2006年,有人为Apache Lucene项目贡献了代码,以实现这一目标.
他们的方法(用Java编写)是使用BreakIterator类,调用getWordInstance()以获取泰语的基于字典的单词迭代器.另请注意,ICU4J项目存在明确的依赖性.我已粘贴下面代码的相关部分:
private BreakIterator breaker = null;
private Token thaiToken = null;
public ThaiWordFilter(TokenStream input) {
super(input);
breaker = BreakIterator.getWordInstance(new Locale("th"));
}
public Token next() throws IOException {
if (thaiToken != null) {
String text = thaiToken.termText();
int start = breaker.current();
int end = breaker.next();
if (end != BreakIterator.DONE) {
return new Token(text.substring(start, end),
thaiToken.startOffset()+start,
thaiToken.startOffset()+end, thaiToken.type());
}
thaiToken = null;
}
Token tk = input.next();
if (tk == null) {
return null;
}
String text = tk.termText();
if (UnicodeBlock.of(text.charAt(0)) != UnicodeBlock.THAI) {
return new Token(text.toLowerCase(),
tk.startOffset(),
tk.endOffset(),
tk.type());
}
thaiToken = tk;
breaker.setText(text);
int end = breaker.next();
if (end != BreakIterator.DONE) {
return new Token(text.substring(0, end),
thaiToken.startOffset(),
thaiToken.startOffset()+end,
thaiToken.type());
}
return null;
}
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