001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.mapred.join;
019
020import org.apache.hadoop.classification.InterfaceAudience;
021import org.apache.hadoop.classification.InterfaceStability;
022import org.apache.hadoop.io.Writable;
023
024/**
025 * This defines an interface to a stateful Iterator that can replay elements
026 * added to it directly.
027 * Note that this does not extend {@link java.util.Iterator}.
028 */
029@InterfaceAudience.Public
030@InterfaceStability.Stable
031public interface ResetableIterator<T extends Writable> 
032    extends org.apache.hadoop.mapreduce.lib.join.ResetableIterator<T> {
033
034  public static class EMPTY<U extends Writable>
035      extends org.apache.hadoop.mapreduce.lib.join.ResetableIterator.EMPTY<U>
036      implements ResetableIterator<U> {
037  }
038}