org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/java/CompletionProposalComputerRegistry.java - jdt/eclipse.jdt.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation 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:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.jdt.internal.ui.text.java;

 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.StringTokenizer;

 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IContributor;
 import org.eclipse.core.runtime.IExtensionRegistry;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.InvalidRegistryObjectException;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.core.runtime.Status;

 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Link;

 import org.eclipse.jface.dialogs.IDialogConstants;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.preference.IPreferenceStore;

 import org.eclipse.ui.dialogs.PreferencesUtil;

 import org.eclipse.jdt.internal.corext.util.Messages;

 import org.eclipse.jdt.ui.PreferenceConstants;

 import org.eclipse.jdt.internal.ui.JavaPlugin;

 /**
  * A registry for all extensions to the
  * <code>org.eclipse.jdt.ui.javaCompletionProposalComputer</code>
  * extension point.
  *
  * @since 3.2
  */
 public final class CompletionProposalComputerRegistry {

 	private static final String EXTENSION_POINT= "javaCompletionProposalComputer"; //$NON-NLS-1$

 	/** The singleton instance. */
 	private static CompletionProposalComputerRegistry fgSingleton= null;

 	/**
 	 * Returns the default computer registry.
 	 * <p>
 	 * TODO keep this or add some other singleton, e.g. JavaPlugin?
 	 * </p>
 	 *
 	 * @return the singleton instance
 	 */
 	public static synchronized CompletionProposalComputerRegistry getDefault() {
 		if (fgSingleton == null) {
 			fgSingleton= new CompletionProposalComputerRegistry();
 		}

 		return fgSingleton;
 	}

 	/**
 	 * The sets of descriptors, grouped by partition type (key type:
 	 * {@link String}, value type:
 	 * {@linkplain List List&lt;CompletionProposalComputerDescriptor&gt;}).
 	 */
 	private final Map fDescriptorsByPartition= new HashMap();
 	/**
 	 * Unmodifiable versions of the sets stored in
 	 * <code>fDescriptorsByPartition</code> (key type: {@link String},
 	 * value type:
 	 * {@linkplain List List&lt;CompletionProposalComputerDescriptor&gt;}).
 	 */
 	private final Map fPublicDescriptorsByPartition= new HashMap();
 	/**
 	 * All descriptors (element type:
 	 * {@link CompletionProposalComputerDescriptor}).
 	 */
 	private final List fDescriptors= new ArrayList();
 	/**
 	 * Unmodifiable view of <code>fDescriptors</code>
 	 */
 	private final List fPublicDescriptors= Collections.unmodifiableList(fDescriptors);

 	private final List fCategories= new ArrayList();
 	private final List fPublicCategories= Collections.unmodifiableList(fCategories);
 	/**
 	 * <code>true</code> if this registry has been loaded.
 	 */
 	private boolean fLoaded= false;

 	/**
 	 * Creates a new instance.
 	 */
 	public CompletionProposalComputerRegistry() {
 	}

 	/**
 	 * Returns the list of {@link CompletionProposalComputerDescriptor}s describing all extensions
 	 * to the <code>javaCompletionProposalComputer</code> extension point for the given partition
 	 * type.
 	 * <p>
 	 * A valid partition is either one of the constants defined in
 	 * {@link org.eclipse.jdt.ui.text.IJavaPartitions} or
 	 * {@link org.eclipse.jface.text.IDocument#DEFAULT_CONTENT_TYPE}. An empty list is returned if
 	 * there are no extensions for the given partition.
 	 * </p>
 	 * <p>
 	 * The returned list is read-only and is sorted in the order that the extensions were read in.
 	 * There are no duplicate elements in the returned list. The returned list may change if plug-ins
 	 * are loaded or unloaded while the application is running or if an extension violates the API
 	 * contract of {@link org.eclipse.jdt.ui.text.java.IJavaCompletionProposalComputer}. When
 	 * computing proposals, it is therefore imperative to copy the returned list before iterating
 	 * over it.
 	 * </p>
 	 *
 	 * @param partition
 	 *        the partition type for which to retrieve the computer descriptors
 	 * @return the list of extensions to the <code>javaCompletionProposalComputer</code> extension
 	 *         point (element type: {@link CompletionProposalComputerDescriptor})
 	 */
 	List getProposalComputerDescriptors(String partition) {
 		ensureExtensionPointRead();
 		List result= (List) fPublicDescriptorsByPartition.get(partition);
 		return result != null ? result : Collections.EMPTY_LIST;
 	}

 	/**
 	 * Returns the list of {@link CompletionProposalComputerDescriptor}s describing all extensions
 	 * to the <code>javaCompletionProposalComputer</code> extension point.
 	 * <p>
 	 * The returned list is read-only and is sorted in the order that the extensions were read in.
 	 * There are no duplicate elements in the returned list. The returned list may change if plug-ins
 	 * are loaded or unloaded while the application is running or if an extension violates the API
 	 * contract of {@link org.eclipse.jdt.ui.text.java.IJavaCompletionProposalComputer}. When
 	 * computing proposals, it is therefore imperative to copy the returned list before iterating
 	 * over it.
 	 * </p>
 	 *
 	 * @return the list of extensions to the <code>javaCompletionProposalComputer</code> extension
 	 *         point (element type: {@link CompletionProposalComputerDescriptor})
 	 */
 	List getProposalComputerDescriptors() {
 		ensureExtensionPointRead();
 		return fPublicDescriptors;
 	}

 	/**
 	 * Returns the list of proposal categories contributed to the
 	 * <code>javaCompletionProposalComputer</code> extension point.
 	 * <p>
 	 * <p>
 	 * The returned list is read-only and is sorted in the order that the extensions were read in.
 	 * There are no duplicate elements in the returned list. The returned list may change if
 	 * plug-ins are loaded or unloaded while the application is running.
 	 * </p>
 	 *
 	 * @return list of proposal categories contributed to the
 	 *         <code>javaCompletionProposalComputer</code> extension point (element type:
 	 *         {@link CompletionProposalCategory})
 	 */
 	public List getProposalCategories() {
 		ensureExtensionPointRead();
 		return fPublicCategories;
 	}

 	/**
 	 * Ensures that the extensions are read and stored in
 	 * <code>fDescriptorsByPartition</code>.
 	 */
 	private void ensureExtensionPointRead() {
 		boolean reload;
 		synchronized (this) {
 			reload= !fLoaded;
 			fLoaded= true;
 		}
 		if (reload)
 			reload();
 	}

 	/**
 	 * Reloads the extensions to the extension point.
 	 * <p>
 	 * This method can be called more than once in order to reload from
 	 * a changed extension registry.
 	 * </p>
 	 */
 	public void reload() {
 		IExtensionRegistry registry= Platform.getExtensionRegistry();
 		List elements= new ArrayList(Arrays.asList(registry.getConfigurationElementsFor(JavaPlugin.getPluginId(), EXTENSION_POINT)));

 		Map map= new HashMap();
 		List all= new ArrayList();

 		List categories= getCategories(elements);
 		for (Iterator iter= elements.iterator(); iter.hasNext();) {
 			IConfigurationElement element= (IConfigurationElement) iter.next();
 			try {
 				CompletionProposalComputerDescriptor desc= new CompletionProposalComputerDescriptor(element, this, categories);
 				Set partitions= desc.getPartitions();
 				for (Iterator it= partitions.iterator(); it.hasNext();) {
 					String partition= (String) it.next();
 					List list= (List) map.get(partition);
 					if (list == null) {
 						list= new ArrayList();
 						map.put(partition, list);
 					}
 					list.add(desc);
 				}
 				all.add(desc);

 			} catch (InvalidRegistryObjectException x) {
 				/*
 				 * Element is not valid any longer as the contributing plug-in was unloaded or for
 				 * some other reason. Do not include the extension in the list and inform the user
 				 * about it.
 				 */
 				Object[] args= {element.toString()};
 				String message= Messages.format(JavaTextMessages.CompletionProposalComputerRegistry_invalid_message, args);
 				IStatus status= new Status(IStatus.WARNING, JavaPlugin.getPluginId(), IStatus.OK, message, x);
 				informUser(status);
 			}
 		}

 		synchronized (this) {
 			fCategories.clear();
 			fCategories.addAll(categories);

 			Set partitions= map.keySet();
 			fDescriptorsByPartition.keySet().retainAll(partitions);
 			fPublicDescriptorsByPartition.keySet().retainAll(partitions);
 			for (Iterator it= partitions.iterator(); it.hasNext();) {
 				String partition= (String) it.next();
 				List old= (List) fDescriptorsByPartition.get(partition);
 				List current= (List) map.get(partition);
 				if (old != null) {
 					old.clear();
 					old.addAll(current);
 				} else {
 					fDescriptorsByPartition.put(partition, current);
 					fPublicDescriptorsByPartition.put(partition, Collections.unmodifiableList(current));
 				}
 			}

 			fDescriptors.clear();
 			fDescriptors.addAll(all);
 		}
 	}

 	private List getCategories(List elements) {
 		IPreferenceStore store= JavaPlugin.getDefault().getPreferenceStore();
 		String preference= store.getString(PreferenceConstants.CODEASSIST_EXCLUDED_CATEGORIES);
 		Set disabled= new HashSet();
 		StringTokenizer tok= new StringTokenizer(preference, "\0");  //$NON-NLS-1$
 		while (tok.hasMoreTokens())
 			disabled.add(tok.nextToken());
 		Map ordered= new HashMap();
 		preference= store.getString(PreferenceConstants.CODEASSIST_CATEGORY_ORDER);
 		tok= new StringTokenizer(preference, "\0"); //$NON-NLS-1$
 		while (tok.hasMoreTokens()) {
 			StringTokenizer inner= new StringTokenizer(tok.nextToken(), ":"); //$NON-NLS-1$
 			String id= inner.nextToken();
 			int rank= Integer.parseInt(inner.nextToken());
 			ordered.put(id, new Integer(rank));
 		}

 		List categories= new ArrayList();
 		for (Iterator iter= elements.iterator(); iter.hasNext();) {
 			IConfigurationElement element= (IConfigurationElement) iter.next();
 			try {
 				if (element.getName().equals("proposalCategory")) { //$NON-NLS-1$
 					iter.remove(); // remove from list to leave only computers

 					CompletionProposalCategory category= new CompletionProposalCategory(element, this);
 					categories.add(category);
 					category.setIncluded(!disabled.contains(category.getId()));
 					Integer rank= (Integer) ordered.get(category.getId());
 					if (rank != null) {
 						int r= rank.intValue();
 						boolean separate= r < 0xffff;
 						category.setSeparateCommand(separate);
 						category.setSortOrder(r);
 					}
 				}
 			} catch (InvalidRegistryObjectException x) {
 				/*
 				 * Element is not valid any longer as the contributing plug-in was unloaded or for
 				 * some other reason. Do not include the extension in the list and inform the user
 				 * about it.
 				 */
 				Object[] args= {element.toString()};
 				String message= Messages.format(JavaTextMessages.CompletionProposalComputerRegistry_invalid_message, args);
 				IStatus status= new Status(IStatus.WARNING, JavaPlugin.getPluginId(), IStatus.OK, message, x);
 				informUser(status);
 			}
 		}
 		return categories;
 	}

 	/**
 	 * Log the status and inform the user about a misbehaving extension.
 	 *
 	 * @param descriptor the descriptor of the misbehaving extension
 	 * @param status a status object that will be logged
 	 */
 	void informUser(CompletionProposalComputerDescriptor descriptor, IStatus status) {
 		JavaPlugin.log(status);
         String title= JavaTextMessages.CompletionProposalComputerRegistry_error_dialog_title;
         CompletionProposalCategory category= descriptor.getCategory();
         IContributor culprit= descriptor.getContributor();
         Set affectedPlugins= getAffectedContributors(category, culprit);

 		final String avoidHint;
 		final String culpritName= culprit == null ? null : culprit.getName();
 		if (affectedPlugins.isEmpty())
 			avoidHint= Messages.format(JavaTextMessages.CompletionProposalComputerRegistry_messageAvoidanceHint, new Object[] {culpritName, category.getDisplayName()});
 		else
 			avoidHint= Messages.format(JavaTextMessages.CompletionProposalComputerRegistry_messageAvoidanceHintWithWarning, new Object[] {culpritName, category.getDisplayName(), toString(affectedPlugins)});

 		String message= status.getMessage();
         // inlined from MessageDialog.openError
         MessageDialog dialog = new MessageDialog(JavaPlugin.getActiveWorkbenchShell(), title, null /* default image */, message, MessageDialog.ERROR, new String[] { IDialogConstants.OK_LABEL }, 0) {
         	protected Control createCustomArea(Composite parent) {
         		Link link= new Link(parent, SWT.NONE);
         		link.setText(avoidHint);
         		link.addSelectionListener(new SelectionAdapter() {
         			public void widgetSelected(SelectionEvent e) {
         				PreferencesUtil.createPreferenceDialogOn(getShell(), "org.eclipse.jdt.ui.preferences.CodeAssistPreferenceAdvanced", null, null).open(); //$NON-NLS-1$
         			}
         		});
         		GridData gridData= new GridData(SWT.FILL, SWT.BEGINNING, true, false);
         		gridData.widthHint= this.getMinimumMessageWidth();
 				link.setLayoutData(gridData);
         		return link;
         	}
         };
         dialog.open();
 	}

 	/**
 	 * Returns the names of contributors affected by disabling a category.
 	 *
 	 * @param category the category that would be disabled
 	 * @param culprit the cuprit plug-in, which is not included in the returned list
 	 * @return the names of the contributors other than <code>culprit</code> that contribute to <code>category</code> (element type: {@link String})
 	 */
 	private Set getAffectedContributors(CompletionProposalCategory category, IContributor culprit) {
 	    Set affectedPlugins= new HashSet();
         for (Iterator it= getProposalComputerDescriptors().iterator(); it.hasNext();) {
 	        CompletionProposalComputerDescriptor desc= (CompletionProposalComputerDescriptor) it.next();
 	        CompletionProposalCategory cat= desc.getCategory();
 	        if (cat.equals(category)) {
 	        	IContributor contributor= desc.getContributor();
 	        	if (contributor != null && !culprit.equals(contributor))
 	        		affectedPlugins.add(contributor.getName());
 	        }
         }
 	    return affectedPlugins;
     }

     private Object toString(Collection collection) {
     	// strip brackets off AbstractCollection.toString()
     	String string= collection.toString();
     	return string.substring(1, string.length() - 1);
     }

 	private void informUser(IStatus status) {
 		JavaPlugin.log(status);
 		String title= JavaTextMessages.CompletionProposalComputerRegistry_error_dialog_title;
 		String message= status.getMessage();
 		MessageDialog.openError(JavaPlugin.getActiveWorkbenchShell(), title, message);
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2006 IBM Corporation 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:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.jdt.internal.ui.text.java;

	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.Iterator;
	import java.util.List;
	import java.util.Map;
	import java.util.Set;
	import java.util.StringTokenizer;

	import org.eclipse.core.runtime.IConfigurationElement;
	import org.eclipse.core.runtime.IContributor;
	import org.eclipse.core.runtime.IExtensionRegistry;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.InvalidRegistryObjectException;
	import org.eclipse.core.runtime.Platform;
	import org.eclipse.core.runtime.Status;

	import org.eclipse.swt.SWT;
	import org.eclipse.swt.events.SelectionAdapter;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Link;

	import org.eclipse.jface.dialogs.IDialogConstants;
	import org.eclipse.jface.dialogs.MessageDialog;
	import org.eclipse.jface.preference.IPreferenceStore;

	import org.eclipse.ui.dialogs.PreferencesUtil;

	import org.eclipse.jdt.internal.corext.util.Messages;

	import org.eclipse.jdt.ui.PreferenceConstants;

	import org.eclipse.jdt.internal.ui.JavaPlugin;

	/**
	* A registry for all extensions to the
	* <code>org.eclipse.jdt.ui.javaCompletionProposalComputer</code>
	* extension point.
	*
	* @since 3.2
	*/
	public final class CompletionProposalComputerRegistry {

	private static final String EXTENSION_POINT= "javaCompletionProposalComputer"; //$NON-NLS-1$

	/** The singleton instance. */
	private static CompletionProposalComputerRegistry fgSingleton= null;

	/**
	* Returns the default computer registry.
	* <p>
	* TODO keep this or add some other singleton, e.g. JavaPlugin?
	* </p>
	*
	* @return the singleton instance
	*/
	public static synchronized CompletionProposalComputerRegistry getDefault() {
	if (fgSingleton == null) {
	fgSingleton= new CompletionProposalComputerRegistry();
	}

	return fgSingleton;
	}

	/**
	* The sets of descriptors, grouped by partition type (key type:
	* {@link String}, value type:
	* {@linkplain List List<CompletionProposalComputerDescriptor>}).
	*/
	private final Map fDescriptorsByPartition= new HashMap();
	/**
	* Unmodifiable versions of the sets stored in
	* <code>fDescriptorsByPartition</code> (key type: {@link String},
	* value type:
	* {@linkplain List List<CompletionProposalComputerDescriptor>}).
	*/
	private final Map fPublicDescriptorsByPartition= new HashMap();
	/**
	* All descriptors (element type:
	* {@link CompletionProposalComputerDescriptor}).
	*/
	private final List fDescriptors= new ArrayList();
	/**
	* Unmodifiable view of <code>fDescriptors</code>
	*/
	private final List fPublicDescriptors= Collections.unmodifiableList(fDescriptors);

	private final List fCategories= new ArrayList();
	private final List fPublicCategories= Collections.unmodifiableList(fCategories);
	/**
	* <code>true</code> if this registry has been loaded.
	*/
	private boolean fLoaded= false;

	/**
	* Creates a new instance.
	*/
	public CompletionProposalComputerRegistry() {
	}

	/**
	* Returns the list of {@link CompletionProposalComputerDescriptor}s describing all extensions
	* to the <code>javaCompletionProposalComputer</code> extension point for the given partition
	* type.
	* <p>
	* A valid partition is either one of the constants defined in
	* {@link org.eclipse.jdt.ui.text.IJavaPartitions} or
	* {@link org.eclipse.jface.text.IDocument#DEFAULT_CONTENT_TYPE}. An empty list is returned if
	* there are no extensions for the given partition.
	* </p>
	* <p>
	* The returned list is read-only and is sorted in the order that the extensions were read in.
	* There are no duplicate elements in the returned list. The returned list may change if plug-ins
	* are loaded or unloaded while the application is running or if an extension violates the API
	* contract of {@link org.eclipse.jdt.ui.text.java.IJavaCompletionProposalComputer}. When
	* computing proposals, it is therefore imperative to copy the returned list before iterating
	* over it.
	* </p>
	*
	* @param partition
	* the partition type for which to retrieve the computer descriptors
	* @return the list of extensions to the <code>javaCompletionProposalComputer</code> extension
	* point (element type: {@link CompletionProposalComputerDescriptor})
	*/
	List getProposalComputerDescriptors(String partition) {
	ensureExtensionPointRead();
	List result= (List) fPublicDescriptorsByPartition.get(partition);
	return result != null ? result : Collections.EMPTY_LIST;
	}

	/**
	* Returns the list of {@link CompletionProposalComputerDescriptor}s describing all extensions
	* to the <code>javaCompletionProposalComputer</code> extension point.
	* <p>
	* The returned list is read-only and is sorted in the order that the extensions were read in.
	* There are no duplicate elements in the returned list. The returned list may change if plug-ins
	* are loaded or unloaded while the application is running or if an extension violates the API
	* contract of {@link org.eclipse.jdt.ui.text.java.IJavaCompletionProposalComputer}. When
	* computing proposals, it is therefore imperative to copy the returned list before iterating
	* over it.
	* </p>
	*
	* @return the list of extensions to the <code>javaCompletionProposalComputer</code> extension
	* point (element type: {@link CompletionProposalComputerDescriptor})
	*/
	List getProposalComputerDescriptors() {
	ensureExtensionPointRead();
	return fPublicDescriptors;
	}

	/**
	* Returns the list of proposal categories contributed to the
	* <code>javaCompletionProposalComputer</code> extension point.
	* <p>
	* <p>
	* The returned list is read-only and is sorted in the order that the extensions were read in.
	* There are no duplicate elements in the returned list. The returned list may change if
	* plug-ins are loaded or unloaded while the application is running.
	* </p>
	*
	* @return list of proposal categories contributed to the
	* <code>javaCompletionProposalComputer</code> extension point (element type:
	* {@link CompletionProposalCategory})
	*/
	public List getProposalCategories() {
	ensureExtensionPointRead();
	return fPublicCategories;
	}

	/**
	* Ensures that the extensions are read and stored in
	* <code>fDescriptorsByPartition</code>.
	*/
	private void ensureExtensionPointRead() {
	boolean reload;
	synchronized (this) {
	reload= !fLoaded;
	fLoaded= true;
	}
	if (reload)
	reload();
	}

	/**
	* Reloads the extensions to the extension point.
	* <p>
	* This method can be called more than once in order to reload from
	* a changed extension registry.
	* </p>
	*/
	public void reload() {
	IExtensionRegistry registry= Platform.getExtensionRegistry();
	List elements= new ArrayList(Arrays.asList(registry.getConfigurationElementsFor(JavaPlugin.getPluginId(), EXTENSION_POINT)));

	Map map= new HashMap();
	List all= new ArrayList();

	List categories= getCategories(elements);
	for (Iterator iter= elements.iterator(); iter.hasNext();) {
	IConfigurationElement element= (IConfigurationElement) iter.next();
	try {
	CompletionProposalComputerDescriptor desc= new CompletionProposalComputerDescriptor(element, this, categories);
	Set partitions= desc.getPartitions();
	for (Iterator it= partitions.iterator(); it.hasNext();) {
	String partition= (String) it.next();
	List list= (List) map.get(partition);
	if (list == null) {
	list= new ArrayList();
	map.put(partition, list);
	}
	list.add(desc);
	}
	all.add(desc);

	} catch (InvalidRegistryObjectException x) {
	/*
	* Element is not valid any longer as the contributing plug-in was unloaded or for
	* some other reason. Do not include the extension in the list and inform the user
	* about it.
	*/
	Object[] args= {element.toString()};
	String message= Messages.format(JavaTextMessages.CompletionProposalComputerRegistry_invalid_message, args);
	IStatus status= new Status(IStatus.WARNING, JavaPlugin.getPluginId(), IStatus.OK, message, x);
	informUser(status);
	}
	}

	synchronized (this) {
	fCategories.clear();
	fCategories.addAll(categories);

	Set partitions= map.keySet();
	fDescriptorsByPartition.keySet().retainAll(partitions);
	fPublicDescriptorsByPartition.keySet().retainAll(partitions);
	for (Iterator it= partitions.iterator(); it.hasNext();) {
	String partition= (String) it.next();
	List old= (List) fDescriptorsByPartition.get(partition);
	List current= (List) map.get(partition);
	if (old != null) {
	old.clear();
	old.addAll(current);
	} else {
	fDescriptorsByPartition.put(partition, current);
	fPublicDescriptorsByPartition.put(partition, Collections.unmodifiableList(current));
	}
	}

	fDescriptors.clear();
	fDescriptors.addAll(all);
	}
	}

	private List getCategories(List elements) {
	IPreferenceStore store= JavaPlugin.getDefault().getPreferenceStore();
	String preference= store.getString(PreferenceConstants.CODEASSIST_EXCLUDED_CATEGORIES);
	Set disabled= new HashSet();
	StringTokenizer tok= new StringTokenizer(preference, "\0"); //$NON-NLS-1$
	while (tok.hasMoreTokens())
	disabled.add(tok.nextToken());
	Map ordered= new HashMap();
	preference= store.getString(PreferenceConstants.CODEASSIST_CATEGORY_ORDER);
	tok= new StringTokenizer(preference, "\0"); //$NON-NLS-1$
	while (tok.hasMoreTokens()) {
	StringTokenizer inner= new StringTokenizer(tok.nextToken(), ":"); //$NON-NLS-1$
	String id= inner.nextToken();
	int rank= Integer.parseInt(inner.nextToken());
	ordered.put(id, new Integer(rank));
	}

	List categories= new ArrayList();
	for (Iterator iter= elements.iterator(); iter.hasNext();) {
	IConfigurationElement element= (IConfigurationElement) iter.next();
	try {
	if (element.getName().equals("proposalCategory")) { //$NON-NLS-1$
	iter.remove(); // remove from list to leave only computers

	CompletionProposalCategory category= new CompletionProposalCategory(element, this);
	categories.add(category);
	category.setIncluded(!disabled.contains(category.getId()));
	Integer rank= (Integer) ordered.get(category.getId());
	if (rank != null) {
	int r= rank.intValue();
	boolean separate= r < 0xffff;
	category.setSeparateCommand(separate);
	category.setSortOrder(r);
	}
	}
	} catch (InvalidRegistryObjectException x) {
	/*
	* Element is not valid any longer as the contributing plug-in was unloaded or for
	* some other reason. Do not include the extension in the list and inform the user
	* about it.
	*/
	Object[] args= {element.toString()};
	String message= Messages.format(JavaTextMessages.CompletionProposalComputerRegistry_invalid_message, args);
	IStatus status= new Status(IStatus.WARNING, JavaPlugin.getPluginId(), IStatus.OK, message, x);
	informUser(status);
	}
	}
	return categories;
	}

	/**
	* Log the status and inform the user about a misbehaving extension.
	*
	* @param descriptor the descriptor of the misbehaving extension
	* @param status a status object that will be logged
	*/
	void informUser(CompletionProposalComputerDescriptor descriptor, IStatus status) {
	JavaPlugin.log(status);
	String title= JavaTextMessages.CompletionProposalComputerRegistry_error_dialog_title;
	CompletionProposalCategory category= descriptor.getCategory();
	IContributor culprit= descriptor.getContributor();
	Set affectedPlugins= getAffectedContributors(category, culprit);

	final String avoidHint;
	final String culpritName= culprit == null ? null : culprit.getName();
	if (affectedPlugins.isEmpty())
	avoidHint= Messages.format(JavaTextMessages.CompletionProposalComputerRegistry_messageAvoidanceHint, new Object[] {culpritName, category.getDisplayName()});
	else
	avoidHint= Messages.format(JavaTextMessages.CompletionProposalComputerRegistry_messageAvoidanceHintWithWarning, new Object[] {culpritName, category.getDisplayName(), toString(affectedPlugins)});

	String message= status.getMessage();
	// inlined from MessageDialog.openError
	MessageDialog dialog = new MessageDialog(JavaPlugin.getActiveWorkbenchShell(), title, null /* default image */, message, MessageDialog.ERROR, new String[] { IDialogConstants.OK_LABEL }, 0) {
	protected Control createCustomArea(Composite parent) {
	Link link= new Link(parent, SWT.NONE);
	link.setText(avoidHint);
	link.addSelectionListener(new SelectionAdapter() {
	public void widgetSelected(SelectionEvent e) {
	PreferencesUtil.createPreferenceDialogOn(getShell(), "org.eclipse.jdt.ui.preferences.CodeAssistPreferenceAdvanced", null, null).open(); //$NON-NLS-1$
	}
	});
	GridData gridData= new GridData(SWT.FILL, SWT.BEGINNING, true, false);
	gridData.widthHint= this.getMinimumMessageWidth();
	link.setLayoutData(gridData);
	return link;
	}
	};
	dialog.open();
	}

	/**
	* Returns the names of contributors affected by disabling a category.
	*
	* @param category the category that would be disabled
	* @param culprit the cuprit plug-in, which is not included in the returned list
	* @return the names of the contributors other than <code>culprit</code> that contribute to <code>category</code> (element type: {@link String})
	*/
	private Set getAffectedContributors(CompletionProposalCategory category, IContributor culprit) {
	Set affectedPlugins= new HashSet();
	for (Iterator it= getProposalComputerDescriptors().iterator(); it.hasNext();) {
	CompletionProposalComputerDescriptor desc= (CompletionProposalComputerDescriptor) it.next();
	CompletionProposalCategory cat= desc.getCategory();
	if (cat.equals(category)) {
	IContributor contributor= desc.getContributor();
	if (contributor != null && !culprit.equals(contributor))
	affectedPlugins.add(contributor.getName());
	}
	}
	return affectedPlugins;
	}

	private Object toString(Collection collection) {
	// strip brackets off AbstractCollection.toString()
	String string= collection.toString();
	return string.substring(1, string.length() - 1);
	}

	private void informUser(IStatus status) {
	JavaPlugin.log(status);
	String title= JavaTextMessages.CompletionProposalComputerRegistry_error_dialog_title;
	String message= status.getMessage();
	MessageDialog.openError(JavaPlugin.getActiveWorkbenchShell(), title, message);
	}
	}