/**
* 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.hadoop.mapreduce;
import java.io.IOException;
import java.util.Iterator;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
/**
* <code>MarkableIteratorInterface</code> is an interface for a iterator that
* supports mark-reset functionality.
*
* <p>Mark can be called at any point during the iteration process and a reset
* will go back to the last record before the call to the previous mark.
*
*/
@InterfaceAudience.Public
@InterfaceStability.Evolving
interface MarkableIteratorInterface<VALUE> extends Iterator<VALUE> {
/**
* Mark the current record. A subsequent call to reset will rewind
* the iterator to this record.
* @throws IOException
*/
void mark() throws IOException;
/**
* Reset the iterator to the last record before a call to the previous mark
* @throws IOException
*/
void reset() throws IOException;
/**
* Clear any previously set mark
* @throws IOException
*/
void clearMark() throws IOException;
}