001/* 002 * Copyright 2002-2012 the original author or authors. 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 * https://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 017package org.springframework.web.context; 018 019import java.util.Enumeration; 020import javax.servlet.ServletContext; 021import javax.servlet.ServletContextEvent; 022import javax.servlet.ServletContextListener; 023 024import org.apache.commons.logging.Log; 025import org.apache.commons.logging.LogFactory; 026 027import org.springframework.beans.factory.DisposableBean; 028 029/** 030 * Web application listener that cleans up remaining disposable attributes 031 * in the ServletContext, i.e. attributes which implement {@link DisposableBean} 032 * and haven't been removed before. This is typically used for destroying objects 033 * in "application" scope, for which the lifecycle implies destruction at the 034 * very end of the web application's shutdown phase. 035 * 036 * @author Juergen Hoeller 037 * @since 3.0 038 * @see org.springframework.web.context.support.ServletContextScope 039 * @see ContextLoaderListener 040 */ 041public class ContextCleanupListener implements ServletContextListener { 042 043 private static final Log logger = LogFactory.getLog(ContextCleanupListener.class); 044 045 046 @Override 047 public void contextInitialized(ServletContextEvent event) { 048 } 049 050 @Override 051 public void contextDestroyed(ServletContextEvent event) { 052 cleanupAttributes(event.getServletContext()); 053 } 054 055 056 /** 057 * Find all ServletContext attributes which implement {@link DisposableBean} 058 * and destroy them, removing all affected ServletContext attributes eventually. 059 * @param sc the ServletContext to check 060 */ 061 static void cleanupAttributes(ServletContext sc) { 062 Enumeration<String> attrNames = sc.getAttributeNames(); 063 while (attrNames.hasMoreElements()) { 064 String attrName = attrNames.nextElement(); 065 if (attrName.startsWith("org.springframework.")) { 066 Object attrValue = sc.getAttribute(attrName); 067 if (attrValue instanceof DisposableBean) { 068 try { 069 ((DisposableBean) attrValue).destroy(); 070 } 071 catch (Throwable ex) { 072 logger.error("Couldn't invoke destroy method of attribute with name '" + attrName + "'", ex); 073 } 074 } 075 } 076 } 077 } 078 079}