1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20 package org.apache.mina.filter.codec.statemachine;
21
22 import org.apache.mina.core.buffer.IoBuffer;
23 import org.apache.mina.filter.codec.ProtocolDecoderOutput;
24
25 /**
26 * {@link DecodingState} which consumes all bytes until a fixed (ASCII)
27 * character is reached. The terminator is skipped.
28 *
29 * @author The Apache MINA Project (dev@mina.apache.org)
30 */
31 public abstract class ConsumeToTerminatorDecodingState implements DecodingState {
32
33 private final byte terminator;
34
35 private IoBuffer buffer;
36
37 /**
38 * Creates a new instance using the specified terminator character.
39 *
40 * @param terminator the terminator character.
41 */
42 public ConsumeToTerminatorDecodingState(byte terminator) {
43 this.terminator = terminator;
44 }
45
46 /**
47 * {@inheritDoc}
48 */
49 public DecodingState decode(IoBuffer in, ProtocolDecoderOutput out)
50 throws Exception {
51 int terminatorPos = in.indexOf(terminator);
52
53 if (terminatorPos >= 0) {
54 int limit = in.limit();
55 IoBuffer product;
56
57 if (in.position() < terminatorPos) {
58 in.limit(terminatorPos);
59
60 if (buffer == null) {
61 product = in.slice();
62 } else {
63 buffer.put(in);
64 product = buffer.flip();
65 buffer = null;
66 }
67
68 in.limit(limit);
69 } else {
70 // When input contained only terminator rather than actual data...
71 if (buffer == null) {
72 product = IoBuffer.allocate(0);
73 } else {
74 product = buffer.flip();
75 buffer = null;
76 }
77 }
78 in.position(terminatorPos + 1);
79 return finishDecode(product, out);
80 }
81
82 if (buffer == null) {
83 buffer = IoBuffer.allocate(in.remaining());
84 buffer.setAutoExpand(true);
85 }
86
87 buffer.put(in);
88 return this;
89 }
90
91 /**
92 * {@inheritDoc}
93 */
94 public DecodingState finishDecode(ProtocolDecoderOutput out)
95 throws Exception {
96 IoBuffer product;
97 // When input contained only terminator rather than actual data...
98 if (buffer == null) {
99 product = IoBuffer.allocate(0);
100 } else {
101 product = buffer.flip();
102 buffer = null;
103 }
104 return finishDecode(product, out);
105 }
106
107 /**
108 * Invoked when this state has reached the terminator byte.
109 *
110 * @param product the read bytes not including the terminator.
111 * @param out the current {@link ProtocolDecoderOutput} used to write
112 * decoded messages.
113 * @return the next state if a state transition was triggered (use
114 * <code>this</code> for loop transitions) or <code>null</code> if
115 * the state machine has reached its end.
116 * @throws Exception if the read data violated protocol specification.
117 */
118 protected abstract DecodingState finishDecode(IoBuffer product,
119 ProtocolDecoderOutput out) throws Exception;
120 }