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.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 public interface CodecEmbedder<E> {
28 /**
29 * Offers an input object to the pipeline of this embedder.
30 *
31 * @return {@code true} if and only if there is something to read in the
32 * product queue (see {@link #poll()} and {@link #peek()})
33 */
34 boolean offer(Object input);
35
36 /**
37 * Signals the pipeline that the encoding or decoding has been finished and
38 * no more data will be offered.
39 *
40 * @return {@code true} if and only if there is something to read in the
41 * product queue (see {@link #poll()} and {@link #peek()})
42 */
43 boolean finish();
44
45 /**
46 * Consumes an encoded or decoded output from the product queue. The output
47 * object is generated by the offered input objects.
48 *
49 * @return an encoded or decoded object.
50 * {@code null} if and only if there is no output object left in the
51 * product queue.
52 */
53 E poll();
54
55 /**
56 * Reads an encoded or decoded output from the head of the product queue.
57 * The difference from {@link #poll()} is that it does not remove the
58 * retrieved object from the product queue.
59 *
60 * @return an encoded or decoded object.
61 * {@code null} if and only if there is no output object left in the
62 * product queue.
63 */
64 E peek();
65
66 /**
67 * Consumes all encoded or decoded output from the product queue. The
68 * output object is generated by the offered input objects. The behavior
69 * of this method is identical with {@link Collection#toArray()} except that
70 * the product queue is cleared.
71 *
72 * @return an array of all encoded or decoded objects.
73 * An empty array is returned if and only if there is no output
74 * object left in the product queue.
75 */
76 Object[] pollAll();
77
78 /**
79 * Consumes all encoded or decoded output from the product queue. The
80 * output object is generated by the offered input objects. The behavior
81 * of this method is identical with {@link Collection#toArray(Object[])}
82 * except that the product queue is cleared.
83 *
84 * @return an array of all encoded or decoded objects.
85 * An empty array is returned if and only if there is no output
86 * object left in the product queue.
87 */
88 <T> T[] pollAll(T[] a);
89
90 /**
91 * Returns the number of encoded or decoded output in the product queue.
92 */
93 int size();
94
95 /**
96 * Returns the {@link ChannelPipeline} that handles the input.
97 */
98 ChannelPipeline getPipeline();
99 }