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1   /*** 
2    * 
3    * Copyright 2004 Hiram Chirino
4    * 
5    * Licensed under the Apache License, Version 2.0 (the "License"); 
6    * you may not use this file except in compliance with the License. 
7    * You may obtain a copy of the License at 
8    * 
9    * http://www.apache.org/licenses/LICENSE-2.0
10   * 
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS, 
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
14   * See the License for the specific language governing permissions and 
15   * limitations under the License. 
16   * 
17   **/
18  
19  package org.activeio.net;
20  
21  import java.io.IOException;
22  import java.net.SocketTimeoutException;
23  import java.nio.ByteBuffer;
24  import java.nio.channels.SocketChannel;
25  
26  import org.activeio.Packet;
27  import org.activeio.SynchChannel;
28  import org.activeio.SynchChannelServer;
29  import org.activeio.Packet.ByteSequence;
30  import org.activeio.packet.ByteBufferPacket;
31  import org.activeio.packet.EOSPacket;
32  import org.activeio.packet.EmptyPacket;
33  
34  /***
35   * A {@see org.activeio.SynchChannel} implementation that uses a {@see java.nio.channels.SocketChannel}
36   * to talk to the network.
37   * 
38   * Using a SocketChannelSynchChannel should be more efficient than using a SocketSynchChannel since
39   * direct ByteBuffer can be used to reduce the jvm overhead needed to copy byte[]s.
40   * 
41   * @version $Revision$
42   */
43  final public class NIOSynchChannel extends NIOBaseChannel implements SynchChannel {
44  
45      private ByteBuffer inputByteBuffer;
46  //    private Packet data2;
47  
48      protected NIOSynchChannel(SocketChannel socketChannel) throws IOException {
49          this(socketChannel, true );
50      }
51  
52      protected NIOSynchChannel(SocketChannel socketChannel, boolean useDirect) throws IOException {
53          super(socketChannel, useDirect);
54      }
55      
56      public Packet read(long timeout) throws IOException {
57          try {
58              
59              if( timeout==SynchChannelServer.WAIT_FOREVER_TIMEOUT )
60                  setSoTimeout( 0 );
61              else if( timeout==SynchChannelServer.NO_WAIT_TIMEOUT )
62                  setSoTimeout( 1 );
63              else 
64                  setSoTimeout( (int)timeout );
65  
66              if( inputByteBuffer==null || !inputByteBuffer.hasRemaining() ) {
67                  inputByteBuffer = allocateBuffer();
68              }
69  
70              int size = socketChannel.read(inputByteBuffer);
71              if( size == -1 )
72                  return EOSPacket.EOS_PACKET;
73              if( size == 0 )
74                  return EmptyPacket.EMPTY_PACKET;
75  
76              ByteBuffer remaining = inputByteBuffer.slice();            
77              Packet data = new ByteBufferPacket(((ByteBuffer)inputByteBuffer.flip()).slice());
78              
79              // Keep the remaining buffer around to fill with data.
80              inputByteBuffer = remaining;
81              return data;
82              
83          } catch (SocketTimeoutException e) {
84              return null;
85          }
86      }
87      
88      public void write(Packet packet) throws IOException {
89      	ByteBuffer data;
90          if( packet.getClass()==ByteBufferPacket.class ) {
91              data = ((ByteBufferPacket)packet).getByteBuffer();            
92          } else {
93          	ByteSequence sequence = packet.asByteSequence();
94          	data = ByteBuffer.wrap(sequence.getData(), sequence.getOffset(), sequence.getLength());
95          }
96          socketChannel.write( data );            
97      }
98  
99  	public void start() throws IOException {
100 	}
101 
102 	public void stop(long timeout) throws IOException {
103 	}
104     
105 }