1 /*
2 * Copyright 2009 Red Hat, Inc.
3 *
4 * Red Hat licenses this file to you under the Apache License, version 2.0
5 * (the "License"); you may not use this file except in compliance with the
6 * 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.codec.embedder;
17
18 import java.util.Collection;
19
20 import org.jboss.netty.channel.ChannelPipeline;
21
22 /**
23 * A helper that wraps an encoder or a decoder (codec) so that they can be used
24 * without doing actual I/O in unit tests or higher level codecs. Please refer
25 * to {@link EncoderEmbedder} and {@link DecoderEmbedder} for more information.
26 *
27 * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
28 * @author <a href="http://gleamynode.net/">Trustin Lee</a>
29 * @version $Rev: 2080 $, $Date: 2010-01-26 18:04:19 +0900 (Tue, 26 Jan 2010) $
30 */
31 public interface CodecEmbedder<E> {
32 /**
33 * Offers an input object to the pipeline of this embedder.
34 *
35 * @return {@code true} if and only if there is something to read in the
36 * product queue (see {@link #poll()} and {@link #peek()})
37 */
38 boolean offer(Object input);
39
40 /**
41 * Signals the pipeline that the encoding or decoding has been finished and
42 * no more data will be offered.
43 *
44 * @return {@code true} if and only if there is something to read in the
45 * product queue (see {@link #poll()} and {@link #peek()})
46 */
47 boolean finish();
48
49 /**
50 * Consumes an encoded or decoded output from the product queue. The output
51 * object is generated by the offered input objects.
52 *
53 * @return an encoded or decoded object.
54 * {@code null} if and only if there is no output object left in the
55 * product queue.
56 */
57 E poll();
58
59 /**
60 * Reads an encoded or decoded output from the head of the product queue.
61 * The difference from {@link #poll()} is that it does not remove the
62 * retrieved object from the product queue.
63 *
64 * @return an encoded or decoded object.
65 * {@code null} if and only if there is no output object left in the
66 * product queue.
67 */
68 E peek();
69
70 /**
71 * Consumes all encoded or decoded output from the product queue. The
72 * output object is generated by the offered input objects. The behavior
73 * of this method is identical with {@link Collection#toArray()} except that
74 * the product queue is cleared.
75 *
76 * @return an array of all encoded or decoded objects.
77 * An empty array is returned if and only if there is no output
78 * object left in the product queue.
79 */
80 Object[] pollAll();
81
82 /**
83 * Consumes all encoded or decoded output from the product queue. The
84 * output object is generated by the offered input objects. The behavior
85 * of this method is identical with {@link Collection#toArray(Object[])}
86 * except that the product queue is cleared.
87 *
88 * @return an array of all encoded or decoded objects.
89 * An empty array is returned if and only if there is no output
90 * object left in the product queue.
91 */
92 <T> T[] pollAll(T[] a);
93
94 /**
95 * Returns the number of encoded or decoded output in the product queue.
96 */
97 int size();
98
99 /**
100 * Returns the {@link ChannelPipeline} that handles the input.
101 */
102 ChannelPipeline getPipeline();
103 }