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Java > Open Source Codes > org > archive > crawler > util > FPUriUniqFilter


1 /* Copyright (C) 2003 Internet Archive.
2  *
3  * This file is part of the Heritrix web crawler (crawler.archive.org).
4  *
5  * Heritrix is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU Lesser Public License as published by
7  * the Free Software Foundation; either version 2.1 of the License, or
8  * any later version.
9  *
10  * Heritrix is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  * GNU Lesser Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser Public License
16  * along with Heritrix; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18  *
19  * MemFPUURISet.java
20  * Created on Oct 1, 2003
21  *
22  * $Header: /cvsroot/archive-crawler/ArchiveOpenCrawler/src/java/org/archive/crawler/util/FPUriUniqFilter.java,v 1.12.14.1 2007/01/13 01:31:29 stack-sf Exp $
23  */
24 package org.archive.crawler.util;
25
26 import java.io.Serializable JavaDoc;
27
28 import org.archive.util.ArchiveUtils;
29 import org.archive.util.fingerprint.LongFPSet;
30
31 import st.ata.util.FPGenerator;
32
33 /**
34  * UriUniqFilter storing 64-bit UURI fingerprints, using an internal LongFPSet
35  * instance.
36  *
37  * The passed LongFPSet internal instance may be disk or memory based. Accesses
38  * to the underlying LongFPSet are synchronized.
39  *
40  * @author gojomo
41  */
42 public class FPUriUniqFilter extends SetBasedUriUniqFilter
43 implements Serializable JavaDoc {
44     // Be robust against trivial implementation changes
45 private static final long serialVersionUID =
46         ArchiveUtils.classnameBasedUID(FPUriUniqFilter.class, 1);
47     
48 // private static Logger logger =
49 // Logger.getLogger(FPUriUniqFilter.class.getName());
50
51     private LongFPSet fpset;
52     private transient FPGenerator fpgen = FPGenerator.std64;
53     
54     /**
55      * Create FPUriUniqFilter wrapping given long set
56      *
57      * @param fpset
58      */
59     public FPUriUniqFilter(LongFPSet fpset) {
60         this.fpset = fpset;
61     }
62     
63     private long getFp(CharSequence JavaDoc canonical) {
64         return fpgen.fp(canonical);
65     }
66
67     protected boolean setAdd(CharSequence JavaDoc uri) {
68         return fpset.add(getFp(uri));
69     }
70
71     protected long setCount() {
72         return fpset.count();
73     }
74
75     protected boolean setRemove(CharSequence JavaDoc uri) {
76         return fpset.remove(getFp(uri));
77     }
78 }
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