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<FONT color="green">001</FONT> package org.maltparser.core.symbol.trie;<a name="line.1"></a>
<FONT color="green">002</FONT> <a name="line.2"></a>
<FONT color="green">003</FONT> import java.util.HashMap;<a name="line.3"></a>
<FONT color="green">004</FONT> <a name="line.4"></a>
<FONT color="green">005</FONT> import org.maltparser.core.symbol.SymbolException;<a name="line.5"></a>
<FONT color="green">006</FONT> <a name="line.6"></a>
<FONT color="green">007</FONT> /**<a name="line.7"></a>
<FONT color="green">008</FONT> <a name="line.8"></a>
<FONT color="green">009</FONT> @author Johan Hall<a name="line.9"></a>
<FONT color="green">010</FONT> @since 1.0<a name="line.10"></a>
<FONT color="green">011</FONT> */<a name="line.11"></a>
<FONT color="green">012</FONT> public class TrieNode {<a name="line.12"></a>
<FONT color="green">013</FONT> /**<a name="line.13"></a>
<FONT color="green">014</FONT> * Initial capacity of the hash maps.<a name="line.14"></a>
<FONT color="green">015</FONT> */<a name="line.15"></a>
<FONT color="green">016</FONT> private final static int INITIAL_CAPACITY = 2;<a name="line.16"></a>
<FONT color="green">017</FONT> /**<a name="line.17"></a>
<FONT color="green">018</FONT> * the character that corresponds to the trie node<a name="line.18"></a>
<FONT color="green">019</FONT> */<a name="line.19"></a>
<FONT color="green">020</FONT> private char character;<a name="line.20"></a>
<FONT color="green">021</FONT> /**<a name="line.21"></a>
<FONT color="green">022</FONT> * Maps a symbol table into an entry (if not cached)<a name="line.22"></a>
<FONT color="green">023</FONT> */<a name="line.23"></a>
<FONT color="green">024</FONT> private HashMap<TrieSymbolTable,TrieEntry> entries;<a name="line.24"></a>
<FONT color="green">025</FONT> /**<a name="line.25"></a>
<FONT color="green">026</FONT> * Maps a symbol table (cachedKeyEntry) into an entry (cachedValueEntry), caches only the first occurrence.<a name="line.26"></a>
<FONT color="green">027</FONT> */<a name="line.27"></a>
<FONT color="green">028</FONT> private TrieSymbolTable cachedKeyEntry;<a name="line.28"></a>
<FONT color="green">029</FONT> private TrieEntry cachedValueEntry;<a name="line.29"></a>
<FONT color="green">030</FONT> <a name="line.30"></a>
<FONT color="green">031</FONT> /**<a name="line.31"></a>
<FONT color="green">032</FONT> * Maps a character into a child trie node (if not cached)<a name="line.32"></a>
<FONT color="green">033</FONT> */<a name="line.33"></a>
<FONT color="green">034</FONT> private HashMap<Character,TrieNode> children;<a name="line.34"></a>
<FONT color="green">035</FONT> private char cachedKeyChar;<a name="line.35"></a>
<FONT color="green">036</FONT> private TrieNode cachedValueTrieNode;<a name="line.36"></a>
<FONT color="green">037</FONT> <a name="line.37"></a>
<FONT color="green">038</FONT> /**<a name="line.38"></a>
<FONT color="green">039</FONT> * The parent trie node<a name="line.39"></a>
<FONT color="green">040</FONT> */<a name="line.40"></a>
<FONT color="green">041</FONT> private TrieNode parent;<a name="line.41"></a>
<FONT color="green">042</FONT> <a name="line.42"></a>
<FONT color="green">043</FONT> /**<a name="line.43"></a>
<FONT color="green">044</FONT> * Constructs a trie node<a name="line.44"></a>
<FONT color="green">045</FONT> * <a name="line.45"></a>
<FONT color="green">046</FONT> * @param character which character that the trie node belongs to<a name="line.46"></a>
<FONT color="green">047</FONT> * @param parent the parent trie node<a name="line.47"></a>
<FONT color="green">048</FONT> */<a name="line.48"></a>
<FONT color="green">049</FONT> public TrieNode(char character, TrieNode parent) {<a name="line.49"></a>
<FONT color="green">050</FONT> this.character = character;<a name="line.50"></a>
<FONT color="green">051</FONT> this.parent = parent;<a name="line.51"></a>
<FONT color="green">052</FONT> }<a name="line.52"></a>
<FONT color="green">053</FONT> <a name="line.53"></a>
<FONT color="green">054</FONT> /**<a name="line.54"></a>
<FONT color="green">055</FONT> * Adds and/or retrieve a child trie node. It only adds a entry if the parameter isWord is true.<a name="line.55"></a>
<FONT color="green">056</FONT> * <a name="line.56"></a>
<FONT color="green">057</FONT> * @param isWord true if it is a word (entry), otherwise false<a name="line.57"></a>
<FONT color="green">058</FONT> * @param c the character to the child node<a name="line.58"></a>
<FONT color="green">059</FONT> * @param table which symbol table to look in or add to<a name="line.59"></a>
<FONT color="green">060</FONT> * @param code the integer representation of the string value<a name="line.60"></a>
<FONT color="green">061</FONT> * @return the child trie node that corresponds to the character<a name="line.61"></a>
<FONT color="green">062</FONT> * @throws SymbolException<a name="line.62"></a>
<FONT color="green">063</FONT> */<a name="line.63"></a>
<FONT color="green">064</FONT> public TrieNode getOrAddChild(boolean isWord, char c, TrieSymbolTable table, int code) throws SymbolException {<a name="line.64"></a>
<FONT color="green">065</FONT> if (cachedValueTrieNode == null) {<a name="line.65"></a>
<FONT color="green">066</FONT> cachedValueTrieNode = new TrieNode(c, this);<a name="line.66"></a>
<FONT color="green">067</FONT> cachedKeyChar = c;<a name="line.67"></a>
<FONT color="green">068</FONT> if (isWord) {<a name="line.68"></a>
<FONT color="green">069</FONT> cachedValueTrieNode.addEntry(table, code);<a name="line.69"></a>
<FONT color="green">070</FONT> } <a name="line.70"></a>
<FONT color="green">071</FONT> return cachedValueTrieNode;<a name="line.71"></a>
<FONT color="green">072</FONT> } else if (cachedKeyChar == c) {<a name="line.72"></a>
<FONT color="green">073</FONT> if (isWord) {<a name="line.73"></a>
<FONT color="green">074</FONT> cachedValueTrieNode.addEntry(table, code);<a name="line.74"></a>
<FONT color="green">075</FONT> } <a name="line.75"></a>
<FONT color="green">076</FONT> return cachedValueTrieNode;<a name="line.76"></a>
<FONT color="green">077</FONT> } else {<a name="line.77"></a>
<FONT color="green">078</FONT> TrieNode child = null; //table.getTrie().addTrieNodeChild(c, this);<a name="line.78"></a>
<FONT color="green">079</FONT> if (children == null) {<a name="line.79"></a>
<FONT color="green">080</FONT> children = new HashMap<Character, TrieNode>(INITIAL_CAPACITY);<a name="line.80"></a>
<FONT color="green">081</FONT> child = new TrieNode(c, this);<a name="line.81"></a>
<FONT color="green">082</FONT> children.put(c,child);<a name="line.82"></a>
<FONT color="green">083</FONT> } else {<a name="line.83"></a>
<FONT color="green">084</FONT> child = children.get(c);<a name="line.84"></a>
<FONT color="green">085</FONT> if (child == null) {<a name="line.85"></a>
<FONT color="green">086</FONT> child = new TrieNode(c, this);<a name="line.86"></a>
<FONT color="green">087</FONT> children.put(c,child);<a name="line.87"></a>
<FONT color="green">088</FONT> }<a name="line.88"></a>
<FONT color="green">089</FONT> }<a name="line.89"></a>
<FONT color="green">090</FONT> if (isWord) {<a name="line.90"></a>
<FONT color="green">091</FONT> child.addEntry(table, code);<a name="line.91"></a>
<FONT color="green">092</FONT> } <a name="line.92"></a>
<FONT color="green">093</FONT> return child;<a name="line.93"></a>
<FONT color="green">094</FONT> }<a name="line.94"></a>
<FONT color="green">095</FONT> } <a name="line.95"></a>
<FONT color="green">096</FONT> <a name="line.96"></a>
<FONT color="green">097</FONT> /**<a name="line.97"></a>
<FONT color="green">098</FONT> * Adds an entry if it does not exist<a name="line.98"></a>
<FONT color="green">099</FONT> * <a name="line.99"></a>
<FONT color="green">100</FONT> * @param table which symbol table to add an entry<a name="line.100"></a>
<FONT color="green">101</FONT> * @param code the integer representation of the string value<a name="line.101"></a>
<FONT color="green">102</FONT> * @throws SymbolException<a name="line.102"></a>
<FONT color="green">103</FONT> */<a name="line.103"></a>
<FONT color="green">104</FONT> private void addEntry(TrieSymbolTable table, int code) throws SymbolException {<a name="line.104"></a>
<FONT color="green">105</FONT> if (table == null) {<a name="line.105"></a>
<FONT color="green">106</FONT> throw new SymbolException("Symbol table cannot be found. ");<a name="line.106"></a>
<FONT color="green">107</FONT> }<a name="line.107"></a>
<FONT color="green">108</FONT> if (cachedValueEntry == null) {<a name="line.108"></a>
<FONT color="green">109</FONT> if (code != -1) {<a name="line.109"></a>
<FONT color="green">110</FONT> cachedValueEntry = new TrieEntry(code,true);<a name="line.110"></a>
<FONT color="green">111</FONT> table.updateValueCounter(code);<a name="line.111"></a>
<FONT color="green">112</FONT> } else {<a name="line.112"></a>
<FONT color="green">113</FONT> cachedValueEntry = new TrieEntry(table.increaseValueCounter(),false);<a name="line.113"></a>
<FONT color="green">114</FONT> }<a name="line.114"></a>
<FONT color="green">115</FONT> cachedKeyEntry = table; <a name="line.115"></a>
<FONT color="green">116</FONT> } else if (!table.equals(cachedKeyEntry)) {<a name="line.116"></a>
<FONT color="green">117</FONT> if (entries == null) {<a name="line.117"></a>
<FONT color="green">118</FONT> entries = new HashMap<TrieSymbolTable, TrieEntry>(INITIAL_CAPACITY);<a name="line.118"></a>
<FONT color="green">119</FONT> }<a name="line.119"></a>
<FONT color="green">120</FONT> if (!entries.containsKey(table)) {<a name="line.120"></a>
<FONT color="green">121</FONT> if (code != -1) {<a name="line.121"></a>
<FONT color="green">122</FONT> entries.put(table, new TrieEntry(code,true));<a name="line.122"></a>
<FONT color="green">123</FONT> table.updateValueCounter(code);<a name="line.123"></a>
<FONT color="green">124</FONT> } else {<a name="line.124"></a>
<FONT color="green">125</FONT> entries.put(table, new TrieEntry(table.increaseValueCounter(),false));<a name="line.125"></a>
<FONT color="green">126</FONT> }<a name="line.126"></a>
<FONT color="green">127</FONT> }<a name="line.127"></a>
<FONT color="green">128</FONT> }<a name="line.128"></a>
<FONT color="green">129</FONT> }<a name="line.129"></a>
<FONT color="green">130</FONT> <a name="line.130"></a>
<FONT color="green">131</FONT> /**<a name="line.131"></a>
<FONT color="green">132</FONT> * Returns the child node that corresponds to the character<a name="line.132"></a>
<FONT color="green">133</FONT> * <a name="line.133"></a>
<FONT color="green">134</FONT> * @param c the character of the child node<a name="line.134"></a>
<FONT color="green">135</FONT> * @return the child node<a name="line.135"></a>
<FONT color="green">136</FONT> */<a name="line.136"></a>
<FONT color="green">137</FONT> public TrieNode getChild(char c) {<a name="line.137"></a>
<FONT color="green">138</FONT> if (cachedKeyChar == c) {<a name="line.138"></a>
<FONT color="green">139</FONT> return cachedValueTrieNode;<a name="line.139"></a>
<FONT color="green">140</FONT> } else if (children != null) {<a name="line.140"></a>
<FONT color="green">141</FONT> return children.get(c);<a name="line.141"></a>
<FONT color="green">142</FONT> }<a name="line.142"></a>
<FONT color="green">143</FONT> return null;<a name="line.143"></a>
<FONT color="green">144</FONT> }<a name="line.144"></a>
<FONT color="green">145</FONT> <a name="line.145"></a>
<FONT color="green">146</FONT> <a name="line.146"></a>
<FONT color="green">147</FONT> <a name="line.147"></a>
<FONT color="green">148</FONT> /**<a name="line.148"></a>
<FONT color="green">149</FONT> * Returns the entry of the symbol table 'table'<a name="line.149"></a>
<FONT color="green">150</FONT> * <a name="line.150"></a>
<FONT color="green">151</FONT> * @param table which symbol table<a name="line.151"></a>
<FONT color="green">152</FONT> * @return the entry of the symbol table 'table'<a name="line.152"></a>
<FONT color="green">153</FONT> */<a name="line.153"></a>
<FONT color="green">154</FONT> public TrieEntry getEntry(TrieSymbolTable table) {<a name="line.154"></a>
<FONT color="green">155</FONT> if (table != null) {<a name="line.155"></a>
<FONT color="green">156</FONT> if (table.equals(cachedKeyEntry)) {<a name="line.156"></a>
<FONT color="green">157</FONT> return cachedValueEntry;<a name="line.157"></a>
<FONT color="green">158</FONT> } else if (entries != null) {<a name="line.158"></a>
<FONT color="green">159</FONT> return entries.get(table);<a name="line.159"></a>
<FONT color="green">160</FONT> }<a name="line.160"></a>
<FONT color="green">161</FONT> }<a name="line.161"></a>
<FONT color="green">162</FONT> return null;<a name="line.162"></a>
<FONT color="green">163</FONT> }<a name="line.163"></a>
<FONT color="green">164</FONT> <a name="line.164"></a>
<FONT color="green">165</FONT> /**<a name="line.165"></a>
<FONT color="green">166</FONT> * Returns the character of the trie node<a name="line.166"></a>
<FONT color="green">167</FONT> * <a name="line.167"></a>
<FONT color="green">168</FONT> * @return the character of the trie node<a name="line.168"></a>
<FONT color="green">169</FONT> */<a name="line.169"></a>
<FONT color="green">170</FONT> public char getCharacter() {<a name="line.170"></a>
<FONT color="green">171</FONT> return character;<a name="line.171"></a>
<FONT color="green">172</FONT> }<a name="line.172"></a>
<FONT color="green">173</FONT> <a name="line.173"></a>
<FONT color="green">174</FONT> /**<a name="line.174"></a>
<FONT color="green">175</FONT> * Returns the parent node<a name="line.175"></a>
<FONT color="green">176</FONT> * <a name="line.176"></a>
<FONT color="green">177</FONT> * @return the parent node<a name="line.177"></a>
<FONT color="green">178</FONT> */<a name="line.178"></a>
<FONT color="green">179</FONT> public TrieNode getParent() {<a name="line.179"></a>
<FONT color="green">180</FONT> return parent;<a name="line.180"></a>
<FONT color="green">181</FONT> }<a name="line.181"></a>
<FONT color="green">182</FONT> <a name="line.182"></a>
<FONT color="green">183</FONT> public boolean equals(Object obj) {<a name="line.183"></a>
<FONT color="green">184</FONT> return super.equals(obj);<a name="line.184"></a>
<FONT color="green">185</FONT> }<a name="line.185"></a>
<FONT color="green">186</FONT> <a name="line.186"></a>
<FONT color="green">187</FONT> public int hashCode() {<a name="line.187"></a>
<FONT color="green">188</FONT> return super.hashCode();<a name="line.188"></a>
<FONT color="green">189</FONT> }<a name="line.189"></a>
<FONT color="green">190</FONT> <a name="line.190"></a>
<FONT color="green">191</FONT> public String toString() {<a name="line.191"></a>
<FONT color="green">192</FONT> final StringBuilder sb = new StringBuilder();<a name="line.192"></a>
<FONT color="green">193</FONT> sb.append(character);<a name="line.193"></a>
<FONT color="green">194</FONT> return sb.toString();<a name="line.194"></a>
<FONT color="green">195</FONT> }<a name="line.195"></a>
<FONT color="green">196</FONT> }<a name="line.196"></a>
</PRE>
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