01: /*
02: * Licensed to the Apache Software Foundation (ASF) under one
03: * or more contributor license agreements. See the NOTICE file
04: * distributed with this work for additional information
05: * regarding copyright ownership. The ASF licenses this file
06: * to you under the Apache License, Version 2.0 (the
07: * "License"); you may not use this file except in compliance
08: * with the License. You may obtain a copy of the License at
09: *
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.common.IoBuffer;
23: import org.apache.mina.filter.codec.ProtocolDecoderOutput;
24:
25: /**
26: * A {@link DecodingState} which consumes all received bytes until a configured
27: * number of read bytes has been reached. Please note that this state can
28: * produce the buffer with less data if the associated session has been
29: * closed unexpectedly.
30: *
31: * @author The Apache MINA Project (dev@mina.apache.org)
32: * @version $Rev: 601994 $, $Date: 2007-12-06 21:58:00 -0700 (Thu, 06 Dec 2007) $
33: */
34: public abstract class FixedLengthDecodingState implements DecodingState {
35:
36: private final int length;
37:
38: private IoBuffer buffer;
39:
40: /**
41: * Constructs with a known decode length.
42: *
43: * @param length The decode length
44: */
45: public FixedLengthDecodingState(int length) {
46: this .length = length;
47: }
48:
49: public DecodingState decode(IoBuffer in, ProtocolDecoderOutput out)
50: throws Exception {
51: if (buffer == null) {
52: if (in.remaining() >= length) {
53: int limit = in.limit();
54: in.limit(in.position() + length);
55: IoBuffer product = in.slice();
56: in.position(in.position() + length);
57: in.limit(limit);
58: return finishDecode(product, out);
59: } else {
60: buffer = IoBuffer.allocate(length);
61: buffer.put(in);
62: return this ;
63: }
64: } else {
65: if (in.remaining() >= length - buffer.position()) {
66: int limit = in.limit();
67: in.limit(in.position() + length - buffer.position());
68: buffer.put(in);
69: in.limit(limit);
70: IoBuffer product = this .buffer;
71: this .buffer = null;
72: return finishDecode(product.flip(), out);
73: } else {
74: buffer.put(in);
75: return this ;
76: }
77: }
78: }
79:
80: public DecodingState finishDecode(ProtocolDecoderOutput out)
81: throws Exception {
82: IoBuffer readData;
83: if (buffer == null) {
84: readData = IoBuffer.allocate(0);
85: } else {
86: readData = buffer.flip();
87: buffer = null;
88: }
89: return finishDecode(readData, out);
90: }
91:
92: protected abstract DecodingState finishDecode(IoBuffer readData,
93: ProtocolDecoderOutput out) throws Exception;
94: }
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