/*
    * 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.logging.log4j.core.appender;
  
  import java.io.Serializable;
  import java.util.concurrent.TimeUnit;
  
  import org.apache.logging.log4j.core.Filter;
  import org.apache.logging.log4j.core.Layout;
  import org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.config.plugins.PluginBuilderAttribute;
  import org.apache.logging.log4j.core.util.Constants;
  
  /**
   * Appends log events as bytes to a byte output stream. The stream encoding is defined in the layout.
   *
   * @param <M> The kind of {@link OutputStreamManager} under management
   */
  public abstract class AbstractOutputStreamAppender<M extends OutputStreamManager> extends AbstractAppender {
  
      /**
       * Subclasses can extend this abstract Builder. 
       * 
       * @param <B> This builder class.
       */
      public abstract static class Builder<B extends Builder<B>> extends AbstractAppender.Builder<B> {
      
          @PluginBuilderAttribute
          private boolean bufferedIo = true;
  
          @PluginBuilderAttribute
          private int bufferSize = Constants.ENCODER_BYTE_BUFFER_SIZE;
  
          @PluginBuilderAttribute
          private boolean immediateFlush = true;
  
          public int getBufferSize() {
              return bufferSize;
          }
  
          public boolean isBufferedIo() {
              return bufferedIo;
          }
  
          public boolean isImmediateFlush() {
              return immediateFlush;
          }
          
          public B withImmediateFlush(final boolean immediateFlush) {
              this.immediateFlush = immediateFlush;
              return asBuilder();
          }
          
          public B withBufferedIo(final boolean bufferedIo) {
              this.bufferedIo = bufferedIo;
              return asBuilder();
          }
  
          public B withBufferSize(final int bufferSize) {
              this.bufferSize = bufferSize;
              return asBuilder();
          }
  
      }
      
      /**
       * Immediate flush means that the underlying writer or output stream will be flushed at the end of each append
       * operation. Immediate flush is slower but ensures that each append request is actually written. If
       * <code>immediateFlush</code> is set to {@code false}, then there is a good chance that the last few logs events
       * are not actually written to persistent media if and when the application crashes.
       */
      private final boolean immediateFlush;
  
      private final M manager;
  
      /**
       * Instantiates a WriterAppender and set the output destination to a new {@link java.io.OutputStreamWriter}
       * initialized with <code>os</code> as its {@link java.io.OutputStream}.
       *
       * @param name The name of the Appender.
       * @param layout The layout to format the message.
       * @param manager The OutputStreamManager.
       */
      protected AbstractOutputStreamAppender(final String name, final Layout<? extends Serializable> layout,
              final Filter filter, final boolean ignoreExceptions, final boolean immediateFlush, final M manager) {
         super(name, filter, layout, ignoreExceptions);
         this.manager = manager;
         this.immediateFlush = immediateFlush;
     }
 
     /**
      * Gets the immediate flush setting.
      *
      * @return immediate flush.
      */
     public boolean getImmediateFlush() {
         return immediateFlush;
     }
 
     /**
      * Gets the manager.
      *
      * @return the manager.
      */
     public M getManager() {
         return manager;
     }
 
     @Override
     public void start() {
         if (getLayout() == null) {
             LOGGER.error("No layout set for the appender named [" + getName() + "].");
         }
         if (manager == null) {
             LOGGER.error("No OutputStreamManager set for the appender named [" + getName() + "].");
         }
         super.start();
     }
 
     @Override
     public boolean stop(final long timeout, final TimeUnit timeUnit) {
         return stop(timeout, timeUnit, true);
     }
 
     @Override
     protected boolean stop(final long timeout, final TimeUnit timeUnit, final boolean changeLifeCycleState) {
         boolean stopped = super.stop(timeout, timeUnit, changeLifeCycleState);
         stopped &= manager.stop(timeout, timeUnit);
         if (changeLifeCycleState) {
             setStopped();
         }
         return stopped;
     }
 
     /**
      * Actual writing occurs here.
      * <p>
      * Most subclasses of <code>AbstractOutputStreamAppender</code> will need to override this method.
      * </p>
      *
      * @param event The LogEvent.
      */
     @Override
     public void append(final LogEvent event) {
         try {
             tryAppend(event);
         } catch (final AppenderLoggingException ex) {
             error("Unable to write to stream " + manager.getName() + " for appender " + getName() + ": " + ex);
             throw ex;
         }
     }
 
     private void tryAppend(final LogEvent event) {
         if (Constants.ENABLE_DIRECT_ENCODERS) {
             directEncodeEvent(event);
         } else {
             writeByteArrayToManager(event);
         }
     }
 
     protected void directEncodeEvent(final LogEvent event) {
         getLayout().encode(event, manager);
         if (this.immediateFlush || event.isEndOfBatch()) {
             manager.flush();
         }
     }
 
     protected void writeByteArrayToManager(final LogEvent event) {
         final byte[] bytes = getLayout().toByteArray(event);
         if (bytes != null && bytes.length > 0) {
             manager.write(bytes, this.immediateFlush || event.isEndOfBatch());
         }
     }
 }