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
019package org.apache.hadoop.mapreduce.lib.db;
020
021import java.sql.ResultSet;
022import java.sql.SQLException;
023import java.util.List;
024
025import org.apache.hadoop.classification.InterfaceAudience;
026import org.apache.hadoop.classification.InterfaceStability;
027import org.apache.hadoop.conf.Configuration;
028import org.apache.hadoop.mapreduce.InputSplit;
029
030/**
031 * DBSplitter will generate DBInputSplits to use with DataDrivenDBInputFormat.
032 * DataDrivenDBInputFormat needs to interpolate between two values that
033 * represent the lowest and highest valued records to import. Depending
034 * on the data-type of the column, this requires different behavior.
035 * DBSplitter implementations should perform this for a data type or family
036 * of data types.
037 */
038@InterfaceAudience.Public
039@InterfaceStability.Evolving
040public interface DBSplitter {
041  /**
042   * Given a ResultSet containing one record (and already advanced to that record)
043   * with two columns (a low value, and a high value, both of the same type), determine
044   * a set of splits that span the given values.
045   */
046  List<InputSplit> split(Configuration conf, ResultSet results, String colName) throws SQLException;
047}