UIDDocIdSet.java

package proj.zoie.api;

/**
 * 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 it.unimi.dsi.fastutil.ints.IntRBTreeSet;

import java.io.IOException;
import java.util.Arrays;

import org.apache.lucene.search.DocIdSet;
import org.apache.lucene.search.DocIdSetIterator;

public class UIDDocIdSet extends DocIdSet {
  private final int[] _sorted;

  public UIDDocIdSet(long[] uidArray, DocIDMapper mapper) {
    if (uidArray == null) {
      throw new IllegalArgumentException("Input uid array is null");
    }
    _sorted = mapUID(uidArray, mapper);
  }

  public static int[] mapUID(long[] uidArray, DocIDMapper mapper) {
    IntRBTreeSet idSet = new IntRBTreeSet();
    for (long uid : uidArray) {
      if (uid != ZoieSegmentReader.DELETED_UID) {
        int docid = mapper.getDocID(uid);
        if (docid != DocIDMapper.NOT_FOUND) {
          idSet.add(docid);
        }
      }
    }
    return idSet.toIntArray();
  }

  @Override
  public DocIdSetIterator iterator() {
    return new DocIdSetIterator() {
      int doc = -1;
      int current = -1;

      @Override
      public int docID() {
        return doc;
      }

      @Override
      public int nextDoc() throws IOException {
        if (current < _sorted.length - 1) {
          current++;
          doc = _sorted[current];
          return doc;
        }
        return DocIdSetIterator.NO_MORE_DOCS;
      }

      @Override
      public int advance(int target) throws IOException {
        int idx = Arrays.binarySearch(_sorted, target);
        if (idx < 0) {
          idx = -(idx + 1);
          if (idx >= _sorted.length) return DocIdSetIterator.NO_MORE_DOCS;
        }
        current = idx;
        doc = _sorted[current];
        return doc;
      }

      // No use, just implement abstract function
      @Override
      public long cost() {
        return 0;
      }
    };
  }

}