//
   //  ========================================================================
   //  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.io;
  
  import java.util.List;
  import java.util.concurrent.CopyOnWriteArrayList;
  import java.util.concurrent.Executor;
  import java.util.concurrent.RejectedExecutionException;
  import java.util.concurrent.TimeoutException;
  
  import org.eclipse.jetty.util.Callback;
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  
  /**
   * <p>A convenience base implementation of {@link Connection}.</p>
   * <p>This class uses the capabilities of the {@link EndPoint} API to provide a
   * more traditional style of async reading.  A call to {@link #fillInterested()}
   * will schedule a callback to {@link #onFillable()} or {@link #onFillInterestedFailed(Throwable)}
   * as appropriate.</p>
   */
  public abstract class AbstractConnection implements Connection
  {
      private static final Logger LOG = Log.getLogger(AbstractConnection.class);
  
      private final List<Listener> listeners = new CopyOnWriteArrayList<>();
      private final long _created=System.currentTimeMillis();
      private final EndPoint _endPoint;
      private final Executor _executor;
      private final Callback _readCallback;
      private int _inputBufferSize=2048;
  
      protected AbstractConnection(EndPoint endp, Executor executor)
      {
          if (executor == null)
              throw new IllegalArgumentException("Executor must not be null!");
          _endPoint = endp;
          _executor = executor;
          _readCallback = new ReadCallback();
      }
  
      @Override
      public void addListener(Listener listener)
      {
          listeners.add(listener);
      }
  
      @Override
      public void removeListener(Listener listener)
      {
          listeners.remove(listener);
      }
  
      public int getInputBufferSize()
      {
          return _inputBufferSize;
      }
  
      public void setInputBufferSize(int inputBufferSize)
      {
          _inputBufferSize = inputBufferSize;
      }
  
      protected Executor getExecutor()
      {
          return _executor;
      }
  
      @Deprecated
      public boolean isDispatchIO()
      {
          return false;
      }
  
      protected void failedCallback(final Callback callback, final Throwable x)
      {
          if (callback.isNonBlocking())
          {
              try
              {
                  callback.failed(x);
              }
              catch (Exception e)
             {
                 LOG.warn(e);
             }
         }
         else
         {
             try
             {
                 getExecutor().execute(new Runnable()
                 {
                     @Override
                     public void run()
                     {
                         try
                         {
                             callback.failed(x);
                         }
                         catch (Exception e)
                         {
                             LOG.warn(e);
                         }
                     }
                 });
             }
             catch(RejectedExecutionException e)
             {
                 LOG.debug(e);
                 callback.failed(x);
             }
         }
     }
 
     /**
      * <p>Utility method to be called to register read interest.</p>
      * <p>After a call to this method, {@link #onFillable()} or {@link #onFillInterestedFailed(Throwable)}
      * will be called back as appropriate.</p>
      * @see #onFillable()
      */
     public void fillInterested()
     {
         if (LOG.isDebugEnabled())
             LOG.debug("fillInterested {}",this);
         getEndPoint().fillInterested(_readCallback);
     }
 
     public boolean isFillInterested()
     {
         return getEndPoint().isFillInterested();
     }
 
     /**
      * <p>Callback method invoked when the endpoint is ready to be read.</p>
      * @see #fillInterested()
      */
     public abstract void onFillable();
 
     /**
      * <p>Callback method invoked when the endpoint failed to be ready to be read.</p>
      * @param cause the exception that caused the failure
      */
     protected void onFillInterestedFailed(Throwable cause)
     {
         if (LOG.isDebugEnabled())
             LOG.debug("{} onFillInterestedFailed {}", this, cause);
         if (_endPoint.isOpen())
         {
             boolean close = true;
             if (cause instanceof TimeoutException)
                 close = onReadTimeout();
             if (close)
             {
                 if (_endPoint.isOutputShutdown())
                     _endPoint.close();
                 else
                 {
                     _endPoint.shutdownOutput();
                     fillInterested();
                 }
             }
         }
     }
 
     /**
      * <p>Callback method invoked when the endpoint failed to be ready to be read after a timeout</p>
      * @return true to signal that the endpoint must be closed, false to keep the endpoint open
      */
     protected boolean onReadTimeout()
     {
         return true;
     }
 
     @Override
     public void onOpen()
     {
         if (LOG.isDebugEnabled())
             LOG.debug("onOpen {}", this);
 
         for (Listener listener : listeners)
             listener.onOpened(this);
     }
 
     @Override
     public void onClose()
     {
         if (LOG.isDebugEnabled())
             LOG.debug("onClose {}",this);
 
         for (Listener listener : listeners)
             listener.onClosed(this);
     }
 
     @Override
     public EndPoint getEndPoint()
     {
         return _endPoint;
     }
 
     @Override
     public void close()
     {
         getEndPoint().close();
     }
 
     @Override
     public boolean onIdleExpired()
     {
         return true;
     }
 
     @Override
     public int getMessagesIn()
     {
         return -1;
     }
 
     @Override
     public int getMessagesOut()
     {
         return -1;
     }
 
     @Override
     public long getBytesIn()
     {
         return -1;
     }
 
     @Override
     public long getBytesOut()
     {
         return -1;
     }
 
     @Override
     public long getCreatedTimeStamp()
     {
         return _created;
     }
 
     @Override
     public String toString()
     {
         return String.format("%s@%x[%s]",
                 getClass().getSimpleName(),
                 hashCode(),
                 _endPoint);
     }
 
     private class ReadCallback implements Callback
     {
         @Override
         public void succeeded()
         {
             onFillable();
         }
 
         @Override
         public void failed(final Throwable x)
         {
             onFillInterestedFailed(x);
         }
 
         @Override
         public String toString()
         {
             return String.format("AC.ReadCB@%x{%s}", AbstractConnection.this.hashCode(),AbstractConnection.this);
         }
     }
 }