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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  package org.jboss.netty.handler.stream;
17  
18  import org.jboss.netty.buffer.ChannelBuffer;
19  
20  /**
21   * A data stream of indefinite length which is consumed by {@link ChunkedWriteHandler}.
22   * @apiviz.landmark
23   */
24  public interface ChunkedInput {
25  
26      /**
27       * Returns {@code true} if and only if there is any data left in the
28       * stream.  Please note that {@code false} does not necessarily mean that
29       * the stream has reached at its end.  In a slow stream, the next chunk
30       * might be unavailable just momentarily.
31       */
32      boolean hasNextChunk() throws Exception;
33  
34      /**
35       * Fetches a chunked data from the stream.  The returned chunk is usually
36       * a {@link ChannelBuffer}, but you could extend an existing implementation
37       * to convert the {@link ChannelBuffer} into a different type that your
38       * handler or encoder understands.  Once this method returns the last chunk
39       * and thus the stream has reached at its end, any subsequent {@link #isEndOfInput()}
40       * call must return {@code false}.
41       *
42       * @return the fetched chunk, which is usually {@link ChannelBuffer}.
43       *         {@code null} if there is no data left in the stream.
44       *         Please note that {@code null} does not necessarily mean that the
45       *         stream has reached at its end.  In a slow stream, the next chunk
46       *         might be unavailable just momentarily.
47       */
48      Object nextChunk() throws Exception;
49  
50      /**
51       * Return {@code true} if and only if there is no data left in the stream
52       * and the stream has reached at its end.
53       */
54      boolean isEndOfInput() throws Exception;
55  
56      /**
57       * Releases the resources associated with the stream.
58       */
59      void close() throws Exception;
60  }