| /* |
| * 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.lucene.util; |
| |
| |
| import org.apache.lucene.search.DocIdSetIterator; |
| |
| /** |
| * A {@link DocIdSetIterator} which iterates over set bits in a |
| * bit set. |
| * @lucene.internal |
| */ |
| public class BitSetIterator extends DocIdSetIterator { |
| |
| private static <T extends BitSet> T getBitSet(DocIdSetIterator iterator, Class<? extends T> clazz) { |
| if (iterator instanceof BitSetIterator) { |
| BitSet bits = ((BitSetIterator) iterator).bits; |
| assert bits != null; |
| if (clazz.isInstance(bits)) { |
| return clazz.cast(bits); |
| } |
| } |
| return null; |
| } |
| |
| /** If the provided iterator wraps a {@link FixedBitSet}, returns it, otherwise returns null. */ |
| public static FixedBitSet getFixedBitSetOrNull(DocIdSetIterator iterator) { |
| return getBitSet(iterator, FixedBitSet.class); |
| } |
| |
| /** If the provided iterator wraps a {@link SparseFixedBitSet}, returns it, otherwise returns null. */ |
| public static SparseFixedBitSet getSparseFixedBitSetOrNull(DocIdSetIterator iterator) { |
| return getBitSet(iterator, SparseFixedBitSet.class); |
| } |
| |
| private final BitSet bits; |
| private final int length; |
| private final long cost; |
| private int doc = -1; |
| |
| /** Sole constructor. */ |
| public BitSetIterator(BitSet bits, long cost) { |
| if (cost < 0) { |
| throw new IllegalArgumentException("cost must be >= 0, got " + cost); |
| } |
| this.bits = bits; |
| this.length = bits.length(); |
| this.cost = cost; |
| } |
| |
| /** Return the wrapped {@link BitSet}. */ |
| public BitSet getBitSet() { |
| return bits; |
| } |
| |
| @Override |
| public int docID() { |
| return doc; |
| } |
| |
| /** Set the current doc id that this iterator is on. */ |
| public void setDocId(int docId) { |
| this.doc = docId; |
| } |
| |
| @Override |
| public int nextDoc() { |
| return advance(doc + 1); |
| } |
| |
| @Override |
| public int advance(int target) { |
| if (target >= length) { |
| return doc = NO_MORE_DOCS; |
| } |
| return doc = bits.nextSetBit(target); |
| } |
| |
| @Override |
| public long cost() { |
| return cost; |
| } |
| |
| } |