Bug 104792 - Content proposal filtering feature.

core/org.eclipse.cdt.ui.tests/plugin.xml

@@ -121,5 +121,12 @@
             id="org.eclipse.cdt.ui.tests.DOMAST.DOMAST.IncludeStatementFilter">
       </filter>
    </extension>
+   <extension
+         point="org.eclipse.cdt.ui.ProposalFilter">
+      <ProposalFilter
+            class="org.eclipse.cdt.ui.tests.text.contentassist.TestProposalFilter"
+            id="org.eclipse.cdt.ui.tests.TestProposalFilter"
+            name="Testing Completion Filter"/>
+   </extension>
 
 </plugin>

core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/contentassist/ProposalFilterPreferencesTest.java

@@ -0,0 +1,50 @@
+package org.eclipse.cdt.ui.tests.text.contentassist;
+
+import org.eclipse.cdt.internal.ui.preferences.ProposalFilterPreferencesUtil;
+import org.eclipse.cdt.internal.ui.preferences.ProposalFilterPreferencesUtil.ComboState;
+import org.eclipse.cdt.internal.ui.text.contentassist.ContentAssistPreference;
+import org.eclipse.cdt.ui.CUIPlugin;
+import org.eclipse.core.runtime.IConfigurationElement;
+import org.eclipse.jface.preference.IPreferenceStore;
+
+import junit.framework.TestCase;
+
+/** 
+ * This test covers the convenience methods 
+ * in org.eclipse.cdt.internal.ui.preferences.ProposalFilterPreferencesUtil
+ */
+public class ProposalFilterPreferencesTest extends TestCase {
+
+	public void testPreferences()  {
+		// Check that the test filter is among the filternames
+		String[] filterNames = ProposalFilterPreferencesUtil.getProposalFilterNames();
+		int index = -1 ;
+		for (int i = 0; i < filterNames.length; i++) {
+			String name = filterNames[i];
+			if (name.equals("Testing Completion Filter"))  {
+				index = i ;
+				break ;
+			}
+		}
+		assertTrue("Did not find expected filter!", index>=0);
+		
+		// Set the preference to the tested filter 
+		IPreferenceStore store = CUIPlugin.getDefault().getPreferenceStore();
+		String filterComboStateString = store.getString(ContentAssistPreference.PROPOSALS_FILTER);
+		ProposalFilterPreferencesUtil.ComboState state = ProposalFilterPreferencesUtil.getComboState(filterComboStateString);
+		StringBuffer newStateText = new StringBuffer();
+		newStateText.append(index+1); // First entry is always the <Default Filter>, index+1 must be selected
+		for (int i = 0; i < state.items.length; i++) {
+			String item = state.items[i];
+			newStateText.append(";");
+			newStateText.append(item);
+		}
+		store.setValue(ContentAssistPreference.PROPOSALS_FILTER, newStateText.toString());
+		
+		// Now we can test preferred filter retrieval:
+		IConfigurationElement preferredElement = ProposalFilterPreferencesUtil.getPreferredFilterElement();
+		String extensionId = preferredElement.getAttribute("id");
+		assertNotNull("Configuration element was not found!", extensionId);
+		assertEquals("Unexpected element id", "org.eclipse.cdt.ui.tests.TestProposalFilter", extensionId);
+	}
+}

core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/contentassist/TestProposalFilter.java

@@ -0,0 +1,19 @@
+package org.eclipse.cdt.ui.tests.text.contentassist;
+
+import org.eclipse.cdt.ui.text.ICCompletionProposal;
+import org.eclipse.cdt.ui.text.contentassist.IProposalFilter;
+
+/**
+ * Dummy filter implementation for testing purposes
+ */
+public class TestProposalFilter implements IProposalFilter {
+
+	/**
+	 * This dummy filter method will return the original proposals unmodified.
+	 */
+	public ICCompletionProposal[] filterProposals(
+			ICCompletionProposal[] proposals) {
+		return proposals ;
+	}
+
+}

core/org.eclipse.cdt.ui/plugin.xml

@@ -17,6 +17,7 @@
    <extension-point id="textHovers" name="%textHoversName"/>
    <extension-point id="IndexerPage" name="Indexer Page" schema="schema/IndexerPage.exsd"/>
    <extension-point id="completionContributors" name="%completionContributors" schema="schema/completionContributors.exsd"/>
+   <extension-point id="ProposalFilter" name="Code Completion Proposal Filter" schema="schema/ProposalFilter.exsd"/>
 
    <extension
          point="org.eclipse.core.runtime.adapters">

core/org.eclipse.cdt.ui/schema/ProposalFilter.exsd

@@ -0,0 +1,122 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<!-- Schema file written by PDE -->
+<schema targetNamespace="org.eclipse.cdt.ui">
+<annotation>
+      <appInfo>
+         <meta.schema plugin="org.eclipse.cdt.ui" id="CodeCompletionFilter" name="Code Completion Filter"/>
+      </appInfo>
+      <documentation>
+         This extension point allows contributors to make their implementation of ICompletionFilter known to the platform.
+      </documentation>
+   </annotation>
+
+   <element name="extension">
+      <complexType>
+         <sequence>
+            <element ref="ProposalFilter"/>
+         </sequence>
+         <attribute name="point" type="string" use="required">
+            <annotation>
+               <documentation>
+                  
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="id" type="string">
+            <annotation>
+               <documentation>
+                  
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="name" type="string">
+            <annotation>
+               <documentation>
+                  
+               </documentation>
+               <appInfo>
+                  <meta.attribute translatable="true"/>
+               </appInfo>
+            </annotation>
+         </attribute>
+      </complexType>
+   </element>
+
+   <element name="ProposalFilter">
+      <complexType>
+         <attribute name="id" type="string" use="required">
+            <annotation>
+               <documentation>
+                  
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="name" type="string" use="required">
+            <annotation>
+               <documentation>
+                  
+               </documentation>
+               <appInfo>
+                  <meta.attribute translatable="true"/>
+               </appInfo>
+            </annotation>
+         </attribute>
+         <attribute name="class" type="string" use="required">
+            <annotation>
+               <documentation>
+                  
+               </documentation>
+               <appInfo>
+                  <meta.attribute kind="java"/>
+               </appInfo>
+            </annotation>
+         </attribute>
+      </complexType>
+   </element>
+
+   <annotation>
+      <appInfo>
+         <meta.section type="since"/>
+      </appInfo>
+      <documentation>
+         CDT 3.1
+      </documentation>
+   </annotation>
+
+   <annotation>
+      <appInfo>
+         <meta.section type="examples"/>
+      </appInfo>
+      <documentation>
+         [Enter extension point usage example here.]
+      </documentation>
+   </annotation>
+
+   <annotation>
+      <appInfo>
+         <meta.section type="apiInfo"/>
+      </appInfo>
+      <documentation>
+         [Enter API information here.]
+      </documentation>
+   </annotation>
+
+   <annotation>
+      <appInfo>
+         <meta.section type="implementation"/>
+      </appInfo>
+      <documentation>
+         [Enter information about supplied implementation of this extension point.]
+      </documentation>
+   </annotation>
+
+   <annotation>
+      <appInfo>
+         <meta.section type="copyright"/>
+      </appInfo>
+      <documentation>
+         
+      </documentation>
+   </annotation>
+
+</schema>

core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/preferences/AbstractPreferencePage.java

@@ -33,6 +33,7 @@ import org.eclipse.swt.graphics.RGB;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Button;
+import org.eclipse.swt.widgets.Combo;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Group;
@@ -63,6 +64,16 @@ public abstract class AbstractPreferencePage extends PreferencePage implements I
 			fOverlayStore.setValue((String) fTextFields.get(text), text.getText());
 		}
 	};
+	
+	protected Map fComboBoxes = new HashMap();
+	private ModifyListener fComboBoxListener = new ModifyListener() {
+		public void modifyText(ModifyEvent e) {
+			Combo combo = (Combo) e.widget;
+			String state = ProposalFilterPreferencesUtil.comboStateAsString(combo);
+			fOverlayStore.setValue((String) fComboBoxes.get(combo), state);
+		}
+	};
+	
 
 	protected Map fCheckBoxes = new HashMap();
 	private SelectionListener fCheckBoxListener = new SelectionListener() {
@@ -157,6 +168,24 @@ public abstract class AbstractPreferencePage extends PreferencePage implements I
 		return textControl;
 	}
 
+	protected void addComboBox(Composite composite, String label, String key, int textLimit, int indentation) {
+
+		Label labelControl = new Label(composite, SWT.NONE);
+		labelControl.setText(label);
+		GridData gd = new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING);
+		gd.horizontalIndent = indentation;
+		labelControl.setLayoutData(gd);
+
+		Combo comboControl = new Combo(composite, SWT.BORDER | SWT.SINGLE | SWT.READ_ONLY);  // TODO: When will the combo be disposed?
+		gd = new GridData(GridData.HORIZONTAL_ALIGN_END);
+		gd.widthHint = convertWidthInCharsToPixels(textLimit + 1);
+		comboControl.setLayoutData(gd);
+		comboControl.setTextLimit(textLimit);
+		fComboBoxes.put(comboControl, key);
+		comboControl.addModifyListener(fComboBoxListener);  // TODO: When will the listener be removed? 
+
+	}
+
 	protected void addFiller(Composite composite) {
 		PixelConverter pixelConverter= new PixelConverter(composite);
 		Label filler= new Label(composite, SWT.LEFT );
@@ -292,11 +321,22 @@ public abstract class AbstractPreferencePage extends PreferencePage implements I
 			String key = (String) fTextFields.get(t);
 			t.setText(fOverlayStore.getString(key));
 		}
+
+		e = fComboBoxes.keySet().iterator();
+		while (e.hasNext()) {
+			Combo c = (Combo) e.next();
+			String key = (String) fComboBoxes.get(c);
+			String state = fOverlayStore.getString(key);
+			// Interpret the state string as a Combo state description
+			ProposalFilterPreferencesUtil.restoreComboFromString(c, state);
+		}
 	}
 
 
 
-	/* (non-Javadoc)
+	/*
+	 * (non-Javadoc)
+	 * 
 	 * @see org.eclipse.ui.IWorkbenchPreferencePage#init(org.eclipse.ui.IWorkbench)
 	 */
 	public void init(IWorkbench workbench) {

core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/preferences/CodeAssistPreferencePage.java

@@ -58,6 +58,7 @@ public class CodeAssistPreferencePage extends AbstractPreferencePage {
 		overlayKeys.add(new OverlayPreferenceStore.OverlayKey(OverlayPreferenceStore.BOOLEAN, ContentAssistPreference.ADD_INCLUDE));
 		overlayKeys.add(new OverlayPreferenceStore.OverlayKey(OverlayPreferenceStore.BOOLEAN, ContentAssistPreference.CURRENT_FILE_SEARCH_SCOPE));        
 		overlayKeys.add(new OverlayPreferenceStore.OverlayKey(OverlayPreferenceStore.BOOLEAN, ContentAssistPreference.PROJECT_SEARCH_SCOPE));
+		overlayKeys.add(new OverlayPreferenceStore.OverlayKey(OverlayPreferenceStore.STRING, ContentAssistPreference.PROPOSALS_FILTER));
 
         OverlayPreferenceStore.OverlayKey[] keys = new OverlayPreferenceStore.OverlayKey[overlayKeys.size()];
 		overlayKeys.toArray(keys);
@@ -135,7 +136,10 @@ public class CodeAssistPreferencePage extends AbstractPreferencePage {
 //		label= PreferencesMessages.getString("CEditorPreferencePage.ContentAssistPage.parameterForegroundColor");
 //		addColorButton(contentAssistComposite, label, ContentAssistPreference.PARAMETERS_FOREGROUND, 0);
 
-    	initializeFields();
+		label = PreferencesMessages.getString("CEditorPreferencePage.ContentAssistPage.proposalFilterSelect") ; //$NON-NLS-1$
+		addComboBox(contentAssistComposite, label, ContentAssistPreference.PROPOSALS_FILTER, 20, 0);
+    	
+		initializeFields();
 
 		PlatformUI.getWorkbench().getHelpSystem().setHelp(contentAssistComposite, ICHelpContextIds.C_EDITOR_CONTENT_ASSIST_PREF_PAGE);
 
@@ -168,6 +172,8 @@ public class CodeAssistPreferencePage extends AbstractPreferencePage {
 		PreferenceConverter.setDefault(store, ContentAssistPreference.PARAMETERS_FOREGROUND, new RGB(0, 0, 0));
 		store.setDefault(ContentAssistPreference.ORDER_PROPOSALS, false);
 		store.setDefault(ContentAssistPreference.ADD_INCLUDE, true);
+		store.setDefault(ContentAssistPreference.PROPOSALS_FILTER, ProposalFilterPreferencesUtil.getProposalFilternamesAsString());  // $NON_NLS 1$
 
 	}
+	
 }

core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/preferences/PreferencesMessages.properties

@@ -85,6 +85,7 @@ CEditorPreferencePage.ContentAssistPage.autoActivationGroupTitle=Auto activation
 CEditorPreferencePage.ContentAssistPage.autoActivationEnableDot=Enable "." as trigger
 CEditorPreferencePage.ContentAssistPage.autoActivationEnableArrow=Enable "->" as trigger
 CEditorPreferencePage.ContentAssistPage.autoActivationDelay=dela&y (ms)
+CEditorPreferencePage.ContentAssistPage.proposalFilterSelect=Completion Proposal Filter:
 CEditorPreferencePage.ContentAssistPage.completionProposalBackgroundColor=&Background for completion proposals:
 CEditorPreferencePage.ContentAssistPage.completionProposalForegroundColor=&Foreground for completion proposals:
 CEditorPreferencePage.ContentAssistPage.parameterBackgroundColor=Bac&kground for method parameters:
@@ -260,3 +261,4 @@ PathEntryVariableSelectionDialog.ExtensionDialog.description = Choose extension
 
 #Indexer
 IndexerPrefs.description=Sets default Indexer Options for new Projects
+ProposalFilterPreferencesUtil.defaultFilterName=<Default Filter>

core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/preferences/ProposalFilterPreferencesUtil.java

@@ -0,0 +1,232 @@
+package org.eclipse.cdt.internal.ui.preferences;
+
+import java.util.ArrayList;
+
+import org.eclipse.cdt.internal.ui.text.contentassist.ContentAssistPreference;
+import org.eclipse.cdt.ui.CUIPlugin;
+import org.eclipse.core.runtime.IConfigurationElement;
+import org.eclipse.core.runtime.IExtension;
+import org.eclipse.core.runtime.IExtensionPoint;
+import org.eclipse.core.runtime.InvalidRegistryObjectException;
+import org.eclipse.core.runtime.Platform;
+import org.eclipse.jface.preference.IPreferenceStore;
+import org.eclipse.swt.widgets.Combo;
+
+/**
+ * A class which encapsulates several utility functions
+ * related to code completion preference settings.
+ */
+public class ProposalFilterPreferencesUtil {
+
+	/**
+	 * Private default constructor prevents instantiation
+	 */
+	private ProposalFilterPreferencesUtil() {
+	}
+
+	/**
+	 * Get an array of proposal filter names
+	 * (i.e. the human-readable text for display
+	 * to fill into the Combo)
+	 */
+	public static String[] getProposalFilterNames() {
+		ArrayList names = new ArrayList();
+		try {
+			IExtensionPoint point = Platform.getExtensionRegistry()
+					.getExtensionPoint(CUIPlugin.PLUGIN_ID, "ProposalFilter"); //$NON-NLS-1$
+			if (point != null) {
+				IExtension[] extensions = point.getExtensions();
+				for (int i = 0; i < extensions.length; i++) {
+					IExtension extension = extensions[i];
+					IConfigurationElement[] elements = extension
+							.getConfigurationElements();
+					for (int j = 0; j < elements.length; ++j) {
+						IConfigurationElement element = elements[j];
+						if ("ProposalFilter".equals(element.getName())) { //$NON-NLS-1$
+							String filterName = element.getAttribute("name");
+							if (null != filterName) {
+								names.add(filterName);
+							}
+						}
+					}
+				}
+			}
+		} catch (InvalidRegistryObjectException e) {
+			// No action required since we will at least be using the fail-safe default filter
+			CUIPlugin.getDefault().log(e);
+		}
+		String[] filterNames = (String[]) names
+				.toArray(new String[names.size()]);
+		return filterNames;
+	}
+
+	/**
+	 * Look up all contributed completion proposal filters 
+	 * and return their names as a semicolon-separated list
+	 * plus a leading entry for the selected index 0,
+	 * plus a leading <default> entry. <br>
+	 * A Combo may be initialized from this string.
+	 * @return The list of filter names
+	 */
+	public static String getProposalFilternamesAsString() {
+		StringBuffer filterNames = new StringBuffer("0;");
+		filterNames.append("<Default Filter>"); // TODO: NP externalize this!
+		String[] names = getProposalFilterNames();
+		for (int i = 0; i < names.length; i++) {
+			String name = names[i];
+			filterNames.append(";");
+			filterNames.append(name);
+		}
+		return filterNames.toString();
+	}
+
+	/**
+	 * Return the configuration element which corresponds 
+	 * to the human-readable filter name
+	 * @param filterName The human-readable filter name
+	 * @return The configuration element, or null if there is none
+	 */
+	public static IConfigurationElement getElementForName(String filterName) {
+		IConfigurationElement element = null;
+		IExtensionPoint point = Platform.getExtensionRegistry()
+				.getExtensionPoint(CUIPlugin.PLUGIN_ID, "ProposalFilter"); //$NON-NLS-1$
+		if (point != null) {
+			try {
+				IExtension[] extensions = point.getExtensions();
+				if (extensions.length >= 1) {
+					for (int i = 0; i < extensions.length; i++) {
+						IExtension extension = extensions[i];
+
+						IConfigurationElement[] elements = extension
+								.getConfigurationElements();
+
+						for (int j = 0; j < elements.length; ++j) {
+							IConfigurationElement testElement = elements[j];
+							if ("ProposalFilter".equals(testElement.getName())) { //$NON-NLS-1$
+								String testName = testElement
+										.getAttribute("name");
+								if ((null != testName)
+										&& (filterName.equals(testName))) {
+									element = testElement;
+									break;
+								}
+							}
+						}
+						// Did we find the corresponding element?
+						if (null != element)
+							break;
+					}
+				}
+			} catch (InvalidRegistryObjectException e) {
+				// In case of failure we'll just return null
+			}
+		}
+
+		return element;
+	}
+
+	/**
+	 * The state of a Combo consists of the list of entries
+	 * and the index of the selected entry.
+	 * This method converts the state of the given Combo 
+	 * to a string representation for storage in a preference store. <br>
+	 * The string contains a semicolon-separated list of entries.
+	 * The first entry is the index of the selected entry.
+	 * The following entries are the texts of the individual fields. <br>
+	 * Since the semicolon is the separator, the entries cannot contain semicolons.
+	 * This method will replace semicolons with commas if any are found.
+	 * @param combo The Combo whose state shall be converted
+	 * @return A string representation of the Combo state
+	 */
+	public static String comboStateAsString(Combo combo) {
+		StringBuffer text = new StringBuffer();
+		int selectionIndex = combo.getSelectionIndex();
+		text.append(selectionIndex);
+		String[] entries = combo.getItems();
+		for (int i = 0; i < entries.length; i++) {
+			text.append(";");
+			String entry = entries[i].replaceAll(";", ",");
+			text.append(entry);
+		}
+		return text.toString();
+	}
+
+	/**
+	 * The state of a Combo consists of the list of entries
+	 * and the index of the selected entry.
+	 * This method takes a string representation of the state (e.g. from a preference store)
+	 * and restores it into the Combo. <br>
+	 * For a description of the text format see method comboStateAsString().
+	 * @param combo The combo to be restored.
+	 * @param text The text representation of the state.
+	 */
+	public static void restoreComboFromString(Combo combo, String text) {
+		try {
+			int endFirstEntry = text.indexOf(";");
+			if (endFirstEntry > 0) { // First entry must contain at least one character
+				String selectedString = text.substring(0, endFirstEntry);
+				int selectedIndex = Integer.parseInt(selectedString);
+				String[] entryList = text.substring(endFirstEntry + 1,
+						text.length()).split(";");
+				combo.setItems(entryList);
+				combo.select(selectedIndex);
+			}
+		} catch (NumberFormatException e) {
+			// If this fails we just return the unmodified Combo
+		}
+	}
+
+	/**
+	 * Convenience class wraps the data to initialize a Combo
+	 */
+	public static class ComboState {
+		public int selectedIndex;
+
+		public String[] items;
+	}
+
+	/** 
+	 * Convenience method to extract the state of a Combo
+	 * from the state string stored e.g. in a preference store
+	 * @param comboPreference The state string
+	 * @return A ComboState instance. 
+	 */
+	public static ComboState getComboState(String comboPreference) {
+		ComboState state = new ComboState();
+		try {
+			int endFirstEntry = comboPreference.indexOf(";");
+			if (endFirstEntry > 0) { // First entry must contain at least one character
+				String selectedString = comboPreference.substring(0,
+						endFirstEntry);
+				state.selectedIndex = Integer.parseInt(selectedString);
+				state.items = comboPreference.substring(endFirstEntry + 1,
+						comboPreference.length()).split(";");
+			}
+		} catch (NumberFormatException e) {
+			// If this fails we return an empty ComboState
+			state.items = new String[0];
+		}
+		return state;
+	}
+
+	/**
+	 * Look up the setting for the preferred proposal filter
+	 * and return it's configuration element.
+	 * @return The configuration element, or null if none is found.
+	 */
+	public static IConfigurationElement getPreferredFilterElement() {
+		IConfigurationElement preferredElement = null;
+		try {
+			IPreferenceStore store = CUIPlugin.getDefault()
+					.getPreferenceStore();
+			String filterComboStateString = store
+					.getString(ContentAssistPreference.PROPOSALS_FILTER);
+			ComboState state = getComboState(filterComboStateString);
+			preferredElement = getElementForName(state.items[state.selectedIndex]);
+		} catch (Exception e) {
+			// If anything goes wrong we'll just return null
+		}
+		return preferredElement;
+	}
+
+}

core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/contentassist/CCompletionProcessor2.java

@@ -11,7 +11,6 @@
 package org.eclipse.cdt.internal.ui.text.contentassist;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.List;
 
 import org.eclipse.cdt.core.dom.CDOM;
@@ -22,17 +21,21 @@ import org.eclipse.cdt.core.dom.IASTServiceProvider.UnsupportedDialectException;
 import org.eclipse.cdt.core.dom.ast.ASTCompletionNode;
 import org.eclipse.cdt.core.model.IWorkingCopy;
 import org.eclipse.cdt.internal.ui.CUIMessages;
+import org.eclipse.cdt.internal.ui.preferences.ProposalFilterPreferencesUtil;
 import org.eclipse.cdt.internal.ui.text.CParameterListValidator;
 import org.eclipse.cdt.internal.ui.util.ExternalEditorInput;
 import org.eclipse.cdt.ui.CUIPlugin;
 import org.eclipse.cdt.ui.text.ICCompletionProposal;
 import org.eclipse.cdt.ui.text.contentassist.ICompletionContributor;
+import org.eclipse.cdt.ui.text.contentassist.IProposalFilter;
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.IStorage;
+import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IExtension;
 import org.eclipse.core.runtime.IExtensionPoint;
+import org.eclipse.core.runtime.InvalidRegistryObjectException;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.jface.text.BadLocationException;
@@ -128,48 +131,12 @@ public class CCompletionProcessor2 implements IContentAssistProcessor {
 				}
 			}
 
-			ICCompletionProposal[] propsArray = null;
+			IProposalFilter filter = getCompletionFilter();
+			ICCompletionProposal[] proposalsInput = (ICCompletionProposal[]) proposals.toArray(new ICCompletionProposal[proposals.size()]) ;
 			
-			if (!proposals.isEmpty()) {
+			ICCompletionProposal[] proposalsFiltered = filter.filterProposals(proposalsInput);
-				errorMessage = null;
-				propsArray = (ICCompletionProposal[])proposals.toArray(new ICCompletionProposal[proposals.size()]);
-				CCompletionProposalComparator propsComp = new CCompletionProposalComparator();
-				propsComp.setOrderAlphabetically(true);
-				Arrays.sort(propsArray, propsComp); 
-				
-				// remove duplicates but leave the ones with return types
-                
-				int last = 0;
-				int removed = 0;
-				for (int i = 1; i < propsArray.length; ++i) {
-					if (propsComp.compare(propsArray[last], propsArray[i]) == 0) {
-                        // We want to leave the one that has the return string if any
-                        boolean lastReturn = propsArray[last].getIdString() != propsArray[last].getDisplayString();
-                        boolean iReturn = propsArray[i].getIdString() != propsArray[i].getDisplayString();
-
-                        if (!lastReturn && iReturn)
-                            // flip i down to last
-                            propsArray[last] = propsArray[i];
-
-                        // Remove the duplicate
-						propsArray[i] = null;
-                        ++removed;
-					} else
-						// update last
-						last = i;
-				}
-				if (removed > 0) {
-					// Strip out the null entries
-					ICCompletionProposal[] newArray = new ICCompletionProposal[propsArray.length - removed];
-					int j = 0;
-					for (int i = 0; i < propsArray.length; ++i)
-						if (propsArray[i] != null)
-							newArray[j++] = propsArray[i];
-					propsArray = newArray;
-				}
-			}
 			
-			return propsArray;
+			return proposalsFiltered;
 			
 		} catch (UnsupportedDialectException e) {
 			errorMessage = CUIMessages.getString(dialectError);
@@ -179,6 +146,32 @@ public class CCompletionProcessor2 implements IContentAssistProcessor {
 		
 		return null;
 	}
+	
+	private IProposalFilter getCompletionFilter() {
+		IProposalFilter filter = null;
+		try {
+			IConfigurationElement filterElement = ProposalFilterPreferencesUtil.getPreferredFilterElement();
+			if (null != filterElement) {
+				Object contribObject = filterElement
+						.createExecutableExtension("class"); //$NON-NLS-1$
+				if ((contribObject instanceof IProposalFilter)) {
+					filter = (IProposalFilter) contribObject;
+				}
+			}
+		} catch (InvalidRegistryObjectException e) {
+			// No action required since we will be using the fail-safe default filter
+			CUIPlugin.getDefault().log(e);
+		} catch (CoreException e) {
+			// No action required since we will be using the fail-safe default filter
+			CUIPlugin.getDefault().log(e);
+		}
+
+		if (null == filter) {
+			// fail-safe default implementation
+			filter = new DefaultProposalFilter();
+		}
+		return filter;
+	}
 
     private String scanPrefix(IDocument document, int end) {
         try {

core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/contentassist/ContentAssistPreference.java

@@ -63,7 +63,9 @@ public class ContentAssistPreference {
 	public final static String CURRENT_FILE_SEARCH_SCOPE= "content_assist_current_file_search_scope";	 //$NON-NLS-1$
 	/** Preference key for completion search scope */
 	public final static String PROJECT_SEARCH_SCOPE= "content_assist_project_search_scope";	 //$NON-NLS-1$
-	
+	/** Preference key for completion filtering */
+	public final static String PROPOSALS_FILTER= "content_assist_proposal_filter"; //$NON_NLS 1$
+
 	private static Color getColor(IPreferenceStore store, String key, IColorManager manager) {
 		RGB rgb= PreferenceConverter.getColor(store, key);
 		return manager.getColor(rgb);

core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/contentassist/DefaultProposalFilter.java

@@ -0,0 +1,58 @@
+package org.eclipse.cdt.internal.ui.text.contentassist;
+
+import java.util.Arrays;
+
+import org.eclipse.cdt.ui.text.ICCompletionProposal;
+import org.eclipse.cdt.ui.text.contentassist.IProposalFilter;
+
+/**
+ * The default code completion filter: Remove duplicate entries on the basis of
+ * their id string. Use CCompletionProposalComparator for sorting.
+ */
+public class DefaultProposalFilter implements IProposalFilter {
+
+	public ICCompletionProposal[] filterProposals(
+			ICCompletionProposal[] proposals) {
+
+		CCompletionProposalComparator propsComp = new CCompletionProposalComparator();
+		propsComp.setOrderAlphabetically(true);
+		Arrays.sort(proposals, propsComp);
+
+		// remove duplicates but leave the ones with return types
+
+		int last = 0;
+		int removed = 0;
+		for (int i = 1; i < proposals.length; ++i) {
+			if (propsComp.compare(proposals[last], proposals[i]) == 0) {
+				// We want to leave the one that has the return string if any
+				boolean lastReturn = proposals[last].getIdString() != proposals[last]
+						.getDisplayString();
+				boolean iReturn = proposals[i].getIdString() != proposals[i]
+						.getDisplayString();
+
+				if (!lastReturn && iReturn)
+					// flip i down to last
+					proposals[last] = proposals[i];
+
+				// Remove the duplicate
+				proposals[i] = null;
+				++removed;
+			} else
+				// update last
+				last = i;
+		}
+		if (removed > 0) {
+			// Strip out the null entries
+			ICCompletionProposal[] newArray = new ICCompletionProposal[proposals.length
+					- removed];
+			int j = 0;
+			for (int i = 0; i < proposals.length; ++i)
+				if (proposals[i] != null)
+					newArray[j++] = proposals[i];
+			proposals = newArray;
+		}
+
+		return proposals;
+	}
+
+}

core/org.eclipse.cdt.ui/src/org/eclipse/cdt/ui/text/contentassist/IProposalFilter.java

@@ -0,0 +1,18 @@
+package org.eclipse.cdt.ui.text.contentassist;
+
+import org.eclipse.cdt.ui.text.ICCompletionProposal;
+
+
+public interface IProposalFilter {
+	
+		/**
+		 * Filter a list of ICCompletionProposals <br>
+		 * - Change the order of entries <br>
+		 * - Remove undesired (duplicate) entries <br>
+		 * - Supplement existing entries with additional information
+		 * @param proposals The List of proposals
+		 * @return The filtered list of proposals as array
+		 */
+		ICCompletionProposal[] filterProposals(ICCompletionProposal[] proposals) ;
+
+}