@@ -0,0 +1,1570 @@
+package org.apache.lucene.search;%0A%0A/**%0A * Licensed to the Apache Software Foundation (ASF) under one or more%0A * contributor license agreements.  See the NOTICE file distributed with%0A * this work for additional information regarding copyright ownership.%0A * The ASF licenses this file to You under the Apache License, Version 2.0%0A * (the %22License%22); you may not use this file except in compliance with%0A * the License.  You may obtain a copy of the License at%0A *%0A *     http://www.apache.org/licenses/LICENSE-2.0%0A *%0A * Unless required by applicable law or agreed to in writing, software%0A * distributed under the License is distributed on an %22AS IS%22 BASIS,%0A * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.%0A * See the License for the specific language governing permissions and%0A * limitations under the License.%0A */%0A%0Aimport java.io.IOException;%0A%0A/**%0A * An empty implementation for %7B@link DocIdSetIterator%7D. This can be used by%0A * classes which receive a null %7B@link DocIdSet%7D from%0A * %7B@link Filter#getDocIdSet(org.apache.lucene.index.IndexReader)%7D.%0A */%0Apublic final class EmptyDocIdSetIterator extends DocIdSetIterator %7B%0A%0A  private static final DocIdSetIterator instance = new EmptyDocIdSetIterator();%0A  %0A  public static DocIdSetIterator getInstance() %7B return instance; %7D%0A  %0A  // to prevent instantiation%0A  private EmptyDocIdSetIterator() %7B %7D%0A  %0A  public int advance(int target) throws IOException %7B return NO_MORE_DOCS; %7D%0A  %0A  public int docID() %7B return NO_MORE_DOCS; %7D%0A  %0A  public int nextDoc() throws IOException %7B return NO_MORE_DOCS; %7D%0A  %0A%7D%0A

add EmptyDocIdSetIterator