/*
    * Copyright 2006-2013 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.item.database;
  
  import java.sql.SQLException;
  import java.util.List;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.springframework.batch.item.ItemWriter;
  import org.springframework.beans.factory.InitializingBean;
  import org.springframework.dao.EmptyResultDataAccessException;
  import org.springframework.dao.InvalidDataAccessResourceUsageException;
  import org.springframework.orm.ibatis.SqlMapClientCallback;
  import org.springframework.orm.ibatis.SqlMapClientTemplate;
  import org.springframework.util.Assert;
  
  import com.ibatis.sqlmap.client.SqlMapClient;
  import com.ibatis.sqlmap.client.SqlMapExecutor;
  import com.ibatis.sqlmap.engine.execution.BatchException;
  import com.ibatis.sqlmap.engine.execution.BatchResult;
  
  /**
   * {@link ItemWriter} that uses the batching features from
   * SqlMapClientTemplate to execute a batch of statements for all items
   * provided.<br/>
   *
   * The user must provide an iBATIS statement id that points to the SQL statement defined
   * in the iBATIS SqlMap configuration.<br/>
   *
   * It is expected that {@link #write(List)} is called inside a transaction.<br/>
   *
   * The writer is thread safe after its properties are set (normal singleton
   * behavior), so it can be used to write in multiple concurrent transactions.
   *
   * @author Thomas Risberg
   * @since 2.0
   */
  public class IbatisBatchItemWriter<T> implements ItemWriter<T>, InitializingBean {
  
  	protected static final Log logger = LogFactory.getLog(IbatisBatchItemWriter.class);
  
  	private SqlMapClientTemplate sqlMapClientTemplate;
  
  	private String statementId;
  
  	private boolean assertUpdates = true;
  
  	/**
  	 * Public setter for the flag that determines whether an assertion is made
  	 * that all items cause at least one row to be updated.
  	 *
  	 * @param assertUpdates the flag to set. Defaults to true;
  	 */
  	public void setAssertUpdates(boolean assertUpdates) {
  		this.assertUpdates = assertUpdates;
  	}
  
  	/**
  	 * Public setter for {@link SqlMapClient} for injection purposes.
  	 *
  	 * @param sqlMapClient the SqlMapClient
  	 */
  	public void setSqlMapClient(SqlMapClient sqlMapClient) {
  		if (sqlMapClientTemplate == null) {
  			this.sqlMapClientTemplate = new SqlMapClientTemplate(sqlMapClient);
  		}
  	}
  
  	/**
  	 * Public setter for the SqlMapClientTemplate.
  	 *
  	 * @param sqlMapClientTemplate the SqlMapClientTemplate
  	 */
  	public void setSqlMapClientTemplate(SqlMapClientTemplate sqlMapClientTemplate) {
  		this.sqlMapClientTemplate = sqlMapClientTemplate;
  	}
  
  	/**
  	 * Public setter for the statement id identifying the statement in the SqlMap
  	 * configuration file.
  	 *
  	 * @param statementId the id for the statement
  	 */
  	public void setStatementId(String statementId) {
  		this.statementId = statementId;
 	}
 
 	/**
 	 * Check mandatory properties - there must be an SqlMapClient and a statementId.
 	 */
 	@Override
 	public void afterPropertiesSet() {
 		Assert.notNull(sqlMapClientTemplate, "A SqlMapClient or a SqlMapClientTemplate is required.");
 		Assert.notNull(statementId, "A statementId is required.");
 	}
 
 	/* (non-Javadoc)
 	 * @see org.springframework.batch.item.ItemWriter#write(java.util.List)
 	 */
 	@Override
 	public void write(final List<? extends T> items) {
 
 		if (!items.isEmpty()) {
 
 			if (logger.isDebugEnabled()) {
 				logger.debug("Executing batch with " + items.size() + " items.");
 			}
 
 			@SuppressWarnings("unchecked")
 			List<BatchResult> results = (List<BatchResult>) sqlMapClientTemplate.execute(
 					new SqlMapClientCallback() {
 						@Override
 						public Object doInSqlMapClient(SqlMapExecutor executor)
 								throws SQLException {
 							executor.startBatch();
 							for (T item : items) {
 								executor.update(statementId, item);
 							}
 							try {
 								return executor.executeBatchDetailed();
 							} catch (BatchException e) {
 								throw e.getBatchUpdateException();
 							}
 						}
 					});
 
 			if (assertUpdates) {
 				if (results.size() != 1) {
 					throw new InvalidDataAccessResourceUsageException("Batch execution returned invalid results. " +
 							"Expected 1 but number of BatchResult objects returned was " + results.size());
 				}
 
 				int[] updateCounts = results.get(0).getUpdateCounts();
 
 				for (int i = 0; i < updateCounts.length; i++) {
 					int value = updateCounts[i];
 					if (value == 0) {
 						throw new EmptyResultDataAccessException("Item " + i + " of " + updateCounts.length
 								+ " did not update any rows: [" + items.get(i) + "]", 1);
 					}
 				}
 			}
 
 		}
 
 	}
 
 }