ChineseTokenizerpublic final class ChineseTokenizer extends Tokenizer | Title: ChineseTokenizer
Description: Extract tokens from the Stream using Character.getType()
Rule: A Chinese character as a single token
Copyright: Copyright (c) 2001
Company:
The difference between thr ChineseTokenizer and the
CJKTokenizer (id=23545) is that they have different
token parsing logic.
Let me use an example. If having a Chinese text
"C1C2C3C4" to be indexed, the tokens returned from the
ChineseTokenizer are C1, C2, C3, C4. And the tokens
returned from the CJKTokenizer are C1C2, C2C3, C3C4.
Therefore the index the CJKTokenizer created is much
larger.
The problem is that when searching for C1, C1C2, C1C3,
C4C2, C1C2C3 ... the ChineseTokenizer works, but the
CJKTokenizer will not work. |
| Fields Summary |
|---|
| private int | offset | | private int | bufferIndex | | private int | dataLen | | private static final int | MAX_WORD_LEN | | private static final int | IO_BUFFER_SIZE | | private final char[] | buffer | | private final char[] | ioBuffer | | private int | length | | private int | start |
| Constructors Summary |
|---|
public ChineseTokenizer(Reader in)
input = in;
|
| Methods Summary |
|---|
| private final org.apache.lucene.analysis.Token | flush()
if (length>0) {
//System.out.println(new String(buffer, 0, length));
return new Token(new String(buffer, 0, length), start, start+length);
}
else
return null;
| | public final org.apache.lucene.analysis.Token | next()
length = 0;
start = offset;
while (true) {
final char c;
offset++;
if (bufferIndex >= dataLen) {
dataLen = input.read(ioBuffer);
bufferIndex = 0;
}
if (dataLen == -1) return flush();
else
c = ioBuffer[bufferIndex++];
switch(Character.getType(c)) {
case Character.DECIMAL_DIGIT_NUMBER:
case Character.LOWERCASE_LETTER:
case Character.UPPERCASE_LETTER:
push(c);
if (length == MAX_WORD_LEN) return flush();
break;
case Character.OTHER_LETTER:
if (length>0) {
bufferIndex--;
offset--;
return flush();
}
push(c);
return flush();
default:
if (length>0) return flush();
break;
}
}
| | private final void | push(char c)
if (length == 0) start = offset-1; // start of token
buffer[length++] = Character.toLowerCase(c); // buffer it
|
|
