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SOLR-1359: DoubleMetaphone filter could skip or reorder tokens, fix and update to new API 

git-svn-id: https://svn.apache.org/repos/asf/lucene/solr/trunk@803971 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Yonik Seeley 2009-08-13 18:10:52 +00:00
parent e654763c48
commit 551e52f899
1 changed files with 61 additions and 40 deletions
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101
src/java/org/apache/solr/analysis/DoubleMetaphoneFilter.java
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@ -23,68 +23,89 @@ import org.apache.commons.codec.language.DoubleMetaphone;
import org.apache.lucene.analysis.Token;
import org.apache.lucene.analysis.TokenFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.TermAttribute;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
public class DoubleMetaphoneFilter extends TokenFilter {
private static final String TOKEN_TYPE = "DoubleMetaphone";
private final LinkedList<Token> remainingTokens = new LinkedList<Token>();
private final LinkedList<State> remainingTokens = new LinkedList<State>();
private final DoubleMetaphone encoder = new DoubleMetaphone();
private final boolean inject;
private final TermAttribute termAtt;
private final PositionIncrementAttribute posAtt;
protected DoubleMetaphoneFilter(TokenStream input, int maxCodeLength, boolean inject) {
super(input);
this.encoder.setMaxCodeLen(maxCodeLength);
this.inject = inject;
this.termAtt = (TermAttribute) addAttribute(TermAttribute.class);
this.posAtt = (PositionIncrementAttribute) addAttribute(PositionIncrementAttribute.class);
}
@Override
public final Token next(Token in) throws IOException {
if (!remainingTokens.isEmpty()) {
return remainingTokens.removeFirst();
}
public boolean incrementToken() throws IOException {
for(;;) {
Token t = input.next(in);
if (t != null && t.termLength() > 0) {
if (inject) {
remainingTokens.addLast(t);
if (!remainingTokens.isEmpty()) {
clearAttributes(); restoreState(remainingTokens.removeFirst());
return true;
}
boolean isPhonetic = false;
String v = new String(t.termBuffer(), 0, t.termLength());
String primaryPhoneticValue = encoder.doubleMetaphone(v);
if (primaryPhoneticValue.length() > 0) {
Token token = (Token) t.clone();
if( inject ) {
token.setPositionIncrement( 0 );
}
token.setType( TOKEN_TYPE );
token.setTermBuffer(primaryPhoneticValue);
remainingTokens.addLast(token);
isPhonetic = true;
}
if (!input.incrementToken()) return false;
String alternatePhoneticValue = encoder.doubleMetaphone(v, true);
if (alternatePhoneticValue.length() > 0
&& !primaryPhoneticValue.equals(alternatePhoneticValue)) {
Token token = (Token) t.clone();
token.setPositionIncrement( 0 );
token.setType( TOKEN_TYPE );
token.setTermBuffer(alternatePhoneticValue);
remainingTokens.addLast(token);
isPhonetic = true;
}
int len = termAtt.termLength();
if (len==0) return true; // pass through zero length terms
// If we did not add something, then go to the next one...
if( !isPhonetic ) {
t = next(in);
if( t != null ) {
t.setPositionIncrement( t.getPositionIncrement()+1 );
int firstAlternativeIncrement = inject ? 0 : posAtt.getPositionIncrement();
String v = new String(termAtt.termBuffer(), 0, len);
String primaryPhoneticValue = encoder.doubleMetaphone(v);
String alternatePhoneticValue = encoder.doubleMetaphone(v, true);
// a flag to lazily save state if needed... this avoids a save/restore when only
// one token will be generated.
boolean saveState=inject;
if (primaryPhoneticValue!=null && primaryPhoneticValue.length() > 0 && !primaryPhoneticValue.equals(v)) {
if (saveState) {
remainingTokens.addLast(captureState());
}
return t;
posAtt.setPositionIncrement( firstAlternativeIncrement );
firstAlternativeIncrement = 0;
termAtt.setTermBuffer(primaryPhoneticValue);
saveState = true;
}
if (alternatePhoneticValue!=null && alternatePhoneticValue.length() > 0
&& !alternatePhoneticValue.equals(primaryPhoneticValue)
&& !primaryPhoneticValue.equals(v)) {
if (saveState) {
remainingTokens.addLast(captureState());
saveState = false;
}
posAtt.setPositionIncrement( firstAlternativeIncrement );
termAtt.setTermBuffer(alternatePhoneticValue);
saveState = true;
}
// Just one token to return, so no need to capture/restore
// any state, simply return it.
if (remainingTokens.isEmpty()) {
return true;
}
if (saveState) {
remainingTokens.addLast(captureState());
}
}
}
return remainingTokens.isEmpty() ? null : remainingTokens.removeFirst();
@Override
public void reset() throws IOException {
input.reset();
remainingTokens.clear();
}
}