AggregatedLoggerManager.java

/*
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.xwiki.contrib.mailarchive.utils.internal;

import java.lang.reflect.Type;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

import javax.inject.Inject;
import javax.inject.Singleton;

import org.slf4j.Logger;
import org.xwiki.component.annotation.Component;
import org.xwiki.contrib.mailarchive.utils.IAggregatedLoggerManager;
import org.xwiki.logging.LogLevel;
import org.xwiki.logging.LoggerManager;

/**
 * A Logger Manager that brings additional features:<br/>
 * <ul>
 * <li>Manages log level of a group of loggers, to avoid having to manage them one by one</li>
 * <li>Ability to restore loggers log levels at their previous state.</li>
 * </ul>
 * The idea is to provide an easy way to manage logs at Application level, from runtime. There is no link to loggers
 * initial configuration.<br/>
 * For example:
 * <p>
 * <blockquote>
 * 
 * <pre>
 *   private IAggregatedLoggerManager myAppLoggerManager;
 *   
 *   ...
 *   
 *   
 *   // Define groupings
 *   myAppLoggerManager.addLogger("myAppPackage1")
 *   myAppLoggerManager.addLogger("myAppPackage2")
 *   ...
 *   
 *   // Enters debug mode
 *   myAppLoggerManager.pushLogLevel(LogLevel.DEBUG)
 *   
 *   // ... from now on everything is logged at DEBUG level for configured loggers
 *   
 *   // Quits debug mode
 *   myAppLoggerManager.popLogLevel()
 *   
 *   // ... from now on loggers log levels are back to their values previous to pushLogLevel()
 * }
 * </pre>
 * 
 * </blockquote>
 * </p>
 * 
 * @author jbousque
 * @version $Id$
 */
@Component
@Singleton
public class AggregatedLoggerManager implements IAggregatedLoggerManager
{

    /**
     * A Map linking logger names to their previous log level.
     */
    private Map<String, LogLevel> loggers;

    @Inject
    LoggerManager loggerManager;

    @Inject
    Logger privateLogger;

    /**
     * {@inheritDoc}
     * 
     * @see org.xwiki.contrib.mailarchive.utils.IAggregatedLoggerManager#pushLogLevel(org.xwiki.logging.LogLevel)
     */
    @Override
    public void pushLogLevel(LogLevel logLevel)
    {
        if (this.loggers != null) {
            for (String logger : loggers.keySet()) {
                privateLogger
                    .debug("Saving log level " + loggerManager.getLoggerLevel(logger) + " for logger " + logger);
                loggers.put(logger, loggerManager.getLoggerLevel(logger));
                privateLogger.debug("Setting log level " + logLevel + " to logger " + logger);
                loggerManager.setLoggerLevel(logger, logLevel);
            }
        }
    }

    /**
     * {@inheritDoc}
     * 
     * @see org.xwiki.contrib.mailarchive.utils.IAggregatedLoggerManager#popLogLevel()
     */
    @Override
    public void popLogLevel()
    {
        if (this.loggers != null) {
            for (String logger : loggers.keySet()) {
                final LogLevel origLogLevel = loggers.get(logger);
                if (origLogLevel != null) {
                    loggerManager.setLoggerLevel(logger, origLogLevel);
                }
            }
        }

    }

    /**
     * {@inheritDoc}
     * 
     * @see org.xwiki.contrib.mailarchive.utils.IAggregatedLoggerManager#addLogger(java.lang.String)
     */
    @Override
    public void addLogger(String loggerName)
    {
        if (this.loggers == null) {
            this.loggers = new HashMap<String, LogLevel>();
        }
        // do not overwrite log level if that logger was already added
        if (!this.loggers.containsKey(loggerName)) {
            final LogLevel previousLogLevel = this.loggerManager.getLoggerLevel(loggerName);
            this.loggers.put(loggerName, previousLogLevel);
        }
    }

    /**
     * {@inheritDoc}
     * 
     * @see org.xwiki.contrib.mailarchive.utils.IAggregatedLoggerManager#removeLogger(java.lang.String)
     */
    @Override
    public void removeLogger(String loggerName)
    {
        if (this.loggers != null && this.loggers.containsKey(loggerName)) {
            this.loggers.remove(loggerName);
        }
    }

    @Override
    public void addComponentLogger(Type roleType)
    {
        privateLogger.warn("addComponentLogger(Type=" + roleType + ')');
        final String clazzName = ((Class< ? >) roleType).getCanonicalName();
        privateLogger.warn("clazzName=" + clazzName);
        String packageName = clazzName.substring(0, clazzName.lastIndexOf('.'));
        if (packageName.endsWith("internal")) {
            packageName = packageName.substring(0, packageName.length() - 9);
        }
        privateLogger.debug("adding managed logger for package " + packageName);
        addLogger(packageName);

    }

    /**
     * {@inheritDoc}
     * 
     * @see org.xwiki.contrib.mailarchive.utils.IAggregatedLoggerManager#setLoggers(java.util.List)
     */
    @Override
    public void setLoggers(Set<String> loggers)
    {
        cleanLoggers();
        for (String logger : loggers) {
            addLogger(logger);
        }
    }

    /**
     * {@inheritDoc}
     * 
     * @see org.xwiki.contrib.mailarchive.utils.IAggregatedLoggerManager#getLoggers()
     */
    @Override
    public Set<String> getLoggers()
    {
        return this.loggers.keySet();
    }

    /**
     * {@inheritDoc}
     * 
     * @see org.xwiki.contrib.mailarchive.utils.IAggregatedLoggerManager#cleanLoggers()
     */
    @Override
    public void cleanLoggers()
    {
        this.loggers = new HashMap<String, LogLevel>();
    }

}