org.apache.lucene.search.FilteredDocIdSetIterator Maven / Gradle / Ivy
/*
* 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.lucene.search;
import java.io.IOException;
/**
* Abstract decorator class of a DocIdSetIterator
* implementation that provides on-demand filter/validation
* mechanism on an underlying DocIdSetIterator.
*/
public abstract class FilteredDocIdSetIterator extends DocIdSetIterator {
protected DocIdSetIterator _innerIter;
private int doc;
/**
* Constructor.
* @param innerIter Underlying DocIdSetIterator.
*/
public FilteredDocIdSetIterator(DocIdSetIterator innerIter) {
if (innerIter == null) {
throw new IllegalArgumentException("null iterator");
}
_innerIter = innerIter;
doc = -1;
}
/** Return the wrapped {@link DocIdSetIterator}. */
public DocIdSetIterator getDelegate() {
return _innerIter;
}
/**
* Validation method to determine whether a docid should be in the result set.
* @param doc docid to be tested
* @return true if input docid should be in the result set, false otherwise.
* @see #FilteredDocIdSetIterator(DocIdSetIterator)
*/
protected abstract boolean match(int doc);
@Override
public int docID() {
return doc;
}
@Override
public int nextDoc() throws IOException {
while ((doc = _innerIter.nextDoc()) != NO_MORE_DOCS) {
if (match(doc)) {
return doc;
}
}
return doc;
}
@Override
public int advance(int target) throws IOException {
doc = _innerIter.advance(target);
if (doc != NO_MORE_DOCS) {
if (match(doc)) {
return doc;
} else {
while ((doc = _innerIter.nextDoc()) != NO_MORE_DOCS) {
if (match(doc)) {
return doc;
}
}
return doc;
}
}
return doc;
}
@Override
public long cost() {
return _innerIter.cost();
}
}