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Java > Open Source Codes > com > jeantessier > classreader > ModifiedOnlyDispatcher


1 /*
2  * Copyright (c) 2001-2005, Jean Tessier
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *
9  * * Redistributions of source code must retain the above copyright
10  * notice, this list of conditions and the following disclaimer.
11  *
12  * * Redistributions in binary form must reproduce the above copyright
13  * notice, this list of conditions and the following disclaimer in the
14  * documentation and/or other materials provided with the distribution.
15  *
16  * * Neither the name of Jean Tessier nor the names of his contributors
17  * may be used to endorse or promote products derived from this software
18  * without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR
24  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
26  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
27  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
28  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
29  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
30  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32
33 package com.jeantessier.classreader;
34
35 import java.io.*;
36 import java.util.*;
37
38 import org.apache.log4j.*;
39
40 public class ModifiedOnlyDispatcher implements ClassfileLoaderDispatcher {
41     private ClassfileLoaderDispatcher delegate;
42
43     private Map timestamps = new HashMap();
44
45     public ModifiedOnlyDispatcher(ClassfileLoaderDispatcher delegate) {
46         this.delegate = delegate;
47     }
48     
49     public int dispatch(String JavaDoc filename) {
50         int result = ACTION_IGNORE;
51
52         File file = new File(filename);
53
54         Long JavaDoc timestamp = (Long JavaDoc) timestamps.get(filename);
55
56         Logger.getLogger(getClass()).debug(filename + " has timestamp " + timestamp);
57         
58         if (file.isDirectory()) {
59             Logger.getLogger(getClass()).debug("Delegating ...");
60             result = delegate.dispatch(filename);
61         } else if (timestamp == null || timestamp.longValue() < file.lastModified()) {
62             timestamp = new Long JavaDoc(file.lastModified());
63             timestamps.put(filename, timestamp);
64
65             Logger.getLogger(getClass()).debug("Delegating ...");
66             result = delegate.dispatch(filename);
67         } else {
68             Logger.getLogger(getClass()).debug("Already dispatched \"" + filename + "\": IGNORE");
69         }
70
71         return result;
72     }
73 }
74
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