1 /************************************************************************
2 * Copyright (c) 2000-2006 The Apache Software Foundation. *
3 * All rights reserved. *
4 * ------------------------------------------------------------------- *
5 * Licensed under the Apache License, Version 2.0 (the "License"); you *
6 * may not use this file except in compliance with the License. You *
7 * may obtain a copy of the License at: *
8 * *
9 * http://www.apache.org/licenses/LICENSE-2.0 *
10 * *
11 * Unless required by applicable law or agreed to in writing, software *
12 * distributed under the License is distributed on an "AS IS" BASIS, *
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or *
14 * implied. See the License for the specific language governing *
15 * permissions and limitations under the License. *
16 ***********************************************************************/
17
18
19 package org.apache.james.util.watchdog;
20
21 import java.io.IOException;
22 import java.io.InputStream;
23
24 /***
25 * This will reset the Watchdog each time a certain amount of data has
26 * been transferred. This allows us to keep the timeout settings low, while
27 * not timing out during large data transfers.
28 */
29 public class BytesReadResetInputStream extends InputStream {
30
31 /***
32 * The wrapped InputStream
33 */
34 private InputStream in = null;
35
36 /***
37 * The Watchdog to be reset every lengthReset bytes
38 */
39 private Watchdog watchdog;
40
41 /***
42 * The number of bytes that need to be read before the counter is reset.
43 */
44 private int lengthReset = 0;
45
46 /***
47 * The number of bytes read since the counter was last reset
48 */
49 int readCounter = 0;
50
51 /***
52 * @param in the InputStream to be wrapped by this stream
53 * @param watchdog the watchdog to be reset
54 * @param lengthReset the number of bytes to be read in between trigger resets
55 */
56 public BytesReadResetInputStream(InputStream in,
57 Watchdog watchdog,
58 int lengthReset) {
59 this.in = in;
60 this.watchdog = watchdog;
61 this.lengthReset = lengthReset;
62
63 readCounter = 0;
64 }
65
66 /***
67 * Read an array of bytes from the stream
68 *
69 * @param b the array of bytes to read from the stream
70 * @param off the index in the array where we start writing
71 * @param len the number of bytes of the array to read
72 *
73 * @return the number of bytes read
74 *
75 * @throws IOException if an exception is encountered when reading
76 */
77 public int read(byte[] b, int off, int len) throws IOException {
78 int l = in.read(b, off, len);
79 readCounter += l;
80
81 if (readCounter > lengthReset) {
82 readCounter = 0;
83 watchdog.reset();
84 }
85
86 return l;
87 }
88
89 /***
90 * Read a byte from the stream
91 *
92 * @return the byte read from the stream
93 * @throws IOException if an exception is encountered when reading
94 */
95 public int read() throws IOException {
96 int b = in.read();
97 readCounter++;
98
99 if (readCounter > lengthReset) {
100 readCounter = 0;
101 watchdog.reset();
102 }
103
104 return b;
105 }
106
107 /***
108 * Close the stream
109 *
110 * @throws IOException if an exception is encountered when closing
111 */
112 public void close() throws IOException {
113 in.close();
114 }
115 }