org.apache.solr.search.FilteredDocIdSet Maven / Gradle / Ivy
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/*
* 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 java.io.IOException;
import java.util.Collection;
import org.apache.lucene.search.DocIdSet;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.search.FilteredDocIdSetIterator;
import org.apache.lucene.util.Accountable;
import org.apache.lucene.util.Bits;
import org.apache.lucene.util.RamUsageEstimator;
/**
* Abstract decorator class for a DocIdSet implementation that provides on-demand
* filtering/validation mechanism on a given DocIdSet.
*
* Technically, this same functionality could be achieved with ChainedFilter (under queries/),
* however the benefit of this class is it never materializes the full bitset for the filter.
* Instead, the {@link #match} method is invoked on-demand, per docID visited during searching. If
* you know few docIDs will be visited, and the logic behind {@link #match} is relatively costly,
* this may be a better way to filter than ChainedFilter.
*
* @see DocIdSet
*/
public abstract class FilteredDocIdSet extends DocIdSet {
private final DocIdSet _innerSet;
/**
* Constructor.
*
* @param innerSet Underlying DocIdSet
*/
public FilteredDocIdSet(DocIdSet innerSet) {
_innerSet = innerSet;
}
/** Return the wrapped {@link DocIdSet}. */
public DocIdSet getDelegate() {
return _innerSet;
}
@Override
public long ramBytesUsed() {
return RamUsageEstimator.NUM_BYTES_OBJECT_REF + _innerSet.ramBytesUsed();
}
@Override
public Collection getChildResources() {
return _innerSet.getChildResources();
}
@Override
public Bits bits() throws IOException {
final Bits bits = _innerSet.bits();
return (bits == null)
? null
: new Bits() {
@Override
public boolean get(int docid) {
return bits.get(docid) && FilteredDocIdSet.this.match(docid);
}
@Override
public int length() {
return bits.length();
}
};
}
/**
* Validation method to determine whether a docid should be in the result set.
*
* @param docid docid to be tested
* @return true if input docid should be in the result set, false otherwise.
*/
protected abstract boolean match(int docid);
/**
* Implementation of the contract to build a DocIdSetIterator.
*
* @see DocIdSetIterator
* @see FilteredDocIdSetIterator
*/
@Override
public DocIdSetIterator iterator() throws IOException {
final DocIdSetIterator iterator = _innerSet.iterator();
if (iterator == null) {
return null;
}
return new FilteredDocIdSetIterator(iterator) {
@Override
protected boolean match(int docid) {
return FilteredDocIdSet.this.match(docid);
}
};
}
}