Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
LengthProtocol |
|
| 2.0;2 |
1 | /* | |
2 | * $Id: LengthProtocol.java 7963 2007-08-21 08:53:15Z dirk.olmes $ | |
3 | * -------------------------------------------------------------------------------------- | |
4 | * Copyright (c) MuleSource, Inc. All rights reserved. http://www.mulesource.com | |
5 | * | |
6 | * The software in this package is published under the terms of the CPAL v1.0 | |
7 | * license, a copy of which has been included with this distribution in the | |
8 | * LICENSE.txt file. | |
9 | */ | |
10 | ||
11 | package org.mule.providers.tcp.protocols; | |
12 | ||
13 | import java.io.DataInputStream; | |
14 | import java.io.DataOutputStream; | |
15 | import java.io.IOException; | |
16 | import java.io.InputStream; | |
17 | import java.io.OutputStream; | |
18 | ||
19 | import org.apache.commons.logging.Log; | |
20 | import org.apache.commons.logging.LogFactory; | |
21 | ||
22 | /** | |
23 | * The LengthProtocol is an application level tcp protocol that can be used to | |
24 | * transfer large amounts of data without risking some data to be loss. The protocol | |
25 | * is defined by sending / reading an integer (the packet length) and then the data | |
26 | * to be transferred. | |
27 | * | |
28 | * <p>Note that use of this protocol must be symmetric - both the sending and receiving | |
29 | * connectors must use the same protocol.</p> | |
30 | */ | |
31 | public class LengthProtocol extends DefaultProtocol | |
32 | { | |
33 | ||
34 | 4 | private static final Log logger = LogFactory.getLog(LengthProtocol.class); |
35 | // TODO - can we not get this from the API somewhere? | |
36 | private static final int SIZE_INT = 4; | |
37 | ||
38 | public LengthProtocol() | |
39 | { | |
40 | 18 | super(NO_STREAM, SIZE_INT); |
41 | 18 | } |
42 | ||
43 | public Object read(InputStream is) throws IOException | |
44 | { | |
45 | // original comments indicated that we nede to use read(byte[]) rather than readInt() | |
46 | // to avoid socket timeouts - don't understand, but don't want to risk change. | |
47 | ||
48 | // first read the data necessary to know the length of the payload | |
49 | 57 | DataInputStream dis = new DataInputStream(is); |
50 | 57 | dis.mark(SIZE_INT); |
51 | // this pulls through SIZE_INT bytes | |
52 | 57 | if (null == super.read(dis, SIZE_INT)) |
53 | { | |
54 | 19 | return null; // eof |
55 | } | |
56 | ||
57 | // reset and read the integer | |
58 | 38 | dis.reset(); |
59 | 38 | int length = dis.readInt(); |
60 | 38 | if (logger.isDebugEnabled()) |
61 | { | |
62 | 0 | logger.debug("length: " + length); |
63 | } | |
64 | ||
65 | // finally read the rest of the data | |
66 | 38 | byte[] buffer = new byte[length]; |
67 | 38 | dis.readFully(buffer); |
68 | 38 | if (logger.isDebugEnabled()) |
69 | { | |
70 | 0 | logger.debug("length read: " + buffer.length); |
71 | } | |
72 | ||
73 | 38 | return buffer; |
74 | } | |
75 | ||
76 | // @Override | |
77 | protected void writeByteArray(OutputStream os, byte[] data) throws IOException | |
78 | { | |
79 | // Write the length and then the data. | |
80 | 32 | DataOutputStream dos = new DataOutputStream(os); |
81 | 32 | dos.writeInt(data.length); |
82 | 32 | dos.write(data); |
83 | 32 | dos.flush(); |
84 | 32 | } |
85 | ||
86 | /** | |
87 | * Read all four bytes for initial integer (limit is set in read) | |
88 | * | |
89 | * @param len Amount transferred last call (-1 on EOF or socket error) | |
90 | * @param available Amount available | |
91 | * @return true if the transfer should continue | |
92 | */ | |
93 | // @Override | |
94 | protected boolean isRepeat(int len, int available) | |
95 | { | |
96 | 21 | return true; |
97 | } | |
98 | ||
99 | } |