001 package org.maltparser.core.symbol.trie; 002 003 004 import org.maltparser.core.symbol.SymbolException; 005 006 /** 007 * 008 * @author Johan Hall 009 * @since 1.0 010 **/ 011 public class Trie { 012 private final TrieNode root; 013 private final StringBuilder sb; 014 015 public Trie() { 016 root = new TrieNode(' ', null); 017 sb = new StringBuilder(); 018 } 019 020 public TrieNode addValue(String value, TrieSymbolTable table, int code) throws SymbolException { 021 TrieNode node = root; 022 final char[] chars = value.toCharArray(); 023 for (int i = chars.length-1; i>=0; i--) { 024 if (i == 0) { 025 node = node.getOrAddChild(true, chars[i], table, code); 026 } else { 027 node = node.getOrAddChild(false, chars[i], table, code); 028 } 029 } 030 return node; 031 } 032 033 public TrieNode addValue(StringBuilder symbol, TrieSymbolTable table, int code) throws SymbolException { 034 TrieNode node = root; 035 for (int i = symbol.length()-1; i>=0; i--) { 036 if (i == 0) { 037 node = node.getOrAddChild(true, symbol.charAt(i), table, code); 038 } else { 039 node = node.getOrAddChild(false, symbol.charAt(i), table, code); 040 } 041 } 042 return node; 043 } 044 045 public String getValue(TrieNode node, TrieSymbolTable table) { 046 sb.setLength(0); 047 TrieNode tmp = node; 048 while (tmp != root) { // && tmp != null) { 049 sb.append(tmp.getCharacter()); 050 tmp = tmp.getParent(); 051 } 052 return sb.toString(); 053 } 054 055 public TrieEntry getEntry(String value, TrieSymbolTable table) { 056 TrieNode node = root; 057 final char[] chars = value.toCharArray(); 058 int i=chars.length-1; 059 for (;i>=0 && node != null;i--) { 060 node = node.getChild(chars[i]); 061 } 062 if (i < 0 && node != null) { 063 return node.getEntry(table); 064 } 065 return null; 066 } 067 068 public boolean equals(Object obj) { 069 if (this == obj) 070 return true; 071 if (obj == null) 072 return false; 073 if (getClass() != obj.getClass()) 074 return false; 075 return ((root == null) ? ((Trie)obj).root == null : root.equals(((Trie)obj).root)); 076 } 077 078 public int hashCode() { 079 return 31 * 7 + (null == root ? 0 : root.hashCode()); 080 } 081 }