package org.apache.lucene.search.join;
/**
* 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 java.util.Set;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter; // javadocs
import org.apache.lucene.index.Term;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.DocIdSet;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.search.Explanation;
import org.apache.lucene.search.Filter;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.search.Searcher;
import org.apache.lucene.search.Weight;
import org.apache.lucene.search.grouping.TopGroups;
import org.apache.lucene.util.ArrayUtil;
import org.apache.lucene.util.FixedBitSet;
/**
* This query requires that you index
* children and parent docs as a single block, using the
* {@link IndexWriter#addDocuments} or {@link
* IndexWriter#updateDocuments} API. In each block, the
* child documents must appear first, ending with the parent
* document. At search time you provide a Filter
* identifying the parents, however this Filter must provide
* an {@link FixedBitSet} per sub-reader.
*
* <p>Once the block index is built, use this query to wrap
* any sub-query matching only child docs and join matches in that
* child document space up to the parent document space.
* You can then use this Query as a clause with
* other queries in the parent document space.</p>
*
* <p>The child documents must be orthogonal to the parent
* documents: the wrapped child query must never
* return a parent document.</p>
*
* If you'd like to retrieve {@link TopGroups} for the
* resulting query, use the {@link BlockJoinCollector}.
* Note that this is not necessary, ie, if you simply want
* to collect the parent documents and don't need to see
* which child documents matched under that parent, then
* you can use any collector.
*
* <p><b>NOTE</b>: If the overall query contains parent-only
* matches, for example you OR a parent-only query with a
* joined child-only query, then the resulting collected documents
* will be correct, however the {@link TopGroups} you get
* from {@link BlockJoinCollector} will not contain every
* child for parents that had matched.
*
* <p>See {@link org.apache.lucene.search.join} for an
* overview. </p>
*
* @lucene.experimental
*/
public class BlockJoinQuery extends Query {
public static enum ScoreMode {None, Avg, Max, Total};
private final Filter parentsFilter;
private final Query childQuery;
// If we are rewritten, this is the original childQuery we
// were passed; we use this for .equals() and
// .hashCode(). This makes rewritten query equal the
// original, so that user does not have to .rewrite() their
// query before searching:
private final Query origChildQuery;
private final ScoreMode scoreMode;
public BlockJoinQuery(Query childQuery, Filter parentsFilter, ScoreMode scoreMode) {
super();
this.origChildQuery = childQuery;
this.childQuery = childQuery;
this.parentsFilter = parentsFilter;
this.scoreMode = scoreMode;
}
private BlockJoinQuery(Query origChildQuery, Query childQuery, Filter parentsFilter, ScoreMode scoreMode) {
super();
this.origChildQuery = origChildQuery;
this.childQuery = childQuery;
this.parentsFilter = parentsFilter;
this.scoreMode = scoreMode;
}
@Override
public Weight createWeight(Searcher searcher) throws IOException {
return new BlockJoinWeight(this, childQuery.createWeight(searcher), parentsFilter, scoreMode);
}
private static class BlockJoinWeight extends Weight {
private final Query joinQuery;
private final Weight childWeight;
private final Filter parentsFilter;
private final ScoreMode scoreMode;
public BlockJoinWeight(Query joinQuery, Weight childWeight, Filter parentsFilter, ScoreMode scoreMode) {
super();
this.joinQuery = joinQuery;
this.childWeight = childWeight;
this.parentsFilter = parentsFilter;
this.scoreMode = scoreMode;
}
@Override
public Query getQuery() {
return joinQuery;
}
@Override
public float getValue() {
return childWeight.getValue();
}
@Override
public float sumOfSquaredWeights() throws IOException {
return childWeight.sumOfSquaredWeights() * joinQuery.getBoost() * joinQuery.getBoost();
}
@Override
public void normalize(float norm) {
childWeight.normalize(norm * joinQuery.getBoost());
}
@Override
public Scorer scorer(IndexReader reader, boolean scoreDocsInOrder, boolean topScorer) throws IOException {
// Pass scoreDocsInOrder true, topScorer false to our sub:
final Scorer childScorer = childWeight.scorer(reader, true, false);
if (childScorer == null) {
// No matches
return null;
}
final int firstChildDoc = childScorer.nextDoc();
if (firstChildDoc == DocIdSetIterator.NO_MORE_DOCS) {
// No matches
return null;
}
final DocIdSet parents = parentsFilter.getDocIdSet(reader);
// TODO: once we do random-access filters we can
// generalize this:
if (parents == null) {
// No matches
return null;
}
if (!(parents instanceof FixedBitSet)) {
throw new IllegalStateException("parentFilter must return FixedBitSet; got " + parents);
}
return new BlockJoinScorer(this, childScorer, (FixedBitSet) parents, firstChildDoc, scoreMode);
}
@Override
public Explanation explain(IndexReader reader, int doc) throws IOException {
// TODO
throw new UnsupportedOperationException(getClass().getName() +
" cannot explain match on parent document");
}
@Override
public boolean scoresDocsOutOfOrder() {
return false;
}
}
static class BlockJoinScorer extends Scorer {
private final Scorer childScorer;
private final FixedBitSet parentBits;
private final ScoreMode scoreMode;
private int parentDoc;
private float parentScore;
private int nextChildDoc;
private int[] pendingChildDocs = new int[5];
private float[] pendingChildScores;
private int childDocUpto;
public BlockJoinScorer(Weight weight, Scorer childScorer, FixedBitSet parentBits, int firstChildDoc, ScoreMode scoreMode) {
super(weight);
//System.out.println("Q.init firstChildDoc=" + firstChildDoc);
this.parentBits = parentBits;
this.childScorer = childScorer;
this.scoreMode = scoreMode;
if (scoreMode != ScoreMode.None) {
pendingChildScores = new float[5];
}
nextChildDoc = firstChildDoc;
}
@Override
public void visitSubScorers(Query parent, BooleanClause.Occur relationship,
ScorerVisitor<Query, Query, Scorer> visitor) {
super.visitSubScorers(parent, relationship, visitor);
//childScorer.visitSubScorers(weight.getQuery(), BooleanClause.Occur.MUST, visitor);
childScorer.visitScorers(visitor);
}
int getChildCount() {
return childDocUpto;
}
int[] swapChildDocs(int[] other) {
final int[] ret = pendingChildDocs;
if (other == null) {
pendingChildDocs = new int[5];
} else {
pendingChildDocs = other;
}
return ret;
}
float[] swapChildScores(float[] other) {
if (scoreMode == ScoreMode.None) {
throw new IllegalStateException("ScoreMode is None");
}
final float[] ret = pendingChildScores;
if (other == null) {
pendingChildScores = new float[5];
} else {
pendingChildScores = other;
}
return ret;
}
@Override
public int nextDoc() throws IOException {
//System.out.println("Q.nextDoc() nextChildDoc=" + nextChildDoc);
if (nextChildDoc == NO_MORE_DOCS) {
//System.out.println(" end");
return parentDoc = NO_MORE_DOCS;
}
// Gather all children sharing the same parent as nextChildDoc
parentDoc = parentBits.nextSetBit(nextChildDoc);
//System.out.println(" parentDoc=" + parentDoc);
assert parentDoc != -1;
float totalScore = 0;
float maxScore = Float.NEGATIVE_INFINITY;
childDocUpto = 0;
do {
//System.out.println(" c=" + nextChildDoc);
if (pendingChildDocs.length == childDocUpto) {
pendingChildDocs = ArrayUtil.grow(pendingChildDocs);
if (scoreMode != ScoreMode.None) {
pendingChildScores = ArrayUtil.grow(pendingChildScores);
}
}
pendingChildDocs[childDocUpto] = nextChildDoc;
if (scoreMode != ScoreMode.None) {
// TODO: specialize this into dedicated classes per-scoreMode
final float childScore = childScorer.score();
pendingChildScores[childDocUpto] = childScore;
maxScore = Math.max(childScore, maxScore);
totalScore += childScore;
}
childDocUpto++;
nextChildDoc = childScorer.nextDoc();
} while (nextChildDoc < parentDoc);
//System.out.println(" nextChildDoc=" + nextChildDoc);
// Parent & child docs are supposed to be orthogonal:
assert nextChildDoc != parentDoc;
switch(scoreMode) {
case Avg:
parentScore = totalScore / childDocUpto;
break;
case Max:
parentScore = maxScore;
break;
case Total:
parentScore = totalScore;
break;
case None:
break;
}
//System.out.println(" return parentDoc=" + parentDoc);
return parentDoc;
}
@Override
public int docID() {
return parentDoc;
}
@Override
public float score() throws IOException {
return parentScore;
}
@Override
public int advance(int parentTarget) throws IOException {
//System.out.println("Q.advance parentTarget=" + parentTarget);
if (parentTarget == NO_MORE_DOCS) {
return parentDoc = NO_MORE_DOCS;
}
// Every parent must have at least one child:
assert parentTarget != 0;
final int prevParentDoc = parentBits.prevSetBit(parentTarget-1);
//System.out.println(" rolled back to prevParentDoc=" + prevParentDoc + " vs parentDoc=" + parentDoc);
assert prevParentDoc >= parentDoc;
if (prevParentDoc > nextChildDoc) {
nextChildDoc = childScorer.advance(prevParentDoc);
// System.out.println(" childScorer advanced to child docID=" + nextChildDoc);
//} else {
//System.out.println(" skip childScorer advance");
}
// Parent & child docs are supposed to be orthogonal:
assert nextChildDoc != prevParentDoc;
final int nd = nextDoc();
//System.out.println(" return nextParentDoc=" + nd);
return nd;
}
}
@Override
public void extractTerms(Set<Term> terms) {
childQuery.extractTerms(terms);
}
@Override
public Query rewrite(IndexReader reader) throws IOException {
final Query childRewrite = childQuery.rewrite(reader);
if (childRewrite != childQuery) {
Query rewritten = new BlockJoinQuery(childQuery,
childRewrite,
parentsFilter,
scoreMode);
rewritten.setBoost(getBoost());
return rewritten;
} else {
return this;
}
}
@Override
public String toString(String field) {
return "BlockJoinQuery ("+childQuery.toString()+")";
}
@Override
public boolean equals(Object _other) {
if (_other instanceof BlockJoinQuery) {
final BlockJoinQuery other = (BlockJoinQuery) _other;
return origChildQuery.equals(other.origChildQuery) &&
parentsFilter.equals(other.parentsFilter) &&
scoreMode == other.scoreMode;
} else {
return false;
}
}
@Override
public int hashCode() {
final int prime = 31;
int hash = 1;
hash = prime * hash + origChildQuery.hashCode();
hash = prime * hash + scoreMode.hashCode();
hash = prime * hash + parentsFilter.hashCode();
return hash;
}
@Override
public Object clone() {
return new BlockJoinQuery((Query) origChildQuery.clone(),
parentsFilter,
scoreMode);
}
}