| /******************************************************************************* |
| * Copyright (c) 2000, 2010 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.gef; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| import org.eclipse.swt.events.KeyEvent; |
| |
| import org.eclipse.jface.action.IAction; |
| |
| /** |
| * The KeyHandler should handle all normal keystrokes on an |
| * <code>EditPartViewer</code>. <I>Normal</i> is simply defined as keystrokes |
| * which are not associated with an Accelerator on the Menu. The KeyHandler will |
| * be forwarded KeyEvents by the active Tool, which is usually the |
| * SelectionTool. The Tool may be in a state where keystrokes should not be |
| * processed, in which case it will not forward the keystrokes. For this reason, |
| * it is important to always handle KeyEvents by using a KeyHandler. |
| * <P> |
| * KeyHandlers can be chained by calling {@link #setParent(KeyHandler)}. If this |
| * KeyHandler does not handle the keystroke, it will pass the keystroke to its |
| * <i>parent</i> KeyHandler. |
| * <P> |
| * KeyHandlers can be implemented using two stragegies. One is to map |
| * {@link KeyStroke KeyStrokes} to {@link org.eclipse.jface.action.IAction |
| * Actions} using the {@link #put(KeyStroke, IAction)} and |
| * {@link #remove(KeyStroke)} API. The other is to subclass KeyHandler, and |
| * override various methods. A combination of the two is also useful. |
| * |
| * @since 2.0 |
| */ |
| public class KeyHandler { |
| |
| private Map actions; |
| private KeyHandler parent; |
| |
| /** |
| * Processes a <i>key pressed</i> event. This method is called by the Tool |
| * whenever a key is pressed, and the Tool is in the proper state. |
| * |
| * @param event |
| * the KeyEvent |
| * @return <code>true</code> if KeyEvent was handled in some way |
| */ |
| public boolean keyPressed(KeyEvent event) { |
| if (performStroke(new KeyStroke(event, true))) { |
| event.doit = false; |
| return true; |
| } |
| return parent != null && parent.keyPressed(event); |
| } |
| |
| /** |
| * Processes a <i>key released</i> event. This method is called by the Tool |
| * whenever a key is released, and the Tool is in the proper state. |
| * |
| * @param event |
| * the KeyEvent |
| * @return <code>true</code> if KeyEvent was handled in some way |
| */ |
| public boolean keyReleased(KeyEvent event) { |
| if (performStroke(new KeyStroke(event, false))) |
| return true; |
| return parent != null && parent.keyReleased(event); |
| } |
| |
| private boolean performStroke(KeyStroke key) { |
| if (actions == null) |
| return false; |
| IAction action = (IAction) actions.get(key); |
| if (action == null) |
| return false; |
| if (action.isEnabled()) |
| action.run(); |
| return true; |
| } |
| |
| /** |
| * Maps a specified <code>KeyStroke</code> to an <code>IAction</code>. When |
| * a KeyEvent occurs matching the given KeyStroke, the Action will be |
| * <code>run()</code> iff it is enabled. |
| * |
| * @param keystroke |
| * the KeyStroke |
| * @param action |
| * the Action to run |
| */ |
| public void put(KeyStroke keystroke, IAction action) { |
| if (actions == null) |
| actions = new HashMap(); |
| actions.put(keystroke, action); |
| } |
| |
| /** |
| * Removed a mapped <code>IAction</code> for the specified |
| * <code>KeyStroke</code>. |
| * |
| * @param keystroke |
| * the KeyStroke to be unmapped |
| */ |
| public void remove(KeyStroke keystroke) { |
| if (actions != null) |
| actions.remove(keystroke); |
| } |
| |
| /** |
| * Sets a <i>parent</i> <code>KeyHandler</code> to which this KeyHandler |
| * will forward un-consumed KeyEvents. This KeyHandler will first attempt to |
| * handle KeyEvents. If it does not recognize a given KeyEvent, that event |
| * is passed to its <i>parent</i> |
| * |
| * @param parent |
| * the <i>parent</i> KeyHandler |
| * @return <code>this</code> for convenience |
| */ |
| public KeyHandler setParent(KeyHandler parent) { |
| this.parent = parent; |
| return this; |
| } |
| |
| } |