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;
/**
* Subclass of FilteredTermEnum for enumerating a single term.
* <p>
* This can be used by {@link MultiTermQuery}s that need only visit one term,
* but want to preserve MultiTermQuery semantics such as
* {@link MultiTermQuery#rewriteMethod}.
*/
public class SingleTermEnum extends FilteredTermEnum {
private Term singleTerm;
private boolean endEnum = false;
/**
* Creates a new <code>SingleTermEnum</code>.
* <p>
* After calling the constructor the enumeration is already pointing to the term,
* if it exists.
*/
public SingleTermEnum(IndexReader reader, Term singleTerm) throws IOException {
super();
this.singleTerm = singleTerm;
setEnum(reader.terms(singleTerm));
}
@Override
public float difference() {
return 1.0F;
}
@Override
protected boolean endEnum() {
return endEnum;
}
@Override
protected boolean termCompare(Term term) {
if (term.equals(singleTerm)) {
return true;
} else {
endEnum = true;
return false;
}
}
}