/*
    * Copyright 2009 Red Hat, Inc.
    *
    * Red Hat 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.jboss.netty.logging;
  
  import org.jboss.netty.util.internal.StackTraceSimplifier;
  
  /**
   * Creates an {@link InternalLogger} or changes the default factory
   * implementation.  This factory allows you to choose what logging framework
   * Netty should use.  The default factory is {@link JdkLoggerFactory}.
   * You can change it to your preferred logging framework before other Netty
   * classes are loaded:
   * <pre>
   * {@link InternalLoggerFactory}.setDefaultFactory(new {@link Log4JLoggerFactory}());
   * </pre>
   * Please note that the new default factory is effective only for the classes
   * which were loaded after the default factory is changed.  Therefore,
   * {@link #setDefaultFactory(InternalLoggerFactory)} should be called as early
   * as possible and shouldn't be called more than once.
   *
   * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
   * @author <a href="http://gleamynode.net/">Trustin Lee</a>
   *
   * @version $Rev: 2122 $, $Date: 2010-02-02 11:00:04 +0900 (Tue, 02 Feb 2010) $
   *
   * @apiviz.landmark
   * @apiviz.has org.jboss.netty.logging.InternalLogger oneway - - creates
   */
  public abstract class InternalLoggerFactory {
      private static volatile InternalLoggerFactory defaultFactory = new JdkLoggerFactory();
  
      static {
          // Load the dependent classes in advance to avoid the case where
          // the VM fails to load the required classes because of too many open
          // files.
          StackTraceSimplifier.simplify(new Exception());
      }
  
      /**
       * Returns the default factory.  The initial default factory is
       * {@link JdkLoggerFactory}.
       */
      public static InternalLoggerFactory getDefaultFactory() {
          return defaultFactory;
      }
  
      /**
       * Changes the default factory.
       */
      public static void setDefaultFactory(InternalLoggerFactory defaultFactory) {
          if (defaultFactory == null) {
              throw new NullPointerException("defaultFactory");
          }
          InternalLoggerFactory.defaultFactory = defaultFactory;
      }
  
      /**
       * Creates a new logger instance with the name of the specified class.
       */
      public static InternalLogger getInstance(Class<?> clazz) {
          return getInstance(clazz.getName());
      }
  
      /**
       * Creates a new logger instance with the specified name.
       */
      public static InternalLogger getInstance(String name) {
          final InternalLogger logger = getDefaultFactory().newInstance(name);
          return new InternalLogger() {
  
              public void debug(String msg) {
                  logger.debug(msg);
              }
  
              public void debug(String msg, Throwable cause) {
                  StackTraceSimplifier.simplify(cause);
                  logger.debug(msg, cause);
              }
  
              public void error(String msg) {
                  logger.error(msg);
              }
  
              public void error(String msg, Throwable cause) {
                  StackTraceSimplifier.simplify(cause);
                  logger.error(msg, cause);
             }
 
             public void info(String msg) {
                 logger.info(msg);
             }
 
             public void info(String msg, Throwable cause) {
                 StackTraceSimplifier.simplify(cause);
                 logger.info(msg, cause);
             }
 
             public boolean isDebugEnabled() {
                 return logger.isDebugEnabled();
             }
 
             public boolean isErrorEnabled() {
                 return logger.isErrorEnabled();
             }
 
             public boolean isInfoEnabled() {
                 return logger.isInfoEnabled();
             }
 
             public boolean isWarnEnabled() {
                 return logger.isWarnEnabled();
             }
 
             public void warn(String msg) {
                 logger.warn(msg);
             }
 
             public void warn(String msg, Throwable cause) {
                 StackTraceSimplifier.simplify(cause);
                 logger.warn(msg, cause);
             }
 
             public boolean isEnabled(InternalLogLevel level) {
                 return logger.isEnabled(level);
             }
 
             public void log(InternalLogLevel level, String msg) {
                 logger.log(level, msg);
             }
 
             public void log(InternalLogLevel level, String msg, Throwable cause) {
                 StackTraceSimplifier.simplify(cause);
                 logger.log(level, msg, cause);
             }
         };
     }
 
     /**
      * Creates a new logger instance with the specified name.
      */
     public abstract InternalLogger newInstance(String name);
 }