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     */
018    package org.apache.hadoop.mapred.join;
019    
020    import org.apache.hadoop.classification.InterfaceAudience;
021    import org.apache.hadoop.classification.InterfaceStability;
022    import 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
031    public 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    }