001 // Copyright 2004, 2005 The Apache Software Foundation 002 // 003 // Licensed under the Apache License, Version 2.0 (the "License"); 004 // you may not use this file except in compliance with the License. 005 // You may obtain a copy of the License at 006 // 007 // http://www.apache.org/licenses/LICENSE-2.0 008 // 009 // Unless required by applicable law or agreed to in writing, software 010 // distributed under the License is distributed on an "AS IS" BASIS, 011 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012 // See the License for the specific language governing permissions and 013 // limitations under the License. 014 015 package org.apache.tapestry.listener; 016 017 import java.util.Map; 018 019 import ognl.ObjectPropertyAccessor; 020 import ognl.OgnlException; 021 022 /** 023 * Exposes {@link org.apache.tapestry.IActionListener} listeners provided by the 024 * {@link org.apache.tapestry.listener.ListenerMap} as read-only properties of the map. 025 * 026 * @author Howard Lewis Ship 027 * @since 2.2 028 */ 029 030 public class ListenerMapPropertyAccessor extends ObjectPropertyAccessor 031 { 032 /** 033 * Checks to see if the ListenerMapImpl provides the named listener, returning the listener if 034 * it does. Otherwise, invokes the super implementation. 035 */ 036 037 public Object getProperty(Map context, Object target, Object name) throws OgnlException 038 { 039 ListenerMap map = (ListenerMap) target; 040 String listenerName = (String) name; 041 042 if (map.canProvideListener(listenerName)) 043 return map.getListener(listenerName); 044 045 return super.getProperty(context, target, name); 046 } 047 048 /** 049 * Returns true if the ListenerMap contains the named listener, otherwise invokes 050 * super-implementation. 051 */ 052 053 public boolean hasGetProperty(Map context, Object target, Object oname) throws OgnlException 054 { 055 ListenerMap map = (ListenerMap) target; 056 String listenerName = (String) oname; 057 058 if (map.canProvideListener(listenerName)) 059 return true; 060 061 return super.hasGetProperty(context, target, oname); 062 } 063 064 }