blob: 8af9d12ed361ea706dac91cb18a903ac288d6586 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
|
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.apache.tools.ant.types.selectors.modifiedselector;
import java.io.File;
import java.io.FileReader;
import java.io.Reader;
import org.apache.tools.ant.util.FileUtils;
/**
* Computes a 'hashvalue' for the content of file using String.hashValue().
* Use of this algorithm doesn't require any additional nested <param>s and
* doesn't support any.
*
* @version 2003-09-13
* @since Ant 1.6
*/
public class HashvalueAlgorithm implements Algorithm {
/**
* This algorithm doesn't need any configuration.
* Therefore it's always valid.
* @return always true
*/
public boolean isValid() {
return true;
}
/**
* Computes a 'hashvalue' for a file content.
* It reads the content of a file, convert that to String and use the
* String.hashCode() method.
* @param file The file for which the value should be computed
* @return the hashvalue or <i>null</i> if the file couldn't be read
*/
// Because the content is only read the file will not be damaged. I tested
// with JPG, ZIP and PDF as binary files.
public String getValue(File file) {
Reader r = null;
try {
if (!file.canRead()) {
return null;
}
r = new FileReader(file);
int hash = FileUtils.readFully(r).hashCode();
return Integer.toString(hash);
} catch (Exception e) {
return null;
} finally {
FileUtils.close(r);
}
}
/**
* Override Object.toString().
* @return information about this comparator
*/
public String toString() {
return "HashvalueAlgorithm";
}
}
|
