source: gs3-extensions/atlas-src/trunk/src/org/greenstone/server/GazetteerTrieNode.java@ 22272

Last change on this file since 22272 was 22272, checked in by sjm84, 14 years ago

Initial version of ATLAS as an extension
File size: 3.3 KB
Line 
1package org.greenstone.server;
2
3
4import java.io.Serializable;
5import java.util.HashMap;
6
7public class GazetteerTrieNode implements Serializable
8{
9 private static final long serialVersionUID = 8121262849365540679L;
10 protected boolean _nameEnd = false;
11 protected GazetteerTrieNode[] _children = new GazetteerTrieNode[26];
12 protected HashMap<Character,GazetteerTrieNode> _unicodeCharacters = null;
13
14 /**
15 * Basic constructor for a non-unicode trie node
16 * @param nameEnd defines whether the new node represents the end of a place name
17 */
18 protected GazetteerTrieNode(boolean nameEnd)
19 {
20 for(int i = 0; i < 26; i++)
21 {
22 _children[i] = null;
23 }
24 _nameEnd = nameEnd;
25 }
26
27 /**
28 * Add a child to the current node
29 * @param c is the character used to decide where to add the child node
30 * @param nameEnd is whether or not this character represents the end of a place name
31 * @return true if a child was added and false if one already existed
32 */
33 protected boolean addChild(char c, boolean nameEnd)
34 {
35 //If the characters is an ASCII letter
36 int index;
37 if(c >= 'A' && c <= 'Z')
38 {
39 index = c - 65;
40 }
41 else if(c >= 'a' && c <= 'z')
42 {
43 index = c - 97;
44 }
45 //If the character is not an ASCII letter
46 else
47 {
48 //If the node does not currently have a unicode character map then make one
49 if(_unicodeCharacters == null)
50 {
51 _unicodeCharacters = new HashMap<Character, GazetteerTrieNode>();
52 _unicodeCharacters.put(c, new GazetteerTrieNode(nameEnd));
53 return true;
54 }
55
56 //Add the unicode character to the map only if it either does not exist already or signifies the end of a place name
57 GazetteerTrieNode value;
58 if((value = _unicodeCharacters.get(c)) != null)
59 {
60 if(value.isNameEnd())
61 {
62 return false;
63 }
64 else
65 {
66 value.setNameEnd(nameEnd);
67 }
68 }
69 else
70 {
71 _unicodeCharacters.put(c, new GazetteerTrieNode(nameEnd));
72 }
73
74 return true;
75 }
76
77 //Add the ascii character if it either does not already exist or it signifies the end of a place name
78 if(_children[index] != null)
79 {
80 if(_children[index].isNameEnd() || nameEnd == false)
81 {
82 return false;
83 }
84 else
85 {
86 _children[index].setNameEnd(true);
87 return true;
88 }
89 }
90 else
91 {
92 _children[index] = new GazetteerTrieNode(nameEnd);
93 return true;
94 }
95 }
96
97 /**
98 * @return whether or not this node represents the end of a place name
99 */
100 protected boolean isNameEnd()
101 {
102 return _nameEnd;
103 }
104
105 /**
106 * Set whether or not this node represents the end of a place name
107 * @param nameEnd is the value to set it to
108 */
109 protected void setNameEnd(boolean nameEnd)
110 {
111 _nameEnd = nameEnd;
112 }
113
114 /**
115 * Returns the child at the given index
116 * @param index is the index of the child to return
117 * @return the child at the given index
118 */
119 protected GazetteerTrieNode getChild(char c)
120 {
121 int index = -1;
122 if(c >= 'A' && c <= 'Z')
123 {
124 index = c - 65;
125 }
126 else if(c >= 'a' && c <= 'z')
127 {
128 index = c - 97;
129 }
130 if(index == -1)
131 {
132 if(_unicodeCharacters == null)
133 {
134 return null;
135 }
136 return _unicodeCharacters.get(c);
137 }
138 return _children[index];
139 }
140
141 public void output()
142 {
143 if(_unicodeCharacters != null && _unicodeCharacters.size() >= 10)
144 {
145 System.out.println(_unicodeCharacters.size());
146 }
147
148 for(GazetteerTrieNode g : _children)
149 {
150 if(g != null)
151 {
152 g.output();
153 }
154 }
155 }
156}
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