solr/core/src/java/org/apache/solr/search/facet/SweepDISI.java

/*
 * 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 java.util.List;

import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.search.DocIdSet;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.solr.search.facet.SlotAcc.CountSlotAcc;
import org.apache.solr.search.facet.SlotAcc.SweepCountAccStruct;

abstract class SweepDISI extends DocIdSetIterator implements SweepCountAware {

  public final int size;
  final CountSlotAcc[] countAccs;

  public SweepDISI(int size, CountSlotAcc[] countAccs) {
    this.size = size;
    this.countAccs = countAccs;
  }

  private static boolean addAcc(SweepCountAccStruct entry, DocIdSetIterator[] subIterators, CountSlotAcc[] activeCountAccs, LeafReaderContext subCtx, int idx) throws IOException {
    final DocIdSet docIdSet = entry.docSet.getTopFilter().getDocIdSet(subCtx, null);
    if (docIdSet == null || (subIterators[idx] = docIdSet.iterator()) == null) {
      return false;
    }
    activeCountAccs[idx] = entry.countAcc;
    return true;
  }

  static SweepDISI newInstance(SweepCountAccStruct base, List<SweepCountAccStruct> others, DocIdSetIterator[] subIterators, CountSlotAcc[] activeCountAccs, LeafReaderContext subCtx) throws IOException {
    int activeCt = 0;
    final int baseIdx;
    if (base == null || !addAcc(base, subIterators, activeCountAccs, subCtx, activeCt)) {
      baseIdx = -1;
    } else {
      baseIdx = activeCt++;
    }
    for (SweepCountAccStruct entry : others) {
      if (addAcc(entry, subIterators, activeCountAccs, subCtx, activeCt)) {
        activeCt++;
      }
    }
    switch (activeCt) {
      case 0:
        return null;
      case 1:
        return new SingletonDISI(subIterators[0], activeCountAccs, baseIdx >= 0); // solr docsets already exclude any deleted docs
      default:
        return new UnionDISI(subIterators, activeCountAccs, activeCt, baseIdx);
    }
  }

  @Override
  public int docID() {
    throw new UnsupportedOperationException("Not supported.");
  }

  @Override
  public int advance(int target) throws IOException {
    throw new UnsupportedOperationException("Not supported.");
  }

  @Override
  public long cost() {
    throw new UnsupportedOperationException("Not supported.");
  }

}