SLF4JLog.java

/*
 * Copyright 2001-2004 The Apache Software Foundation.
 * 
 * Licensed 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.ObjectStreamException;
import java.io.Serializable;

import org.apache.commons.logging.Log;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Implementation of {@link Log org.apache.commons.logging.Log} interface which
 * delegates all processing to a wrapped {@link Logger org.slf4j.Logger}
 * instance.
 * 
 * <p>
 * JCL's FATAL level is mapped to ERROR. All other levels map one to one.
 * 
 * @author Ceki Gülcü
 */
public class SLF4JLog implements Log, Serializable {

  private static final long serialVersionUID = 680728617011167209L;

  // used to store this logger's name to recreate it after serialization
  protected String name;

  // in both Log4jLogger and Jdk14Logger classes in the original JCL, the
  // logger instance is transient
  private transient Logger logger;

  SLF4JLog(Logger logger) {
    this.logger = logger;
    this.name = logger.getName();
  }

  /**
   * Directly delegates to the wrapped <code>org.slf4j.Logger</code> instance.
   */
  public boolean isDebugEnabled() {
    return logger.isDebugEnabled();
  }

  /**
   * Directly delegates to the wrapped <code>org.slf4j.Logger</code> instance.
   */
  public boolean isErrorEnabled() {
    return logger.isErrorEnabled();
  }

  /**
   * Delegates to the <code>isErrorEnabled<code> method of the wrapped 
   * <code>org.slf4j.Logger</code> instance.
   */
  public boolean isFatalEnabled() {
    return logger.isErrorEnabled();
  }

  /**
   * Directly delegates to the wrapped <code>org.slf4j.Logger</code> instance.
   */
  public boolean isInfoEnabled() {
    return logger.isInfoEnabled();
  }

  /**
   * Delegates to the <code>isDebugEnabled<code> method of the wrapped 
   * <code>org.slf4j.Logger</code> instance.
   */
  public boolean isTraceEnabled() {
    return logger.isTraceEnabled();
  }

  /**
   * Directly delegates to the wrapped <code>org.slf4j.Logger</code> instance.
   */
  public boolean isWarnEnabled() {
    return logger.isWarnEnabled();
  }

  /**
   * Converts the input parameter to String and then delegates to the debug
   * method of the wrapped <code>org.slf4j.Logger</code> instance.
   * 
   * @param message
   *          the message to log. Converted to {@link String}
   */
  public void trace(Object message) {
    logger.trace(String.valueOf(message));
  }

  /**
   * Converts the first input parameter to String and then delegates to the
   * debug method of the wrapped <code>org.slf4j.Logger</code> instance.
   * 
   * @param message
   *          the message to log. Converted to {@link String}
   * @param t
   *          the exception to log
   */
  public void trace(Object message, Throwable t) {
    logger.trace(String.valueOf(message), t);
  }

  /**
   * Converts the input parameter to String and then delegates to the wrapped
   * <code>org.slf4j.Logger</code> instance.
   * 
   * @param message
   *          the message to log. Converted to {@link String}
   */
  public void debug(Object message) {
    logger.debug(String.valueOf(message));
  }

  /**
   * Converts the first input parameter to String and then delegates to the
   * wrapped <code>org.slf4j.Logger</code> instance.
   * 
   * @param message
   *          the message to log. Converted to {@link String}
   * @param t
   *          the exception to log
   */
  public void debug(Object message, Throwable t) {
    logger.debug(String.valueOf(message), t);
  }

  /**
   * Converts the input parameter to String and then delegates to the wrapped
   * <code>org.slf4j.Logger</code> instance.
   * 
   * @param message
   *          the message to log. Converted to {@link String}
   */
  public void info(Object message) {
    logger.info(String.valueOf(message));
  }

  /**
   * Converts the first input parameter to String and then delegates to the
   * wrapped <code>org.slf4j.Logger</code> instance.
   * 
   * @param message
   *          the message to log. Converted to {@link String}
   * @param t
   *          the exception to log
   */
  public void info(Object message, Throwable t) {
    logger.info(String.valueOf(message), t);
  }

  /**
   * Converts the input parameter to String and then delegates to the wrapped
   * <code>org.slf4j.Logger</code> instance.
   * 
   * @param message
   *          the message to log. Converted to {@link String}
   */
  public void warn(Object message) {
    logger.warn(String.valueOf(message));
  }

  /**
   * Converts the first input parameter to String and then delegates to the
   * wrapped <code>org.slf4j.Logger</code> instance.
   * 
   * @param message
   *          the message to log. Converted to {@link String}
   * @param t
   *          the exception to log
   */
  public void warn(Object message, Throwable t) {
    logger.warn(String.valueOf(message), t);
  }

  /**
   * Converts the input parameter to String and then delegates to the wrapped
   * <code>org.slf4j.Logger</code> instance.
   * 
   * @param message
   *          the message to log. Converted to {@link String}
   */
  public void error(Object message) {
    logger.error(String.valueOf(message));
  }

  /**
   * Converts the first input parameter to String and then delegates to the
   * wrapped <code>org.slf4j.Logger</code> instance.
   * 
   * @param message
   *          the message to log. Converted to {@link String}
   * @param t
   *          the exception to log
   */
  public void error(Object message, Throwable t) {
    logger.error(String.valueOf(message), t);
  }

  /**
   * Converts the input parameter to String and then delegates to the error
   * method of the wrapped <code>org.slf4j.Logger</code> instance.
   * 
   * @param message
   *          the message to log. Converted to {@link String}
   */
  public void fatal(Object message) {
    logger.error(String.valueOf(message));
  }

  /**
   * Converts the first input parameter to String and then delegates to the
   * error method of the wrapped <code>org.slf4j.Logger</code> instance.
   * 
   * @param message
   *          the message to log. Converted to {@link String}
   * @param t
   *          the exception to log
   */
  public void fatal(Object message, Throwable t) {
    logger.error(String.valueOf(message), t);
  }

  /**
   * Replace this instance with a homonymous (same name) logger returned by
   * LoggerFactory. Note that this method is only called during deserialization.
   * 
   * @return logger with same name as returned by LoggerFactory
   * @throws ObjectStreamException
   */
  protected Object readResolve() throws ObjectStreamException {
    Logger logger = LoggerFactory.getLogger(this.name);
    return new SLF4JLog(logger);
  }
}