| /* |
| * 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.join; |
| |
| import java.io.IOException; |
| import java.util.Set; |
| |
| import org.apache.lucene.index.IndexReader; |
| import org.apache.lucene.index.LeafReaderContext; |
| import org.apache.lucene.index.ReaderUtil; |
| import org.apache.lucene.index.Term; |
| import org.apache.lucene.search.DocIdSetIterator; |
| import org.apache.lucene.search.Explanation; |
| import org.apache.lucene.search.IndexSearcher; |
| import org.apache.lucene.search.Query; |
| import org.apache.lucene.search.QueryVisitor; |
| import org.apache.lucene.search.Scorer; |
| import org.apache.lucene.search.Weight; |
| import org.apache.lucene.util.BitSet; |
| |
| /** |
| * A query that returns all the matching child documents for a specific parent document |
| * indexed together in the same block. The provided child query determines which matching |
| * child doc is being returned. |
| * |
| * @lucene.experimental |
| */ |
| public class ParentChildrenBlockJoinQuery extends Query { |
| |
| private final BitSetProducer parentFilter; |
| private final Query childQuery; |
| private final int parentDocId; |
| |
| /** |
| * Creates a <code>ParentChildrenBlockJoinQuery</code> instance |
| * |
| * @param parentFilter A filter identifying parent documents. |
| * @param childQuery A child query that determines which child docs are matching |
| * @param parentDocId The top level doc id of that parent to return children documents for |
| */ |
| public ParentChildrenBlockJoinQuery(BitSetProducer parentFilter, Query childQuery, int parentDocId) { |
| this.parentFilter = parentFilter; |
| this.childQuery = childQuery; |
| this.parentDocId = parentDocId; |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (sameClassAs(obj) == false) { |
| return false; |
| } |
| ParentChildrenBlockJoinQuery other = (ParentChildrenBlockJoinQuery) obj; |
| return parentFilter.equals(other.parentFilter) |
| && childQuery.equals(other.childQuery) |
| && parentDocId == other.parentDocId; |
| } |
| |
| @Override |
| public int hashCode() { |
| int hash = classHash(); |
| hash = 31 * hash + parentFilter.hashCode(); |
| hash = 31 * hash + childQuery.hashCode(); |
| hash = 31 * hash + parentDocId; |
| return hash; |
| } |
| |
| @Override |
| public String toString(String field) { |
| return "ParentChildrenBlockJoinQuery (" + childQuery + ")"; |
| } |
| |
| @Override |
| public void visit(QueryVisitor visitor) { |
| visitor.visitLeaf(this); |
| } |
| |
| @Override |
| public Query rewrite(IndexReader reader) throws IOException { |
| final Query childRewrite = childQuery.rewrite(reader); |
| if (childRewrite != childQuery) { |
| return new ParentChildrenBlockJoinQuery(parentFilter, childRewrite, parentDocId); |
| } else { |
| return super.rewrite(reader); |
| } |
| } |
| |
| @Override |
| public Weight createWeight(IndexSearcher searcher, org.apache.lucene.search.ScoreMode scoreMode, float boost) throws IOException { |
| final Weight childWeight = childQuery.createWeight(searcher, scoreMode, boost); |
| final int readerIndex = ReaderUtil.subIndex(parentDocId, searcher.getIndexReader().leaves()); |
| return new Weight(this) { |
| |
| @Override |
| public void extractTerms(Set<Term> terms) { |
| childWeight.extractTerms(terms); |
| } |
| |
| @Override |
| public Explanation explain(LeafReaderContext context, int doc) throws IOException { |
| return Explanation.noMatch("Not implemented, use ToParentBlockJoinQuery explain why a document matched"); |
| } |
| |
| @Override |
| public Scorer scorer(LeafReaderContext context) throws IOException { |
| // Childs docs only reside in a single segment, so no need to evaluate all segments |
| if (context.ord != readerIndex) { |
| return null; |
| } |
| |
| final int localParentDocId = parentDocId - context.docBase; |
| // If parentDocId == 0 then a parent doc doesn't have child docs, because child docs are stored |
| // before the parent doc and because parent doc is 0 we can safely assume that there are no child docs. |
| if (localParentDocId == 0) { |
| return null; |
| } |
| |
| final BitSet parents = parentFilter.getBitSet(context); |
| final int firstChildDocId = parents.prevSetBit(localParentDocId - 1) + 1; |
| // A parent doc doesn't have child docs, so we can early exit here: |
| if (firstChildDocId == localParentDocId) { |
| return null; |
| } |
| |
| final Scorer childrenScorer = childWeight.scorer(context); |
| if (childrenScorer == null) { |
| return null; |
| } |
| DocIdSetIterator childrenIterator = childrenScorer.iterator(); |
| final DocIdSetIterator it = new DocIdSetIterator() { |
| |
| int doc = -1; |
| |
| @Override |
| public int docID() { |
| return doc; |
| } |
| |
| @Override |
| public int nextDoc() throws IOException { |
| return advance(doc + 1); |
| } |
| |
| @Override |
| public int advance(int target) throws IOException { |
| target = Math.max(firstChildDocId, target); |
| if (target >= localParentDocId) { |
| // We're outside the child nested scope, so it is done |
| return doc = NO_MORE_DOCS; |
| } else { |
| int advanced = childrenIterator.advance(target); |
| if (advanced >= localParentDocId) { |
| // We're outside the child nested scope, so it is done |
| return doc = NO_MORE_DOCS; |
| } else { |
| return doc = advanced; |
| } |
| } |
| } |
| |
| @Override |
| public long cost() { |
| return Math.min(childrenIterator.cost(), localParentDocId - firstChildDocId); |
| } |
| |
| }; |
| return new Scorer(this) { |
| @Override |
| public int docID() { |
| return it.docID(); |
| } |
| |
| @Override |
| public float score() throws IOException { |
| return childrenScorer.score(); |
| } |
| |
| @Override |
| public float getMaxScore(int upTo) throws IOException { |
| return Float.POSITIVE_INFINITY; |
| } |
| @Override |
| public DocIdSetIterator iterator() { |
| return it; |
| } |
| }; |
| } |
| |
| @Override |
| public boolean isCacheable(LeafReaderContext ctx) { |
| return false; // TODO delegate to BitSetProducer? |
| } |
| |
| }; |
| } |
| } |