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comparison servlet/src/digilib/auth/HashTree.java @ 1:0ff3ede32060

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Initial revision
author robcast
date Thu, 17 Jan 2002 15:25:46 +0100
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children 398d39ee1014 9cedd170b581
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0:ffd2df307e81 1:0ff3ede32060
1 /* HashTree -- Tree in a Hashtable
2
3 Digital Image Library servlet components
4
5 Copyright (C) 2001, 2002 Robert Casties (robcast@mail.berlios.de)
6
7 This program is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 2 of the License, or (at your
10 option) any later version.
11
12 Please read license.txt for the full details. A copy of the GPL
13 may be found at http://www.gnu.org/copyleft/lgpl.html
14
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18
19 */
20
21 package digilib.auth;
22
23 import java.util.*;
24
25 public class HashTree {
26
27 private Hashtable table;
28 private String twigSep = "/";
29 private String leafSep = ",";
30
31 public HashTree() {
32 table = new Hashtable();
33 }
34
35 public HashTree(Hashtable t, String twig_separator, String leaf_separator) {
36 table = t;
37 twigSep = twig_separator;
38 leafSep = leaf_separator;
39 optimizeTable();
40 }
41
42 void optimizeTable() {
43 }
44
45 List match(String branch) {
46 String b = "";
47 String m;
48 LinkedList matches = new LinkedList();
49
50 // split branch
51 StringTokenizer twig = new StringTokenizer(branch, twigSep);
52 // walk branch and check with tree
53 while (twig.hasMoreTokens()) {
54 if (b.length() == 0) {
55 b = twig.nextToken();
56 } else {
57 b += twigSep + twig.nextToken();
58 }
59 m = (String)table.get(b);
60 //System.out.println("CHECK: "+b+" = "+m);
61 if (m != null) {
62 if (m.indexOf(leafSep) < 0) {
63 // single leaf
64 matches.add(m);
65 } else {
66 // split leaves
67 StringTokenizer leaf = new StringTokenizer(m, leafSep);
68 while (leaf.hasMoreTokens()) {
69 matches.add(leaf.nextToken());
70 }
71 }
72 }
73 }
74 if (matches.size() > 0) {
75 return matches;
76 } else {
77 return null;
78 }
79 }
80 }