@Christian That was the missing piece... Thank you very much! Best regards, Jens
Gesendet: Dienstag, 18. April 2017 um 10:10 Uhr Von: "Christian Schneider" <[email protected]> An: [email protected] Betreff: Re: Updating entities with Aries JPA in Declarative Services Transaction type JTA means that you need a JTA transaction instead of a local transaction on the em. In both cases it is necessary to be in a transaction when you do changes to the database. The JPATemplate allows to transparently begin and commit the transaction. It also demarcates the lifecycle of the em. So outside the outermost JPATemplate execution the em is closed and your entities are detached. Your code without a transaction might work but rather as a side effect of persistence manager caching. For example hibernate does not directly write to the database when you change properties. So simply changing the properties might work outside the transaction. Still I would not recommend it as you never know when hibernate decides to write to the db. Christian On 18.04.2017 08:59, Jens Offenbach wrote: > Hallo, > I have got a question regarding updates of JPA entities using Aries JPA with > Declarative Services (DS). Hopefully, someone can help me. > > Let's assume we have the Task entity from the example here: > https://github.com/apache/aries/blob/trunk/jpa/examples/tasklist-model/src/main/java/org/apache/aries/jpa/example/tasklist/model/Task.java > > When e.g. the fields "title" and "description" must be updated, is it > mandatory to do it via JpaTemplate within a transaction like this: > > jpa.tx(em -> { > task.setDescription("New description"); > task.setTitle("New title"); > em.flush(); > }); > > or can safely be done without any transaction like this: > > task.setDescription("New description"); > task.setTitle("New title"); > > I would say, it can be done directly without any transactions on > application-level because transaction-type is "JTA" and not "RESOURCE_LOCAL". > > persistence.xml: > <?xml version="1.0" encoding="UTF-8"?> > <persistence xmlns="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[http://java.sun.com/xml/ns/persistence] > http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd[http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd]"; > version="2.0"> > <persistence-unit name="treedb" transaction-type="JTA"> > > <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider> > <!-- Only used when transaction-type=JTA --> > <jta-data-source>osgi:service/javax.sql.DataSource/(osgi.jndi.service.name=jdbc/treedb)</jta-data-source> > <!-- Only used when transaction-type=RESOURCE_LOCAL --> > <non-jta-data-source>osgi:service/javax.sql.DataSource/(osgi.jndi.service.name=jdbc/treedb)</non-jta-data-source> > > <class>...</class> > <exclude-unlisted-classes>true</exclude-unlisted-classes> > > <properties> > <property name="eclipselink.target-database" > value="org.eclipse.persistence.platform.database.H2Platform" /> > > <property name="eclipselink.weaving" value = "static"/> > <property name="eclipselink.weaving.internal" value="true"/> > <property name="eclipselink.weaving.lazy" value="true" /> > <property name="eclipselink.weaving.changetracking" value="true" /> > <property name="eclipselink.weaving.fetchgroups" value="true" /> > <property name="eclipselink.weaving.eager" value="false" /> > > <property name="eclipselink.ddl-generation" value="create-tables" /> > <property name="eclipselink.ddl-generation.output-mode" value="database" /> > <property name="eclipselink.logging.level" value="FINEST" /> > </properties> > </persistence-unit> > </persistence> > > Thank you very much. > > Regards, > Jens -- Christian Schneider http://www.liquid-reality.de[http://www.liquid-reality.de] Open Source Architect http://www.talend.com[http://www.talend.com]
