/******************************************************************************* * Copyright (c) 2005, 2010, 2012 IBM Corporation, Gerhardt Informatics Kft. 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 * Gerhardt Informatics Kft. - GEFGWT port *******************************************************************************/ package org.eclipse.gef; import org.eclipse.swt.SWT; import org.eclipse.swt.widgets.Event; /** * 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 + ")"; //$NON-NLS-1$ //$NON-NLS-2$ } } }