| package org.apache.lucene.util; |
| |
| /* |
| * 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.util.BitSet; |
| |
| import org.apache.lucene.search.DocIdSet; |
| import org.apache.lucene.search.DocIdSetIterator; |
| |
| |
| /** Simple DocIdSet and DocIdSetIterator backed by a BitSet */ |
| public class DocIdBitSet extends DocIdSet implements Bits { |
| |
| private static final long BASE_RAM_BYTES_USED = |
| RamUsageEstimator.shallowSizeOfInstance(DocIdBitSet.class) |
| + RamUsageEstimator.shallowSizeOfInstance(BitSet.class) |
| + RamUsageEstimator.NUM_BYTES_ARRAY_HEADER; // the array that stores the bits |
| |
| private final BitSet bitSet; |
| |
| public DocIdBitSet(BitSet bitSet) { |
| this.bitSet = bitSet; |
| } |
| |
| @Override |
| public DocIdSetIterator iterator() { |
| return new DocIdBitSetIterator(bitSet); |
| } |
| |
| @Override |
| public Bits bits() { |
| return this; |
| } |
| |
| /** This DocIdSet implementation is cacheable. */ |
| @Override |
| public boolean isCacheable() { |
| return true; |
| } |
| |
| /** |
| * Returns the underlying BitSet. |
| */ |
| public BitSet getBitSet() { |
| return this.bitSet; |
| } |
| |
| @Override |
| public boolean get(int index) { |
| return bitSet.get(index); |
| } |
| |
| @Override |
| public int length() { |
| // the size may not be correct... |
| return bitSet.size(); |
| } |
| |
| @Override |
| public long ramBytesUsed() { |
| // unfortunately this is likely underestimated if the Bitset implementation |
| // over-sizes the array that stores the bits |
| return BASE_RAM_BYTES_USED + (bitSet.size() + 7) >>> 3; |
| } |
| |
| private static class DocIdBitSetIterator extends DocIdSetIterator { |
| private int docId; |
| private BitSet bitSet; |
| |
| DocIdBitSetIterator(BitSet bitSet) { |
| this.bitSet = bitSet; |
| this.docId = -1; |
| } |
| |
| @Override |
| public int docID() { |
| return docId; |
| } |
| |
| @Override |
| public int nextDoc() { |
| // (docId + 1) on next line requires -1 initial value for docNr: |
| int d = bitSet.nextSetBit(docId + 1); |
| // -1 returned by BitSet.nextSetBit() when exhausted |
| docId = d == -1 ? NO_MORE_DOCS : d; |
| return docId; |
| } |
| |
| @Override |
| public int advance(int target) { |
| int d = bitSet.nextSetBit(target); |
| // -1 returned by BitSet.nextSetBit() when exhausted |
| docId = d == -1 ? NO_MORE_DOCS : d; |
| return docId; |
| } |
| |
| @Override |
| public long cost() { |
| // upper bound |
| return bitSet.length(); |
| } |
| } |
| } |