001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.wicket.ajax; 018 019import org.apache.wicket.Component; 020import org.apache.wicket.ajax.attributes.AjaxCallListener; 021import org.apache.wicket.ajax.markup.html.AjaxFallbackLink; 022 023/** 024 * Decorator that can be used to cancel the regular action if ajax call was performed. This allows 025 * us to, for example, cancel the default anchor behavior (requesting href url) if an ajax call was 026 * made in the onclick event handler. Ajax call cannot be performed if javascript has been turned 027 * off or no compatible XmlHttpRequest object can be found. This decorator will make javascript 028 * return true if the ajax call was made, and false otherwise. 029 * 030 * @see AjaxFallbackLink 031 * 032 * @since 6.0 033 * 034 * @author Igor Vaynberg (ivaynberg) 035 * 036 */ 037public final class CancelEventIfAjaxListener extends AjaxCallListener 038{ 039 private static final long serialVersionUID = 1L; 040 041 @Override 042 public CharSequence getBeforeHandler(Component component) 043 { 044 return "if (attrs.event) { attrs.event.preventDefault(); }"; 045 } 046}