/*
    * Copyright 2006-2012 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 org.springframework.batch.sample.common;
  
  import javax.sql.DataSource;
  
  import org.springframework.batch.core.listener.StepListenerSupport;
  import org.springframework.batch.item.ItemReader;
  import org.springframework.beans.factory.InitializingBean;
  import org.springframework.dao.OptimisticLockingFailureException;
  import org.springframework.jdbc.core.JdbcOperations;
  import org.springframework.jdbc.core.JdbcTemplate;
  import org.springframework.util.Assert;
  
  /**
   * Thread-safe database {@link ItemReader} implementing the process indicator
   * pattern.
   */
  public class StagingItemListener extends StepListenerSupport<Long, Long> implements InitializingBean {
  
  	private JdbcOperations jdbcTemplate;
  
  	public void setDataSource(DataSource dataSource) {
  		jdbcTemplate = new JdbcTemplate(dataSource);
  	}
  
  	public final void afterPropertiesSet() throws Exception {
  		Assert.notNull(jdbcTemplate, "You must provide a DataSource.");
  	}
  
  	@Override
  	public void afterRead(Long id) {
  		int count = jdbcTemplate.update("UPDATE BATCH_STAGING SET PROCESSED=? WHERE ID=? AND PROCESSED=?",
  				StagingItemWriter.DONE, id, StagingItemWriter.NEW);
  		if (count != 1) {
  			throw new OptimisticLockingFailureException("The staging record with ID=" + id
  					+ " was updated concurrently when trying to mark as complete (updated " + count + " records.");
  		}
  	}
  
  }