JdbcTasklet.java

/*
 * Copyright 2006-2014 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
 *
 *      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 com.springdeveloper.data.jdbc.batch;

import java.util.List;
import java.util.Map;

import javax.sql.DataSource;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.batch.core.ExitStatus;
import org.springframework.batch.core.StepContribution;
import org.springframework.batch.core.StepExecution;
import org.springframework.batch.core.scope.context.ChunkContext;
import org.springframework.batch.core.step.tasklet.Tasklet;
import org.springframework.batch.repeat.RepeatStatus;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.jdbc.core.namedparam.BeanPropertySqlParameterSource;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
import org.springframework.util.Assert;

/**
 * @author Dave Syer,
 * @author Christian Tzolov
 * @author Thomas Risberg
 * 
 */
public class JdbcTasklet implements Tasklet, InitializingBean {

	private static final Log logger = LogFactory.getLog(JdbcTasklet.class);

	private NamedParameterJdbcTemplate jdbcTemplate;

	private String sql;

	/**
	 * An SQL query to execute in the tasklet. The query can be a select,
	 * update, delete or insert, and it can contain embedded query parameters
	 * using a {@link BeanPropertySqlParameterSource} whose root context is the
	 * step context. So for example
	 * 
	 * <pre>
	 * DELETE from LEAD_INPUTS where ID=:jobParameters[idToDelete]
	 * </pre>
	 * 
	 * Note that the syntax for the named parameters is different from and not
	 * as flexible as Spring EL. So it might be better anyway if possible to
	 * use late binding to push step context properties into the query, e.g.
	 * this will work in a bean definition which is step scoped:
	 * 
	 * <pre>
	 * <bean id="tasklet" class="org...JdbcTasklet" scope="step">
	 *   <property name="sql">
	 *     <value>
	 * DELETE from LEAD_INPUTS where ID=#{jobParameters['i.to.delete']?:-1}
	 *     </value>
	 *   </property>
	 * </bean>
	 * </pre>
	 * 
	 * @see BeanPropertySqlParameterSource
	 * 
	 * @param sql the sql to set
	 */
	public void setSql(String sql) {
		this.sql = sql;
	}

	/**
	 * @param dataSource the dataSource to set
	 */
	public void setDataSource(DataSource dataSource) {
		this.jdbcTemplate = new NamedParameterJdbcTemplate(dataSource);
	}

	public void afterPropertiesSet() throws Exception {
		Assert.state(jdbcTemplate != null, "A DataSource must be provided");
		Assert.state(sql != null, "A SQL query must be provided");
	}

	/**
	 * Execute the {@link #setSql(String) SQL query} provided. If the query
	 * starts with "select" (case insensitive) the result is a list of maps,
	 * which is logged and added to the step execution exit status. Otherwise
	 * the query is executed and the result is an indication, also in the exit
	 * status, of the number of rows updated.
	 */
	public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception {

		StepExecution stepExecution = chunkContext.getStepContext().getStepExecution();
		ExitStatus exitStatus = stepExecution.getExitStatus();

		if (sql.trim().toUpperCase().startsWith("SELECT")) {
			logger.debug("Executing: " + sql);
			List<Map<String, Object>> result = jdbcTemplate.queryForList(sql, new BeanPropertySqlParameterSource(
					chunkContext.getStepContext()));
			String msg = "Result: " + result;
			logger.debug(msg);
			stepExecution.setExitStatus(exitStatus.addExitDescription(msg));
		}
		else {
			logger.debug("Updating : " + sql);
			int updated = jdbcTemplate.update(sql, new BeanPropertySqlParameterSource(chunkContext.getStepContext()));
			String msg = "Updated: " + updated + " rows";
			logger.debug(msg);
			stepExecution.setExitStatus(exitStatus.addExitDescription(msg));
		}
		return RepeatStatus.FINISHED;

	}

}