content: package org.apache.solr.search.grouping.collector;
  
  /*
   * 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 org.apache.lucene.index.IndexReader;
  import org.apache.lucene.search.Collector;
  import org.apache.lucene.search.Scorer;
  import org.apache.solr.search.DocSet;
  
  import java.io.IOException;
  
  /**
   * A collector that filters incoming doc ids that are not in the filter.
   *
   * @lucene.experimental
   */
  public class FilterCollector extends Collector {
  
    private final DocSet filter;
    private final Collector delegate;
    private int docBase;
    private int matches;
  
    public FilterCollector(DocSet filter, Collector delegate) throws IOException {
      this.filter = filter;
      this.delegate = delegate;
    }
  
    public void setScorer(Scorer scorer) throws IOException {
      delegate.setScorer(scorer);
    }
  
    public void collect(int doc) throws IOException {
      matches++;
      if (filter.exists(doc + docBase)) {
        delegate.collect(doc);
      }
    }
  
    public void setNextReader(IndexReader indexReader, int docBase) throws IOException {
      this.docBase = docBase;
      delegate.setNextReader(indexReader, docBase);
    }
  
    public boolean acceptsDocsOutOfOrder() {
      return delegate.acceptsDocsOutOfOrder();
    }
  
    public int getMatches() {
      return matches;
    }
  
    /**
     * Returns the delegate collector
     *
     * @return the delegate collector
     */
    public Collector getDelegate() {
      return delegate;
    }
  }
  