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1   /*
2    * Copyright 2012 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    * http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  
17  package io.netty.handler.codec.sctp;
18  
19  import io.netty.buffer.ByteBuf;
20  import io.netty.channel.ChannelHandlerContext;
21  import io.netty.channel.sctp.SctpMessage;
22  import io.netty.handler.codec.CodecException;
23  import io.netty.handler.codec.MessageToMessageDecoder;
24  
25  import java.util.List;
26  
27  /**
28   * A ChannelHandler which receives {@link SctpMessage}s which belong to a application protocol form a specific
29   * SCTP Stream  and decode it as {@link ByteBuf}.
30   */
31  public class SctpInboundByteStreamHandler extends MessageToMessageDecoder<SctpMessage> {
32      private final int protocolIdentifier;
33      private final int streamIdentifier;
34  
35      /**
36       * @param streamIdentifier   accepted stream number, this should be >=0 or <= max stream number of the association.
37       * @param protocolIdentifier supported application protocol.
38       */
39      public SctpInboundByteStreamHandler(int protocolIdentifier, int streamIdentifier) {
40          this.protocolIdentifier = protocolIdentifier;
41          this.streamIdentifier = streamIdentifier;
42      }
43  
44      @Override
45      public final boolean acceptInboundMessage(Object msg) throws Exception {
46          if (super.acceptInboundMessage(msg)) {
47              return acceptInboundMessage((SctpMessage) msg);
48          }
49          return false;
50      }
51  
52      protected boolean acceptInboundMessage(SctpMessage msg) {
53          return msg.protocolIdentifier() == protocolIdentifier && msg.streamIdentifier() == streamIdentifier;
54      }
55  
56      @Override
57      protected void decode(ChannelHandlerContext ctx, SctpMessage msg, List<Object> out) throws Exception {
58          if (!msg.isComplete()) {
59              throw new CodecException(String.format("Received SctpMessage is not complete, please add %s in the " +
60                      "pipeline before this handler", SctpMessageCompletionHandler.class.getSimpleName()));
61          }
62          out.add(msg.content().retain());
63      }
64  }