bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/navigator/NavigatorActivationService.java - platform/eclipse.platform.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2003, 2005 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.ui.navigator;

 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Set;
 import java.util.StringTokenizer;

 import org.eclipse.core.runtime.ListenerList;
 import org.eclipse.core.runtime.Preferences;
 import org.eclipse.ui.navigator.internal.NavigatorPlugin;
 import org.eclipse.ui.navigator.internal.extensions.NavigatorContentDescriptorManager;

 /**
  *
  * The activation service determines if an extension is 'active' within the
  * context of a given viewer. If an extension is 'active' then the extension
  * will contribute functionality to the viewer. If an extension is not 'active',
  * then the extension will not be given opportunities to contribute
  * functionality to the given viewer. See {@link INavigatorContentService} for
  * more detail on what 'states' are associated with a content extension.
  *
  * <p>
  * <strong>EXPERIMENTAL</strong>. This class or interface has been added as
  * part of a work in progress. There is a guarantee neither that this API will
  * work nor that it will remain the same. Please do not use this API without
  * consulting with the Platform/UI team.
  * </p>
  *
  * @since 3.2
  */
 public final class NavigatorActivationService {

 	private static final String ACTIVATED_EXTENSIONS = ".activatedExtensions"; //$NON-NLS-1$

 	private static final String EXTENSION_ACTIVATED_SUFFIX = ".extensionActivated"; //$NON-NLS-1$

 	private static final NavigatorActivationService INSTANCE = new NavigatorActivationService();

 	private static final NavigatorContentDescriptorManager CONTENT_DESCRIPTOR_REGISTRY = NavigatorContentDescriptorManager
 			.getInstance();

 	/*
 	 * Map of activated extensions stored by the Viewer ID as a Set.
 	 *
 	 * That is, (ViewerID, Set of Extension Activations)-pairs.
 	 */
 	private final Map activatedExtensionsMap = new HashMap();

 	/*
 	 * Map of (ViewerID, ListenerLists of IExtensionActivationListener)-pairs.
 	 */
 	private final Map contentServiceListenersMap = new HashMap();

 	/**
 	 * Create an instance of the service.
 	 */
 	private NavigatorActivationService() {
 		super();
 	}

 	/**
 	 * Returns the singleton instance of the known activations.
 	 *
 	 * @return The single instance of the activation service.
 	 */
 	public static NavigatorActivationService getInstance() {
 		return INSTANCE;
 	}

 	/**
 	 *
 	 * Checks the known activation state for the given viewer id to determine if
 	 * the given navigator extension is 'active'.
 	 *
 	 * @param aViewerId
 	 *            The unique identifier for a defined viewer that uses an
 	 *            INavigatorContentService for its content.
 	 * @param aNavigatorExtensionId
 	 *            The unique identifier associated with a given extension.
 	 *
 	 * @return True if the extension is active in the context of the viewer id.
 	 */
 	public boolean isNavigatorExtensionActive(String aViewerId,
 			String aNavigatorExtensionId) {
 		return getActiveExtensions(aViewerId, true).contains(
 				getExtensionActivationPreferenceKey(aNavigatorExtensionId));
 	}

 	/**
 	 * Set the activation state for the given extension in the context of the
 	 * given viewer id. Each instance of an INavigatorContentService listens for
 	 * the activation service to update; and if those instances were created
 	 * with viewers, they will issue a refresh. Otherwise, clients are
 	 * responsible for refreshing the viewers.
 	 *
 	 * <p>
 	 * Clients must call {@link #persistExtensionActivations(String)} to save
 	 * the the activation state.
 	 * </p>
 	 *
 	 * <p>
 	 * When clients are updating a batch of extensions, consider using
 	 * {@link #activateNavigatorExtension(String, String[], boolean)} when
 	 * possible to avoid unnecessary notifications.
 	 * </p>
 	 *
 	 * @param aViewerId
 	 *            The unique identifier for a defined viewer that uses an
 	 *            INavigatorContentService for its content.
 	 * @param aNavigatorExtensionId
 	 *            The unique identifier associated with a given extension.
 	 * @param toEnable
 	 *            True indicates the extension should be enabled; False
 	 *            indicates otherwise.
 	 *
 	 */
 	public void activateNavigatorExtension(String aViewerId,
 			String aNavigatorExtensionId, boolean toEnable) {

 		boolean currentlyActive = isNavigatorExtensionActive(aViewerId,
 				aNavigatorExtensionId);
 		if (currentlyActive == toEnable)
 			return;

 		Set activatedExtensions = getActiveExtensions(aViewerId, true);
 		if (toEnable)
 			activatedExtensions
 					.add(getExtensionActivationPreferenceKey(aNavigatorExtensionId));
 		else
 			activatedExtensions
 					.remove(getExtensionActivationPreferenceKey(aNavigatorExtensionId));
 		notifyListeners(aViewerId, new String[] { aNavigatorExtensionId },
 				toEnable);

 	}

 	/**
 	 * Set the activation state for the given extension in the context of the
 	 * given viewer id. Each instance of an INavigatorContentService listens for
 	 * the activation service to update; and if those instances were created
 	 * with viewers, they will issue a refresh. Otherwise, clients are
 	 * responsible for refreshing the viewers.
 	 *
 	 * <p>
 	 * Clients must call {@link #persistExtensionActivations(String)} to save
 	 * the the activation state.
 	 * </p>
 	 *
 	 * @param aViewerId
 	 *            The unique identifier for a defined viewer that uses an
 	 *            INavigatorContentService for its content.
 	 * @param aNavigatorExtensionIds
 	 *            An array of unique identifiers associated with existing
 	 *            extension.
 	 * @param toEnable
 	 *            True indicates the extension should be enabled; False
 	 *            indicates otherwise.
 	 *
 	 */
 	public void activateNavigatorExtension(String aViewerId,
 			String[] aNavigatorExtensionIds, boolean toEnable) {

 		Set activatedExtensions = getActiveExtensions(aViewerId, true);
 		if (toEnable)
 			for (int i = 0; i < aNavigatorExtensionIds.length; i++)
 				activatedExtensions
 						.add(getExtensionActivationPreferenceKey(aNavigatorExtensionIds[i]));

 		else
 			for (int i = 0; i < aNavigatorExtensionIds.length; i++)
 				activatedExtensions
 						.remove(getExtensionActivationPreferenceKey(aNavigatorExtensionIds[i]));
 		notifyListeners(aViewerId, aNavigatorExtensionIds, toEnable);

 	}

 	/**
 	 * Save the activation state for the given viewer.
 	 *
 	 * @param aViewerId
 	 *            The unique identifier for a defined viewer that uses an
 	 *            INavigatorContentService for its content.
 	 */
 	public void persistExtensionActivations(String aViewerId) {

 		Set activatedExtensions = getActiveExtensions(aViewerId, false);
 		if (activatedExtensions == null)
 			return;

 		Preferences preferences = NavigatorPlugin.getDefault()
 				.getPluginPreferences();

 		synchronized (activatedExtensions) {
 			Iterator activatedExtensionsIterator = activatedExtensions
 					.iterator();
 			/* ensure that the preference will be non-empty */
 			StringBuffer activatedExtensionsStringBuffer = new StringBuffer(";"); //$NON-NLS-1$
 			while (activatedExtensionsIterator.hasNext()) {
 				activatedExtensionsStringBuffer.append(
 						activatedExtensionsIterator.next()).append(";"); //$NON-NLS-1$
 			}

 			preferences.setValue(getPreferenceKey(aViewerId),
 					activatedExtensionsStringBuffer.toString());
 		}
 		NavigatorPlugin.getDefault().savePluginPreferences();
 	}

 	/**
 	 * Request notification when the activation state changes for the given
 	 * viewer id.
 	 *
 	 * @param aViewerId
 	 *            The unique identifier for a defined viewer that uses an
 	 *            INavigatorContentService for its content.
 	 * @param aListener
 	 *            An implementation of {@link IExtensionActivationListener}
 	 */
 	public void addExtensionActivationListener(String aViewerId,
 			IExtensionActivationListener aListener) {
 		synchronized (contentServiceListenersMap) {
 			ListenerList listeners = getExtensionActivationListeners(aViewerId,
 					true);
 			listeners.add(aListener);
 		}
 	}

 	/**
 	 * No longer receive notification when activation state changes.
 	 *
 	 * @param aViewerId
 	 *            The unique identifier for a defined viewer that uses an
 	 *            INavigatorContentService for its content.
 	 * @param aListener
 	 *            An implementation of {@link IExtensionActivationListener}
 	 */
 	public void removeExtensionActivationListener(String aViewerId,
 			IExtensionActivationListener aListener) {
 		synchronized (contentServiceListenersMap) {
 			ListenerList listeners = getExtensionActivationListeners(aViewerId,
 					true);
 			listeners.remove(aListener);
 		}
 	}

 	private void notifyListeners(String aViewerId,
 			String[] navigatorExtensionIds, boolean toEnable) {
 		synchronized (contentServiceListenersMap) {
 			ListenerList listeners = (ListenerList) contentServiceListenersMap
 					.get(aViewerId);
 			if (listeners != null) {
 				Object[] listenerArray = listeners.getListeners();
 				for (int i = 0; i < listenerArray.length; i++)
 					((IExtensionActivationListener) listenerArray[i])
 							.onExtensionActivation(aViewerId,
 									navigatorExtensionIds, toEnable);

 			}
 		}
 	}

 	private ListenerList getExtensionActivationListeners(String aViewerId,
 			boolean initializeIfNecessary) {
 		ListenerList listeners = (ListenerList) contentServiceListenersMap
 				.get(aViewerId);
 		if (listeners != null || !initializeIfNecessary)
 			return listeners;

 		synchronized (contentServiceListenersMap) {
 			listeners = (ListenerList) contentServiceListenersMap
 					.get(aViewerId);
 			if (listeners == null)
 				contentServiceListenersMap.put(aViewerId,
 						(listeners = new ListenerList()));
 		}
 		return listeners;
 	}

 	private Set getActiveExtensions(String aViewerId,
 			boolean initializeIfNecessary) {
 		/* enabled by default if no setting is present ... */
 		Set activatedExtensions = (Set) activatedExtensionsMap.get(aViewerId);
 		if (activatedExtensions != null || !initializeIfNecessary)
 			return activatedExtensions;

 		synchronized (activatedExtensionsMap) {
 			activatedExtensions = (Set) activatedExtensionsMap.get(aViewerId);
 			if (activatedExtensions == null) {
 				activatedExtensions = revertExtensionActivations(aViewerId);
 				activatedExtensionsMap.put(aViewerId, activatedExtensions);
 			}
 		}
 		return activatedExtensions;
 	}

 	private Set revertExtensionActivations(String aViewerId) {

 		Preferences preferences = NavigatorPlugin.getDefault()
 				.getPluginPreferences();

 		Set activatedExtensions = new HashSet();
 		String activatedExtensionsString = preferences
 				.getString(getPreferenceKey(aViewerId));

 		if (activatedExtensionsString != null
 				&& activatedExtensionsString.length() > 0) {
 			String activatedExtensionKey = null;
 			StringTokenizer tokenizer = new StringTokenizer(
 					activatedExtensionsString, ";"); //$NON-NLS-1$
 			while (tokenizer.hasMoreTokens()) {
 				activatedExtensionKey = tokenizer.nextToken();
 				if (activatedExtensionKey.length() > 0)
 					activatedExtensions.add(activatedExtensionKey);
 			}
 		} else {
 			INavigatorContentDescriptor[] contentDescriptors = CONTENT_DESCRIPTOR_REGISTRY
 					.getAllContentDescriptors();
 			for (int i = 0; i < contentDescriptors.length; i++)
 				if (contentDescriptors[i].isEnabledByDefault())
 					activatedExtensions
 							.add(getExtensionActivationPreferenceKey(contentDescriptors[i]
 									.getId()));
 		}
 		return activatedExtensions;
 	}

 	private String getPreferenceKey(String aViewerId) {
 		return aViewerId + ACTIVATED_EXTENSIONS;
 	}

 	private String getExtensionActivationPreferenceKey(
 			String aNavigatorExtensionId) {
 		return aNavigatorExtensionId + EXTENSION_ACTIVATED_SUFFIX;
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2003, 2005 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.ui.navigator;

	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.Iterator;
	import java.util.Map;
	import java.util.Set;
	import java.util.StringTokenizer;

	import org.eclipse.core.runtime.ListenerList;
	import org.eclipse.core.runtime.Preferences;
	import org.eclipse.ui.navigator.internal.NavigatorPlugin;
	import org.eclipse.ui.navigator.internal.extensions.NavigatorContentDescriptorManager;

	/**
	*
	* The activation service determines if an extension is 'active' within the
	* context of a given viewer. If an extension is 'active' then the extension
	* will contribute functionality to the viewer. If an extension is not 'active',
	* then the extension will not be given opportunities to contribute
	* functionality to the given viewer. See {@link INavigatorContentService} for
	* more detail on what 'states' are associated with a content extension.
	*
	* <p>
	* <strong>EXPERIMENTAL</strong>. This class or interface has been added as
	* part of a work in progress. There is a guarantee neither that this API will
	* work nor that it will remain the same. Please do not use this API without
	* consulting with the Platform/UI team.
	* </p>
	*
	* @since 3.2
	*/
	public final class NavigatorActivationService {

	private static final String ACTIVATED_EXTENSIONS = ".activatedExtensions"; //$NON-NLS-1$

	private static final String EXTENSION_ACTIVATED_SUFFIX = ".extensionActivated"; //$NON-NLS-1$

	private static final NavigatorActivationService INSTANCE = new NavigatorActivationService();

	private static final NavigatorContentDescriptorManager CONTENT_DESCRIPTOR_REGISTRY = NavigatorContentDescriptorManager
	.getInstance();

	/*
	* Map of activated extensions stored by the Viewer ID as a Set.
	*
	* That is, (ViewerID, Set of Extension Activations)-pairs.
	*/
	private final Map activatedExtensionsMap = new HashMap();

	/*
	* Map of (ViewerID, ListenerLists of IExtensionActivationListener)-pairs.
	*/
	private final Map contentServiceListenersMap = new HashMap();

	/**
	* Create an instance of the service.
	*/
	private NavigatorActivationService() {
	super();
	}

	/**
	* Returns the singleton instance of the known activations.
	*
	* @return The single instance of the activation service.
	*/
	public static NavigatorActivationService getInstance() {
	return INSTANCE;
	}

	/**
	*
	* Checks the known activation state for the given viewer id to determine if
	* the given navigator extension is 'active'.
	*
	* @param aViewerId
	* The unique identifier for a defined viewer that uses an
	* INavigatorContentService for its content.
	* @param aNavigatorExtensionId
	* The unique identifier associated with a given extension.
	*
	* @return True if the extension is active in the context of the viewer id.
	*/
	public boolean isNavigatorExtensionActive(String aViewerId,
	String aNavigatorExtensionId) {
	return getActiveExtensions(aViewerId, true).contains(
	getExtensionActivationPreferenceKey(aNavigatorExtensionId));
	}

	/**
	* Set the activation state for the given extension in the context of the
	* given viewer id. Each instance of an INavigatorContentService listens for
	* the activation service to update; and if those instances were created
	* with viewers, they will issue a refresh. Otherwise, clients are
	* responsible for refreshing the viewers.
	*
	* <p>
	* Clients must call {@link #persistExtensionActivations(String)} to save
	* the the activation state.
	* </p>
	*
	* <p>
	* When clients are updating a batch of extensions, consider using
	* {@link #activateNavigatorExtension(String, String[], boolean)} when
	* possible to avoid unnecessary notifications.
	* </p>
	*
	* @param aViewerId
	* The unique identifier for a defined viewer that uses an
	* INavigatorContentService for its content.
	* @param aNavigatorExtensionId
	* The unique identifier associated with a given extension.
	* @param toEnable
	* True indicates the extension should be enabled; False
	* indicates otherwise.
	*
	*/
	public void activateNavigatorExtension(String aViewerId,
	String aNavigatorExtensionId, boolean toEnable) {

	boolean currentlyActive = isNavigatorExtensionActive(aViewerId,
	aNavigatorExtensionId);
	if (currentlyActive == toEnable)
	return;

	Set activatedExtensions = getActiveExtensions(aViewerId, true);
	if (toEnable)
	activatedExtensions
	.add(getExtensionActivationPreferenceKey(aNavigatorExtensionId));
	else
	activatedExtensions
	.remove(getExtensionActivationPreferenceKey(aNavigatorExtensionId));
	notifyListeners(aViewerId, new String[] { aNavigatorExtensionId },
	toEnable);

	}

	/**
	* Set the activation state for the given extension in the context of the
	* given viewer id. Each instance of an INavigatorContentService listens for
	* the activation service to update; and if those instances were created
	* with viewers, they will issue a refresh. Otherwise, clients are
	* responsible for refreshing the viewers.
	*
	* <p>
	* Clients must call {@link #persistExtensionActivations(String)} to save
	* the the activation state.
	* </p>
	*
	* @param aViewerId
	* The unique identifier for a defined viewer that uses an
	* INavigatorContentService for its content.
	* @param aNavigatorExtensionIds
	* An array of unique identifiers associated with existing
	* extension.
	* @param toEnable
	* True indicates the extension should be enabled; False
	* indicates otherwise.
	*
	*/
	public void activateNavigatorExtension(String aViewerId,
	String[] aNavigatorExtensionIds, boolean toEnable) {

	Set activatedExtensions = getActiveExtensions(aViewerId, true);
	if (toEnable)
	for (int i = 0; i < aNavigatorExtensionIds.length; i++)
	activatedExtensions
	.add(getExtensionActivationPreferenceKey(aNavigatorExtensionIds[i]));

	else
	for (int i = 0; i < aNavigatorExtensionIds.length; i++)
	activatedExtensions
	.remove(getExtensionActivationPreferenceKey(aNavigatorExtensionIds[i]));
	notifyListeners(aViewerId, aNavigatorExtensionIds, toEnable);

	}

	/**
	* Save the activation state for the given viewer.
	*
	* @param aViewerId
	* The unique identifier for a defined viewer that uses an
	* INavigatorContentService for its content.
	*/
	public void persistExtensionActivations(String aViewerId) {

	Set activatedExtensions = getActiveExtensions(aViewerId, false);
	if (activatedExtensions == null)
	return;

	Preferences preferences = NavigatorPlugin.getDefault()
	.getPluginPreferences();

	synchronized (activatedExtensions) {
	Iterator activatedExtensionsIterator = activatedExtensions
	.iterator();
	/* ensure that the preference will be non-empty */
	StringBuffer activatedExtensionsStringBuffer = new StringBuffer(";"); //$NON-NLS-1$
	while (activatedExtensionsIterator.hasNext()) {
	activatedExtensionsStringBuffer.append(
	activatedExtensionsIterator.next()).append(";"); //$NON-NLS-1$
	}

	preferences.setValue(getPreferenceKey(aViewerId),
	activatedExtensionsStringBuffer.toString());
	}
	NavigatorPlugin.getDefault().savePluginPreferences();
	}

	/**
	* Request notification when the activation state changes for the given
	* viewer id.
	*
	* @param aViewerId
	* The unique identifier for a defined viewer that uses an
	* INavigatorContentService for its content.
	* @param aListener
	* An implementation of {@link IExtensionActivationListener}
	*/
	public void addExtensionActivationListener(String aViewerId,
	IExtensionActivationListener aListener) {
	synchronized (contentServiceListenersMap) {
	ListenerList listeners = getExtensionActivationListeners(aViewerId,
	true);
	listeners.add(aListener);
	}
	}

	/**
	* No longer receive notification when activation state changes.
	*
	* @param aViewerId
	* The unique identifier for a defined viewer that uses an
	* INavigatorContentService for its content.
	* @param aListener
	* An implementation of {@link IExtensionActivationListener}
	*/
	public void removeExtensionActivationListener(String aViewerId,
	IExtensionActivationListener aListener) {
	synchronized (contentServiceListenersMap) {
	ListenerList listeners = getExtensionActivationListeners(aViewerId,
	true);
	listeners.remove(aListener);
	}
	}

	private void notifyListeners(String aViewerId,
	String[] navigatorExtensionIds, boolean toEnable) {
	synchronized (contentServiceListenersMap) {
	ListenerList listeners = (ListenerList) contentServiceListenersMap
	.get(aViewerId);
	if (listeners != null) {
	Object[] listenerArray = listeners.getListeners();
	for (int i = 0; i < listenerArray.length; i++)
	((IExtensionActivationListener) listenerArray[i])
	.onExtensionActivation(aViewerId,
	navigatorExtensionIds, toEnable);

	}
	}
	}

	private ListenerList getExtensionActivationListeners(String aViewerId,
	boolean initializeIfNecessary) {
	ListenerList listeners = (ListenerList) contentServiceListenersMap
	.get(aViewerId);
	if (listeners != null \|\| !initializeIfNecessary)
	return listeners;

	synchronized (contentServiceListenersMap) {
	listeners = (ListenerList) contentServiceListenersMap
	.get(aViewerId);
	if (listeners == null)
	contentServiceListenersMap.put(aViewerId,
	(listeners = new ListenerList()));
	}
	return listeners;
	}

	private Set getActiveExtensions(String aViewerId,
	boolean initializeIfNecessary) {
	/* enabled by default if no setting is present ... */
	Set activatedExtensions = (Set) activatedExtensionsMap.get(aViewerId);
	if (activatedExtensions != null \|\| !initializeIfNecessary)
	return activatedExtensions;

	synchronized (activatedExtensionsMap) {
	activatedExtensions = (Set) activatedExtensionsMap.get(aViewerId);
	if (activatedExtensions == null) {
	activatedExtensions = revertExtensionActivations(aViewerId);
	activatedExtensionsMap.put(aViewerId, activatedExtensions);
	}
	}
	return activatedExtensions;
	}

	private Set revertExtensionActivations(String aViewerId) {

	Preferences preferences = NavigatorPlugin.getDefault()
	.getPluginPreferences();

	Set activatedExtensions = new HashSet();
	String activatedExtensionsString = preferences
	.getString(getPreferenceKey(aViewerId));

	if (activatedExtensionsString != null
	&& activatedExtensionsString.length() > 0) {
	String activatedExtensionKey = null;
	StringTokenizer tokenizer = new StringTokenizer(
	activatedExtensionsString, ";"); //$NON-NLS-1$
	while (tokenizer.hasMoreTokens()) {
	activatedExtensionKey = tokenizer.nextToken();
	if (activatedExtensionKey.length() > 0)
	activatedExtensions.add(activatedExtensionKey);
	}
	} else {
	INavigatorContentDescriptor[] contentDescriptors = CONTENT_DESCRIPTOR_REGISTRY
	.getAllContentDescriptors();
	for (int i = 0; i < contentDescriptors.length; i++)
	if (contentDescriptors[i].isEnabledByDefault())
	activatedExtensions
	.add(getExtensionActivationPreferenceKey(contentDescriptors[i]
	.getId()));
	}
	return activatedExtensions;
	}

	private String getPreferenceKey(String aViewerId) {
	return aViewerId + ACTIVATED_EXTENSIONS;
	}

	private String getExtensionActivationPreferenceKey(
	String aNavigatorExtensionId) {
	return aNavigatorExtensionId + EXTENSION_ACTIVATED_SUFFIX;
	}

	}