HHH-6073
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@ -8,7 +8,7 @@
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<xi:include href="Preface.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
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<xi:include href="Database_Access.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
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<xi:include href="Transactions.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
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<xi:include href="Data_Operations.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
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<xi:include href="Persistence_Context.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
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<xi:include href="Batch_Processing.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
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<xi:include href="Locking.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
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<xi:include href="Caching.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
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@ -8,8 +8,9 @@
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<para>
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Both the <interfacename>org.hibernate.Session</interfacename> API and
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<interfacename>javax.persistence.EntityManager</interfacename> API provide methods for working with entities.
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This chapter will explore the available operations in each.
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<interfacename>javax.persistence.EntityManager</interfacename> API represent a context for dealing with
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persistent data. This concept is called a <literal>persistence context</literal>. Persistent data has a
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state in relation to both a persistence context and the underlying database.
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</para>
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<itemizedlist>
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@ -307,4 +308,79 @@ return managed;]]>
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</section>
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</section>
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<section>
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<title>Checking persistent state</title>
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<para>
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An application can verify the state of entities and collections in relation to the persistence context.
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</para>
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<example>
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<title>Examples of verifying managed state</title>
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<programlisting><![CDATA[assert session.contains( cat );]]></programlisting>
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<programlisting><![CDATA[assert entityManager.contains( cat );]]></programlisting>
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</example>
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<example>
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<title>Examples of verifying laziness</title>
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<programlisting>
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<![CDATA[if ( Hibernate.isInitialized( customer.getAddress() ) {
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//display address if loaded
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}
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if ( Hibernate.isInitialized( customer.getOrders ) ) {
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//display orders if loaded
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}
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if (Hibernate.isPropertyInitialized(customer, "detailedBio") ) {
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//display property detailedBio if loaded
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}]]>
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</programlisting>
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<programlisting>
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<![CDATA[javax.persistence.PersistenceUnitUtil jpaUtil = entityManager.getEntityManagerFactory().getPersistenceUnitUtil();
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if ( jpaUtil.isLoaded( customer.getAddress() ) {
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//display address if loaded
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}
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if ( jpaUtil.isLoaded( customer.getOrders ) ) {
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//display orders if loaded
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}
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if (jpaUtil.isLoaded(customer, "detailedBio") ) {
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//display property detailedBio if loaded
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}]]>
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</programlisting>
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</example>
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<para>
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In JPA there is an alternative means to check laziness using the following
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<interfacename>javax.persistence.PersistenceUtil</interfacename> pattern. However, the
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<interfacename>javax.persistence.PersistenceUnitUtil</interfacename> is recommended where ever possible
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</para>
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<example>
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<title>Alternative JPA means to verify laziness</title>
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<programlisting>
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<![CDATA[javax.persistence.PersistenceUtil jpaUtil = javax.persistence.Persistence.getPersistenceUtil();
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if ( jpaUtil.isLoaded( customer.getAddress() ) {
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//display address if loaded
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}
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if ( jpaUtil.isLoaded( customer.getOrders ) ) {
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//display orders if loaded
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}
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if (jpaUtil.isLoaded(customer, "detailedBio") ) {
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//display property detailedBio if loaded
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}]]>
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</programlisting>
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</example>
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</section>
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<section>
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<title>Accessing Hibernate APIs from JPA</title>
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<para>
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JPA defines an incredibly useful method to allow applications access to the APIs of the underlying provider.
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</para>
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<example>
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<title>Usage of EntityManager.unwrap</title>
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<programlisting>
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<![CDATA[Session session = entityManager.unwrap( Session.class );
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SessionImplementor sessionImplementor = entityManager.unwrap( SessionImplementor.class );]]>
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</programlisting>
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</example>
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</section>
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</chapter>
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@ -1,7 +1,15 @@
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sessionFactory.evict(Cat.class, catId); //evict a particular Cat
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sessionFactory.getCache().containsEntity(Cat.class, catId); // is this particular Cat currently in the cache
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sessionFactory.evict(Cat.class); //evict all Cats
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sessionFactory.getCache().evictEntity(Cat.class, catId); // evict a particular Cat
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sessionFactory.evictCollection("Cat.kittens", catId); //evict a particular collection of kittens
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sessionFactory.getCache().evictEntityRegion(Cat.class); // evict all Cats
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sessionFactory.evictCollection("Cat.kittens"); //evict all kitten collections
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sessionFactory.getCache().evictEntityRegions(); // evict all entity data
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sessionFactory.getCache().containsCollection("Cat.kittens", catId); // is this particular collection currently in the cache
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sessionFactory.getCache().evictCollection("Cat.kittens", catId); // evict a particular collection of kittens
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sessionFactory.getCache().evictCollectionRegion("Cat.kittens"); // evict all kitten collections
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sessionFactory.getCache().evictCollectionRegions(); // evict all collection data
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@ -102,10 +102,10 @@
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<xi:include href="modules/architecture.xml"
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xmlns:xi="http://www.w3.org/2001/XInclude" />
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<xi:include href="modules/configuration.xml"
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<xi:include href="modules/migrated/configuration.xml"
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xmlns:xi="http://www.w3.org/2001/XInclude" />
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<xi:include href="modules/entitymanagerapi.xml"
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<xi:include href="modules/migrated/entitymanagerapi.xml"
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xmlns:xi="http://www.w3.org/2001/XInclude" />
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<xi:include href="modules/metamodel.xml"
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<xi:include href="modules/listeners.xml"
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xmlns:xi="http://www.w3.org/2001/XInclude" />
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<xi:include href="modules/batch.xml"
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<xi:include href="modules/migrated/batch.xml"
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xmlns:xi="http://www.w3.org/2001/XInclude" />
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<xi:include href="modules/query_ejbql.xml"
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