/*
    * 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.log4j.rewrite;
  
  import org.apache.log4j.Appender;
  import org.apache.log4j.AppenderSkeleton;
  import org.apache.log4j.helpers.AppenderAttachableImpl;
  import org.apache.log4j.spi.AppenderAttachable;
  import org.apache.log4j.spi.LoggingEvent;
  import org.apache.log4j.spi.OptionHandler;
  import org.apache.log4j.xml.UnrecognizedElementHandler;
  import org.w3c.dom.Element;
  
  import java.util.Enumeration;
  import java.util.Properties;
  
  /**
   * This appender forwards a logging request to another
   * appender after possibly rewriting the logging event.
   * <p>
   * This appender (with the appropriate policy)
   * replaces the MapFilter, PropertyFilter and ReflectionFilter
   * from log4j 1.3.
   */
  public class RewriteAppender extends AppenderSkeleton
      implements AppenderAttachable, UnrecognizedElementHandler {
      /**
       * Rewrite policy.
       */
      private RewritePolicy policy;
      /**
       * Nested appenders.
       */
      private final AppenderAttachableImpl appenders;
  
      public RewriteAppender() {
          appenders = new AppenderAttachableImpl();
      }
  
      /**
       * {@inheritDoc}
       */
      protected void append(final LoggingEvent event) {
          LoggingEvent rewritten = event;
          if (policy != null) {
              rewritten = policy.rewrite(event);
          }
          if (rewritten != null) {
              synchronized (appenders) {
                  appenders.appendLoopOnAppenders(rewritten);
              }
          }
      }
  
      /**
       * Add appender.
       *
       * @param newAppender appender to add, may not be null.
       */
      public void addAppender(final Appender newAppender) {
          synchronized (appenders) {
              appenders.addAppender(newAppender);
          }
      }
  
      /**
       * Get iterator over attached appenders.
       *
       * @return iterator or null if no attached appenders.
       */
      public Enumeration getAllAppenders() {
          synchronized (appenders) {
              return appenders.getAllAppenders();
          }
      }
  
      /**
       * Get appender by name.
       *
       * @param name name, may not be null.
       * @return matching appender or null.
       */
      public Appender getAppender(final String name) {
          synchronized (appenders) {
              return appenders.getAppender(name);
         }
     }
 
 
     /**
      * Close this <code>AsyncAppender</code> by interrupting the dispatcher
      * thread which will process all pending events before exiting.
      */
     public void close() {
         closed = true;
         //
         //    close all attached appenders.
         //
         synchronized (appenders) {
             Enumeration iter = appenders.getAllAppenders();
 
             if (iter != null) {
                 while (iter.hasMoreElements()) {
                     Object next = iter.nextElement();
 
                     if (next instanceof Appender) {
                         ((Appender) next).close();
                     }
                 }
             }
         }
     }
 
     /**
      * Determines if specified appender is attached.
      *
      * @param appender appender.
      * @return true if attached.
      */
     public boolean isAttached(final Appender appender) {
         synchronized (appenders) {
             return appenders.isAttached(appender);
         }
     }
 
     /**
      * {@inheritDoc}
      */
     public boolean requiresLayout() {
         return false;
     }
 
     /**
      * Removes and closes all attached appenders.
      */
     public void removeAllAppenders() {
         synchronized (appenders) {
             appenders.removeAllAppenders();
         }
     }
 
     /**
      * Removes an appender.
      *
      * @param appender appender to remove.
      */
     public void removeAppender(final Appender appender) {
         synchronized (appenders) {
             appenders.removeAppender(appender);
         }
     }
 
     /**
      * Remove appender by name.
      *
      * @param name name.
      */
     public void removeAppender(final String name) {
         synchronized (appenders) {
             appenders.removeAppender(name);
         }
     }
 
 
     public void setRewritePolicy(final RewritePolicy rewritePolicy) {
         policy = rewritePolicy;
     }
 
     /**
      * {@inheritDoc}
      */
     public boolean parseUnrecognizedElement(final Element element,
                                             final Properties props) throws Exception {
         final String nodeName = element.getNodeName();
         if ("rewritePolicy".equals(nodeName)) {
             Object rewritePolicy =
                 org.apache.log4j.xml.DOMConfigurator.parseElement(
                     element, props, RewritePolicy.class);
             if (rewritePolicy != null) {
                 if (rewritePolicy instanceof OptionHandler) {
                     ((OptionHandler) rewritePolicy).activateOptions();
                 }
                 this.setRewritePolicy((RewritePolicy) rewritePolicy);
             }
             return true;
         }
         return false;
     }
 
 }