    001/**
    002 * Copyright (c) 2004-2011 QOS.ch
    003 * All rights reserved.
    004 *
    005 * Permission is hereby granted, free  of charge, to any person obtaining
    006 * a  copy  of this  software  and  associated  documentation files  (the
    007 * "Software"), to  deal in  the Software without  restriction, including
    008 * without limitation  the rights to  use, copy, modify,  merge, publish,
    009 * distribute,  sublicense, and/or sell  copies of  the Software,  and to
    010 * permit persons to whom the Software  is furnished to do so, subject to
    011 * the following conditions:
    012 *
    013 * The  above  copyright  notice  and  this permission  notice  shall  be
    014 * included in all copies or substantial portions of the Software.
    015 *
    016 * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
    017 * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
    018 * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
    019 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
    020 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
    021 * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
    022 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
    023 *
    024 */
    025package org.slf4j.impl;
    026
    027import java.util.concurrent.ConcurrentHashMap;
    028import java.util.concurrent.ConcurrentMap;
    029
    030import org.apache.commons.logging.LogFactory;
    031import org.slf4j.ILoggerFactory;
    032import org.slf4j.Logger;
    033import org.slf4j.helpers.Util;
    034
    035/**
    036 * JCLLoggerFactory is an implementation of {@link ILoggerFactory} returning the
    037 * appropriately named {@link JCLLoggerAdapter} instance.
    038 *
    039 * @author Ceki G&uuml;lc&uuml;
    040 */
    041public class JCLLoggerFactory implements ILoggerFactory {
    042
    043    private static final String JCL_DELEGATION_LOOP_URL = "http://www.slf4j.org/codes.html#jclDelegationLoop";
    044
    045    // check for delegation loops
    046    static {
    047        try {
    048            Class.forName("org.apache.commons.logging.impl.SLF4JLogFactory");
    049            String part1 = "Detected both jcl-over-slf4j.jar AND bound slf4j-jcl.jar on the class path, preempting StackOverflowError. ";
    050            String part2 = "See also " + JCL_DELEGATION_LOOP_URL + " for more details.";
    051
    052            Util.report(part1);
    053            Util.report(part2);
    054            throw new IllegalStateException(part1 + part2);
    055        } catch (ClassNotFoundException e) {
    056            // this is the good case
    057        }
    058    }
    059
    060    // key: name (String), value: a JCLLoggerAdapter;
    061    final ConcurrentMap<String, Logger> loggerMap;
    062
    063    public JCLLoggerFactory() {
    064        loggerMap = new ConcurrentHashMap<String, Logger>();
    065    }
    066
    067    /*
    068     * (non-Javadoc)
    069     *
    070     * @see org.slf4j.ILoggerFactory#getLogger(java.lang.String)
    071     */
    072    public Logger getLogger(String name) {
    073        Logger slf4jLogger = loggerMap.get(name);
    074        if (slf4jLogger != null) {
    075            return slf4jLogger;
    076        } else {
    077            org.apache.commons.logging.Log jclLogger = LogFactory.getLog(name);
    078            Logger newInstance = new JCLLoggerAdapter(jclLogger, name);
    079            Logger oldInstance = loggerMap.putIfAbsent(name, newInstance);
    080            return oldInstance == null ? newInstance : oldInstance;
    081        }
    082    }
    083}