1 Reply Latest reply on Dec 2, 2009 9:59 AM by Hans-Michael Rupp

    Persistence Context Transaction

    Hans-Michael Rupp Novice

      I am experimentig with JPA and I have difficulties to reproduce an example taken from JavaMagazin 9/09 about the ECB Pattern.
      JBoss 5.1.0 GA, MySQL 5.0



      The "boundary" (facade)

      @Stateless
      public class OrderServiceBean implements OrderService {
      
      
      
       @EJB
       DeliveryService deliveryService;
      
       @EJB
       Warehouse warehouse;
      
       @TransactionAttribute(TransactionAttributeType.REQUIRED)
       public Order order(Order newOrder) throws BillingException {
      
       Order order = warehouse.checkout(newOrder);
      
      
       deliveryService.deliver(order);
       return order;
       }
      }
      
      


      The Warehouse Bean persists the order. This works like expected:

      @Stateless
      public class WarehouseBean implements Warehouse {
      
       @PersistenceContext(unitName="ECB")
       EntityManager entityManager;
      
       @TransactionAttribute(TransactionAttributeType.MANDATORY)
       public Order checkout(Order order) {
       this.entityManager.merge(order);
       return order;
       }
      }


      However the DeliveryService modifies the order:
      @Stateless
      public class DeliveryServiceBean implements DeliveryService{
      
       @TransactionAttribute(TransactionAttributeType.MANDATORY)
       public void deliver(Order order) {
       order.setDelivered(true);
       order.setProductId(2);
       }
      }


      Since the transaction should be still running, I expect that order is still in the persistence context and that the changes made by the DeliveryService should be automatically persisted. However they never arrive in the database.

      Do I get the whole concept or persistence context wrong? Or is there some bug in my code?
      <?xml version="1.0" encoding="UTF-8"?>
      
      <!-- $Id: mysql-ds.xml 71535 2008-04-01 07:05:03Z adrian@jboss.org $ -->
      <!-- Datasource config for MySQL using 3.0.9 available from:
      http://www.mysql.com/downloads/api-jdbc-stable.html
      -->
      
      <datasources>
       <local-tx-datasource>
       <jndi-name>ECBDS</jndi-name>
       <connection-url>jdbc:mysql://localhost:3306/ecb</connection-url>
       <driver-class>com.mysql.jdbc.Driver</driver-class>
       <user-name>root</user-name>
       <password>ritak1</password>
       <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLExceptionSorter</exception-sorter-class-name>
       <!-- should only be used on drivers after 3.22.1 with "ping" support
       <valid-connection-checker-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLValidConnectionChecker</valid-connection-checker-class-name>
       -->
       <!-- sql to call when connection is created
       <new-connection-sql>some arbitrary sql</new-connection-sql>
       -->
       <!-- sql to call on an existing pooled connection when it is obtained from pool - MySQLValidConnectionChecker is preferred for newer drivers
       <check-valid-connection-sql>some arbitrary sql</check-valid-connection-sql>
       -->
      
       <!-- corresponding type-mapping in the standardjbosscmp-jdbc.xml (optional) -->
       <metadata>
       <type-mapping>mySQL</type-mapping>
       </metadata>
       </local-tx-datasource>
      </datasources>
      




      <?xml version="1.0" encoding="UTF-8"?>
      <persistence:persistence version="1.0"
       xmlns:persistence="http://java.sun.com/xml/ns/persistence"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://java.sun.com/xml/ns/persistence persistence_1_0.xsd">
       <persistence:persistence-unit name="ECB">
       <persistence:description>ECB</persistence:description>
       <persistence:jta-data-source>java:ECBDS</persistence:jta-data-source>
       <persistence:properties>
       <persistence:property name="hibernate.hbm2ddl.auto" value="create-drop" />
       <persistence:property name="dialect" value="org.hibernate.dialect.MySQLDialect" />
       <persistence:property name="hibernate.show_sql" value="true" />
       <persistence:property name="hibernate.format_sql" value="true" />
       </persistence:properties>
       </persistence:persistence-unit>
      </persistence:persistence>
      


        • 1. Re: Persistence Context Transaction
          Hans-Michael Rupp Novice

          I found the bug:

          The checkout method must return the order returned by the entity manager.

          @Stateless
          public class WarehouseBean implements Warehouse {
          
           @PersistenceContext(unitName="ECB")
           EntityManager entityManager;
          
           @TransactionAttribute(TransactionAttributeType.MANDATORY)
           public Order checkout(Order order) {
           return this.entityManager.merge(order);
           //wrong: return order
           }
          }