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 */ 017 package org.apache.logging.log4j.core.web; 018 019 import javax.servlet.ServletContext; 020 import javax.servlet.ServletContextEvent; 021 import javax.servlet.ServletContextListener; 022 023 import org.apache.logging.log4j.core.LoggerContext; 024 import org.apache.logging.log4j.core.config.Configurator; 025 import org.apache.logging.log4j.core.lookup.Interpolator; 026 import org.apache.logging.log4j.core.lookup.StrLookup; 027 import org.apache.logging.log4j.core.lookup.StrSubstitutor; 028 029 /** 030 * Saves the LoggerContext into the ServletContext as an attribute. 031 */ 032 public class Log4jContextListener implements ServletContextListener { 033 034 /** 035 * The name of the attribute to use to store the LoggerContext into the ServletContext. 036 */ 037 public static final String LOG4J_CONTEXT_ATTRIBUTE = "Log4jContext"; 038 039 /** 040 * The location of the configuration. 041 */ 042 public static final String LOG4J_CONFIG = "log4jConfiguration"; 043 044 /** 045 * The name of the LoggerContext. 046 */ 047 public static final String LOG4J_CONTEXT_NAME = "log4jContextName"; 048 049 private final StrSubstitutor subst = new StrSubstitutor(new Interpolator()); 050 051 /** 052 * Initialize Logging for the web application. 053 * @param event The ServletContextEvent. 054 */ 055 @Override 056 public void contextInitialized(final ServletContextEvent event) { 057 final ServletContext context = event.getServletContext(); 058 final String locn = subst.replace(context.getInitParameter(LOG4J_CONFIG)); 059 String name = subst.replace(context.getInitParameter(LOG4J_CONTEXT_NAME)); 060 if (name == null) { 061 name = context.getServletContextName(); 062 } 063 if (name == null && locn == null) { 064 context.log("No Log4j context configuration provided"); 065 return; 066 } 067 context.setAttribute(LOG4J_CONTEXT_ATTRIBUTE, Configurator.initialize(name, getClassLoader(context), locn)); 068 } 069 070 /** 071 * Shutdown logging for the web application. 072 * @param event The ServletContextEvent. 073 */ 074 @Override 075 public void contextDestroyed(final ServletContextEvent event) { 076 final LoggerContext ctx = (LoggerContext) event.getServletContext().getAttribute(LOG4J_CONTEXT_ATTRIBUTE); 077 Configurator.shutdown(ctx); 078 } 079 080 private ClassLoader getClassLoader(final ServletContext context) { 081 try { 082 // if container is Servlet 3.0, use its getClassLoader method 083 return (ClassLoader)context.getClass().getMethod("getClassLoader").invoke(context); 084 } catch (Exception ignore) { 085 // otherwise, use this class's class loader 086 return Log4jContextListener.class.getClassLoader(); 087 } 088 } 089 }