001    /*
002     * Copyright 2006 Google Inc.
003     * 
004     * Licensed under the Apache License, Version 2.0 (the "License"); you may not
005     * use this file except in compliance with the License. You may obtain a copy of
006     * the License at
007     * 
008     * http://www.apache.org/licenses/LICENSE-2.0
009     * 
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
012     * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
013     * License for the specific language governing permissions and limitations under
014     * the License.
015     */
016    package com.google.gwt.user.client;
017    
018    /**
019     * A listener interface for previewing browser events.
020     * 
021     * @see com.google.gwt.user.client.DOM#addEventPreview(EventPreview)
022     */
023    public interface EventPreview {
024    
025      /**
026       * Called when a browser event occurs and this event preview is on top of the
027       * preview stack.
028       * 
029       * @param event the browser event
030       * @return <code>false</code> to cancel the event
031       * @see DOM#addEventPreview(EventPreview)
032       */
033      boolean onEventPreview(Event event);
034    }