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 <a href="http://mina.apache.org">Apache MINA Project</a>
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) throws Exception {
50 int terminatorPos = in.indexOf(terminator);
51
52 if (terminatorPos >= 0) {
53 int limit = in.limit();
54 IoBuffer product;
55
56 if (in.position() < terminatorPos) {
57 in.limit(terminatorPos);
58
59 if (buffer == null) {
60 product = in.slice();
61 } else {
62 buffer.put(in);
63 product = buffer.flip();
64 buffer = null;
65 }
66
67 in.limit(limit);
68 } else {
69 // When input contained only terminator rather than actual data...
70 if (buffer == null) {
71 product = IoBuffer.allocate(0);
72 } else {
73 product = buffer.flip();
74 buffer = null;
75 }
76 }
77 in.position(terminatorPos + 1);
78 return finishDecode(product, out);
79 }
80
81 if (buffer == null) {
82 buffer = IoBuffer.allocate(in.remaining());
83 buffer.setAutoExpand(true);
84 }
85
86 buffer.put(in);
87 return this;
88 }
89
90 /**
91 * {@inheritDoc}
92 */
93 public DecodingState finishDecode(ProtocolDecoderOutput out) throws Exception {
94 IoBuffer product;
95 // When input contained only terminator rather than actual data...
96 if (buffer == null) {
97 product = IoBuffer.allocate(0);
98 } else {
99 product = buffer.flip();
100 buffer = null;
101 }
102 return finishDecode(product, out);
103 }
104
105 /**
106 * Invoked when this state has reached the terminator byte.
107 *
108 * @param product the read bytes not including the terminator.
109 * @param out the current {@link ProtocolDecoderOutput} used to write
110 * decoded messages.
111 * @return the next state if a state transition was triggered (use
112 * <code>this</code> for loop transitions) or <code>null</code> if
113 * the state machine has reached its end.
114 * @throws Exception if the read data violated protocol specification.
115 */
116 protected abstract DecodingState finishDecode(IoBuffer product, ProtocolDecoderOutput out) throws Exception;
117 }