src/main/java/org/apache/commons/logging/impl/Log4JLogger.java - commons-logging - 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.commons.logging.impl;

 import java.io.Serializable;
 import org.apache.commons.logging.Log;
 import org.apache.log4j.Logger;
 import org.apache.log4j.Priority;
 import org.apache.log4j.Level;

 /**
  * Implementation of {@link Log} that maps directly to a
  * <strong>Logger</strong> for log4J version 1.2.
  * <p>
  * Initial configuration of the corresponding Logger instances should be done
  * in the usual manner, as outlined in the Log4J documentation.
  * <p>
  * The reason this logger is distinct from the 1.3 logger is that in version 1.2
  * of Log4J:
  * <ul>
  * <li>class Logger takes Priority parameters not Level parameters.
  * <li>class Level extends Priority
  * </ul>
  * Log4J1.3 is expected to change Level so it no longer extends Priority, which is
  * a non-binary-compatible change. The class generated by compiling this code against
  * log4j 1.2 will therefore not run against log4j 1.3.
  *
  * @version $Id$
  */
 public class Log4JLogger implements Log, Serializable {

     /** Serializable version identifier. */
     private static final long serialVersionUID = 5160705895411730424L;

     // ------------------------------------------------------------- Attributes

     /** The fully qualified name of the Log4JLogger class. */
     private static final String FQCN = Log4JLogger.class.getName();

     /** Log to this logger */
     private transient volatile Logger logger = null;

     /** Logger name */
     private final String name;

     private static final Priority traceLevel;

     // ------------------------------------------------------------
     // Static Initializer.
     //
     // Note that this must come after the static variable declarations
     // otherwise initialiser expressions associated with those variables
     // will override any settings done here.
     //
     // Verify that log4j is available, and that it is version 1.2.
     // If an ExceptionInInitializerError is generated, then LogFactoryImpl
     // will treat that as meaning that the appropriate underlying logging
     // library is just not present - if discovery is in progress then
     // discovery will continue.
     // ------------------------------------------------------------

     static {
         if (!Priority.class.isAssignableFrom(Level.class)) {
             // nope, this is log4j 1.3, so force an ExceptionInInitializerError
             throw new InstantiationError("Log4J 1.2 not available");
         }

         // Releases of log4j1.2 >= 1.2.12 have Priority.TRACE available, earlier
         // versions do not. If TRACE is not available, then we have to map
         // calls to Log.trace(...) onto the DEBUG level.

         Priority _traceLevel;
         try {
             _traceLevel = (Priority) Level.class.getDeclaredField("TRACE").get(null);
         } catch(Exception ex) {
             // ok, trace not available
             _traceLevel = Level.DEBUG;
         }
         traceLevel = _traceLevel;
     }

     // ------------------------------------------------------------ Constructor

     public Log4JLogger() {
         name = null;
     }

     /**
      * Base constructor.
      */
     public Log4JLogger(String name) {
         this.name = name;
         this.logger = getLogger();
     }

     /**
      * For use with a log4j factory.
      */
     public Log4JLogger(Logger logger) {
         if (logger == null) {
             throw new IllegalArgumentException(
                 "Warning - null logger in constructor; possible log4j misconfiguration.");
         }
         this.name = logger.getName();
         this.logger = logger;
     }

     /**
      * Logs a message with <code>org.apache.log4j.Priority.TRACE</code>.
      * When using a log4j version that does not support the <code>TRACE</code>
      * level, the message will be logged at the <code>DEBUG</code> level.
      *
      * @param message to log
      * @see org.apache.commons.logging.Log#trace(Object)
      */
     public void trace(Object message) {
         getLogger().log(FQCN, traceLevel, message, null);
     }

     /**
      * Logs a message with <code>org.apache.log4j.Priority.TRACE</code>.
      * When using a log4j version that does not support the <code>TRACE</code>
      * level, the message will be logged at the <code>DEBUG</code> level.
      *
      * @param message to log
      * @param t log this cause
      * @see org.apache.commons.logging.Log#trace(Object, Throwable)
      */
     public void trace(Object message, Throwable t) {
         getLogger().log(FQCN, traceLevel, message, t);
     }

     /**
      * Logs a message with <code>org.apache.log4j.Priority.DEBUG</code>.
      *
      * @param message to log
      * @see org.apache.commons.logging.Log#debug(Object)
      */
     public void debug(Object message) {
         getLogger().log(FQCN, Level.DEBUG, message, null);
     }

     /**
      * Logs a message with <code>org.apache.log4j.Priority.DEBUG</code>.
      *
      * @param message to log
      * @param t log this cause
      * @see org.apache.commons.logging.Log#debug(Object, Throwable)
      */
     public void debug(Object message, Throwable t) {
         getLogger().log(FQCN, Level.DEBUG, message, t);
     }

     /**
      * Logs a message with <code>org.apache.log4j.Priority.INFO</code>.
      *
      * @param message to log
      * @see org.apache.commons.logging.Log#info(Object)
      */
     public void info(Object message) {
         getLogger().log(FQCN, Level.INFO, message, null);
     }

     /**
      * Logs a message with <code>org.apache.log4j.Priority.INFO</code>.
      *
      * @param message to log
      * @param t log this cause
      * @see org.apache.commons.logging.Log#info(Object, Throwable)
      */
     public void info(Object message, Throwable t) {
         getLogger().log(FQCN, Level.INFO, message, t);
     }

     /**
      * Logs a message with <code>org.apache.log4j.Priority.WARN</code>.
      *
      * @param message to log
      * @see org.apache.commons.logging.Log#warn(Object)
      */
     public void warn(Object message) {
         getLogger().log(FQCN, Level.WARN, message, null);
     }

     /**
      * Logs a message with <code>org.apache.log4j.Priority.WARN</code>.
      *
      * @param message to log
      * @param t log this cause
      * @see org.apache.commons.logging.Log#warn(Object, Throwable)
      */
     public void warn(Object message, Throwable t) {
         getLogger().log(FQCN, Level.WARN, message, t);
     }

     /**
      * Logs a message with <code>org.apache.log4j.Priority.ERROR</code>.
      *
      * @param message to log
      * @see org.apache.commons.logging.Log#error(Object)
      */
     public void error(Object message) {
         getLogger().log(FQCN, Level.ERROR, message, null);
     }

     /**
      * Logs a message with <code>org.apache.log4j.Priority.ERROR</code>.
      *
      * @param message to log
      * @param t log this cause
      * @see org.apache.commons.logging.Log#error(Object, Throwable)
      */
     public void error(Object message, Throwable t) {
         getLogger().log(FQCN, Level.ERROR, message, t);
     }

     /**
      * Logs a message with <code>org.apache.log4j.Priority.FATAL</code>.
      *
      * @param message to log
      * @see org.apache.commons.logging.Log#fatal(Object)
      */
     public void fatal(Object message) {
         getLogger().log(FQCN, Level.FATAL, message, null);
     }

     /**
      * Logs a message with <code>org.apache.log4j.Priority.FATAL</code>.
      *
      * @param message to log
      * @param t log this cause
      * @see org.apache.commons.logging.Log#fatal(Object, Throwable)
      */
     public void fatal(Object message, Throwable t) {
         getLogger().log(FQCN, Level.FATAL, message, t);
     }

     /**
      * Return the native Logger instance we are using.
      */
     public Logger getLogger() {
         Logger result = logger;
         if (result == null) {
             synchronized(this) {
                 result = logger;
                 if (result == null) {
                     logger = result = Logger.getLogger(name);
                 }
             }
         }
         return result;
     }

     /**
      * Check whether the Log4j Logger used is enabled for <code>DEBUG</code> priority.
      */
     public boolean isDebugEnabled() {
         return getLogger().isDebugEnabled();
     }

     /**
      * Check whether the Log4j Logger used is enabled for <code>ERROR</code> priority.
      */
     public boolean isErrorEnabled() {
         return getLogger().isEnabledFor(Level.ERROR);
     }

     /**
      * Check whether the Log4j Logger used is enabled for <code>FATAL</code> priority.
      */
     public boolean isFatalEnabled() {
         return getLogger().isEnabledFor(Level.FATAL);
     }

     /**
      * Check whether the Log4j Logger used is enabled for <code>INFO</code> priority.
      */
     public boolean isInfoEnabled() {
         return getLogger().isInfoEnabled();
     }

     /**
      * Check whether the Log4j Logger used is enabled for <code>TRACE</code> priority.
      * When using a log4j version that does not support the TRACE level, this call
      * will report whether <code>DEBUG</code> is enabled or not.
      */
     public boolean isTraceEnabled() {
         return getLogger().isEnabledFor(traceLevel);
     }

     /**
      * Check whether the Log4j Logger used is enabled for <code>WARN</code> priority.
      */
     public boolean isWarnEnabled() {
         return getLogger().isEnabledFor(Level.WARN);
     }
 }
	/*
	* 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.commons.logging.impl;

	import java.io.Serializable;
	import org.apache.commons.logging.Log;
	import org.apache.log4j.Logger;
	import org.apache.log4j.Priority;
	import org.apache.log4j.Level;

	/**
	* Implementation of {@link Log} that maps directly to a
	* <strong>Logger</strong> for log4J version 1.2.
	* <p>
	* Initial configuration of the corresponding Logger instances should be done
	* in the usual manner, as outlined in the Log4J documentation.
	* <p>
	* The reason this logger is distinct from the 1.3 logger is that in version 1.2
	* of Log4J:
	* <ul>
	* <li>class Logger takes Priority parameters not Level parameters.
	* <li>class Level extends Priority
	* </ul>
	* Log4J1.3 is expected to change Level so it no longer extends Priority, which is
	* a non-binary-compatible change. The class generated by compiling this code against
	* log4j 1.2 will therefore not run against log4j 1.3.
	*
	* @version $Id$
	*/
	public class Log4JLogger implements Log, Serializable {

	/** Serializable version identifier. */
	private static final long serialVersionUID = 5160705895411730424L;

	// ------------------------------------------------------------- Attributes

	/** The fully qualified name of the Log4JLogger class. */
	private static final String FQCN = Log4JLogger.class.getName();

	/** Log to this logger */
	private transient volatile Logger logger = null;

	/** Logger name */
	private final String name;

	private static final Priority traceLevel;

	// ------------------------------------------------------------
	// Static Initializer.
	//
	// Note that this must come after the static variable declarations
	// otherwise initialiser expressions associated with those variables
	// will override any settings done here.
	//
	// Verify that log4j is available, and that it is version 1.2.
	// If an ExceptionInInitializerError is generated, then LogFactoryImpl
	// will treat that as meaning that the appropriate underlying logging
	// library is just not present - if discovery is in progress then
	// discovery will continue.
	// ------------------------------------------------------------

	static {
	if (!Priority.class.isAssignableFrom(Level.class)) {
	// nope, this is log4j 1.3, so force an ExceptionInInitializerError
	throw new InstantiationError("Log4J 1.2 not available");
	}

	// Releases of log4j1.2 >= 1.2.12 have Priority.TRACE available, earlier
	// versions do not. If TRACE is not available, then we have to map
	// calls to Log.trace(...) onto the DEBUG level.

	Priority _traceLevel;
	try {
	_traceLevel = (Priority) Level.class.getDeclaredField("TRACE").get(null);
	} catch(Exception ex) {
	// ok, trace not available
	_traceLevel = Level.DEBUG;
	}
	traceLevel = _traceLevel;
	}

	// ------------------------------------------------------------ Constructor

	public Log4JLogger() {
	name = null;
	}

	/**
	* Base constructor.
	*/
	public Log4JLogger(String name) {
	this.name = name;
	this.logger = getLogger();
	}

	/**
	* For use with a log4j factory.
	*/
	public Log4JLogger(Logger logger) {
	if (logger == null) {
	throw new IllegalArgumentException(
	"Warning - null logger in constructor; possible log4j misconfiguration.");
	}
	this.name = logger.getName();
	this.logger = logger;
	}

	/**
	* Logs a message with <code>org.apache.log4j.Priority.TRACE</code>.
	* When using a log4j version that does not support the <code>TRACE</code>
	* level, the message will be logged at the <code>DEBUG</code> level.
	*
	* @param message to log
	* @see org.apache.commons.logging.Log#trace(Object)
	*/
	public void trace(Object message) {
	getLogger().log(FQCN, traceLevel, message, null);
	}

	/**
	* Logs a message with <code>org.apache.log4j.Priority.TRACE</code>.
	* When using a log4j version that does not support the <code>TRACE</code>
	* level, the message will be logged at the <code>DEBUG</code> level.
	*
	* @param message to log
	* @param t log this cause
	* @see org.apache.commons.logging.Log#trace(Object, Throwable)
	*/
	public void trace(Object message, Throwable t) {
	getLogger().log(FQCN, traceLevel, message, t);
	}

	/**
	* Logs a message with <code>org.apache.log4j.Priority.DEBUG</code>.
	*
	* @param message to log
	* @see org.apache.commons.logging.Log#debug(Object)
	*/
	public void debug(Object message) {
	getLogger().log(FQCN, Level.DEBUG, message, null);
	}

	/**
	* Logs a message with <code>org.apache.log4j.Priority.DEBUG</code>.
	*
	* @param message to log
	* @param t log this cause
	* @see org.apache.commons.logging.Log#debug(Object, Throwable)
	*/
	public void debug(Object message, Throwable t) {
	getLogger().log(FQCN, Level.DEBUG, message, t);
	}

	/**
	* Logs a message with <code>org.apache.log4j.Priority.INFO</code>.
	*
	* @param message to log
	* @see org.apache.commons.logging.Log#info(Object)
	*/
	public void info(Object message) {
	getLogger().log(FQCN, Level.INFO, message, null);
	}

	/**
	* Logs a message with <code>org.apache.log4j.Priority.INFO</code>.
	*
	* @param message to log
	* @param t log this cause
	* @see org.apache.commons.logging.Log#info(Object, Throwable)
	*/
	public void info(Object message, Throwable t) {
	getLogger().log(FQCN, Level.INFO, message, t);
	}

	/**
	* Logs a message with <code>org.apache.log4j.Priority.WARN</code>.
	*
	* @param message to log
	* @see org.apache.commons.logging.Log#warn(Object)
	*/
	public void warn(Object message) {
	getLogger().log(FQCN, Level.WARN, message, null);
	}

	/**
	* Logs a message with <code>org.apache.log4j.Priority.WARN</code>.
	*
	* @param message to log
	* @param t log this cause
	* @see org.apache.commons.logging.Log#warn(Object, Throwable)
	*/
	public void warn(Object message, Throwable t) {
	getLogger().log(FQCN, Level.WARN, message, t);
	}

	/**
	* Logs a message with <code>org.apache.log4j.Priority.ERROR</code>.
	*
	* @param message to log
	* @see org.apache.commons.logging.Log#error(Object)
	*/
	public void error(Object message) {
	getLogger().log(FQCN, Level.ERROR, message, null);
	}

	/**
	* Logs a message with <code>org.apache.log4j.Priority.ERROR</code>.
	*
	* @param message to log
	* @param t log this cause
	* @see org.apache.commons.logging.Log#error(Object, Throwable)
	*/
	public void error(Object message, Throwable t) {
	getLogger().log(FQCN, Level.ERROR, message, t);
	}

	/**
	* Logs a message with <code>org.apache.log4j.Priority.FATAL</code>.
	*
	* @param message to log
	* @see org.apache.commons.logging.Log#fatal(Object)
	*/
	public void fatal(Object message) {
	getLogger().log(FQCN, Level.FATAL, message, null);
	}

	/**
	* Logs a message with <code>org.apache.log4j.Priority.FATAL</code>.
	*
	* @param message to log
	* @param t log this cause
	* @see org.apache.commons.logging.Log#fatal(Object, Throwable)
	*/
	public void fatal(Object message, Throwable t) {
	getLogger().log(FQCN, Level.FATAL, message, t);
	}

	/**
	* Return the native Logger instance we are using.
	*/
	public Logger getLogger() {
	Logger result = logger;
	if (result == null) {
	synchronized(this) {
	result = logger;
	if (result == null) {
	logger = result = Logger.getLogger(name);
	}
	}
	}
	return result;
	}

	/**
	* Check whether the Log4j Logger used is enabled for <code>DEBUG</code> priority.
	*/
	public boolean isDebugEnabled() {
	return getLogger().isDebugEnabled();
	}

	/**
	* Check whether the Log4j Logger used is enabled for <code>ERROR</code> priority.
	*/
	public boolean isErrorEnabled() {
	return getLogger().isEnabledFor(Level.ERROR);
	}

	/**
	* Check whether the Log4j Logger used is enabled for <code>FATAL</code> priority.
	*/
	public boolean isFatalEnabled() {
	return getLogger().isEnabledFor(Level.FATAL);
	}

	/**
	* Check whether the Log4j Logger used is enabled for <code>INFO</code> priority.
	*/
	public boolean isInfoEnabled() {
	return getLogger().isInfoEnabled();
	}

	/**
	* Check whether the Log4j Logger used is enabled for <code>TRACE</code> priority.
	* When using a log4j version that does not support the TRACE level, this call
	* will report whether <code>DEBUG</code> is enabled or not.
	*/
	public boolean isTraceEnabled() {
	return getLogger().isEnabledFor(traceLevel);
	}

	/**
	* Check whether the Log4j Logger used is enabled for <code>WARN</code> priority.
	*/
	public boolean isWarnEnabled() {
	return getLogger().isEnabledFor(Level.WARN);
	}
	}