package org.apache.lucene.search;
/**
* 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.
*/
import java.io.IOException;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
abstract class TermCollectingRewrite<Q extends Query> extends MultiTermQuery.RewriteMethod {
/** Return a suitable top-level Query for holding all expanded terms. */
protected abstract Q getTopLevelQuery() throws IOException;
/** Add a MultiTermQuery term to the top-level query */
protected abstract void addClause(Q topLevel, Term term, float boost) throws IOException;
protected final void collectTerms(IndexReader reader, MultiTermQuery query, TermCollector collector) throws IOException {
final FilteredTermEnum enumerator = query.getEnum(reader);
try {
do {
final Term t = enumerator.term();
if (t == null || !collector.collect(t, enumerator.difference()))
break;
} while (enumerator.next());
} finally {
enumerator.close();
}
}
protected interface TermCollector {
/** return false to stop collecting */
boolean collect(Term t, float boost) throws IOException;
}
}