| /* |
| * 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.search; |
| |
| |
| import java.io.IOException; |
| |
| /** |
| * Abstract decorator class of a DocIdSetIterator |
| * implementation that provides on-demand filter/validation |
| * mechanism on an underlying DocIdSetIterator. |
| */ |
| public abstract class FilteredDocIdSetIterator extends DocIdSetIterator { |
| protected DocIdSetIterator _innerIter; |
| private int doc; |
| |
| /** |
| * Constructor. |
| * @param innerIter Underlying DocIdSetIterator. |
| */ |
| public FilteredDocIdSetIterator(DocIdSetIterator innerIter) { |
| if (innerIter == null) { |
| throw new IllegalArgumentException("null iterator"); |
| } |
| _innerIter = innerIter; |
| doc = -1; |
| } |
| |
| /** Return the wrapped {@link DocIdSetIterator}. */ |
| public DocIdSetIterator getDelegate() { |
| return _innerIter; |
| } |
| |
| /** |
| * Validation method to determine whether a docid should be in the result set. |
| * @param doc docid to be tested |
| * @return true if input docid should be in the result set, false otherwise. |
| * @see #FilteredDocIdSetIterator(DocIdSetIterator) |
| */ |
| protected abstract boolean match(int doc); |
| |
| @Override |
| public int docID() { |
| return doc; |
| } |
| |
| @Override |
| public int nextDoc() throws IOException { |
| while ((doc = _innerIter.nextDoc()) != NO_MORE_DOCS) { |
| if (match(doc)) { |
| return doc; |
| } |
| } |
| return doc; |
| } |
| |
| @Override |
| public int advance(int target) throws IOException { |
| doc = _innerIter.advance(target); |
| if (doc != NO_MORE_DOCS) { |
| if (match(doc)) { |
| return doc; |
| } else { |
| while ((doc = _innerIter.nextDoc()) != NO_MORE_DOCS) { |
| if (match(doc)) { |
| return doc; |
| } |
| } |
| return doc; |
| } |
| } |
| return doc; |
| } |
| |
| @Override |
| public long cost() { |
| return _innerIter.cost(); |
| } |
| } |