| /******************************************************************************* |
| * Copyright (c) 2005, 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 org.eclipse.swt.widgets.Event; |
| |
| import org.eclipse.swt.SWT; |
| |
| /** |
| * MouseWheelHandlers can be |
| * {@link org.eclipse.gef.EditPartViewer#setProperty(String, Object) registered} |
| * on an EditPartViewer with keys generated by the KeyGenerator. GEF tools |
| * delegate handling of mouse-wheel events to MouseWheelHandlers, if there are |
| * no drag trackers active. |
| * |
| * @author Pratik Shah |
| * @since 3.1 |
| */ |
| public interface MouseWheelHandler { |
| |
| /** |
| * Handles mouse-wheel events. If the given event was handled in some way, |
| * its {@link Event#doit doit} field should be set to false so as to prevent |
| * further processing of that event. |
| * |
| * @param event |
| * The SWT event that was generated as a result of the |
| * mouse-wheel scrolling |
| * @param viewer |
| * The originating viewer |
| */ |
| void handleMouseWheel(Event event, EditPartViewer viewer); |
| |
| /** |
| * A utility class used to generate keys from a given stateMask. A |
| * MouseWheelHandler registered with such a key would only be asked to |
| * handle mouse-wheel events that have the same stateMask as the one that |
| * was used to generate the key. |
| * |
| * @author Pratik Shah |
| * @since 3.1 |
| */ |
| public class KeyGenerator { |
| /** |
| * The returned String is guaranteed to be equal for two different |
| * invocations with the same stateMask. |
| * <p> |
| * Valid stateMasks are SWT.NONE, SWT.CTRL, SWT.COMMAND, SWT.ALT, |
| * SWT.SHIFT, SWT.MOD1, SWT.MOD2, SWT.MOD3, SWT.MOD4, SWT.BUTTON* or any |
| * combination thereof. |
| * |
| * @param stateMask |
| * the state indicating which buttons/modifiers are active |
| * @return key for the given stateMask |
| * @throws IllegalArgumentException |
| * if the given stateMask is not valid |
| */ |
| public static String getKey(int stateMask) { |
| if ((stateMask & ~(SWT.BUTTON_MASK | SWT.MODIFIER_MASK)) != 0) |
| throw new IllegalArgumentException( |
| "Illegal state: " + stateMask); //$NON-NLS-1$ |
| return "MouseWheelHandler(" + stateMask + ")"; //$NON-NLS-1$ //$NON-NLS-2$ |
| } |
| } |
| |
| } |