1 /*
2 * Copyright 2006 Simon Raess
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * 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,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package net.sf.beep4j.internal;
17
18 import java.nio.ByteBuffer;
19
20 /**
21 * ParseState responsible to read the payload of a frame.
22 *
23 * @author Simon Raess
24 */
25 final class PayloadState implements ParseState {
26
27 /**
28 * The number of bytes to read.
29 */
30 private int size;
31
32 /**
33 * The current position. This number specifies how many bytes
34 * have already been read.
35 */
36 private int position;
37
38 /**
39 * Holds the read payload.
40 */
41 private ByteBuffer payload;
42
43 /**
44 * Creates a new PayloadState that reads exactly <var>payloadSize</var>
45 * bytes from the incoming buffers.
46 *
47 * @param payloadSize the number of bytes in the payload
48 */
49 PayloadState(int payloadSize) {
50 this.position = 0;
51 this.size = payloadSize;
52 this.payload = ByteBuffer.allocate(payloadSize);
53 }
54
55 public final boolean process(ByteBuffer buffer, ParseStateContext context) {
56 // calculate the number of bytes to be read
57 int available = buffer.remaining();
58 int remaining = size - position;
59 int actual = Math.min(available, remaining);
60
61 // write actual number of bytes to the payload buffer
62 int limit = buffer.limit();
63 buffer.limit(buffer.position() + actual);
64 payload.put(buffer);
65 buffer.limit(limit);
66
67 // update the position
68 position += actual;
69
70 // have we read enough?
71 if (position == size) {
72 payload.flip();
73 context.handlePayload(payload);
74 return buffer.hasRemaining();
75 }
76
77 return false;
78 }
79
80 }