org.mule.module.logging.MuleLogFactory.java Source code

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Here is the source code for org.mule.module.logging.MuleLogFactory.java

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/*
 * $Id$
 * --------------------------------------------------------------------------------------
 * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
 *
 * The software in this package is published under the terms of the CPAL v1.0
 * license, a copy of which has been included with this distribution in the
 * LICENSE.txt file.
 */

package org.mule.module.logging;

import java.lang.ref.PhantomReference;
import java.lang.ref.ReferenceQueue;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogConfigurationException;
import org.apache.commons.logging.impl.MuleLocationAwareLog;
import org.apache.commons.logging.impl.MuleLog;
import org.apache.commons.logging.impl.SLF4JLogFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.slf4j.spi.LocationAwareLogger;

public class MuleLogFactory extends SLF4JLogFactory {
    protected ConcurrentHashMap<Integer, ConcurrentMap<String, Log>> repository = new ConcurrentHashMap<Integer, ConcurrentMap<String, Log>>();

    protected static final Integer NO_CCL_CLASSLOADER = 0;

    protected ReferenceQueue<ClassLoader> referenceQueue = new ReferenceQueue<ClassLoader>();
    // map ref back to the classloader hash for cleanup of repository map, as both Weak- and SoftReference's get() return null by this time
    protected Map<PhantomReference<ClassLoader>, Integer> refs = new HashMap<PhantomReference<ClassLoader>, Integer>();

    public MuleLogFactory() {
        new LoggerReferenceHandler("Mule.log.clogging.ref.handler", referenceQueue, refs, repository);
    }

    public Log getInstance(String name) throws LogConfigurationException {
        final ClassLoader ccl = Thread.currentThread().getContextClassLoader();
        ConcurrentMap<String, Log> loggerMap = repository.get(ccl == null ? NO_CCL_CLASSLOADER : ccl.hashCode());

        if (loggerMap == null) {
            loggerMap = new ConcurrentHashMap<String, Log>();

            final ConcurrentMap<String, Log> previous = repository
                    .putIfAbsent(ccl == null ? NO_CCL_CLASSLOADER : ccl.hashCode(), loggerMap);
            if (previous != null) {
                loggerMap = previous;
            }

            if (ccl != null) {
                // must save a strong ref to the PhantomReference in order for it to stay alive and work
                refs.put(new PhantomReference<ClassLoader>(ccl, referenceQueue), ccl.hashCode());
            }

        }

        Log instance = loggerMap.get(name);

        if (instance == null) {
            Logger logger = LoggerFactory.getLogger(name);
            if (logger instanceof LocationAwareLogger) {
                instance = new MuleLocationAwareLog((LocationAwareLogger) logger);
            } else {
                instance = new MuleLog(logger);
            }
            final Log previous = loggerMap.putIfAbsent(name, instance);
            if (previous != null) {
                // someone got there before us
                instance = previous;
            }
        }

        return instance;
    }
}