org.apache.solr.search.facet.BlockJoin.java Source code

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Here is the source code for org.apache.solr.search.facet.BlockJoin.java

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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.facet;

import java.io.IOException;

import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.util.FixedBitSet;
import org.apache.solr.search.BitDocSet;
import org.apache.solr.search.DocIterator;
import org.apache.solr.search.DocSet;
import org.apache.solr.search.DocSetCollector;
import org.apache.solr.search.QueryContext;

/** @lucene.experimental */
public class BlockJoin {

    /** acceptDocs will normally be used to avoid deleted documents from being generated as part of the answer DocSet (just use *:*)
     *  although it can be used to further constrain the generated documents.
     */
    public static DocSet toChildren(DocSet parentInput, BitDocSet parentList, DocSet acceptDocs,
            QueryContext qcontext) throws IOException {
        FixedBitSet parentBits = parentList.getBits();
        DocSetCollector collector = new DocSetCollector(qcontext.searcher().maxDoc());
        DocIterator iter = parentInput.iterator();
        while (iter.hasNext()) {
            int parentDoc = iter.nextDoc();
            if (!parentList.exists(parentDoc) || parentDoc == 0) { // test for parentDoc==0 here to avoid passing -1 to prevSetBit later on
                // not a parent, or parent has no children
                continue;
            }
            int prevParent = parentBits.prevSetBit(parentDoc - 1);
            for (int childDoc = prevParent + 1; childDoc < parentDoc; childDoc++) {
                if (acceptDocs != null && !acceptDocs.exists(childDoc))
                    continue; // only select live docs
                collector.collect(childDoc);
            }
        }
        return collector.getDocSet();
    }

    /** childInput may also contain parents (i.e. a parent or below will all roll up to that parent) */
    public static DocSet toParents(DocSet childInput, BitDocSet parentList, QueryContext qcontext)
            throws IOException {
        FixedBitSet parentBits = parentList.getBits();
        DocSetCollector collector = new DocSetCollector(qcontext.searcher().maxDoc());
        DocIterator iter = childInput.iterator();
        int currentParent = -1;
        while (iter.hasNext()) {
            int childDoc = iter.nextDoc(); // TODO: skipping
            if (childDoc <= currentParent) { // use <= since we also allow parents in the input
                // we already visited this parent
                continue;
            }
            currentParent = parentBits.nextSetBit(childDoc);
            if (currentParent != DocIdSetIterator.NO_MORE_DOCS) {
                // only collect the parent the first time we skip to it
                collector.collect(currentParent);
            }
        }
        return collector.getDocSet();
    }

}