core/plugins/org.eclipse.dltk.ui/src/org/eclipse/dltk/ui/text/completion/CompletionProposalComputerRegistry.java - dltk/org.eclipse.dltk.core - Gitiles

 /*******************************************************************************
  * Copyright (c) 2000, 2017 IBM Corporation and others.
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
  * http://www.eclipse.org/legal/epl-2.0.
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  *******************************************************************************/
 package org.eclipse.dltk.ui.text.completion;

 import java.text.MessageFormat;
 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.dltk.ui.DLTKUIPlugin;
 import org.eclipse.dltk.ui.PreferenceConstants;
 import org.eclipse.jface.dialogs.IDialogConstants;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.preference.IPreferenceStore;
 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.Display;
 import org.eclipse.swt.widgets.Link;
 import org.eclipse.ui.dialogs.PreferencesUtil;

 public final class CompletionProposalComputerRegistry {

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

 	/** 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 CompletionProposalComputerRegistry getDefault() {
 		if (fgSingleton == null) {
 			synchronized (CompletionProposalComputerRegistry.class) {
 				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<String, List<CompletionProposalComputerDescriptor>> 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<String, List<CompletionProposalComputerDescriptor>> fPublicDescriptorsByPartition = new HashMap<>();
 	/**
 	 * All descriptors (element type: {@link CompletionProposalComputerDescriptor}).
 	 */
 	private final List<CompletionProposalComputerDescriptor> fDescriptors = new ArrayList<>();
 	/**
 	 * Unmodifiable view of <code>fDescriptors</code>
 	 */
 	private final List<CompletionProposalComputerDescriptor> fPublicDescriptors = Collections
 			.unmodifiableList(fDescriptors);

 	private final List<CompletionProposalCategory> fCategories = new ArrayList<>();
 	private final List<CompletionProposalCategory> 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.dltk.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.dltk.ui.text.java.IScriptCompletionProposalComputer}. 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<CompletionProposalComputerDescriptor> getProposalComputerDescriptors(String partition) {
 		ensureExtensionPointRead();
 		List<CompletionProposalComputerDescriptor> result = fPublicDescriptorsByPartition.get(partition);
 		return result != null ? result : Collections.<CompletionProposalComputerDescriptor>emptyList();
 	}

 	/**
 	 * 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.dltk.ui.text.java.IScriptCompletionProposalComputer}. 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<CompletionProposalComputerDescriptor> 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<CompletionProposalCategory> 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<IConfigurationElement> elements = new ArrayList<>(
 				Arrays.asList(registry.getConfigurationElementsFor(DLTKUIPlugin.getPluginId(), EXTENSION_POINT)));

 		Map<String, List<CompletionProposalComputerDescriptor>> map = new HashMap<>();
 		List<CompletionProposalComputerDescriptor> all = new ArrayList<>();

 		List<CompletionProposalCategory> categories = getCategories(elements);
 		for (Iterator<IConfigurationElement> iter = elements.iterator(); iter.hasNext();) {
 			IConfigurationElement element = iter.next();
 			try {
 				CompletionProposalComputerDescriptor desc = new CompletionProposalComputerDescriptor(element, this,
 						categories);
 				final Set<String> partitions = desc.getPartitions();
 				for (String partition : partitions) {
 					List<CompletionProposalComputerDescriptor> 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.
 				 */
 				String message = MessageFormat.format(
 						ScriptTextMessages.CompletionProposalComputerRegistry_invalid_message, element.toString());
 				IStatus status = new Status(IStatus.WARNING, DLTKUIPlugin.getPluginId(), IStatus.OK, message, x);
 				informUser(status);
 			}
 		}

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

 			Set<String> partitions = map.keySet();
 			fDescriptorsByPartition.keySet().retainAll(partitions);
 			fPublicDescriptorsByPartition.keySet().retainAll(partitions);
 			for (Iterator<String> it = partitions.iterator(); it.hasNext();) {
 				String partition = it.next();
 				List<CompletionProposalComputerDescriptor> old = fDescriptorsByPartition.get(partition);
 				List<CompletionProposalComputerDescriptor> current = 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<CompletionProposalCategory> getCategories(List<IConfigurationElement> elements) {
 		IPreferenceStore store = DLTKUIPlugin.getDefault().getPreferenceStore();
 		String preference = store.getString(PreferenceConstants.CODEASSIST_EXCLUDED_CATEGORIES);
 		Set<String> disabled = new HashSet<>();
 		StringTokenizer tok = new StringTokenizer(preference, "\0"); //$NON-NLS-1$
 		while (tok.hasMoreTokens())
 			disabled.add(tok.nextToken());
 		Map<String, Integer> 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, Integer.valueOf(rank));
 		}

 		List<CompletionProposalCategory> categories = new ArrayList<>();
 		for (Iterator<IConfigurationElement> iter = elements.iterator(); iter.hasNext();) {
 			IConfigurationElement element = 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 = 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.
 				 */
 				String message = MessageFormat.format(
 						ScriptTextMessages.CompletionProposalComputerRegistry_invalid_message, element.toString());
 				IStatus status = new Status(IStatus.WARNING, DLTKUIPlugin.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) {
 		DLTKUIPlugin.log(status);
 		String title = ScriptTextMessages.CompletionProposalComputerRegistry_error_dialog_title;
 		CompletionProposalCategory category = descriptor.getCategory();
 		IContributor culprit = descriptor.getContributor();
 		Set<String> affectedPlugins = getAffectedContributors(category, culprit);

 		final String avoidHint;
 		final String culpritName = culprit == null ? null : culprit.getName();
 		if (affectedPlugins.isEmpty())
 			avoidHint = MessageFormat.format(ScriptTextMessages.CompletionProposalComputerRegistry_messageAvoidanceHint,
 					culpritName, category.getDisplayName());
 		else
 			avoidHint = MessageFormat.format(
 					ScriptTextMessages.CompletionProposalComputerRegistry_messageAvoidanceHintWithWarning, culpritName,
 					category.getDisplayName(), toString(affectedPlugins));

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

 	/**
 	 * 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<String> getAffectedContributors(CompletionProposalCategory category, IContributor culprit) {
 		Set<String> affectedPlugins = new HashSet<>();
 		for (Iterator<CompletionProposalComputerDescriptor> it = getProposalComputerDescriptors().iterator(); it
 				.hasNext();) {
 			CompletionProposalComputerDescriptor desc = 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<String> collection) {
 		// strip brackets off AbstractCollection.toString()
 		String string = collection.toString();
 		return string.substring(1, string.length() - 1);
 	}

 	private void informUser(IStatus status) {
 		DLTKUIPlugin.log(status);
 		String title = ScriptTextMessages.CompletionProposalComputerRegistry_error_dialog_title;
 		String message = status.getMessage();
 		MessageDialog.openError(DLTKUIPlugin.getActiveWorkbenchShell(), title, message);
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2017 IBM Corporation and others.
	* This program and the accompanying materials are made available under the
	* terms of the Eclipse Public License v. 2.0 which is available at
	* http://www.eclipse.org/legal/epl-2.0.
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	*******************************************************************************/
	package org.eclipse.dltk.ui.text.completion;

	import java.text.MessageFormat;
	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.dltk.ui.DLTKUIPlugin;
	import org.eclipse.dltk.ui.PreferenceConstants;
	import org.eclipse.jface.dialogs.IDialogConstants;
	import org.eclipse.jface.dialogs.MessageDialog;
	import org.eclipse.jface.preference.IPreferenceStore;
	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.Display;
	import org.eclipse.swt.widgets.Link;
	import org.eclipse.ui.dialogs.PreferencesUtil;

	public final class CompletionProposalComputerRegistry {

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

	/** 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 CompletionProposalComputerRegistry getDefault() {
	if (fgSingleton == null) {
	synchronized (CompletionProposalComputerRegistry.class) {
	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<String, List<CompletionProposalComputerDescriptor>> 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<String, List<CompletionProposalComputerDescriptor>> fPublicDescriptorsByPartition = new HashMap<>();
	/**
	* All descriptors (element type: {@link CompletionProposalComputerDescriptor}).
	*/
	private final List<CompletionProposalComputerDescriptor> fDescriptors = new ArrayList<>();
	/**
	* Unmodifiable view of <code>fDescriptors</code>
	*/
	private final List<CompletionProposalComputerDescriptor> fPublicDescriptors = Collections
	.unmodifiableList(fDescriptors);

	private final List<CompletionProposalCategory> fCategories = new ArrayList<>();
	private final List<CompletionProposalCategory> 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.dltk.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.dltk.ui.text.java.IScriptCompletionProposalComputer}. 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<CompletionProposalComputerDescriptor> getProposalComputerDescriptors(String partition) {
	ensureExtensionPointRead();
	List<CompletionProposalComputerDescriptor> result = fPublicDescriptorsByPartition.get(partition);
	return result != null ? result : Collections.<CompletionProposalComputerDescriptor>emptyList();
	}

	/**
	* 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.dltk.ui.text.java.IScriptCompletionProposalComputer}. 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<CompletionProposalComputerDescriptor> 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<CompletionProposalCategory> 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<IConfigurationElement> elements = new ArrayList<>(
	Arrays.asList(registry.getConfigurationElementsFor(DLTKUIPlugin.getPluginId(), EXTENSION_POINT)));

	Map<String, List<CompletionProposalComputerDescriptor>> map = new HashMap<>();
	List<CompletionProposalComputerDescriptor> all = new ArrayList<>();

	List<CompletionProposalCategory> categories = getCategories(elements);
	for (Iterator<IConfigurationElement> iter = elements.iterator(); iter.hasNext();) {
	IConfigurationElement element = iter.next();
	try {
	CompletionProposalComputerDescriptor desc = new CompletionProposalComputerDescriptor(element, this,
	categories);
	final Set<String> partitions = desc.getPartitions();
	for (String partition : partitions) {
	List<CompletionProposalComputerDescriptor> 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.
	*/
	String message = MessageFormat.format(
	ScriptTextMessages.CompletionProposalComputerRegistry_invalid_message, element.toString());
	IStatus status = new Status(IStatus.WARNING, DLTKUIPlugin.getPluginId(), IStatus.OK, message, x);
	informUser(status);
	}
	}

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

	Set<String> partitions = map.keySet();
	fDescriptorsByPartition.keySet().retainAll(partitions);
	fPublicDescriptorsByPartition.keySet().retainAll(partitions);
	for (Iterator<String> it = partitions.iterator(); it.hasNext();) {
	String partition = it.next();
	List<CompletionProposalComputerDescriptor> old = fDescriptorsByPartition.get(partition);
	List<CompletionProposalComputerDescriptor> current = 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<CompletionProposalCategory> getCategories(List<IConfigurationElement> elements) {
	IPreferenceStore store = DLTKUIPlugin.getDefault().getPreferenceStore();
	String preference = store.getString(PreferenceConstants.CODEASSIST_EXCLUDED_CATEGORIES);
	Set<String> disabled = new HashSet<>();
	StringTokenizer tok = new StringTokenizer(preference, "\0"); //$NON-NLS-1$
	while (tok.hasMoreTokens())
	disabled.add(tok.nextToken());
	Map<String, Integer> 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, Integer.valueOf(rank));
	}

	List<CompletionProposalCategory> categories = new ArrayList<>();
	for (Iterator<IConfigurationElement> iter = elements.iterator(); iter.hasNext();) {
	IConfigurationElement element = 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 = 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.
	*/
	String message = MessageFormat.format(
	ScriptTextMessages.CompletionProposalComputerRegistry_invalid_message, element.toString());
	IStatus status = new Status(IStatus.WARNING, DLTKUIPlugin.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) {
	DLTKUIPlugin.log(status);
	String title = ScriptTextMessages.CompletionProposalComputerRegistry_error_dialog_title;
	CompletionProposalCategory category = descriptor.getCategory();
	IContributor culprit = descriptor.getContributor();
	Set<String> affectedPlugins = getAffectedContributors(category, culprit);

	final String avoidHint;
	final String culpritName = culprit == null ? null : culprit.getName();
	if (affectedPlugins.isEmpty())
	avoidHint = MessageFormat.format(ScriptTextMessages.CompletionProposalComputerRegistry_messageAvoidanceHint,
	culpritName, category.getDisplayName());
	else
	avoidHint = MessageFormat.format(
	ScriptTextMessages.CompletionProposalComputerRegistry_messageAvoidanceHintWithWarning, culpritName,
	category.getDisplayName(), toString(affectedPlugins));

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

	/**
	* 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<String> getAffectedContributors(CompletionProposalCategory category, IContributor culprit) {
	Set<String> affectedPlugins = new HashSet<>();
	for (Iterator<CompletionProposalComputerDescriptor> it = getProposalComputerDescriptors().iterator(); it
	.hasNext();) {
	CompletionProposalComputerDescriptor desc = 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<String> collection) {
	// strip brackets off AbstractCollection.toString()
	String string = collection.toString();
	return string.substring(1, string.length() - 1);
	}

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