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2 * Licensed to the Apache Software Foundation (ASF) under one *
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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 *
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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
21
22 package org.apache.james.util.watchdog;
23
24 import java.io.IOException;
25 import java.io.InputStream;
26
27 /**
28 * This will reset the Watchdog each time a certain amount of data has
29 * been transferred. This allows us to keep the timeout settings low, while
30 * not timing out during large data transfers.
31 */
32 public class BytesReadResetInputStream extends InputStream {
33
34 /**
35 * The wrapped InputStream
36 */
37 private InputStream in = null;
38
39 /**
40 * The Watchdog to be reset every lengthReset bytes
41 */
42 private Watchdog watchdog;
43
44 /**
45 * The number of bytes that need to be read before the counter is reset.
46 */
47 private int lengthReset = 0;
48
49 /**
50 * The number of bytes read since the counter was last reset
51 */
52 int readCounter = 0;
53
54 /**
55 * @param in the InputStream to be wrapped by this stream
56 * @param watchdog the watchdog to be reset
57 * @param lengthReset the number of bytes to be read in between trigger resets
58 */
59 public BytesReadResetInputStream(InputStream in,
60 Watchdog watchdog,
61 int lengthReset) {
62 this.in = in;
63 this.watchdog = watchdog;
64 this.lengthReset = lengthReset;
65
66 readCounter = 0;
67 }
68
69 /**
70 * Read an array of bytes from the stream
71 *
72 * @param b the array of bytes to read from the stream
73 * @param off the index in the array where we start writing
74 * @param len the number of bytes of the array to read
75 *
76 * @return the number of bytes read
77 *
78 * @throws IOException if an exception is encountered when reading
79 */
80 public int read(byte[] b, int off, int len) throws IOException {
81 int l = in.read(b, off, len);
82 readCounter += l;
83
84 if (readCounter > lengthReset) {
85 readCounter = 0;
86 watchdog.reset();
87 }
88
89 return l;
90 }
91
92 /**
93 * Read a byte from the stream
94 *
95 * @return the byte read from the stream
96 * @throws IOException if an exception is encountered when reading
97 */
98 public int read() throws IOException {
99 int b = in.read();
100 readCounter++;
101
102 if (readCounter > lengthReset) {
103 readCounter = 0;
104 watchdog.reset();
105 }
106
107 return b;
108 }
109
110 /**
111 * Close the stream
112 *
113 * @throws IOException if an exception is encountered when closing
114 */
115 public void close() throws IOException {
116 in.close();
117 }
118 }