alfresco-community-repo/source/java/org/alfresco/repo/admin/Log4JHierarchyInit.java

/*
 * Copyright (C) 2005-2007 Alfresco Software Limited.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

 * As a special exception to the terms and conditions of version 2.0 of
 * the GPL, you may redistribute this Program in connection with Free/Libre
 * and Open Source Software ("FLOSS") applications as described in Alfresco's
 * FLOSS exception.  You should have recieved a copy of the text describing
 * the FLOSS exception, and it is also available here:
 * http://www.alfresco.com/legal/licensing"
 */
package org.alfresco.repo.admin;

import java.io.BufferedInputStream;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.Properties;
import org.apache.log4j.jmx.HierarchyDynamicMBean;
import org.apache.log4j.Logger;
import org.apache.log4j.LogManager;
import org.apache.log4j.PropertyConfigurator;
import org.apache.log4j.spi.LoggerRepository;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;


/**
 * Initialises Log4j's HierarchyDynamicMBean (refer to core-services-context.xml)
 * and any overriding log4.properties files.
 * <p>
 * Alfresco modules can provide their own log4j.properties file,
 * which augments/overrides the global log4j.properties within 
 * the Alfresco webapp.  Within the module's source tree, suppose 
 * you create:<pre>
 *      config/alfresco/module/{module.id}/log4j.properties</pre>
 * At deployment time, this log4j.properties file will be placed in:<pre>
 *      WEB-INF/classes/alfresco/module/{module.id}/log4j.properties</pre>
 * Where {module.id} is whatever value is set within the AMP's 
 * module.properties file.  For details, see: 
 * <a href='http://wiki.alfresco.com/wiki/Developing_an_Alfresco_Module'>Developing an Alfresco Module</a>
 * <p> 
 * For example, if {module.id} is "org.alfresco.module.avmCompare", then 
 * within your source code you'll have:<pre>
 *      config/alfresco/module/org.alfresco.module.avmCompare/log4j.properties</pre>
 * This would be deployed to:<pre>
 *      WEB-INF/classes/alfresco/module/org.alfresco.module.avmCompare/log4j.properties</pre>
 * By default the 'overriding_log4j_properties' property of the 
 * 'log4JHierarchyInit' bean within core-services-context.xml is:<pre>
 *      classpath&#042;:alfresco/module/&#042;/log4j.properties</pre>
 * Therefore, Log4JHierarchyInit will discover this supplimentary log4j.properties 
 * file, and merge it with the main log4j.file (WEB-INF/classes/log4j.properties). 
 *  For example, the org.alfresco.module.avmCompare log4j.properties file might look like this:
 * <pre>
 *    #-----------------------------------------------------------------------
 *    # webscript module log4j.properties
 *    #                                  
 *    #   NOTE                           
 *    #   ----
 *    #
 *    #      Log4j uses the following logging levels:
 *    #      debug,info,warn,error,fatal
 *    #
 *    #      To set the logging level of {fullClassName} to {loglevel},
 *    #      add a line to this file of the following form:
 *    #
 *    #               log4j.logger.{fullClassName}={loglevel}
 *    #
 *    #      For example, to make 'com.example.MyExample' produce 'debug'
 *    #      logs, add a line like this:
 *    #
 *    #               log4j.logger.com.example.MyExample=debug
 *    #
 *    #
 *    #   WARNING
 *    #   -------
 *    #       Log properties in this log4j.properties file override/augment
 *    #       those in the webapp's main log4j.properties.
 *    #
 *    #-----------------------------------------------------------------------
 *    
 *    log4j.logger.org.alfresco.module.avmCompare.AvmCompare=info
 *    </pre>
 *    
 *    This system allows the author of any module to provide rich logging control 
 *    without concern for corrupting the central log4j.properties file during
 *    AMP installation/deinstallation.   For details, see:
 *    <a href='http://wiki.alfresco.com/wiki/Module_Management_Tool'>Module Management Tool</a>
 */
public class Log4JHierarchyInit
{
    private HierarchyDynamicMBean log4jHierarchy;
    private List<String>          extra_log4j_urls;
    
    public Log4JHierarchyInit()
    {   
        extra_log4j_urls = new ArrayList<String>();
    }


    /**
    *  Loads a set of augmenting/overriding log4j.properties files
    *  from locations specified via an array of 'spring_urls'
    *  (typically provided by a core-services-context.xml).
    * 
    *  This function supports Spring's syntax for retrieving 
    *  multiple class path resources with the same name, 
    *  via the "classpath&#042;:" prefix.   For details, see:
    *  <a href='http://www.jdocs.com/spring/1.2.8/org/springframework/core/io/support/PathMatchingResourcePatternResolver.html'>PathMatchingResourcePatternResolver</a>.
    */
    public void setOverriding_log4j_properties(List<String> spring_urls)
    {
        for ( String url : spring_urls ) { extra_log4j_urls.add( url ); }
    }

    public void setLog4jHierarchy(HierarchyDynamicMBean log4jHierarchy)
    {
        this.log4jHierarchy = log4jHierarchy;
    }
    
    @SuppressWarnings("unchecked")
    public void init()
    {
        // Add each logger (that has a level set) from 
        // the Log4J Repository to the Hierarchy MBean        

        LoggerRepository r = LogManager.getLoggerRepository();


        // Include overriding loggers
        //
        //       Typically, extra loggers come from AMP modules, but you
        //       could add others by augmenting core-services-context.xml
        //       This mechanism allows modules to have their own local
        //       log4j.properties file within:
        //      
        //          WEB-INF/classes/alfresco/module/{module.id}/log4j.properties
        //      
        //       Where:  module.id is whatever value is set within the AMP's
        //               'module.properties' file.
        //      
        //       See also:
        //         http://wiki.alfresco.com/wiki/Developing_an_Alfresco_Module
        //         (the module.properties section)
        //      
        //       And:
        //         core-services-context.xml

        set_overriding_loggers( r );

    
        Enumeration loggers = r.getCurrentLoggers();
        Logger logger = null;
       
        while (loggers.hasMoreElements())
        {
            logger = (Logger)loggers.nextElement();
            if (logger.getLevel() != null)
            {
                log4jHierarchy.addLoggerMBean(logger.getName());
            }
        }
    }

    void set_overriding_loggers( LoggerRepository hierarchy )
    {
        for ( String spring_url  : extra_log4j_urls )
        {
            set_overriding_logger( spring_url, hierarchy );
        }
    }

    void set_overriding_logger( String           spring_url, 
                                LoggerRepository hierarchy )
    {
        PathMatchingResourcePatternResolver resolver;
        PropertyConfigurator                prop_config;

        prop_config = new PropertyConfigurator();
        resolver    = new PathMatchingResourcePatternResolver();

        Resource[]  resources    = null;

        try
        {
            resources = resolver.getResources( spring_url ); 
        }
        catch (Exception e) { return ; }


        // Read each resource
        for (Resource resource : resources )
        {
            try
            {
                InputStream istream   = new BufferedInputStream(resource.getInputStream());
                Properties properties = new Properties();
                properties.load(istream);

                prop_config.doConfigure(properties, hierarchy);
            }
            catch (Throwable e) { /* do nothing */ }
        }
    }
}