ICompletionProposal#displayString</code> with
+	 * matching prefix values.
+	 * 
+	 * @param completionProposalList
+	 *            matching {@link ICompletionProposal} to sort and filter
+	 * @param model
+	 *            - the most specific model element under the cursor.
+	 * @param prefix
+	 *            - the prefix under the cursor or null if there is no prefix
+	 * @param offset
+	 * @param document
+	 * @return the sorted and filtered <code>ICompletionProposal</code> list.
+	 * 
+	 */
+	protected List<? extends ICompletionProposal> doSortAndFilter(
+			List<? extends ICompletionProposal> completionProposalList, EObject model, String prefix,
+			IDocument document, int offset) {
+
+		if (model instanceof LeafNode) {
+
+			LeafNode leafNode = (LeafNode) model;
+
+			Map<String, ICompletionProposal> displayString2ICompletionProposalMap = new HashMap<String, ICompletionProposal>();
+
+			for (Iterator<? extends ICompletionProposal> iterator = completionProposalList.iterator(); iterator
+					.hasNext();) {
+
+				ICompletionProposal completionProposal = iterator.next();
+
+				// filter duplicate displayString
+				if (!displayString2ICompletionProposalMap.containsKey(completionProposal.getDisplayString())) {
+
+					displayString2ICompletionProposalMap.put(completionProposal.getDisplayString(), completionProposal);
+
+					boolean cursorIsAtTheEndOfTheLastElement = offset == (leafNode.getOffset() + leafNode.getLength());
+					/**
+					 * 1. filter and trim proposal's matching the prefix of the
+					 * current leafNode (e.g. leafNode 'kin' for keyword 'kind'
+					 * will be trimmed to 'd' , displayString stays the same)
+					 * <p/>
+					 * 2. special case for crossref: if the cursor is at the end
+					 * of the previous element kind>|< we want to apply the
+					 * filter only to instances of the previous grammarElement
+					 * in order to always show all matches for 'right-to-left'
+					 * backtracking use-cases
+					 */
+					if ((leafNode.isHidden() || cursorIsAtTheEndOfTheLastElement)
+							&& !"".equals(leafNode.getText().trim())
+							&& completionProposal instanceof XtextCompletionProposal) {
+
+						XtextCompletionProposal xtextCompletionProposal = (XtextCompletionProposal) completionProposal;
+
+						AbstractElement abstractElement = xtextCompletionProposal.getAbstractElement();
+
+						EObject grammarElement = leafNode.getGrammarElement();
+						// at the end of the last element we want to filter only
+						// the CompletionProposal for the same grammar element
+						if (completionProposal.getDisplayString().startsWith(leafNode.getText())) {
+							xtextCompletionProposal.setText(xtextCompletionProposal.getText().substring(
+									leafNode.getText().length()));
+						}
+						else if ((cursorIsAtTheEndOfTheLastElement && abstractElement.equals(grammarElement))
+								|| !cursorIsAtTheEndOfTheLastElement) {
+							if (logger.isDebugEnabled()) {
+								logger.debug("filter completionProposal '" + completionProposal + "'");
+							}
+							iterator.remove();
+						}
+					}
+				}
+				else {
+					if (logger.isDebugEnabled()) {
+						logger.debug("filter duplicate completionProposal '" + completionProposal + "'");
+					}
+
+					iterator.remove();
+				}
+			}
+		}
+
+		return completionProposalList;
 	}
 
 	/**
-	 * @param text to apply
+	 * @param text
+	 *            to apply
 	 * @return the provided string with the first letter capitalized
 	 */
 	protected final String firstLetterCapitalized(String text) {
diff --git a/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/DefaultContentAssistProcessor.java b/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/DefaultContentAssistProcessor.java
index 7b3c99e..3a31dc3 100644
--- a/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/DefaultContentAssistProcessor.java
+++ b/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/DefaultContentAssistProcessor.java
@@ -1,13 +1,8 @@
 package org.eclipse.xtext.ui.common.editor.codecompletion;
 
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
 import java.util.ArrayList;
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.Iterator;
+import java.util.LinkedHashSet;
 import java.util.List;
-import java.util.Map;
 import java.util.Set;
 
 import org.apache.log4j.Logger;
@@ -25,15 +20,9 @@ import org.eclipse.jface.text.contentassist.IContentAssistProcessor;
 import org.eclipse.jface.text.contentassist.IContextInformation;
 import org.eclipse.jface.text.contentassist.IContextInformationValidator;
 import org.eclipse.xtext.AbstractElement;
-import org.eclipse.xtext.AbstractRule;
-import org.eclipse.xtext.Assignment;
 import org.eclipse.xtext.CrossReference;
 import org.eclipse.xtext.EcoreUtil2;
 import org.eclipse.xtext.GrammarUtil;
-import org.eclipse.xtext.Keyword;
-import org.eclipse.xtext.ParserRule;
-import org.eclipse.xtext.RuleCall;
-import org.eclipse.xtext.TypeRef;
 import org.eclipse.xtext.parser.IParseResult;
 import org.eclipse.xtext.parsetree.AbstractNode;
 import org.eclipse.xtext.parsetree.CompositeNode;
@@ -58,7 +47,6 @@ public class DefaultContentAssistProcessor implements IContentAssistProcessor {
 	@Inject
 	private IProposalProvider proposalProvider;
 
-	private final Map<String, Method> methodLookupMap = new HashMap<String, Method>();
 
 	/**
 	 * computes the possible grammar elements following the one at the given
@@ -93,25 +81,37 @@ public class DefaultContentAssistProcessor implements IContentAssistProcessor {
 				LeafNode currentLeafNode = ParseTreeUtil.getCurrentNodeByOffset(rootNode, offset);
 
 				String prefix = null==currentLeafNode ? "" : currentLeafNode.getText();
-
-				Set<AbstractElement> nextValidElementSet = ParseTreeUtil.getElementSetValidFromOffset(rootNode,lastCompleteNode, offset);
+				
+				Set<AbstractElement> nextValidElementSet = new LinkedHashSet<AbstractElement>();
+				/**
+				 * in the case of a non linked crossreference we delegate to proposalProvider (again) 
+				 */
+				if (lastCompleteNode.getGrammarElement() instanceof CrossReference && !isLinked(lastCompleteNode)) {
+					
+					nextValidElementSet.add((AbstractElement) lastCompleteNode.getGrammarElement());
+				} 
 				/**
-				 * in the case of a non linked crossreference we delegate to proposalProvider (again)  
+				 * in the case we are at the end of the completed previous element add for 'right-to-left' backtracking cases
 				 */
-				if (lastCompleteNode.getGrammarElement() instanceof CrossReference && !isLinked(lastCompleteNode) ) {
-					nextValidElementSet.add((AbstractElement) lastCompleteNode.getGrammarElement().eContainer());
+				else if (currentLeafNode==lastCompleteNode) {
+					nextValidElementSet.add((AbstractElement) lastCompleteNode.getGrammarElement());
 				}
 				
+				nextValidElementSet.addAll(ParseTreeUtil.getElementSetValidFromOffset(rootNode,lastCompleteNode, offset));
+				
+				ProposalProviderInvokerSwitch proposalProviderInvokerSwitch = new ProposalProviderInvokerSwitch(
+						lastCompleteNode, document, offset, prefix, proposalProvider);
+				
 				for (List<EObject> resolvedElementOrRuleList : new ProposalCandidateResolverSwitch(nextValidElementSet)) {
 
-					List<ICompletionProposal> collectedCompletionProposalList = collectCompletionProposalList(resolvedElementOrRuleList,  xtextDocument,
-							lastCompleteNode, prefix, offset);
+					List<ICompletionProposal> collectedCompletionProposalList = 
+						proposalProviderInvokerSwitch.collectCompletionProposalList(resolvedElementOrRuleList);
 					
 					completionProposalList.addAll(collectedCompletionProposalList);
 				}
 
 				if (completionProposalList != null) {
-					List<? extends ICompletionProposal> sortAndFilter = proposalProvider.sortAndFilter(completionProposalList,currentLeafNode,prefix);
+					List<? extends ICompletionProposal> sortAndFilter = proposalProvider.sortAndFilter(completionProposalList,currentLeafNode,prefix,document,offset);
 					completionProposals =  sortAndFilter.toArray(new ICompletionProposal[] {});
 				}
 			}
@@ -140,210 +140,42 @@ public class DefaultContentAssistProcessor implements IContentAssistProcessor {
 		return new ContextInformationValidator(this);
 	}
 
-	private List<ICompletionProposal> collectCompletionProposalList(List<EObject> resolvedElementOrRuleList, IDocument document, AbstractNode currentLeafNode,
-			String prefix, final int offset) {
-
-		List<ICompletionProposal> completionProposalList = new ArrayList<ICompletionProposal>();
-		
-		for (Iterator<EObject> elementOrRuleIterator = resolvedElementOrRuleList.iterator(); elementOrRuleIterator
-				.hasNext();) {
-			EObject abstractElement = elementOrRuleIterator.next();
-
-			if (abstractElement instanceof Keyword) {
-				completionProposalList.addAll(proposalProvider.completeKeyword((Keyword) abstractElement,
-						currentLeafNode, prefix, document, offset));
-			}
-			else if (abstractElement instanceof Assignment) {
-
-				Assignment assignment = (Assignment) abstractElement;
-
-				ParserRule parserRule = GrammarUtil.containingParserRule(assignment);
-
-				EObject model = null == ((CompositeNode) currentLeafNode.eContainer()).getElement() ? currentLeafNode
-						.eContainer() : ((CompositeNode) currentLeafNode.eContainer()).getElement();
-
-				Method method = findMethod(proposalProvider.getClass(), "complete"
-						+ firstLetterCapitalized(parserRule.getName())
-						+ firstLetterCapitalized(assignment.getFeature()), Assignment.class, model.getClass(),
-						String.class, document.getClass(), int.class);
-
-				Collection<? extends ICompletionProposal> assignmentProposalList = null == method ? null
-						: invokeMethod(method, proposalProvider, assignment, model, prefix, document, offset);
-
-				if (null != assignmentProposalList) {
-					completionProposalList.addAll(assignmentProposalList);
-				}
-
-			}
-			else if (abstractElement instanceof RuleCall) {
-
-				EObject model = null == ((CompositeNode) currentLeafNode.eContainer()).getElement() ? currentLeafNode
-						.eContainer() : ((CompositeNode) currentLeafNode.eContainer()).getElement();
-
-				List<? extends ICompletionProposal> ruleCallProposalList = this.proposalProvider.completeRuleCall(
-						(RuleCall) abstractElement, model, prefix, document, offset);
-
-				if (null != ruleCallProposalList) {
-					completionProposalList.addAll(ruleCallProposalList);
-				}
-
-				AbstractRule calledRule = GrammarUtil.calledRule((RuleCall) abstractElement);
-
-				if (calledRule.getType() != null) {
-
-					TypeRef typeRef = calledRule.getType();
-
-					Method method = findMethod(proposalProvider.getClass(), "complete"
-							+ firstLetterCapitalized(typeRef.getAlias()) + firstLetterCapitalized(typeRef.getName()),
-							RuleCall.class, model.getClass(), String.class, document.getClass(), int.class);
-
-					Collection<? extends ICompletionProposal> proposalList = null == method ? null : invokeMethod(
-							method, proposalProvider, abstractElement, model, prefix, document, offset);
-
-					if (null != proposalList) {
-						completionProposalList.addAll(proposalList);
-					}
-
-				}
-			}
-		}
-		
-		return completionProposalList;
-	}
-
-	private final Method findMethod(Class<?> clazz, String name, Class<?>... paramTypes) {
-		Assert.isNotNull(clazz, "Class must not be null");
-		Assert.isNotNull(name, "Method name must not be null");
-		Method result = methodLookupMap.get(name);
-		Class<?> searchType = clazz;
-		while (!Object.class.equals(searchType) && searchType != null && null == result) {
-			Method[] methods = (searchType.isInterface() ? searchType.getMethods() : searchType.getDeclaredMethods());
-			for (int i = 0; i < methods.length; i++) {
-				Method method = methods[i];
-				if (name.equals(method.getName())
-						&& (paramTypes == null || equalOrAssignableTypes(method.getParameterTypes(), paramTypes))) {
-					if (result == null
-							|| equalOrAssignableTypes(result.getParameterTypes(), method.getParameterTypes())) {
-						result = method;
-						methodLookupMap.put(name, method);
-					}
-				}
-			}
-			searchType = searchType.getSuperclass();
-		}
-		return result;
-	}
 	
 	@SuppressWarnings("unchecked")
-	private final Collection<ICompletionProposal> invokeMethod(Method method, Object target, Object... args) {
-
-		try {
-			return (Collection<ICompletionProposal>) method.invoke(target, args);
-		}
-		catch (Exception ex) {
-			handleReflectionException(ex);
-		}
-		throw new IllegalStateException("huh?");
-	}
-
-	private void handleReflectionException(Exception ex) {
-		if (ex instanceof NoSuchMethodException) {
-			throw new IllegalStateException("Method not found: " + ex.getMessage());
-		}
-		if (ex instanceof IllegalAccessException) {
-			throw new IllegalStateException("Could not access method: " + ex.getMessage());
-		}
-		if (ex instanceof InvocationTargetException) {
-			rethrowRuntimeException(((InvocationTargetException) ex).getTargetException());
-		}
-		if (ex instanceof RuntimeException) {
-			throw (RuntimeException) ex;
-		}
-		handleUnexpectedException(ex);
-	}
-
-	private void handleUnexpectedException(Throwable ex) {
-		IllegalStateException isex = new IllegalStateException("Unexpected exception thrown");
-		isex.initCause(ex);
-		throw isex;
-	}
-
-	private final void rethrowRuntimeException(Throwable ex) {
-		if (ex instanceof RuntimeException) {
-			throw (RuntimeException) ex;
-		}
-		if (ex instanceof Error) {
-			throw (Error) ex;
-		}
-		handleUnexpectedException(ex);
-	}
-
-	private boolean equalOrAssignableTypes(Class<?>[] a, Class<?>[] a2) {
-		if (a == a2) {
-			return true;
-		}
-
-		if (a == null || a2 == null) {
-			return false;
-		}
+	private boolean isLinked(AbstractNode lastCompleteNode) {
 
-		int length = a.length;
+		EObject semanticModel = NodeUtil.getNearestSemanticObject(lastCompleteNode);
 
-		if (a2.length != length) {
-			return false;
-		}
+		EReference eReference = getReference((CrossReference) lastCompleteNode.getGrammarElement(), semanticModel
+				.eClass());
 
-		for (int i = 0; i < length; i++) {
-			Class<?> o1 = a[i];
-			Class<?> o2 = a2[i];
+		if (eReference.getUpperBound() == 1) {
 
-			if (!(o1 == null ? o2 == null : o1.equals(o2) || o1.isAssignableFrom(o2))) {
-				return false;
-			}
-		}
-		return true;
-	}
-	
-	private final String firstLetterCapitalized(String name) {
-		return name.substring(0, 1).toUpperCase() + name.substring(1);
-	}
-	
-	@SuppressWarnings("unchecked")
-	private boolean isLinked(AbstractNode lastCompleteNode) {
-		
-		EObject semanticModel = NodeUtil.getNearestSemanticObject(lastCompleteNode);
-				
-		EReference eReference = getReference((CrossReference) lastCompleteNode.getGrammarElement(), semanticModel.eClass());
-		
-		if (eReference.getUpperBound() == 1 ) {
-		
-			if (null!=semanticModel.eGet(eReference)) {
+			if (null != semanticModel.eGet(eReference)) {
 				return true;
 			}
 		}
-		else { 
-			
+		else {
+
 			EcoreEList<EObject> ecoreEList = (EcoreEList<EObject>) semanticModel.eGet(eReference);
-			
-			for (Iterator<EObject> iterator = ecoreEList.iterator(); iterator.hasNext();) {
-				
-				EObject object = iterator.next();
-				
-				if (EcoreUtil2.getURIFragment(object).equalsIgnoreCase(((LeafNode)lastCompleteNode).getText())) {
+
+			for (EObject object : ecoreEList) {
+
+				if (EcoreUtil2.getURIFragment(object).equalsIgnoreCase(((LeafNode) lastCompleteNode).getText())) {
 					return true;
 				}
 			}
 		}
-		
+
 		return false;
 	}
-	
+
 	private EReference getReference(CrossReference ref, EClass class1) {
-		
+
 		EList<EReference> references = class1.getEAllReferences();
-		
+
 		String feature = GrammarUtil.containingAssignment(ref).getFeature();
-		
+
 		for (EReference reference : references) {
 			if (!reference.isContainment() && reference.getName().equals(feature))
 				return reference;
diff --git a/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/IProposalProvider.java b/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/IProposalProvider.java
index 394988f..88db9a5 100644
--- a/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/IProposalProvider.java
+++ b/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/IProposalProvider.java
@@ -71,8 +71,8 @@ public interface IProposalProvider {
 	 * This method is invoked by the framework after all possible completions have been collected.
 	 * @param completionProposalList matching {@link ICompletionProposal} to sort and filter
 	 * @param model - the most specific model element under the cursor. 
-	 * @param prefix - the prefix under the cursor or null if there is no prefix
 	 * @return the sorted and filtered <code>ICompletionProposal</code> list.
+	 * 
 	 */
-	public List<? extends ICompletionProposal> sortAndFilter(List<? extends ICompletionProposal> completionProposalList,EObject model,String prefix);
+	public List<? extends ICompletionProposal> sortAndFilter(List<? extends ICompletionProposal> completionProposalList,EObject model, String prefix, IDocument document,int offset);
 }
diff --git a/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/ProposalCandidateResolverSwitch.java b/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/ProposalCandidateResolverSwitch.java
index 4028f49..b3e31ea 100644
--- a/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/ProposalCandidateResolverSwitch.java
+++ b/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/ProposalCandidateResolverSwitch.java
@@ -19,6 +19,7 @@ import org.eclipse.xtext.AbstractElement;
 import org.eclipse.xtext.AbstractRule;
 import org.eclipse.xtext.Alternatives;
 import org.eclipse.xtext.Assignment;
+import org.eclipse.xtext.CrossReference;
 import org.eclipse.xtext.GrammarUtil;
 import org.eclipse.xtext.Group;
 import org.eclipse.xtext.ParserRule;
@@ -26,7 +27,7 @@ import org.eclipse.xtext.RuleCall;
 import org.eclipse.xtext.util.XtextSwitch;
 
 /**
- * Represents <b>Switch</b> for the model's inheritance hierarchy to resolve
+ * Represents a <b>Switch</b> for the Xtext model's inheritance hierarchy to resolve
  * potential completion proposal candidate's.
  * 
  * It supports the call {@link #doSwitch(EObject) doSwitch(object)} instead of
@@ -115,6 +116,11 @@ public class ProposalCandidateResolverSwitch extends XtextSwitch<List<EObject>>
 		}
 		return elementList;
 	}
+	
+	@Override
+	public List<EObject> caseCrossReference(CrossReference crossReference) {
+		return Collections.singletonList(crossReference.eContainer());
+	}
 
 	@Override
 	public List<EObject> defaultCase(EObject object) {
diff --git a/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/ProposalProviderInvokerSwitch.java b/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/ProposalProviderInvokerSwitch.java
new file mode 100644
index 0000000..b12e918
--- a/dev/null
+++ b/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/ProposalProviderInvokerSwitch.java
@@ -0,0 +1,271 @@
+/*******************************************************************************
+ * Copyright (c) 2008 itemis AG (http://www.itemis.eu) 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
+ *
+ *******************************************************************************/
+package org.eclipse.xtext.ui.common.editor.codecompletion;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+
+import org.eclipse.core.runtime.Assert;
+import org.eclipse.emf.ecore.EObject;
+import org.eclipse.jface.text.IDocument;
+import org.eclipse.jface.text.contentassist.ICompletionProposal;
+import org.eclipse.xtext.AbstractRule;
+import org.eclipse.xtext.Assignment;
+import org.eclipse.xtext.GrammarUtil;
+import org.eclipse.xtext.Keyword;
+import org.eclipse.xtext.ParserRule;
+import org.eclipse.xtext.RuleCall;
+import org.eclipse.xtext.TypeRef;
+import org.eclipse.xtext.parsetree.AbstractNode;
+import org.eclipse.xtext.parsetree.CompositeNode;
+import org.eclipse.xtext.util.XtextSwitch;
+
+/**
+ * Represents a <b>Switch</b> for the Xtext model's inheritance hierarchy to
+ * callback and invoke the completion methods of <code>IProposalProvider</code>
+ * implementations to gather and collect <code>ICompletionProposal</code> to be
+ * displayed for Content Assist.
+ * 
+ * It supports the call {@link #doSwitch(EObject) doSwitch(object)} instead of
+ * typical <code>if (x instanceof y)</code> code blocks.
+ * 
+ * @author Michael Clay - Initial contribution and API
+ * @see IProposalProvider
+ * @see org.eclipse.xtext.util.XtextSwitch
+ */
+public class ProposalProviderInvokerSwitch extends XtextSwitch<List<ICompletionProposal>> {
+
+	private List<ICompletionProposal> completionProposalList = new ArrayList<ICompletionProposal>();
+
+	private final IProposalProvider proposalProvider;
+
+	private final IDocument document;
+
+	private final AbstractNode currentLeafNode;
+
+	private final String prefix;
+
+	private int offset;
+
+	private static final Map<String, Method> methodLookupMap = new HashMap<String, Method>();
+
+	/**
+	 * 
+	 * @param currentLeafNode
+	 *            the last node in the document
+	 * @param document
+	 *            the document itself
+	 * @param offset
+	 *            the position in the offset from which CA was triggered
+	 * @param prefix
+	 *            the prefix normally consisting of the text content of the
+	 *            currentLeafNode
+	 * @param proposalProvider
+	 *            the proposalProvider to callback and invoke
+	 */
+	public ProposalProviderInvokerSwitch(AbstractNode currentLeafNode, IDocument document, int offset, String prefix,
+			IProposalProvider proposalProvider) {
+		super();
+		this.currentLeafNode = currentLeafNode;
+		this.document = document;
+		this.offset = offset;
+		this.prefix = prefix;
+		this.proposalProvider = proposalProvider;
+	}
+
+	/**
+	 * Collect a list of <code>ICompletionProposal</code> for the given
+	 * elementList through callback and reflective invocations to
+	 * <code>IProposalProvider</code>
+	 * 
+	 * @param elementList
+	 *            the list of <code>EObject</code> to collect
+	 *            <code>ICompletionProposal</code> for
+	 * @return a list of matching <code>ICompletionProposal</code>
+	 */
+	public List<ICompletionProposal> collectCompletionProposalList(List<EObject> elementList) {
+
+		completionProposalList = new ArrayList<ICompletionProposal>();
+
+		for (Iterator<EObject> elementOrRuleIterator = elementList.iterator(); elementOrRuleIterator.hasNext();) {
+			EObject abstractElement = elementOrRuleIterator.next();
+			doSwitch(abstractElement);
+		}
+
+		return completionProposalList;
+
+	}
+
+	@Override
+	public List<ICompletionProposal> caseAssignment(Assignment assignment) {
+		ParserRule parserRule = GrammarUtil.containingParserRule(assignment);
+
+		EObject model = null == ((CompositeNode) currentLeafNode.eContainer()).getElement() ? currentLeafNode
+				.eContainer() : ((CompositeNode) currentLeafNode.eContainer()).getElement();
+
+		Method method = findMethod(proposalProvider.getClass(), "complete"
+				+ firstLetterCapitalized(parserRule.getName()) + firstLetterCapitalized(assignment.getFeature()),
+				Assignment.class, model.getClass(), String.class, document.getClass(), int.class);
+
+		Collection<? extends ICompletionProposal> assignmentProposalList = null == method ? null : invokeMethod(method,
+				proposalProvider, assignment, model, prefix, document, offset);
+
+		if (null != assignmentProposalList) {
+			completionProposalList.addAll(assignmentProposalList);
+		}
+
+		return null;
+	}
+
+	@Override
+	public List<ICompletionProposal> caseKeyword(Keyword keyword) {
+		completionProposalList.addAll(proposalProvider.completeKeyword(keyword, currentLeafNode, prefix, document,
+				offset));
+		return null;
+	}
+
+	@Override
+	public List<ICompletionProposal> caseRuleCall(RuleCall ruleCall) {
+		
+		EObject model = null == ((CompositeNode) currentLeafNode.eContainer()).getElement() ? currentLeafNode
+				.eContainer() : ((CompositeNode) currentLeafNode.eContainer()).getElement();
+
+				
+		List<? extends ICompletionProposal> ruleCallProposalList = this.proposalProvider.completeRuleCall(ruleCall,
+				model, prefix, document, offset);
+
+		if (null != ruleCallProposalList) {
+			completionProposalList.addAll(ruleCallProposalList);
+		}
+
+		AbstractRule calledRule = GrammarUtil.calledRule(ruleCall);
+
+		if (calledRule.getType() != null) {
+
+			TypeRef typeRef = calledRule.getType();
+
+			Method method = findMethod(proposalProvider.getClass(), "complete"
+					+ firstLetterCapitalized(typeRef.getAlias()) + firstLetterCapitalized(typeRef.getName()),
+					RuleCall.class, model.getClass(), String.class, document.getClass(), int.class);
+
+			Collection<? extends ICompletionProposal> proposalList = null == method ? null : invokeMethod(method,
+					proposalProvider, ruleCall, model, prefix, document, offset);
+
+			if (null != proposalList) {
+				completionProposalList.addAll(proposalList);
+			}
+
+		}
+		return null;
+	}
+
+	private final Method findMethod(Class<?> clazz, String name, Class<?>... paramTypes) {
+		Assert.isNotNull(clazz, "Class must not be null");
+		Assert.isNotNull(name, "Method name must not be null");
+		Method result = methodLookupMap.get(name);
+		Class<?> searchType = clazz;
+		while (!Object.class.equals(searchType) && searchType != null && null == result) {
+			Method[] methods = (searchType.isInterface() ? searchType.getMethods() : searchType.getDeclaredMethods());
+			for (int i = 0; i < methods.length; i++) {
+				Method method = methods[i];
+				if (name.equals(method.getName())
+						&& (paramTypes == null || equalOrAssignableTypes(method.getParameterTypes(), paramTypes))) {
+					if (result == null
+							|| equalOrAssignableTypes(result.getParameterTypes(), method.getParameterTypes())) {
+						result = method;
+						methodLookupMap.put(name, method);
+					}
+				}
+			}
+			searchType = searchType.getSuperclass();
+		}
+		return result;
+	}
+
+	@SuppressWarnings("unchecked")
+	private final Collection<ICompletionProposal> invokeMethod(Method method, Object target, Object... args) {
+
+		try {
+			return (Collection<ICompletionProposal>) method.invoke(target, args);
+		}
+		catch (Exception ex) {
+			handleReflectionException(ex);
+		}
+		throw new IllegalStateException("huh?");
+	}
+
+	private void handleReflectionException(Exception ex) {
+		if (ex instanceof NoSuchMethodException) {
+			throw new IllegalStateException("Method not found: " + ex.getMessage());
+		}
+		if (ex instanceof IllegalAccessException) {
+			throw new IllegalStateException("Could not access method: " + ex.getMessage());
+		}
+		if (ex instanceof InvocationTargetException) {
+			rethrowRuntimeException(((InvocationTargetException) ex).getTargetException());
+		}
+		if (ex instanceof RuntimeException) {
+			throw (RuntimeException) ex;
+		}
+		handleUnexpectedException(ex);
+	}
+
+	private void handleUnexpectedException(Throwable ex) {
+		IllegalStateException isex = new IllegalStateException("Unexpected exception thrown");
+		isex.initCause(ex);
+		throw isex;
+	}
+
+	private final void rethrowRuntimeException(Throwable ex) {
+		if (ex instanceof RuntimeException) {
+			throw (RuntimeException) ex;
+		}
+		if (ex instanceof Error) {
+			throw (Error) ex;
+		}
+		handleUnexpectedException(ex);
+	}
+
+	private boolean equalOrAssignableTypes(Class<?>[] a, Class<?>[] a2) {
+		if (a == a2) {
+			return true;
+		}
+
+		if (a == null || a2 == null) {
+			return false;
+		}
+
+		int length = a.length;
+
+		if (a2.length != length) {
+			return false;
+		}
+
+		for (int i = 0; i < length; i++) {
+			Class<?> o1 = a[i];
+			Class<?> o2 = a2[i];
+
+			if (!(o1 == null ? o2 == null : o1.equals(o2) || o1.isAssignableFrom(o2))) {
+				return false;
+			}
+		}
+		return true;
+	}
+
+	private final String firstLetterCapitalized(String name) {
+		return name.substring(0, 1).toUpperCase() + name.substring(1);
+	}
+
+}
diff --git a/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/XtextCompletionProposal.java b/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/XtextCompletionProposal.java
index 9428dbd..ffeef6d 100644
--- a/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/XtextCompletionProposal.java
+++ b/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/codecompletion/XtextCompletionProposal.java
@@ -2,6 +2,7 @@ package org.eclipse.xtext.ui.common.editor.codecompletion;
 
 import org.apache.log4j.Logger;
 import org.eclipse.core.runtime.Assert;
+import org.eclipse.emf.ecore.EObject;
 import org.eclipse.jface.resource.JFaceResources;
 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.DocumentEvent;
@@ -15,6 +16,7 @@ import org.eclipse.jface.text.contentassist.IContextInformation;
 import org.eclipse.jface.viewers.StyledString;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.graphics.Point;
+import org.eclipse.xtext.AbstractElement;
 
 /**
  * Default Xtext implementation of interface <code>ICompletionProposal</code>.
@@ -28,8 +30,11 @@ import org.eclipse.swt.graphics.Point;
 public class XtextCompletionProposal implements ICompletionProposal,
 		ICompletionProposalExtension2, ICompletionProposalExtension6 {
 	
-	private Logger logger = Logger.getLogger(XtextCompletionProposal.class);
+	protected final Logger logger = Logger.getLogger(XtextCompletionProposal.class);
 
+	
+	private EObject model;
+	private AbstractElement abstractElement;
 	private String text;
 	private String description;
 	private Image image;
@@ -38,6 +43,9 @@ public class XtextCompletionProposal implements ICompletionProposal,
 	private String pluginIdentifier;
 
 	/**
+	 * @param element
+	 *            the element for which this CompletionProposal is created for
+	 * @param model the last semtantically complete object 
 	 * @param text
 	 *            the text value to be replaced/inserted
 	 * @param label
@@ -52,12 +60,14 @@ public class XtextCompletionProposal implements ICompletionProposal,
 	 * @param offset
 	 *            the offset of the text
 	 */
-	public XtextCompletionProposal(String text, StyledString label,
+	public XtextCompletionProposal(AbstractElement element,EObject model,String text, StyledString label,
 			String description, String imageFilePath, String pluginIdentifier,
 			int offset) {
 		Assert.isNotNull(text, "parameter 'text' must not be null");
 		Assert.isNotNull(pluginIdentifier,
 				"pluginIdentifier 'text' must not be null");
+		this.abstractElement = element;
+		this.model = model;
 		this.text = text;
 		this.description = description;
 		this.offset = offset;
@@ -74,6 +84,45 @@ public class XtextCompletionProposal implements ICompletionProposal,
 	}
 	
 	/**
+	 * 
+	 * Getter for model property.
+	 * 
+	 * @return the associated model object
+	 */
+	public EObject getModel() {
+		return model;
+	}
+	
+	/**
+	 * Setter for model property.
+	 * 
+	 * @param model to set
+	 */
+	public void setModel(EObject model) {
+		this.model = model;
+	}
+
+
+	/**
+	 * Getter for abstractElement property.
+	 * 
+	 * @return the associated element
+	 */
+	public AbstractElement getAbstractElement() {
+		return abstractElement;
+	}
+
+
+	/**
+	 * Setter for abstractElement property.
+	 * @param abstractElement to set
+	 */
+	public void setAbstractElement(AbstractElement abstractElement) {
+		this.abstractElement = abstractElement;
+	}
+
+
+	/**
 	 * Setter for the text to insert
 	 * 
 	 * @param text
@@ -227,6 +276,11 @@ public class XtextCompletionProposal implements ICompletionProposal,
 	public Point getSelection(IDocument document) {
 		return new Point(offset + this.text.length(), 0);
 	}
+	
+	@Override
+	public String toString() {
+		return "XtextCompletionPoposal[text='"+getText()+"']";
+	}
 
 	private void initializeImage(String imageName) {
 		Image newImage = JFaceResources.getImage(imageName);