/*
    * 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;
  
  import org.apache.log4j.spi.ErrorHandler;
  import org.apache.log4j.spi.Filter;
  import org.apache.log4j.spi.LoggingEvent;
  import org.apache.log4j.spi.OptionHandler;
  
  /**
   * The base class for Appenders in Log4j 1. Appenders constructed using this are ignored in Log4j 2.
   */
  public abstract class AppenderSkeleton implements Appender, OptionHandler {
  
      protected Layout layout;
  
      protected String name;
  
      protected Priority threshold;
  
      protected ErrorHandler errorHandler = new NoOpErrorHandler();
  
      protected Filter headFilter;
  
      protected Filter tailFilter;
  
      protected boolean closed = false;
  
      /**
       * Create new instance.
       */
      public AppenderSkeleton() {
      }
  
      protected AppenderSkeleton(final boolean isActive) {
      }
  
      @Override
      public void activateOptions() {
      }
  
      @Override
      public void addFilter(final Filter newFilter) {
          if(headFilter == null) {
              headFilter = tailFilter = newFilter;
          } else {
              tailFilter.setNext(newFilter);
              tailFilter = newFilter;
          }
      }
  
      protected abstract void append(LoggingEvent event);
  
      @Override
      public void clearFilters() {
          headFilter = tailFilter = null;
      }
  
      @Override
      public void finalize() {
      }
  
      @Override
      public ErrorHandler getErrorHandler() {
          return this.errorHandler;
      }
  
      @Override
      public Filter getFilter() {
          return headFilter;
      }
  
      public final Filter getFirstFilter() {
          return headFilter;
      }
  
      @Override
      public Layout getLayout() {
          return layout;
      }
  
      @Override
      public final String getName() {
          return this.name;
      }
 
     public Priority getThreshold() {
         return threshold;
     }
 
     public boolean isAsSevereAsThreshold(final Priority priority) {
         return ((threshold == null) || priority.isGreaterOrEqual(threshold));
     }
 
     /**
      * This method is never going to be called in Log4j 2 so there isn't much point in having any code in it.
      * @param event The LoggingEvent.
      */
     @Override
     public void doAppend(final LoggingEvent event) {
         append(event);
     }
 
     /**
      * Sets the {@link ErrorHandler} for this Appender.
      *
      * @since 0.9.0
      */
     @Override
     public synchronized void setErrorHandler(final ErrorHandler eh) {
         if (eh != null) {
             this.errorHandler = eh;
         }
     }
 
     @Override
     public void setLayout(final Layout layout) {
         this.layout = layout;
     }
 
     @Override
     public void setName(final String name) {
         this.name = name;
     }
 
     public void setThreshold(final Priority threshold) {
         this.threshold = threshold;
     }
 
     public static class NoOpErrorHandler implements ErrorHandler {
         @Override
         public void setLogger(final Logger logger) {
 
         }
 
         @Override
         public void error(final String message, final Exception e, final int errorCode) {
 
         }
 
         @Override
         public void error(final String message) {
 
         }
 
         @Override
         public void error(final String message, final Exception e, final int errorCode, final LoggingEvent event) {
 
         }
 
         @Override
         public void setAppender(final Appender appender) {
 
         }
 
         @Override
         public void setBackupAppender(final Appender appender) {
 
         }
     }
 }