MouseWheelHelper.java

/*******************************************************************************
 * Copyright (c) 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.gef;

import org.eclipse.swt.widgets.Event;

/**
 * MouseWheelHelpers provide each EditPart to handle mouse-wheel events in their own
 * desired way.  By default, when mouse-wheel events are generated that have no stateMask,
 * a default {@link MouseWheelHandler} delegates the task to the MouseWheelHelper that is
 * returned by the getAdapter() method of the EditPart in focus.
 * <p>
 * The most common usage of MouseWheelHelpers involves scrolling of an EditPart's figure.
 * They should be returned in the EditPart's getAdapter() method.
 * @see org.eclipse.gef.editparts.ViewportMouseWheelHelper 
 * @author Pratik Shah
 * @since 3.1
 */
public interface MouseWheelHelper
{

/**
 * 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
 */
void handleMouseWheelScrolled(Event event);

}