/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.solr.search;
import org.apache.lucene.search.Filter;
import org.apache.lucene.search.DocIdSet;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.TermEnum;
import org.apache.lucene.index.TermDocs;
import org.apache.lucene.util.OpenBitSet;
import java.io.IOException;
/**
* @version $Id: PrefixFilter.java 922957 2010-03-14 20:58:32Z markrmiller $
*/
public class PrefixFilter extends Filter {
protected final Term prefix;
PrefixFilter(Term prefix) {
this.prefix = prefix;
}
Term getPrefix() { return prefix; }
@Override
public DocIdSet getDocIdSet(IndexReader reader) throws IOException {
final OpenBitSet bitSet = new OpenBitSet(reader.maxDoc());
new PrefixGenerator(prefix) {
public void handleDoc(int doc) {
bitSet.set(doc);
}
}.generate(reader);
return bitSet;
}
@Override
public boolean equals(Object o) {
return o instanceof PrefixFilter && ((PrefixFilter)o).prefix.equals(this.prefix);
}
@Override
public int hashCode() {
return 0xcecf7fe2 + prefix.hashCode();
}
@Override
public String toString () {
StringBuilder sb = new StringBuilder();
sb.append("PrefixFilter(");
sb.append(prefix.toString());
sb.append(")");
return sb.toString();
}
}
// keep this protected until I decide if it's a good way
// to separate id generation from collection (or should
// I just reuse hitcollector???)
interface IdGenerator {
public void generate(IndexReader reader) throws IOException;
public void handleDoc(int doc);
}
abstract class PrefixGenerator implements IdGenerator {
protected final Term prefix;
PrefixGenerator(Term prefix) {
this.prefix = prefix;
}
public void generate(IndexReader reader) throws IOException {
TermEnum enumerator = reader.terms(prefix);
TermDocs termDocs = reader.termDocs();
try {
String prefixText = prefix.text();
String prefixField = prefix.field();
do {
Term term = enumerator.term();
if (term != null &&
term.text().startsWith(prefixText) &&
term.field() == prefixField)
{
termDocs.seek(term);
while (termDocs.next()) {
handleDoc(termDocs.doc());
}
} else {
break;
}
} while (enumerator.next());
} finally {
termDocs.close();
enumerator.close();
}
}
}