/*
 * 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 org.apache.avalon.framework.logger.Logger;
import org.apache.commons.logging.Log;

Implementation of commons-logging Log interface that delegates all
logging calls to the Avalon logging abstraction: the Logger interface.

There are two ways in which this class can be used:

the instance can be constructed with an Avalon logger (by calling AvalonLogger(Logger)). In this case, it acts as a simple thin wrapping implementation over the logger. This is particularly useful when using a property setter. 
the setDefaultLogger class property can be called which sets the ancestral Avalon logger for this class. Any AvalonLogger
instances created through the LogFactory mechanisms will output
to child loggers of this Logger.



Note: AvalonLogger does not implement Serializable
because the constructors available for it make this impossible to achieve in all
circumstances; there is no way to "reconnect" to an underlying Logger object on
deserialization if one was just passed in to the constructor of the original
object. This class was marked Serializable in the 1.0.4 release of
commons-logging, but this never actually worked (a NullPointerException would
be thrown as soon as the deserialized object was used), so removing this marker
is not considered to be an incompatible change.
Version:
$Id: AvalonLogger.java 1435115 2013-01-18 12:40:19Z tn $/**
 * Implementation of commons-logging Log interface that delegates all
 * logging calls to the Avalon logging abstraction: the Logger interface.
 * <p>
 * There are two ways in which this class can be used:
 * <ul>
 * <li>the instance can be constructed with an Avalon logger
 * (by calling {@link #AvalonLogger(Logger)}). In this case, it acts
 * as a simple thin wrapping implementation over the logger. This is
 * particularly useful when using a property setter.
 * </li>
 * <li>the {@link #setDefaultLogger} class property can be called which
 * sets the ancestral Avalon logger for this class. Any <code>AvalonLogger</code>
 * instances created through the <code>LogFactory</code> mechanisms will output
 * to child loggers of this <code>Logger</code>.
 * </li>
 * </ul>
 * <p>
 * <strong>Note:</strong> <code>AvalonLogger</code> does not implement Serializable
 * because the constructors available for it make this impossible to achieve in all
 * circumstances; there is no way to "reconnect" to an underlying Logger object on
 * deserialization if one was just passed in to the constructor of the original
 * object. This class <i>was</i> marked Serializable in the 1.0.4 release of
 * commons-logging, but this never actually worked (a NullPointerException would
 * be thrown as soon as the deserialized object was used), so removing this marker
 * is not considered to be an incompatible change.
 *
 * @version $Id: AvalonLogger.java 1435115 2013-01-18 12:40:19Z tn $
 */
public class AvalonLogger implements Log {

    
Ancestral Avalon logger. /** Ancestral Avalon logger. */
    private static volatile Logger defaultLogger = null;
    
Avalon logger used to perform log. /** Avalon logger used to perform log. */
    private final transient Logger logger;

    
Constructs an AvalonLogger that outputs to the given
Logger instance.
Params:
logger – the Avalon logger implementation to delegate to/**
     * Constructs an <code>AvalonLogger</code> that outputs to the given
     * <code>Logger</code> instance.
     *
     * @param logger the Avalon logger implementation to delegate to
     */
    public AvalonLogger(Logger logger) {
        this.logger = logger;
    }

    
Constructs an AvalonLogger that will log to a child
of the Logger set by calling setDefaultLogger. 
Params:
name – the name of the avalon logger implementation to delegate to/**
     * Constructs an <code>AvalonLogger</code> that will log to a child
     * of the <code>Logger</code> set by calling {@link #setDefaultLogger}.
     *
     * @param name the name of the avalon logger implementation to delegate to
     */
    public AvalonLogger(String name) {
        if (defaultLogger == null) {
            throw new NullPointerException("default logger has to be specified if this constructor is used!");
        }
        this.logger = defaultLogger.getChildLogger(name);
    }

    
Gets the Avalon logger implementation used to perform logging.
Returns:
avalon logger implementation/**
     * Gets the Avalon logger implementation used to perform logging.
     *
     * @return avalon logger implementation
     */
    public Logger getLogger() {
        return logger;
    }

    
Sets the ancestral Avalon logger from which the delegating loggers will descend.
Params:
logger – the default avalon logger,
in case there is no logger instance supplied in constructor/**
     * Sets the ancestral Avalon logger from which the delegating loggers will descend.
     *
     * @param logger the default avalon logger,
     * in case there is no logger instance supplied in constructor
     */
    public static void setDefaultLogger(Logger logger) {
        defaultLogger = logger;
    }

    
Logs a message with org.apache.avalon.framework.logger.Logger.debug.
Params:
message – to log
t – log this cause
See Also:
Log.debug(Object, Throwable)/**
    * Logs a message with <code>org.apache.avalon.framework.logger.Logger.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) {
        if (getLogger().isDebugEnabled()) {
            getLogger().debug(String.valueOf(message), t);
        }
    }

    
Logs a message with org.apache.avalon.framework.logger.Logger.debug.
Params:
message – to log.
See Also:
Log.debug(Object)/**
     * Logs a message with <code>org.apache.avalon.framework.logger.Logger.debug</code>.
     *
     * @param message to log.
     * @see org.apache.commons.logging.Log#debug(Object)
     */
    public void debug(Object message) {
        if (getLogger().isDebugEnabled()) {
            getLogger().debug(String.valueOf(message));
        }
    }

    
Logs a message with org.apache.avalon.framework.logger.Logger.error.
Params:
message – to log
t – log this cause
See Also:
Log.error(Object, Throwable)/**
     * Logs a message with <code>org.apache.avalon.framework.logger.Logger.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) {
        if (getLogger().isErrorEnabled()) {
            getLogger().error(String.valueOf(message), t);
        }
    }

    
Logs a message with org.apache.avalon.framework.logger.Logger.error.
Params:
message – to log
See Also:
Log.error(Object)/**
     * Logs a message with <code>org.apache.avalon.framework.logger.Logger.error</code>.
     *
     * @param message to log
     * @see org.apache.commons.logging.Log#error(Object)
     */
    public void error(Object message) {
        if (getLogger().isErrorEnabled()) {
            getLogger().error(String.valueOf(message));
        }
    }

    
Logs a message with org.apache.avalon.framework.logger.Logger.fatalError.
Params:
message – to log.
t – log this cause.
See Also:
Log.fatal(Object, Throwable)/**
     * Logs a message with <code>org.apache.avalon.framework.logger.Logger.fatalError</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) {
        if (getLogger().isFatalErrorEnabled()) {
            getLogger().fatalError(String.valueOf(message), t);
        }
    }

    
Logs a message with org.apache.avalon.framework.logger.Logger.fatalError.
Params:
message – to log
See Also:
Log.fatal(Object)/**
     * Logs a message with <code>org.apache.avalon.framework.logger.Logger.fatalError</code>.
     *
     * @param message to log
     * @see org.apache.commons.logging.Log#fatal(Object)
     */
    public void fatal(Object message) {
        if (getLogger().isFatalErrorEnabled()) {
            getLogger().fatalError(String.valueOf(message));
        }
    }

    
Logs a message with org.apache.avalon.framework.logger.Logger.info.
Params:
message – to log
t – log this cause
See Also:
Log.info(Object, Throwable)/**
     * Logs a message with <code>org.apache.avalon.framework.logger.Logger.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) {
        if (getLogger().isInfoEnabled()) {
            getLogger().info(String.valueOf(message), t);
        }
    }

    
Logs a message with org.apache.avalon.framework.logger.Logger.info.
Params:
message – to log
See Also:
Log.info(Object)/**
     * Logs a message with <code>org.apache.avalon.framework.logger.Logger.info</code>.
     *
     * @param message to log
     * @see org.apache.commons.logging.Log#info(Object)
     */
    public void info(Object message) {
        if (getLogger().isInfoEnabled()) {
            getLogger().info(String.valueOf(message));
        }
    }

    
Is logging to org.apache.avalon.framework.logger.Logger.debug enabled?
See Also:
isDebugEnabled.isDebugEnabled()/**
     * Is logging to <code>org.apache.avalon.framework.logger.Logger.debug</code> enabled?
     * @see org.apache.commons.logging.Log#isDebugEnabled()
     */
    public boolean isDebugEnabled() {
        return getLogger().isDebugEnabled();
    }

    
Is logging to org.apache.avalon.framework.logger.Logger.error enabled?
See Also:
isErrorEnabled.isErrorEnabled()/**
     * Is logging to <code>org.apache.avalon.framework.logger.Logger.error</code> enabled?
     * @see org.apache.commons.logging.Log#isErrorEnabled()
     */
    public boolean isErrorEnabled() {
        return getLogger().isErrorEnabled();
    }

    
Is logging to org.apache.avalon.framework.logger.Logger.fatalError enabled?
See Also:
isFatalEnabled.isFatalEnabled()/**
     * Is logging to <code>org.apache.avalon.framework.logger.Logger.fatalError</code> enabled?
     * @see org.apache.commons.logging.Log#isFatalEnabled()
     */
    public boolean isFatalEnabled() {
        return getLogger().isFatalErrorEnabled();
    }

    
Is logging to org.apache.avalon.framework.logger.Logger.info enabled?
See Also:
isInfoEnabled.isInfoEnabled()/**
     * Is logging to <code>org.apache.avalon.framework.logger.Logger.info</code> enabled?
     * @see org.apache.commons.logging.Log#isInfoEnabled()
     */
    public boolean isInfoEnabled() {
        return getLogger().isInfoEnabled();
    }

    
Is logging to org.apache.avalon.framework.logger.Logger.debug enabled?
See Also:
isTraceEnabled.isTraceEnabled()/**
     * Is logging to <code>org.apache.avalon.framework.logger.Logger.debug</code> enabled?
     * @see org.apache.commons.logging.Log#isTraceEnabled()
     */
    public boolean isTraceEnabled() {
        return getLogger().isDebugEnabled();
    }

    
Is logging to org.apache.avalon.framework.logger.Logger.warn enabled?
See Also:
isWarnEnabled.isWarnEnabled()/**
     * Is logging to <code>org.apache.avalon.framework.logger.Logger.warn</code> enabled?
     * @see org.apache.commons.logging.Log#isWarnEnabled()
     */
    public boolean isWarnEnabled() {
        return getLogger().isWarnEnabled();
    }

    
Logs a message with org.apache.avalon.framework.logger.Logger.debug.
Params:
message – to log.
t – log this cause.
See Also:
Log.trace(Object, Throwable)/**
     * Logs a message with <code>org.apache.avalon.framework.logger.Logger.debug</code>.
     *
     * @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) {
        if (getLogger().isDebugEnabled()) {
            getLogger().debug(String.valueOf(message), t);
        }
    }

    
Logs a message with org.apache.avalon.framework.logger.Logger.debug.
Params:
message – to log
See Also:
Log.trace(Object)/**
     * Logs a message with <code>org.apache.avalon.framework.logger.Logger.debug</code>.
     *
     * @param message to log
     * @see org.apache.commons.logging.Log#trace(Object)
     */
    public void trace(Object message) {
        if (getLogger().isDebugEnabled()) {
            getLogger().debug(String.valueOf(message));
        }
    }

    
Logs a message with org.apache.avalon.framework.logger.Logger.warn.
Params:
message – to log
t – log this cause
See Also:
Log.warn(Object, Throwable)/**
     * Logs a message with <code>org.apache.avalon.framework.logger.Logger.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) {
        if (getLogger().isWarnEnabled()) {
            getLogger().warn(String.valueOf(message), t);
        }
    }

    
Logs a message with org.apache.avalon.framework.logger.Logger.warn.
Params:
message – to log
See Also:
Log.warn(Object)/**
     * Logs a message with <code>org.apache.avalon.framework.logger.Logger.warn</code>.
     *
     * @param message to log
     * @see org.apache.commons.logging.Log#warn(Object)
     */
    public void warn(Object message) {
        if (getLogger().isWarnEnabled()) {
            getLogger().warn(String.valueOf(message));
        }
    }
}