Enterprise JavaBeans 3.1, 6th Edition

Interacting with an EntityManager

Now that you have learned how to deploy and obtain a reference to an entity manager, you are ready to learn the semantics of interacting with it. The EntityManager API has methods to insert and remove entities from a database as well as merge updates from detached entity instances. There is also a rich query API that you can access by creating query objects from certain EntityManager methods:

package javax.persistence; import java.util.Map; import javax.persistence.metamodel.Metamodel; import javax.persistence.criteria.CriteriaBuilder; import javax.persistence.criteria.CriteriaQuery; public interface EntityManager { public void persist(Object entity); public <T> T merge(T entity); public void remove(Object entity); public <T> T find(Class<T> entityClass, Object primaryKey); public <T> T find(Class<T> entityClass, Object primaryKey, Map<String, Object> properties); public <T> T find(Class<T> entityClass, Object primaryKey, LockModeType lockMode); public <T> T find(Class<T> entityClass, Object primaryKey, LockModeType lockMode, Map<String, Object> properties); public <T> T getReference(Class<T> entityClass, Object primaryKey); public void flush(); public void setFlushMode(FlushModeType flushMode); public FlushModeType getFlushMode(); public void lock(Object entity, LockModeType lockMode); public void lock(Object entity, LockModeType lockMode, Map<String, Object> properties); public void refresh(Object entity); public void refresh(Object entity, Map<String, ...