/*
    * Copyright 2006-2007 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 java.io.Serializable;
  import java.sql.PreparedStatement;
  import java.sql.SQLException;
  import java.util.List;
  import java.util.ListIterator;
  
  import org.springframework.batch.core.ExitStatus;
  import org.springframework.batch.core.StepExecution;
  import org.springframework.batch.core.StepExecutionListener;
  import org.springframework.batch.item.ItemWriter;
  import org.springframework.batch.support.SerializationUtils;
  import org.springframework.jdbc.core.BatchPreparedStatementSetter;
  import org.springframework.jdbc.core.support.JdbcDaoSupport;
  import org.springframework.jdbc.support.incrementer.DataFieldMaxValueIncrementer;
  import org.springframework.util.Assert;
  import org.springframework.util.ClassUtils;
  
  /**
   * Database {@link ItemWriter} implementing the process indicator pattern.
   */
  public class StagingItemWriter<T> extends JdbcDaoSupport implements StepExecutionListener, ItemWriter<T> {
  
  	public static final String NEW = "N";
  
  	public static final String DONE = "Y";
  
  	public static final Object WORKING = "W";
  
  	private DataFieldMaxValueIncrementer incrementer;
  
  	private StepExecution stepExecution;
  
  	/**
  	 * Check mandatory properties.
  	 * 
  	 * @see org.springframework.dao.support.DaoSupport#initDao()
  	 */
  	protected void initDao() throws Exception {
  		super.initDao();
  		Assert.notNull(incrementer, "DataFieldMaxValueIncrementer is required - set the incrementer property in the "
  				+ ClassUtils.getShortName(StagingItemWriter.class));
  	}
  
  	/**
  	 * Setter for the key generator for the staging table.
  	 * 
  	 * @param incrementer the {@link DataFieldMaxValueIncrementer} to set
  	 */
  	public void setIncrementer(DataFieldMaxValueIncrementer incrementer) {
  		this.incrementer = incrementer;
  	}
  
  	/**
  	 * Serialize the item to the staging table, and add a NEW processed flag.
  	 * 
  	 * @see ItemWriter#write(java.util.List)
  	 */
  	public void write(final List<? extends T> items) {
  
  		final ListIterator<? extends T> itemIterator = items.listIterator();
  		getJdbcTemplate().batchUpdate("INSERT into BATCH_STAGING (ID, JOB_ID, VALUE, PROCESSED) values (?,?,?,?)",
  				new BatchPreparedStatementSetter() {
  
  					public int getBatchSize() {
  						return items.size();
  					}
  
  					public void setValues(PreparedStatement ps, int i) throws SQLException {
  
  						long id = incrementer.nextLongValue();
  						long jobId = stepExecution.getJobExecution().getJobId();
  
  						Assert.state(itemIterator.nextIndex() == i,
  								"Item ordering must be preserved in batch sql update");
  
  						byte[] blob = SerializationUtils.serialize((Serializable) itemIterator.next());
  
  						ps.setLong(1, id);
  						ps.setLong(2, jobId);
  						ps.setBytes(3, blob);
  						ps.setString(4, NEW);
 					}
 				});
 
 	}
 
 	/*
 	 * (non-Javadoc)
 	 * 
 	 * @see
 	 * org.springframework.batch.core.domain.StepListener#afterStep(StepExecution
 	 * )
 	 */
 	public ExitStatus afterStep(StepExecution stepExecution) {
 		return null;
 	}
 
 	/*
 	 * (non-Javadoc)
 	 * 
 	 * @seeorg.springframework.batch.core.domain.StepListener#beforeStep(org.
 	 * springframework.batch.core.domain.StepExecution)
 	 */
 	public void beforeStep(StepExecution stepExecution) {
 		this.stepExecution = stepExecution;
 	}
 
 }