| /* |
| * 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. |
| * |
| * <p> |
| * 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<Accountable> 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); |
| } |
| }; |
| } |
| } |