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Java > Open Source Codes > websphinx > workbench > DualPredicate


1 /*
2  * WebSphinx web-crawling toolkit
3  *
4  * Copyright (c) 1998-2002 Carnegie Mellon University. All rights
5  * reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  * notice, this list of conditions and the following disclaimer.
13  *
14  * 2. Redistributions in binary form must reproduce the above copyright
15  * notice, this list of conditions and the following disclaimer in
16  * the documentation and/or other materials provided with the
17  * distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY CARNEGIE MELLON UNIVERSITY ``AS IS'' AND
20  * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY
23  * NOR ITS EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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29  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  *
31  */
32
33 package websphinx.workbench;
34
35 import websphinx.*;
36
37 public class DualPredicate implements LinkPredicate, PagePredicate {
38     Object JavaDoc positive, negative;
39
40     public DualPredicate (Object JavaDoc positive, Object JavaDoc negative) {
41         this.positive = positive;
42         this.negative = negative;
43     }
44     public boolean equals (Object JavaDoc object) {
45         if (! (object instanceof DualPredicate))
46             return false;
47         DualPredicate p = (DualPredicate)object;
48         return p.positive.equals (positive) && p.negative.equals (negative);
49     }
50
51     public Object JavaDoc getPositivePredicate () {
52         return positive;
53     }
54
55     public Object JavaDoc getNegativePredicate () {
56         return negative;
57     }
58
59     public void connected (Crawler crawler) {
60         if (positive instanceof LinkPredicate)
61             ((LinkPredicate)positive).connected (crawler);
62         else if (positive instanceof PagePredicate)
63             ((LinkPredicate)positive).connected (crawler);
64
65         if (negative instanceof LinkPredicate)
66             ((LinkPredicate)negative).connected (crawler);
67         else if (negative instanceof PagePredicate)
68             ((LinkPredicate)negative).connected (crawler);
69     }
70
71     public void disconnected (Crawler crawler) {
72         if (positive instanceof LinkPredicate)
73             ((LinkPredicate)positive).disconnected (crawler);
74         else if (positive instanceof PagePredicate)
75             ((LinkPredicate)positive).disconnected (crawler);
76
77         if (negative instanceof LinkPredicate)
78             ((LinkPredicate)negative).disconnected (crawler);
79         else if (negative instanceof PagePredicate)
80             ((LinkPredicate)negative).disconnected (crawler);
81     }
82     
83     public boolean shouldVisit (Link link) {
84         return ((LinkPredicate)positive).shouldVisit (link)
85             && !((LinkPredicate)negative).shouldVisit (link);
86     }
87     public boolean shouldActOn (Page page) {
88         return ((PagePredicate)positive).shouldActOn (page)
89             && !((PagePredicate)negative).shouldActOn (page);
90     }
91 }
92
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