001/* 002 * (C) Copyright 2006-2011 Nuxeo SA (http://nuxeo.com/) and others. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of 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, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 * 016 * Contributors: 017 * Nuxeo - initial API and implementation 018 * 019 * $Id$ 020 */ 021 022package org.nuxeo.runtime.services.event; 023 024import java.util.Arrays; 025 026import org.apache.commons.logging.Log; 027import org.apache.commons.logging.LogFactory; 028import org.nuxeo.common.xmap.annotation.XNode; 029import org.nuxeo.common.xmap.annotation.XNodeList; 030import org.nuxeo.common.xmap.annotation.XObject; 031 032/** 033 * @author <a href="mailto:bs@nuxeo.com">Bogdan Stefanescu</a> 034 */ 035@XObject("listener") 036public class ListenerDescriptor { 037 038 private static final NullListener NULL_LISTENER = new NullListener(); 039 040 private static final Log log = LogFactory.getLog(ListenerDescriptor.class); 041 042 @XNodeList(value = "topic", type = String[].class, componentType = String.class) 043 String[] topics; 044 045 EventListener listener; 046 047 @XNode("@class") 048 public void setListener(Class<EventListener> listenerClass) { 049 try { 050 listener = listenerClass.newInstance(); 051 } catch (ReflectiveOperationException e) { 052 log.error(e); 053 listener = NULL_LISTENER; 054 } 055 } 056 057 @Override 058 public String toString() { 059 return listener + " { " + Arrays.toString(topics) + " }"; 060 } 061 062} 063 064class NullListener implements EventListener { 065 066 @Override 067 public boolean aboutToHandleEvent(Event event) { 068 return false; 069 } 070 071 @Override 072 public void handleEvent(Event event) { 073 } 074 075}