/*
* Copyright 2003 Federal Chancellery Austria
*
* 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 at.gv.egovernment.moa.logging;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * A utility class acting as a facade to the logging subsystem.
 * 
 * Configure the logging defaultHierarchy that the <code>Logger</code> uses by
 * calling <code>setHierarchy</code> once before calling any of the logging
 * output functions.
 * 
 * @author Patrick Peck
 * @version $Id$
 */
public class Logger {
  
  /** The default logging hierarchy. */
  private static String defaultHierarchy = "";
  
  /**
   * Get the <code>Log</code> object for the default hierarchy.
   * 
   * @return The <code>Log</code> object to write log messages to.
   */
  private static Log getLog() {
    return LogFactory.getLog(defaultHierarchy);
  }

  /**
   * Get the <code>Log</code> object for a given hierarchy.
   * 
   * @param hierarchy The logging hierarchy for which to return the logger. 
   * @return The <code>Log</code> object to write log messages to.
   */
  private static Log getLog(String hierarchy) {
    return LogFactory.getLog(hierarchy);
  }
  
  /**
   * Set the default hierarchy to which the <code>Logger</code> should send its
   * logging output.
   * @param hierarchy The logging defaultHierarchy.
   */
  public static void setHierarchy(String hierarchy) {
    defaultHierarchy = hierarchy;
  }

  /**
   * Test, if the trace log level is enabled.
   * 
   * @return boolean <code>true</code>, if tracing output is enabled
   * <code>false</code> otherwise.
   */
  public static boolean isTraceEnabled() {
    return getLog().isTraceEnabled();
  }
  
  /**
   * Test, if the trace log level is enabled for a given hierarchy.
   * 
   * @param hierarchy requested log hierarchy
   * @return boolean <code>true</code>, if tracing output is enabled
   * <code>false</code> otherwise.
   */
  public static boolean isTraceEnabled(String hierarchy) {
    return getLog(hierarchy).isTraceEnabled();
  }
  
  /**
   * Trace a message.
   * 
   * @param message The message to trace.
   */
  public static void trace(Object message) {
    getLog().trace(message);
  }
  
  /**
   * Test, if the debug log level is enabled.
   * 
   * @return boolean <code>true</code>, if debug output is enabled
   * <code>false</code> otherwise.
   */
  public static boolean isDebugEnabled() {
    return getLog().isDebugEnabled();
  }
  
  /**
   * Test, if the debug log level is enabled for a given hierarchy.
   * 
   * @param hierarchy requested log hierarchy
   * @return boolean <code>true</code>, if debug output is enabled
   * <code>false</code> otherwise.
   */
  public static boolean isDebugEnabled(String hierarchy) {
    return getLog(hierarchy).isDebugEnabled();
  }
  
  /**
   * Log a debug message.
   * 
   * @param message The message to log.
   */
  public static void debug(Object message) {
    getLog().debug(message);
  }
  
  /**
   * Log an info message.
   * 
   * @param message The message to log.
   */
  public static void info(Object message) {
    getLog().info(message);
  }
  
  /**
   * Log a warning message.
   * 
   * @param message The message to log.
   */
  public static void warn(Object message) {
    getLog().warn(message);
  }

  /**
   * Log a warning message.
   * 
   * @param message The message to log.
   * @param t An exception that may be the cause of the warning.
   */
  public static void warn(Object message, Throwable t) {
    getLog().warn(message, t);
  }
  
  /**
   * Log an error message.
   * 
   * @param message The message to log.
   */
  public static void error(Object message) {
    getLog().error(message);
  }

  /**
   * Log an error message.
   * 
   * @param message The message to log.
   * @param t An exception that may be the cause of the error.
   */
  public static void error(Object message, Throwable t) {
    getLog().error(message, t);
  }
  
  /**
   * Log a fatal error message.
   * 
   * @param message The message to log.
   */
  public static void fatal(Object message) {
    getLog().fatal(message);
  }

  /**
   * Log a fatal error message.
   * 
   * @param message The message to log.
   * @param t An exception that may be the cause of the error.
   */
  public static void fatal(Object message, Throwable t) {
    getLog().fatal(message, t);
  }

}