Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2015 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.jface.action; import java.text.MessageFormat; import java.util.Collections; import java.util.HashMap; import java.util.HashSet; import java.util.Iterator; import java.util.Map; import java.util.Map.Entry; import java.util.ResourceBundle; import java.util.Set; import org.eclipse.core.commands.Command; import org.eclipse.core.commands.CommandEvent; import org.eclipse.core.commands.CommandManager; import org.eclipse.core.commands.ExecutionEvent; import org.eclipse.core.commands.ExecutionException; import org.eclipse.core.commands.ICommandListener; import org.eclipse.core.commands.NotEnabledException; import org.eclipse.core.commands.ParameterizedCommand; import org.eclipse.core.commands.common.NotDefinedException; import org.eclipse.core.runtime.IStatus; import org.eclipse.core.runtime.ListenerList; import org.eclipse.core.runtime.Status; import org.eclipse.jface.bindings.BindingManager; import org.eclipse.jface.bindings.BindingManagerEvent; import org.eclipse.jface.bindings.IBindingManagerListener; import org.eclipse.jface.bindings.Trigger; import org.eclipse.jface.bindings.TriggerSequence; import org.eclipse.jface.bindings.keys.KeySequence; import org.eclipse.jface.bindings.keys.KeyStroke; import org.eclipse.jface.bindings.keys.SWTKeySupport; import org.eclipse.jface.util.IPropertyChangeListener; import org.eclipse.jface.util.Policy; import org.eclipse.jface.util.PropertyChangeEvent; import org.eclipse.jface.util.Util; import org.eclipse.swt.widgets.Event; /** * <p> * A manager for a callback facility which is capable of querying external * interfaces for additional information about actions and action contribution * items. This information typically includes things like accelerators and * textual representations. * </p> * <p> * <em>It is only necessary to use this mechanism if you will be using a mix of * actions and commands, and wish the interactions to work properly.</em> * </p> * <p> * For example, in the Eclipse workbench, this mechanism is used to allow the * command architecture to override certain values in action contribution items. * </p> * <p> * This class is not intended to be called or extended by any external clients. * </p> * * @since 3.0 */ public final class ExternalActionManager { /** * A simple implementation of the <code>ICallback</code> mechanism that * simply takes a <code>BindingManager</code> and a * <code>CommandManager</code>. * <p> * <b>Note:</b> this class is not intended to be subclassed by clients. * </p> * * @since 3.1 */ public static class CommandCallback implements IBindingManagerListener, IBindingManagerCallback, IExecuteCallback { /** * The internationalization bundle for text produced by this class. */ private static final ResourceBundle RESOURCE_BUNDLE = ResourceBundle .getBundle(ExternalActionManager.class.getName()); /** * The callback capable of responding to whether a command is active. */ private final IActiveChecker activeChecker; /** * Check the applicability of firing an execution event for an action. */ private final IExecuteApplicable applicabilityChecker; /** * The binding manager for your application. Must not be * <code>null</code>. */ private final BindingManager bindingManager; /** * Whether a listener has been attached to the binding manager yet. */ private boolean bindingManagerListenerAttached = false; /** * The command manager for your application. Must not be * <code>null</code>. */ private final CommandManager commandManager; /** * A set of all the command identifiers that have been logged as broken * so far. For each of these, there will be a listener on the * corresponding command. If the command ever becomes defined, the item * will be removed from this set and the listener removed. This value * may be empty, but never <code>null</code>. */ private final Set<String> loggedCommandIds = new HashSet<>(); /** * The list of listeners that have registered for property change * notification. This is a map of command identifiers (<code>String</code>) * to listeners (<code>IPropertyChangeListener</code> or * <code>ListenerList</code> of <code>IPropertyChangeListener</code>). */ private final Map<String, Object> registeredListeners = new HashMap<>(); /** * Constructs a new instance of <code>CommandCallback</code> with the * workbench it should be using. All commands will be considered active. * * @param bindingManager * The binding manager which will provide the callback; must * not be <code>null</code>. * @param commandManager * The command manager which will provide the callback; must * not be <code>null</code>. * * @since 3.1 */ public CommandCallback(final BindingManager bindingManager, final CommandManager commandManager) { this(bindingManager, commandManager, commandId -> true, action -> true); } /** * Constructs a new instance of <code>CommandCallback</code> with the * workbench it should be using. * * @param bindingManager * The binding manager which will provide the callback; must * not be <code>null</code>. * @param commandManager * The command manager which will provide the callback; must * not be <code>null</code>. * @param activeChecker * The callback mechanism for checking whether a command is * active; must not be <code>null</code>. * * @since 3.1 */ public CommandCallback(final BindingManager bindingManager, final CommandManager commandManager, final IActiveChecker activeChecker) { this(bindingManager, commandManager, activeChecker, action -> true); } /** * Constructs a new instance of <code>CommandCallback</code> with the * workbench it should be using. * * @param bindingManager * The binding manager which will provide the callback; must * not be <code>null</code>. * @param commandManager * The command manager which will provide the callback; must * not be <code>null</code>. * @param activeChecker * The callback mechanism for checking whether a command is * active; must not be <code>null</code>. * @param checker * The callback to check if an IAction should fire execution * events. * * @since 3.4 */ public CommandCallback(final BindingManager bindingManager, final CommandManager commandManager, final IActiveChecker activeChecker, final IExecuteApplicable checker) { if (bindingManager == null) { throw new NullPointerException("The callback needs a binding manager"); //$NON-NLS-1$ } if (commandManager == null) { throw new NullPointerException("The callback needs a command manager"); //$NON-NLS-1$ } if (activeChecker == null) { throw new NullPointerException("The callback needs an active callback"); //$NON-NLS-1$ } if (checker == null) { throw new NullPointerException("The callback needs an applicable callback"); //$NON-NLS-1$ } this.activeChecker = activeChecker; this.bindingManager = bindingManager; this.commandManager = commandManager; this.applicabilityChecker = checker; } /** * @see org.eclipse.jface.action.ExternalActionManager.ICallback#addPropertyChangeListener(String, * IPropertyChangeListener) */ @Override public final void addPropertyChangeListener(final String commandId, final IPropertyChangeListener listener) { Object existing = registeredListeners.get(commandId); if (existing instanceof ListenerList) { ((ListenerList) existing).add(listener); } else if (existing != null) { ListenerList listeners = new ListenerList(ListenerList.IDENTITY); listeners.add(existing); listeners.add(listener); registeredListeners.put(commandId, listeners); } else { registeredListeners.put(commandId, listener); } if (!bindingManagerListenerAttached) { bindingManager.addBindingManagerListener(this); bindingManagerListenerAttached = true; } } @Override public final void bindingManagerChanged(final BindingManagerEvent event) { if (event.isActiveBindingsChanged()) { final Iterator<Entry<String, Object>> listenerItr = registeredListeners.entrySet().iterator(); while (listenerItr.hasNext()) { final Entry<String, Object> entry = listenerItr.next(); final String commandId = entry.getKey(); final Command command = commandManager.getCommand(commandId); final ParameterizedCommand parameterizedCommand = new ParameterizedCommand(command, null); if (event.isActiveBindingsChangedFor(parameterizedCommand)) { Object value = entry.getValue(); PropertyChangeEvent propertyChangeEvent = new PropertyChangeEvent(event.getManager(), IAction.TEXT, null, null); if (value instanceof ListenerList) { Object[] listeners = ((ListenerList) value).getListeners(); for (Object l : listeners) { final IPropertyChangeListener listener = (IPropertyChangeListener) l; listener.propertyChange(propertyChangeEvent); } } else { final IPropertyChangeListener listener = (IPropertyChangeListener) value; listener.propertyChange(propertyChangeEvent); } } } } } /** * @see org.eclipse.jface.action.ExternalActionManager.ICallback#getAccelerator(String) */ @Override public final Integer getAccelerator(final String commandId) { final TriggerSequence triggerSequence = bindingManager.getBestActiveBindingFor(commandId); if (triggerSequence != null) { final Trigger[] triggers = triggerSequence.getTriggers(); if (triggers.length == 1) { final Trigger trigger = triggers[0]; if (trigger instanceof KeyStroke) { final KeyStroke keyStroke = (KeyStroke) trigger; final int accelerator = SWTKeySupport.convertKeyStrokeToAccelerator(keyStroke); return Integer.valueOf(accelerator); } } } return null; } /** * @see org.eclipse.jface.action.ExternalActionManager.ICallback#getAcceleratorText(String) */ @Override public final String getAcceleratorText(final String commandId) { final TriggerSequence triggerSequence = bindingManager.getBestActiveBindingFor(commandId); if (triggerSequence == null) { return null; } return triggerSequence.format(); } /** * Returns the active bindings for a particular command identifier. * * @param commandId * The identifier of the command whose bindings are * requested. This argument may be <code>null</code>. It * is assumed that the command has no parameters. * @return The array of active triggers (<code>TriggerSequence</code>) * for a particular command identifier. This value is guaranteed * not to be <code>null</code>, but it may be empty. * @since 3.2 */ @Override public final TriggerSequence[] getActiveBindingsFor(final String commandId) { return bindingManager.getActiveBindingsFor(commandId); } /** * @see org.eclipse.jface.action.ExternalActionManager.ICallback#isAcceleratorInUse(int) */ @Override public final boolean isAcceleratorInUse(final int accelerator) { final KeySequence keySequence = KeySequence .getInstance(SWTKeySupport.convertAcceleratorToKeyStroke(accelerator)); return bindingManager.isPerfectMatch(keySequence) || bindingManager.isPartialMatch(keySequence); } /** * {@inheritDoc} * * Calling this method with an undefined command id will generate a log * message. */ @Override public final boolean isActive(final String commandId) { if (commandId != null) { final Command command = commandManager.getCommand(commandId); if (!command.isDefined() && (!loggedCommandIds.contains(commandId))) { // The command is not yet defined, so we should log this. final String message = MessageFormat.format( Util.translateString(RESOURCE_BUNDLE, "undefinedCommand.WarningMessage", null), //$NON-NLS-1$ command.getId()); IStatus status = new Status(IStatus.ERROR, "org.eclipse.jface", //$NON-NLS-1$ 0, message, new Exception()); Policy.getLog().log(status); // And remember this item so we don't log it again. loggedCommandIds.add(commandId); command.addCommandListener(new ICommandListener() { @Override public final void commandChanged(final CommandEvent commandEvent) { if (command.isDefined()) { command.removeCommandListener(this); loggedCommandIds.remove(commandId); } } }); return true; } return activeChecker.isActive(commandId); } return true; } /** * @see org.eclipse.jface.action.ExternalActionManager.ICallback#removePropertyChangeListener(String, * IPropertyChangeListener) */ @Override public final void removePropertyChangeListener(final String commandId, final IPropertyChangeListener listener) { Object existing = registeredListeners.get(commandId); if (existing == listener) { registeredListeners.remove(commandId); if (registeredListeners.isEmpty()) { bindingManager.removeBindingManagerListener(this); bindingManagerListenerAttached = false; } } else if (existing instanceof ListenerList) { ListenerList existingList = (ListenerList) existing; existingList.remove(listener); if (existingList.size() == 1) { registeredListeners.put(commandId, existingList.getListeners()[0]); } } } /** * @since 3.4 */ @Override public void preExecute(IAction action, Event event) { String actionDefinitionId = action.getActionDefinitionId(); if (actionDefinitionId == null || !applicabilityChecker.isApplicable(action)) { return; } Command command = commandManager.getCommand(actionDefinitionId); ExecutionEvent executionEvent = new ExecutionEvent(command, Collections.EMPTY_MAP, event, null); commandManager.firePreExecute(actionDefinitionId, executionEvent); } /** * @since 3.4 */ @Override public void postExecuteSuccess(IAction action, Object returnValue) { String actionDefinitionId = action.getActionDefinitionId(); if (actionDefinitionId == null || !applicabilityChecker.isApplicable(action)) { return; } commandManager.firePostExecuteSuccess(actionDefinitionId, returnValue); } /** * @since 3.4 */ @Override public void postExecuteFailure(IAction action, ExecutionException exception) { String actionDefinitionId = action.getActionDefinitionId(); if (actionDefinitionId == null || !applicabilityChecker.isApplicable(action)) { return; } commandManager.firePostExecuteFailure(actionDefinitionId, exception); } /** * @since 3.4 */ @Override public void notDefined(IAction action, NotDefinedException exception) { String actionDefinitionId = action.getActionDefinitionId(); if (actionDefinitionId == null || !applicabilityChecker.isApplicable(action)) { return; } commandManager.fireNotDefined(actionDefinitionId, exception); } /** * @since 3.4 */ @Override public void notEnabled(IAction action, NotEnabledException exception) { String actionDefinitionId = action.getActionDefinitionId(); if (actionDefinitionId == null || !applicabilityChecker.isApplicable(action)) { return; } commandManager.fireNotEnabled(actionDefinitionId, exception); } } /** * Defines a callback mechanism for developer who wish to further control * the visibility of legacy action-based contribution items. * * @since 3.1 */ public interface IActiveChecker { /** * Checks whether the command with the given identifier should be * considered active. This can be used in systems using some kind of * user interface filtering (e.g., activities in the Eclipse workbench). * * @param commandId * The identifier for the command; must not be * <code>null</code> * @return <code>true</code> if the command is active; * <code>false</code> otherwise. */ boolean isActive(String commandId); } /** * <p> * A callback which communicates with the applications binding manager. This * interface provides more information from the binding manager, which * allows greater integration. Implementing this interface is preferred over * {@link ExternalActionManager.ICallback}. * </p> * <p> * Clients may implement this interface, but must not extend. * </p> * * @since 3.2 */ public interface IBindingManagerCallback extends ICallback { /** * <p> * Returns the active bindings for a particular command identifier. * </p> * * @param commandId * The identifier of the command whose bindings are * requested. This argument may be <code>null</code>. It * is assumed that the command has no parameters. * @return The array of active triggers (<code>TriggerSequence</code>) * for a particular command identifier. This value is guaranteed * not to be <code>null</code>, but it may be empty. */ TriggerSequence[] getActiveBindingsFor(String commandId); } /** * An overridable mechanism to filter certain IActions from the execution * bridge. * * @since 3.4 */ public interface IExecuteApplicable { /** * Allow the callback to filter out actions that should not fire * execution events. * * @param action * The action with an actionDefinitionId * @return true if this action should be considered. */ boolean isApplicable(IAction action); } /** * <p> * A callback for executing execution events. Allows * <code>ActionContributionItems</code> to fire useful events. * </p> * <p> * Clients must not implement this interface and must not extend. * </p> * * @since 3.4 * */ public interface IExecuteCallback { /** * Fires a <code>NotEnabledException</code> because the action was not * enabled. * * @param action * The action contribution that caused the exception, * never <code>null</code>. * @param exception * The <code>NotEnabledException</code>, never <code>null</code>. */ void notEnabled(IAction action, NotEnabledException exception); /** * Fires a <code>NotDefinedException</code> because the action was not * defined. * * @param action * The action contribution that caused the exception, * never <code>null</code>. * @param exception * The <code>NotDefinedException</code>, never <code>null</code>. */ void notDefined(IAction action, NotDefinedException exception); /** * Fires an execution event before an action is run. * * @param action * The action contribution that requires an * execution event to be fired. Cannot be <code>null</code>. * @param e * The SWT Event, may be <code>null</code>. * */ void preExecute(IAction action, Event e); /** * Fires an execution event when the action returned a success. * * @param action * The action contribution that requires an * execution event to be fired. Cannot be <code>null</code>. * @param returnValue * The command's result, may be <code>null</code>. * */ void postExecuteSuccess(IAction action, Object returnValue); /** * Creates an <code>ExecutionException</code> when the action returned * a failure. * * @param action * The action contribution that caused the exception, * never <code>null</code>. * @param exception * The <code>ExecutionException</code>, never <code>null</code>. */ void postExecuteFailure(IAction action, ExecutionException exception); } /** * A callback mechanism for some external tool to communicate extra * information to actions and action contribution items. * * @since 3.0 */ public interface ICallback { /** * <p> * Adds a listener to the object referenced by <code>identifier</code>. * This listener will be notified if a property of the item is to be * changed. This identifier is specific to mechanism being used. In the * case of the Eclipse workbench, this is the command identifier. * </p> * <p> * Has no effect if an identical listener has already been added for * the <code>identifier</code>. * </p> * * @param identifier * The identifier of the item to which the listener should be * attached; must not be <code>null</code>. * @param listener * The listener to be added; must not be <code>null</code>. */ void addPropertyChangeListener(String identifier, IPropertyChangeListener listener); /** * An accessor for the accelerator associated with the item indicated by * the identifier. This identifier is specific to mechanism being used. * In the case of the Eclipse workbench, this is the command identifier. * * @param identifier * The identifier of the item from which the accelerator * should be obtained ; must not be <code>null</code>. * @return An integer representation of the accelerator. This is the * same accelerator format used by SWT. */ Integer getAccelerator(String identifier); /** * An accessor for the accelerator text associated with the item * indicated by the identifier. This identifier is specific to mechanism * being used. In the case of the Eclipse workbench, this is the command * identifier. * * @param identifier * The identifier of the item from which the accelerator text * should be obtained ; must not be <code>null</code>. * @return A string representation of the accelerator. This is the * string representation that should be displayed to the user. */ String getAcceleratorText(String identifier); /** * Checks to see whether the given accelerator is being used by some * other mechanism (outside of the menus controlled by JFace). This is * used to keep JFace from trying to grab accelerators away from someone * else. * * @param accelerator * The accelerator to check -- in SWT's internal accelerator * format. * @return <code>true</code> if the accelerator is already being used * and shouldn't be used again; <code>false</code> otherwise. */ boolean isAcceleratorInUse(int accelerator); /** * Checks whether the item matching this identifier is active. This is * used to decide whether a contribution item with this identifier * should be made visible. An inactive item is not visible. * * @param identifier * The identifier of the item from which the active state * should be retrieved; must not be <code>null</code>. * @return <code>true</code> if the item is active; <code>false</code> * otherwise. */ boolean isActive(String identifier); /** * Removes a listener from the object referenced by * <code>identifier</code>. This identifier is specific to mechanism * being used. In the case of the Eclipse workbench, this is the command * identifier. * * @param identifier * The identifier of the item to from the listener should be * removed; must not be <code>null</code>. * @param listener * The listener to be removed; must not be <code>null</code>. */ void removePropertyChangeListener(String identifier, IPropertyChangeListener listener); } /** * The singleton instance of this class. This value may be <code>null</code>-- * if it has not yet been initialized. */ private static ExternalActionManager instance; /** * Retrieves the current singleton instance of this class. * * @return The singleton instance; this value is never <code>null</code>. */ public static ExternalActionManager getInstance() { if (instance == null) { instance = new ExternalActionManager(); } return instance; } /** * The callback mechanism to use to retrieve extra information. */ private ICallback callback; /** * Constructs a new instance of <code>ExternalActionManager</code>. */ private ExternalActionManager() { // This is a singleton class. Only this class should create an instance. } /** * An accessor for the current call back. * * @return The current callback mechanism being used. This is the callback * that should be queried for extra information about actions and * action contribution items. This value may be <code>null</code> * if there is no extra information. */ public ICallback getCallback() { return callback; } /** * A mutator for the current call back * * @param callbackToUse * The new callback mechanism to use; this value may be * <code>null</code> if the default is acceptable (i.e., no * extra information will provided to actions). */ public void setCallback(ICallback callbackToUse) { callback = callbackToUse; } }