/*
    * EL4J, the Extension Library for the J2EE, adds incremental enhancements to
    * the spring framework, http://el4j.sf.net
    * Copyright (C) 2006 by ELCA Informatique SA, Av. de la Harpe 22-24,
    * 1000 Lausanne, Switzerland, http://www.elca.ch
    *
    * EL4J is published under the GNU Lesser General Public License (LGPL)
    * Version 2.1. See http://www.gnu.org/licenses/
    *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
   * GNU Lesser General Public License for more details.
   *
   * For alternative licensing, please contact info@elca.ch
   */
  package ch.elca.el4j.core.transaction;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  
  import org.springframework.transaction.interceptor.RollbackRuleAttribute;
  import org.springframework.transaction.interceptor.RuleBasedTransactionAttribute;
  import org.springframework.transaction.interceptor.TransactionAttribute;
  
  /**
   * Meta data source for transactional metadata of type
   * <b>Commons Attributes</b>.
   *
   * @svnLink $Revision: 3873 $;$Date: 2009-08-04 13:59:45 +0200 (Di, 04. Aug 2009) $;$Author: swismer $;$URL: https://el4j.svn.sourceforge.net/svnroot/el4j/branches/el4j_3_1/el4j/framework/modules/core/src/main/java/ch/elca/el4j/core/transaction/CommonsAttributesTransactionMetaDataSource.java $
   *
   * @author Martin Zeltner (MZE)
   */
  public class CommonsAttributesTransactionMetaDataSource
  	extends TransactionMetaDataSource {
  	
  	/**
  	 * Searches for one transaction attribute and adds found found rollback
  	 * rules for rule based transaction attributes.
  	 *
  	 * {@inheritDoc}
  	 */
  	@Override
  	protected Collection filterMetaData(Collection metaData) {
  		if (metaData == null || metaData.isEmpty()) {
  			return null;
  		}
  		
  		TransactionAttribute txAttribute = null;
  
  		// Check whether there is a transaction attribute.
  		for (Iterator itMetaData = metaData.iterator();
  			itMetaData.hasNext() && txAttribute == null;) {
  			Object att = itMetaData.next();
  			if (att instanceof TransactionAttribute) {
  				txAttribute = (TransactionAttribute) att;
  			}
  		}
  
  		// Check if we have a RuleBasedTransactionAttribute.
  		if (txAttribute != null
  			&& txAttribute instanceof RuleBasedTransactionAttribute) {
  			RuleBasedTransactionAttribute rbta
  				= (RuleBasedTransactionAttribute) txAttribute;
  			// We really want value: bit of a hack.
  			List<RollbackRuleAttribute> rollbackRules
  				= new ArrayList<RollbackRuleAttribute>();
  			for (Iterator itMetaData = metaData.iterator();
  				itMetaData.hasNext();) {
  				Object attribute = itMetaData.next();
  				if (attribute instanceof RollbackRuleAttribute) {
  					rollbackRules.add((RollbackRuleAttribute) attribute);
  				}
  			}
  			// Repeatedly setting this isn't elegant, but it works.
  			rbta.setRollbackRules(rollbackRules);
  			
  			// Finalize the rollback rule behavior.
  			finalizeRollbackBehavior(rbta);
  		}
  		
  		return txAttribute == null ? Collections.EMPTY_SET
  			: Collections.singleton(txAttribute);
  	}
  }