hotfix/source/openejb-core_4.5.2/src/main/java/org/apache/openejb/util/Logger.java - virgo/org.eclipse.virgo.eclipse-mirror - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to You under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 package org.apache.openejb.util;

 import org.apache.openejb.loader.IO;
 import org.apache.openejb.loader.SystemInstance;

 import java.io.File;
 import java.io.IOException;
 import java.text.MessageFormat;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 import java.util.MissingResourceException;
 import java.util.Properties;
 import java.util.ResourceBundle;

 public class Logger {
     private static final String SUFFIX = ".Messages";
     private static final String OPENEJB = "org.apache.openejb";
     private static LogStreamFactory logStreamFactory;

     static {
         configure();
     }

     public static synchronized void configure() {
         if (logStreamFactory != null) {
             return;
         }

         //See if user factory has been specified
         String factoryName = SystemInstance.get().getOptions().get("openejb.log.factory", JuliLogStreamFactory.class.getName());

         if ("jul".equalsIgnoreCase(factoryName) || "juli".equalsIgnoreCase(factoryName)) {

             factoryName = JuliLogStreamFactory.class.getName();

         } else if ("slf4j".equalsIgnoreCase(factoryName)) {

             factoryName = Slf4jLogStreamFactory.class.getName();

         } else if ("log4j".equalsIgnoreCase(factoryName)) {

             if (exists("org.apache.log4j.Logger")) {

                 // don't use .class to avoid to force loading since log4j is not mandatory
                 factoryName = "org.apache.openejb.util.Log4jLogStreamFactory";

             } else {

                 System.out.println("Cannot respect 'openejb.log.factory=log4j' setting as Log4j is not in the classpath.");

             }

         } else if ("pax".equalsIgnoreCase(factoryName)) {

             factoryName = "org.apache.openejb.util.PaxLogStreamFactory";
         }

         if (factoryName != null) {

             logStreamFactory = createFactory(factoryName);
         }

         if (isLog4jImplied()) {
             logStreamFactory = createFactory("org.apache.openejb.util.Log4jLogStreamFactory");
         }

         //Fall back -> JUL
         if (logStreamFactory == null) {
             logStreamFactory = new JuliLogStreamFactory();
         }

         checkForIgnoredLog4jConfig();
     }

     private static void checkForIgnoredLog4jConfig() {
         if (logStreamFactory.getClass().getName().equals("org.apache.openejb.util.Log4jLogStreamFactory")) return;

         try {
             final Properties configFile = log4j(loadLoggingProperties());

             final Properties systemProperties = log4j(SystemInstance.get().getProperties());

             if (configFile.size() == 0 && systemProperties.size() == 0) return;

             final LogStream stream = logStreamFactory.createLogStream(LogCategory.OPENEJB);

             stream.warn("Log4j not installed. The following properties will be ignored.");

             final String format = "Ignored %s property '%s'";

             for (final Object key : configFile.keySet()) {
                 stream.warn(String.format(format, "conf/logging.properties", key));
             }

             for (final Object key : systemProperties.keySet()) {
                 stream.warn(String.format(format, "Property overrides", key));
             }
         } catch (Throwable e) {
             // added strong catch block just in case
             // This check is only a convenience
         }
     }

     private static LogStreamFactory createFactory(final String factoryName) {

         final Class<?> factoryClass = load(factoryName);

         if (factoryClass == null) return null;

         try {
             //Try and use the user specified factory
             return (LogStreamFactory) factoryClass.newInstance();
         } catch (Throwable e) {
             //Ignore
         }

         return null;
     }

     private static Class<?> load(final String factoryName) {
         try {
             final ClassLoader classLoader = Logger.class.getClassLoader();
             return classLoader.loadClass(factoryName);
         } catch (Throwable e) {
             //Ignore
         }

         try {
             final ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
             return contextClassLoader.loadClass(factoryName);
         } catch (Throwable e1) {
             //Ignore
         }

         try {
             return Class.forName(factoryName);
         } catch (Throwable e2) {
             //Ignore
         }

         return null;
     }

     /**
      * Computes the parent of a resource name. E.g. if we pass in a key of
      * a.b.c, it returns the value a.b
      */
     private static final Computable<String, String> heirarchyResolver = new Computable<String, String>() {
         @Override
         public String compute(final String key) throws InterruptedException {
             final int index = key.lastIndexOf(".");
             final String parent = key.substring(0, index);
             if (parent.contains(OPENEJB))
                 return parent;
             return null;
         }
     };

     /**
      * Simply returns the ResourceBundle for a given baseName
      */
     private static final Computable<String, ResourceBundle> bundleResolver = new Computable<String, ResourceBundle>() {
         @Override
         public ResourceBundle compute(final String baseName) throws InterruptedException {
             try {
                 return ResourceBundle.getBundle(baseName + SUFFIX);
             } catch (MissingResourceException e) {
                 return null;
             }
         }
     };

     /**
      * Builds a Logger object and returns it
      */
     private static final Computable<Object[], Logger> loggerResolver = new Computable<Object[], Logger>() {
         @Override
         public Logger compute(final Object[] args) throws InterruptedException {
             final LogCategory category = (LogCategory) args[0];
             final LogStream logStream = logStreamFactory.createLogStream(category);
             final String baseName = (String) args[1];
             return new Logger(category, logStream, baseName);
         }
     };

     /**
      * Creates a MessageFormat object for a message and returns it
      */
     private static final Computable<String, MessageFormat> messageFormatResolver = new Computable<String, MessageFormat>() {
         @Override
         public MessageFormat compute(final String message) throws InterruptedException {
             return new MessageFormat(message);
         }
     };

     /**
      * Cache of parent-child relationships between resource names
      */
     private static final Computable<String, String> heirarchyCache = new Memoizer<String, String>(heirarchyResolver);

     /**
      * Cache of ResourceBundles
      */
     private static final Computable<String, ResourceBundle> bundleCache = new Memoizer<String, ResourceBundle>(bundleResolver);

     /**
      * Cache of Loggers
      */
     private static final Computable<Object[], Logger> loggerCache = new Memoizer<Object[], Logger>(loggerResolver);

     /**
      * Cache of MessageFormats
      */
     private static final Computable<String, MessageFormat> messageFormatCache = new Memoizer<String, MessageFormat>(messageFormatResolver);

     /**
      * Finds a Logger from the cache and returns it. If not found in cache then builds a Logger and returns it.
      *
      * @param category - The category of the logger
      * @param baseName - The baseName for the ResourceBundle
      * @return Logger
      */
     public static Logger getInstance(final LogCategory category, final String baseName) {
         try {
             return loggerCache.compute(new Object[]{category, baseName});
         } catch (InterruptedException e) {
             // Don't return null here. Just create a new Logger and set it up.
             // It will not be stored in the cache, but a later lookup for the
             // same Logger would probably end up in the cache
             final LogStream logStream = logStreamFactory.createLogStream(category);
             return new Logger(category, logStream, baseName);
         }
     }

     private final LogCategory category;
     private final LogStream logStream;
     private final String baseName;

     public Logger(final LogCategory category, final LogStream logStream, final String baseName) {
         this.category = category;
         this.logStream = logStream;
         this.baseName = baseName;
     }

     public static Logger getInstance(final LogCategory category, final Class clazz) {
         return getInstance(category, packageName(clazz));
     }

     private static String packageName(final Class clazz) {
         final String name = clazz.getName();
         return name.substring(0, name.lastIndexOf("."));
     }

     private static Boolean isLog4j = null;

     public static boolean isLog4jImplied() {

         if (null == isLog4j) {

             isLog4j = false;

             final List<String> locations = new ArrayList<String>();
             {
                 final Properties configFile = log4j(loadLoggingProperties());

                 final Properties systemProperties = log4j(SystemInstance.get().getProperties());

                 if (configFile.size() > 0) locations.add("conf/logging.properties");
                 if (systemProperties.size() > 0) locations.add("Properties overrides");
             }

             if (locations.size() > 0) {
                 if (exists("org.apache.log4j.Logger")) {
                     isLog4j = true;
                 }
             }
         }

         return isLog4j;
     }

     private static boolean exists(final String s) {
         return load(s) != null;
     }

     private static Properties log4j(final Properties system) {
         final Properties properties = new Properties();
         for (final Map.Entry<Object, Object> entry : system.entrySet()) {
             final String key = entry.getKey().toString();
             if (key.startsWith("log4j.") && !key.equals("log4j.configuration")) {
                 properties.put(key, entry.getValue());
             }
         }
         return properties;
     }

     private static Properties loadLoggingProperties() {
         try {
             final File conf = SystemInstance.get().getConf(null);

             final File file = new File(conf, "logging.properties");

             return IO.readProperties(file);
         } catch (IOException e) {
             return new Properties();
         }
     }

     public Logger getChildLogger(final String child) {
         return Logger.getInstance(this.category.createChild(child), this.baseName);
     }

     /**
      * Formats a given message
      *
      * @param message String
      * @param args    Object...
      * @return the formatted message
      */
     private String formatMessage(final String message, final Object... args) {
         if (args.length == 0) return message;

         try {
             final MessageFormat mf = messageFormatCache.compute(message);
             return mf.format(args);
         } catch (Exception e) {
             return "Error in formatting message " + message;
         }

     }

     public boolean isDebugEnabled() {
         return logStream.isDebugEnabled();
     }

     public boolean isErrorEnabled() {
         return logStream.isErrorEnabled();
     }

     public boolean isFatalEnabled() {
         return logStream.isFatalEnabled();
     }

     public boolean isInfoEnabled() {
         return logStream.isInfoEnabled();
     }

     public boolean isWarningEnabled() {
         return logStream.isWarnEnabled();
     }

     public boolean isLevelEnable(final String level) {
         if ("info".equals(level.toLowerCase())) {
             return isInfoEnabled();
         } else if ("debug".equals(level.toLowerCase())) {
             return isDebugEnabled();
         } else if ("warning".equals(level.toLowerCase())) {
             return isWarningEnabled();
         } else if ("fatal".equals(level.toLowerCase())) {
             return isFatalEnabled();
         } else if ("error".equals(level.toLowerCase())) {
             return isErrorEnabled();
         }
         return false;
     }

     public void log(final String level, final String message) {
         if ("info".equals(level.toLowerCase())) {
             info(message);
         } else if ("debug".equals(level.toLowerCase())) {
             debug(message);
         } else if ("warning".equals(level.toLowerCase())) {
             warning(message);
         } else if ("fatal".equals(level.toLowerCase())) {
             fatal(message);
         } else if ("error".equals(level.toLowerCase())) {
             error(message);
         }
     }

     /**
      * If this level is enabled, then it finds a message for the given key  and logs it
      *
      * @param message - This could be a plain message or a key in Messages.properties
      * @return the formatted i18n message
      */
     public String debug(final String message) {

         if (isDebugEnabled()) {
             final String msg = getMessage(message, baseName);
             logStream.debug(msg);
             return msg;
         }
         return message;
     }

     public String debug(final String message, final Object... args) {

         if (isDebugEnabled()) {
             String msg = getMessage(message, baseName);
             msg = formatMessage(msg, args);
             logStream.debug(msg);
             return msg;
         }
         return message;
     }

     public String debug(final String message, final Throwable t) {

         if (isDebugEnabled()) {
             final String msg = getMessage(message, baseName);
             logStream.debug(msg, t);
             return msg;
         }
         return message;
     }

     public String debug(final String message, final Throwable t, final Object... args) {

         if (isDebugEnabled()) {
             String msg = getMessage(message, baseName);
             msg = formatMessage(msg, args);
             logStream.debug(msg, t);
             return msg;
         }
         return message;
     }

     public String error(final String message) {

         if (isErrorEnabled()) {
             final String msg = getMessage(message, baseName);
             logStream.error(msg);
             return msg;
         }
         return message;
     }

     public String error(final String message, final Object... args) {

         if (isErrorEnabled()) {
             String msg = getMessage(message, baseName);
             msg = formatMessage(msg, args);
             logStream.error(msg);
             return msg;
         }
         return message;
     }

     public String error(final String message, final Throwable t) {

         if (isErrorEnabled()) {
             final String msg = getMessage(message, baseName);
             logStream.error(msg, t);
             return msg;
         }
         return message;
     }

     public String error(final String message, final Throwable t, final Object... args) {

         if (isErrorEnabled()) {
             String msg = getMessage(message, baseName);
             msg = formatMessage(msg, args);
             logStream.error(msg, t);
             return msg;
         }
         return message;
     }

     public String fatal(final String message) {
         if (isFatalEnabled()) {
             final String msg = getMessage(message, baseName);
             logStream.fatal(msg);
             return msg;
         }
         return message;
     }

     public String fatal(final String message, final Object... args) {
         if (isFatalEnabled()) {
             String msg = getMessage(message, baseName);
             msg = formatMessage(msg, args);
             logStream.fatal(msg);
             return msg;
         }
         return message;
     }

     public String fatal(final String message, final Throwable t) {
         if (isFatalEnabled()) {
             final String msg = getMessage(message, baseName);
             logStream.fatal(msg, t);
             return msg;
         }
         return message;
     }

     public String fatal(final String message, final Throwable t, final Object... args) {
         if (isFatalEnabled()) {
             String msg = getMessage(message, baseName);
             msg = formatMessage(msg, args);
             logStream.fatal(msg, t);
             return msg;
         }
         return message;
     }

     public String info(final String message) {
         if (isInfoEnabled()) {
             final String msg = getMessage(message, baseName);
             logStream.info(msg);
             return msg;
         }
         return message;
     }

     public String info(final String message, final Object... args) {
         if (isInfoEnabled()) {
             String msg = getMessage(message, baseName);
             msg = formatMessage(msg, args);
             logStream.info(msg);
             return msg;
         }
         return message;
     }

     public String info(final String message, final Throwable t) {
         if (isInfoEnabled()) {
             final String msg = getMessage(message, baseName);
             logStream.info(msg, t);
             return msg;
         }
         return message;
     }

     public String info(final String message, final Throwable t, final Object... args) {
         if (isInfoEnabled()) {
             String msg = getMessage(message, baseName);
             msg = formatMessage(msg, args);
             logStream.info(msg, t);
             return msg;
         }
         return message;
     }

     public String warning(final String message) {
         if (isWarningEnabled()) {
             final String msg = getMessage(message, baseName);
             logStream.warn(msg);
             return msg;
         }
         return message;
     }

     public String warning(final String message, final Object... args) {
         if (isWarningEnabled()) {
             String msg = getMessage(message, baseName);
             msg = formatMessage(msg, args);
             logStream.warn(msg);
             return msg;
         }
         return message;
     }

     public String warning(final String message, final Throwable t) {
         if (isWarningEnabled()) {
             final String msg = getMessage(message, baseName);
             logStream.warn(msg, t);
             return msg;
         }
         return message;
     }

     public String warning(final String message, final Throwable t, final Object... args) {
         if (isWarningEnabled()) {
             String msg = getMessage(message, baseName);
             msg = formatMessage(msg, args);
             logStream.warn(msg, t);
             return msg;
         }
         return message;
     }

     /**
      * Given a key and a baseName, this method computes a message for a key. if
      * the key is not found in this ResourceBundle for this baseName, then it
      * recursively looks up its parent to find the message for a key. If no
      * message is found for a key, the key is returned as is and is logged by
      * the logger.
      *
      * @param key      String
      * @param baseName String
      * @return String
      */
     private String getMessage(final String key, final String baseName) {
         try {

             final ResourceBundle bundle = bundleCache.compute(baseName);
             if (bundle != null) {
                 try {
                     return bundle.getString(key);
                 } catch (MissingResourceException e) {
                     final String parentName = heirarchyCache.compute(baseName);
                     if (parentName == null)
                         return key;
                     else
                         return getMessage(key, parentName);
                 }

             } else {
                 final String parentName = heirarchyCache.compute(baseName);
                 if (parentName == null)
                     return key;
                 else
                     return getMessage(key, parentName);

             }
         } catch (InterruptedException e) {
             // ignore
         }
         return key;
     }

 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	package org.apache.openejb.util;

	import org.apache.openejb.loader.IO;
	import org.apache.openejb.loader.SystemInstance;

	import java.io.File;
	import java.io.IOException;
	import java.text.MessageFormat;
	import java.util.ArrayList;
	import java.util.List;
	import java.util.Map;
	import java.util.MissingResourceException;
	import java.util.Properties;
	import java.util.ResourceBundle;

	public class Logger {
	private static final String SUFFIX = ".Messages";
	private static final String OPENEJB = "org.apache.openejb";
	private static LogStreamFactory logStreamFactory;

	static {
	configure();
	}

	public static synchronized void configure() {
	if (logStreamFactory != null) {
	return;
	}

	//See if user factory has been specified
	String factoryName = SystemInstance.get().getOptions().get("openejb.log.factory", JuliLogStreamFactory.class.getName());

	if ("jul".equalsIgnoreCase(factoryName) \|\| "juli".equalsIgnoreCase(factoryName)) {

	factoryName = JuliLogStreamFactory.class.getName();

	} else if ("slf4j".equalsIgnoreCase(factoryName)) {

	factoryName = Slf4jLogStreamFactory.class.getName();

	} else if ("log4j".equalsIgnoreCase(factoryName)) {

	if (exists("org.apache.log4j.Logger")) {

	// don't use .class to avoid to force loading since log4j is not mandatory
	factoryName = "org.apache.openejb.util.Log4jLogStreamFactory";

	} else {

	System.out.println("Cannot respect 'openejb.log.factory=log4j' setting as Log4j is not in the classpath.");

	}

	} else if ("pax".equalsIgnoreCase(factoryName)) {

	factoryName = "org.apache.openejb.util.PaxLogStreamFactory";
	}

	if (factoryName != null) {

	logStreamFactory = createFactory(factoryName);
	}

	if (isLog4jImplied()) {
	logStreamFactory = createFactory("org.apache.openejb.util.Log4jLogStreamFactory");
	}

	//Fall back -> JUL
	if (logStreamFactory == null) {
	logStreamFactory = new JuliLogStreamFactory();
	}

	checkForIgnoredLog4jConfig();
	}

	private static void checkForIgnoredLog4jConfig() {
	if (logStreamFactory.getClass().getName().equals("org.apache.openejb.util.Log4jLogStreamFactory")) return;

	try {
	final Properties configFile = log4j(loadLoggingProperties());

	final Properties systemProperties = log4j(SystemInstance.get().getProperties());

	if (configFile.size() == 0 && systemProperties.size() == 0) return;

	final LogStream stream = logStreamFactory.createLogStream(LogCategory.OPENEJB);

	stream.warn("Log4j not installed. The following properties will be ignored.");

	final String format = "Ignored %s property '%s'";

	for (final Object key : configFile.keySet()) {
	stream.warn(String.format(format, "conf/logging.properties", key));
	}

	for (final Object key : systemProperties.keySet()) {
	stream.warn(String.format(format, "Property overrides", key));
	}
	} catch (Throwable e) {
	// added strong catch block just in case
	// This check is only a convenience
	}
	}

	private static LogStreamFactory createFactory(final String factoryName) {

	final Class<?> factoryClass = load(factoryName);

	if (factoryClass == null) return null;

	try {
	//Try and use the user specified factory
	return (LogStreamFactory) factoryClass.newInstance();
	} catch (Throwable e) {
	//Ignore
	}

	return null;
	}

	private static Class<?> load(final String factoryName) {
	try {
	final ClassLoader classLoader = Logger.class.getClassLoader();
	return classLoader.loadClass(factoryName);
	} catch (Throwable e) {
	//Ignore
	}

	try {
	final ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
	return contextClassLoader.loadClass(factoryName);
	} catch (Throwable e1) {
	//Ignore
	}

	try {
	return Class.forName(factoryName);
	} catch (Throwable e2) {
	//Ignore
	}

	return null;
	}

	/**
	* Computes the parent of a resource name. E.g. if we pass in a key of
	* a.b.c, it returns the value a.b
	*/
	private static final Computable<String, String> heirarchyResolver = new Computable<String, String>() {
	@Override
	public String compute(final String key) throws InterruptedException {
	final int index = key.lastIndexOf(".");
	final String parent = key.substring(0, index);
	if (parent.contains(OPENEJB))
	return parent;
	return null;
	}
	};

	/**
	* Simply returns the ResourceBundle for a given baseName
	*/
	private static final Computable<String, ResourceBundle> bundleResolver = new Computable<String, ResourceBundle>() {
	@Override
	public ResourceBundle compute(final String baseName) throws InterruptedException {
	try {
	return ResourceBundle.getBundle(baseName + SUFFIX);
	} catch (MissingResourceException e) {
	return null;
	}
	}
	};

	/**
	* Builds a Logger object and returns it
	*/
	private static final Computable<Object[], Logger> loggerResolver = new Computable<Object[], Logger>() {
	@Override
	public Logger compute(final Object[] args) throws InterruptedException {
	final LogCategory category = (LogCategory) args[0];
	final LogStream logStream = logStreamFactory.createLogStream(category);
	final String baseName = (String) args[1];
	return new Logger(category, logStream, baseName);
	}
	};

	/**
	* Creates a MessageFormat object for a message and returns it
	*/
	private static final Computable<String, MessageFormat> messageFormatResolver = new Computable<String, MessageFormat>() {
	@Override
	public MessageFormat compute(final String message) throws InterruptedException {
	return new MessageFormat(message);
	}
	};

	/**
	* Cache of parent-child relationships between resource names
	*/
	private static final Computable<String, String> heirarchyCache = new Memoizer<String, String>(heirarchyResolver);

	/**
	* Cache of ResourceBundles
	*/
	private static final Computable<String, ResourceBundle> bundleCache = new Memoizer<String, ResourceBundle>(bundleResolver);

	/**
	* Cache of Loggers
	*/
	private static final Computable<Object[], Logger> loggerCache = new Memoizer<Object[], Logger>(loggerResolver);

	/**
	* Cache of MessageFormats
	*/
	private static final Computable<String, MessageFormat> messageFormatCache = new Memoizer<String, MessageFormat>(messageFormatResolver);

	/**
	* Finds a Logger from the cache and returns it. If not found in cache then builds a Logger and returns it.
	*
	* @param category - The category of the logger
	* @param baseName - The baseName for the ResourceBundle
	* @return Logger
	*/
	public static Logger getInstance(final LogCategory category, final String baseName) {
	try {
	return loggerCache.compute(new Object[]{category, baseName});
	} catch (InterruptedException e) {
	// Don't return null here. Just create a new Logger and set it up.
	// It will not be stored in the cache, but a later lookup for the
	// same Logger would probably end up in the cache
	final LogStream logStream = logStreamFactory.createLogStream(category);
	return new Logger(category, logStream, baseName);
	}
	}

	private final LogCategory category;
	private final LogStream logStream;
	private final String baseName;

	public Logger(final LogCategory category, final LogStream logStream, final String baseName) {
	this.category = category;
	this.logStream = logStream;
	this.baseName = baseName;
	}

	public static Logger getInstance(final LogCategory category, final Class clazz) {
	return getInstance(category, packageName(clazz));
	}

	private static String packageName(final Class clazz) {
	final String name = clazz.getName();
	return name.substring(0, name.lastIndexOf("."));
	}

	private static Boolean isLog4j = null;

	public static boolean isLog4jImplied() {

	if (null == isLog4j) {

	isLog4j = false;

	final List<String> locations = new ArrayList<String>();
	{
	final Properties configFile = log4j(loadLoggingProperties());

	final Properties systemProperties = log4j(SystemInstance.get().getProperties());

	if (configFile.size() > 0) locations.add("conf/logging.properties");
	if (systemProperties.size() > 0) locations.add("Properties overrides");
	}

	if (locations.size() > 0) {
	if (exists("org.apache.log4j.Logger")) {
	isLog4j = true;
	}
	}
	}

	return isLog4j;
	}

	private static boolean exists(final String s) {
	return load(s) != null;
	}

	private static Properties log4j(final Properties system) {
	final Properties properties = new Properties();
	for (final Map.Entry<Object, Object> entry : system.entrySet()) {
	final String key = entry.getKey().toString();
	if (key.startsWith("log4j.") && !key.equals("log4j.configuration")) {
	properties.put(key, entry.getValue());
	}
	}
	return properties;
	}

	private static Properties loadLoggingProperties() {
	try {
	final File conf = SystemInstance.get().getConf(null);

	final File file = new File(conf, "logging.properties");

	return IO.readProperties(file);
	} catch (IOException e) {
	return new Properties();
	}
	}

	public Logger getChildLogger(final String child) {
	return Logger.getInstance(this.category.createChild(child), this.baseName);
	}

	/**
	* Formats a given message
	*
	* @param message String
	* @param args Object...
	* @return the formatted message
	*/
	private String formatMessage(final String message, final Object... args) {
	if (args.length == 0) return message;

	try {
	final MessageFormat mf = messageFormatCache.compute(message);
	return mf.format(args);
	} catch (Exception e) {
	return "Error in formatting message " + message;
	}

	}

	public boolean isDebugEnabled() {
	return logStream.isDebugEnabled();
	}

	public boolean isErrorEnabled() {
	return logStream.isErrorEnabled();
	}

	public boolean isFatalEnabled() {
	return logStream.isFatalEnabled();
	}

	public boolean isInfoEnabled() {
	return logStream.isInfoEnabled();
	}

	public boolean isWarningEnabled() {
	return logStream.isWarnEnabled();
	}

	public boolean isLevelEnable(final String level) {
	if ("info".equals(level.toLowerCase())) {
	return isInfoEnabled();
	} else if ("debug".equals(level.toLowerCase())) {
	return isDebugEnabled();
	} else if ("warning".equals(level.toLowerCase())) {
	return isWarningEnabled();
	} else if ("fatal".equals(level.toLowerCase())) {
	return isFatalEnabled();
	} else if ("error".equals(level.toLowerCase())) {
	return isErrorEnabled();
	}
	return false;
	}

	public void log(final String level, final String message) {
	if ("info".equals(level.toLowerCase())) {
	info(message);
	} else if ("debug".equals(level.toLowerCase())) {
	debug(message);
	} else if ("warning".equals(level.toLowerCase())) {
	warning(message);
	} else if ("fatal".equals(level.toLowerCase())) {
	fatal(message);
	} else if ("error".equals(level.toLowerCase())) {
	error(message);
	}
	}

	/**
	* If this level is enabled, then it finds a message for the given key and logs it
	*
	* @param message - This could be a plain message or a key in Messages.properties
	* @return the formatted i18n message
	*/
	public String debug(final String message) {

	if (isDebugEnabled()) {
	final String msg = getMessage(message, baseName);
	logStream.debug(msg);
	return msg;
	}
	return message;
	}

	public String debug(final String message, final Object... args) {

	if (isDebugEnabled()) {
	String msg = getMessage(message, baseName);
	msg = formatMessage(msg, args);
	logStream.debug(msg);
	return msg;
	}
	return message;
	}

	public String debug(final String message, final Throwable t) {

	if (isDebugEnabled()) {
	final String msg = getMessage(message, baseName);
	logStream.debug(msg, t);
	return msg;
	}
	return message;
	}

	public String debug(final String message, final Throwable t, final Object... args) {

	if (isDebugEnabled()) {
	String msg = getMessage(message, baseName);
	msg = formatMessage(msg, args);
	logStream.debug(msg, t);
	return msg;
	}
	return message;
	}

	public String error(final String message) {

	if (isErrorEnabled()) {
	final String msg = getMessage(message, baseName);
	logStream.error(msg);
	return msg;
	}
	return message;
	}

	public String error(final String message, final Object... args) {

	if (isErrorEnabled()) {
	String msg = getMessage(message, baseName);
	msg = formatMessage(msg, args);
	logStream.error(msg);
	return msg;
	}
	return message;
	}

	public String error(final String message, final Throwable t) {

	if (isErrorEnabled()) {
	final String msg = getMessage(message, baseName);
	logStream.error(msg, t);
	return msg;
	}
	return message;
	}

	public String error(final String message, final Throwable t, final Object... args) {

	if (isErrorEnabled()) {
	String msg = getMessage(message, baseName);
	msg = formatMessage(msg, args);
	logStream.error(msg, t);
	return msg;
	}
	return message;
	}

	public String fatal(final String message) {
	if (isFatalEnabled()) {
	final String msg = getMessage(message, baseName);
	logStream.fatal(msg);
	return msg;
	}
	return message;
	}

	public String fatal(final String message, final Object... args) {
	if (isFatalEnabled()) {
	String msg = getMessage(message, baseName);
	msg = formatMessage(msg, args);
	logStream.fatal(msg);
	return msg;
	}
	return message;
	}

	public String fatal(final String message, final Throwable t) {
	if (isFatalEnabled()) {
	final String msg = getMessage(message, baseName);
	logStream.fatal(msg, t);
	return msg;
	}
	return message;
	}

	public String fatal(final String message, final Throwable t, final Object... args) {
	if (isFatalEnabled()) {
	String msg = getMessage(message, baseName);
	msg = formatMessage(msg, args);
	logStream.fatal(msg, t);
	return msg;
	}
	return message;
	}

	public String info(final String message) {
	if (isInfoEnabled()) {
	final String msg = getMessage(message, baseName);
	logStream.info(msg);
	return msg;
	}
	return message;
	}

	public String info(final String message, final Object... args) {
	if (isInfoEnabled()) {
	String msg = getMessage(message, baseName);
	msg = formatMessage(msg, args);
	logStream.info(msg);
	return msg;
	}
	return message;
	}

	public String info(final String message, final Throwable t) {
	if (isInfoEnabled()) {
	final String msg = getMessage(message, baseName);
	logStream.info(msg, t);
	return msg;
	}
	return message;
	}

	public String info(final String message, final Throwable t, final Object... args) {
	if (isInfoEnabled()) {
	String msg = getMessage(message, baseName);
	msg = formatMessage(msg, args);
	logStream.info(msg, t);
	return msg;
	}
	return message;
	}

	public String warning(final String message) {
	if (isWarningEnabled()) {
	final String msg = getMessage(message, baseName);
	logStream.warn(msg);
	return msg;
	}
	return message;
	}

	public String warning(final String message, final Object... args) {
	if (isWarningEnabled()) {
	String msg = getMessage(message, baseName);
	msg = formatMessage(msg, args);
	logStream.warn(msg);
	return msg;
	}
	return message;
	}

	public String warning(final String message, final Throwable t) {
	if (isWarningEnabled()) {
	final String msg = getMessage(message, baseName);
	logStream.warn(msg, t);
	return msg;
	}
	return message;
	}

	public String warning(final String message, final Throwable t, final Object... args) {
	if (isWarningEnabled()) {
	String msg = getMessage(message, baseName);
	msg = formatMessage(msg, args);
	logStream.warn(msg, t);
	return msg;
	}
	return message;
	}

	/**
	* Given a key and a baseName, this method computes a message for a key. if
	* the key is not found in this ResourceBundle for this baseName, then it
	* recursively looks up its parent to find the message for a key. If no
	* message is found for a key, the key is returned as is and is logged by
	* the logger.
	*
	* @param key String
	* @param baseName String
	* @return String
	*/
	private String getMessage(final String key, final String baseName) {
	try {

	final ResourceBundle bundle = bundleCache.compute(baseName);
	if (bundle != null) {
	try {
	return bundle.getString(key);
	} catch (MissingResourceException e) {
	final String parentName = heirarchyCache.compute(baseName);
	if (parentName == null)
	return key;
	else
	return getMessage(key, parentName);
	}

	} else {
	final String parentName = heirarchyCache.compute(baseName);
	if (parentName == null)
	return key;
	else
	return getMessage(key, parentName);

	}
	} catch (InterruptedException e) {
	// ignore
	}
	return key;
	}

	}