/* * Copyright 2009-2014 the original author or authors. * * Licensed 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 * * https://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.springframework.batch.sample.common;import java.util.HashMap;import java.util.Map;import javax.sql.DataSource;import org.springframework.batch.core.partition.support.Partitioner;import org.springframework.batch.item.ExecutionContext;import org.springframework.jdbc.core.JdbcOperations;import org.springframework.jdbc.core.JdbcTemplate;/** * Simple minded partitioner for a range of values of a column in a database * table. Works best if the values are uniformly distributed (e.g. * auto-generated primary key values). * * @author Dave Syer * */public class ColumnRangePartitioner implements Partitioner { private JdbcOperations jdbcTemplate; private String table; private String column; /** * The name of the SQL table the data are in. * * @param table the name of the table */ public void setTable(String table) { this.table = table; } /** * The name of the column to partition. * * @param column the column name. */ public void setColumn(String column) { this.column = column; } /** * The data source for connecting to the database. * * @param dataSource a {@link DataSource} */ public void setDataSource(DataSource dataSource) { jdbcTemplate = new JdbcTemplate(dataSource); } /** * Partition a database table assuming that the data in the column specified * are uniformly distributed. The execution context values will have keys * <code>minValue</code> and <code>maxValue</code> specifying the range of * values to consider in each partition. * * @see Partitioner#partition(int) */ @Override public Map<String, ExecutionContext> partition(int gridSize) {