001/**
002 * Logback: the reliable, generic, fast and flexible logging framework.
003 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
004 *
005 * This program and the accompanying materials are dual-licensed under
006 * either the terms of the Eclipse Public License v1.0 as published by
007 * the Eclipse Foundation
008 *
009 *   or (per the licensee's choosing)
010 *
011 * under the terms of the GNU Lesser General Public License version 2.1
012 * as published by the Free Software Foundation.
013 */
014package ch.qos.logback.classic.selector.servlet;
015
016import java.io.IOException;
017
018import javax.servlet.Filter;
019import javax.servlet.FilterChain;
020import javax.servlet.FilterConfig;
021import javax.servlet.ServletException;
022import javax.servlet.ServletRequest;
023import javax.servlet.ServletResponse;
024
025import org.slf4j.LoggerFactory;
026
027import ch.qos.logback.classic.LoggerContext;
028import ch.qos.logback.classic.selector.ContextJNDISelector;
029import ch.qos.logback.classic.selector.ContextSelector;
030import ch.qos.logback.classic.util.ContextSelectorStaticBinder;
031
032/**
033 * A servlet filter that puts the environment dependent LoggerContext in a
034 * ThreadLocal variable, removing it after the request is processed.
035 * 
036 * <p>
037 * To use it, add the following lines to a web.xml file
038 * 
039 * <filter> <filter-name>LoggerContextFilter</filter-name> <filter-class>
040 * ch.qos.logback.classic.selector.servlet.LoggerContextFilter </filter-class>
041 * </filter> <filter-mapping> <filter-name>LoggerContextFilter</filter-name>
042 * <url-pattern>/*</url-pattern> </filter-mapping>
043 * 
044 * @author S&eacute;bastien Pennec
045 */
046public class LoggerContextFilter implements Filter {
047
048    public void destroy() {
049        // do nothing
050    }
051
052    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
053            throws IOException, ServletException {
054
055        LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
056        ContextSelector selector = ContextSelectorStaticBinder.getSingleton().getContextSelector();
057        ContextJNDISelector sel = null;
058
059        if (selector instanceof ContextJNDISelector) {
060            sel = (ContextJNDISelector) selector;
061            sel.setLocalContext(lc);
062        }
063
064        try {
065            chain.doFilter(request, response);
066        } finally {
067            if (sel != null) {
068                sel.removeLocalContext();
069            }
070        }
071    }
072
073    public void init(FilterConfig arg0) throws ServletException {
074        // do nothing
075    }
076}