Spring 2.0 with Toplink Essentials

Intro

Recently I joined a project working with JEE 5 and Sun Application Server a.k.a. Glassfish. The default object-relational mapping solution in Glassfish is TopLink. More spefically TopLink® Essentials (sorry, almost forgot the ®), as Oracle calls it "the official open source reference implementation". I assume they are trying to win back some market share from Hibernate.

Although by reputation a proper framework I never took the time to work with TopLink because is was closed source (and cost mon€y). Now that it opened up I decided to give it a go. And fortunately (and to be honest as expected) Spring delivers an excellent integration.

Setup

    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="url" value="xxx" />
        <property name="driverClassName" value="xxx" />
        <property name="username" value="xxx" />
        <property name="password" value="xxx" />
    </bean>

    <bean id="entityManagerFactory"
        class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.TopLinkJpaVendorAdapter">
                <property name="showSql" value="true" />
                <property name="generateDdl" value="false" />
                <property name="databasePlatform"
                    value="oracle.toplink.essentials.platform.database.oracle.OraclePlatform" />
            </bean>
        </property>
        <property name="loadTimeWeaver">
            <bean class="org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver"/>
        </property>        
    </bean>

    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory"/>
        <property name="dataSource" ref="dataSource"/>
    </bean>

    <tx:annotation-driven/>

    <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />

I also added the file persistence.xml with some TL specific settings.

    <persistence-unit name="stuf" transaction-type="RESOURCE_LOCAL">
        <provider>oracle.toplink.essentials.PersistenceProvider</provider>
        
        <class>Foo</class>
        <class>Bar</class>

        <properties>
            <property name="toplink.weaving" value="false" />
            <property name="toplink.logging.timestamp" value="false" />
            <property name="toplink.logging.thread" value="false" />
            <property name="toplink.logging.session" value="false" />
            <property name="toplink.throw.orm.exceptions" value="true" />
        </properties>
    </persistence-unit>

Snags

Id generation strategy

The database independent way of generating primary keys in JPA is using the @GeneratedValue(strategy=GenerationType.AUTO) annotation. TL's implementation expects a table named SEQUENCE to be present. Here is the script for an Oracle database.

  CREATE TABLE "SEQUENCE" 
   (	"SEQ_NAME" VARCHAR2(50 BYTE) NOT NULL ENABLE, 
	"SEQ_COUNT" NUMBER(38,0) DEFAULT 0 NOT NULL ENABLE, 
	 CONSTRAINT "SEQUENCE_PK" PRIMARY KEY ("SEQ_NAME") ENABLE
   ) ;

Note that the case of the tablename should be the default of the underlying database. So for Oracle this is uppercase, for PostgreSQL it is lowercase.

Maven dependencies

Unfortunately - but not unexpectedly mr. Elli$on - the jars are not available in the main maven repository. So we have to load it into the local repo by hand.

For my own convience I attached the jar and pom file. The maven command to install them:

mvn install:install-file -Dfile=<path-to-file> -DpomFile=<path-to-file> -DgroupId=com.oracle.toplink -DartifactId=toplink-essentials -DcreateChecksum=true

Next the following dependency can be added to the project's pom.

<dependency>
    <groupId>com.oracle.toplink</groupId>
    <artifactId>toplink-essentials</artifactId>
    <version>2.0-b58fcs</version>
</dependency>

Resources

Oracle & Spring announcement