org.hibernate.StatelessSession Maven / Gradle / Ivy
Show all versions of beangle-hibernate-core Show documentation
/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* License: GNU Lesser General Public License (LGPL), version 2.1 or later.
* See the lgpl.txt file in the root directory or .
*/
package org.hibernate;
import jakarta.persistence.EntityGraph;
import org.hibernate.graph.GraphSemantic;
/**
* A command-oriented API often used for performing bulk operations against
* the database. A stateless session has no persistence context, and always
* works directly with detached entity instances. When a method of this
* interface is called, any necessary interaction with the database happens
* immediately and synchronously.
*
* Viewed in opposition to {@link Session}, the {@code StatelessSession} is
* a whole competing programming model, one preferred by some developers
* for its simplicity and somewhat lower level of abstraction. But the two
* kinds of session are not enemies, and may comfortably coexist in a single
* program.
*
* A stateless session comes some with designed-in limitations:
*
* - it does not have a first-level cache,
*
- nor interact with any second-level cache,
*
- nor does it implement transactional write-behind or automatic dirty
* checking.
*
*
* Furthermore, the basic operations of a stateless session do not have
* corresponding {@linkplain jakarta.persistence.CascadeType cascade types},
* and so an operation performed via a stateless session never cascades to
* associated instances.
*
* The basic operations of a stateless session are {@link #get(Class, Object)},
* {@link #insert(Object)}, {@link #update(Object)}, {@link #delete(Object)},
* and {@link #upsert(Object)}. These operations are always performed
* synchronously, resulting in immediate access to the database. Notice that
* update is an explicit operation. There is no "flush" operation for a
* stateless session, and so modifications to entities are never automatically
* detected and made persistent.
*
* Similarly, lazy association fetching is an explicit operation. A collection
* or proxy may be fetched by calling {@link #fetch(Object)}.
*
* Stateless sessions are vulnerable to data aliasing effects, due to the
* lack of a first-level cache.
*
* On the other hand, for certain kinds of transactions, a stateless session
* may perform slightly faster than a stateful session.
*
* Certain rules applying to stateful sessions are relaxed in a stateless
* session:
*
* - it is not necessary to discard a session and its entities after an
* exception is thrown by a stateless sessions, and
*
- when an exception is thrown by a stateless session, the current
* transaction is not automatically marked for rollback.
*
*
* @author Gavin King
*/
public interface StatelessSession extends SharedSessionContract {
/**
* Close the stateless session and release the JDBC connection.
*/
void close();
/**
* Insert a record.
*
* If the entity {@code @Id} field is declared to be generated,
* for example, if it is annotated {@code @GeneratedId}, the id
* is generated and assigned to the given instance.
*
* The {@link jakarta.persistence.PostPersist} callback will be
* triggered if the operation is successful.
*
* @param entity a new transient instance
*
* @return The identifier of the inserted entity
*/
Object insert(Object entity);
/**
* Insert a record.
*
* The {@link jakarta.persistence.PostPersist} callback will be
* triggered if the operation is successful.
*
* @param entityName The entityName for the entity to be inserted
* @param entity a new transient instance
*
* @return the identifier of the instance
*/
Object insert(String entityName, Object entity);
/**
* Update a record.
*
* The {@link jakarta.persistence.PostUpdate} callback will be
* triggered if the operation is successful.
*
* @param entity a detached entity instance
*/
void update(Object entity);
/**
* Update a record.
*
* The {@link jakarta.persistence.PostUpdate} callback will be
* triggered if the operation is successful.
*
* @param entityName The entityName for the entity to be updated
* @param entity a detached entity instance
*/
void update(String entityName, Object entity);
/**
* Delete a record.
*
* The {@link jakarta.persistence.PostRemove} callback will be
* triggered if the operation is successful.
*
* @param entity a detached entity instance
*/
void delete(Object entity);
/**
* Delete a record.
*
* The {@link jakarta.persistence.PostRemove} callback will be
* triggered if the operation is successful.
*
* @param entityName The entityName for the entity to be deleted
* @param entity a detached entity instance
*/
void delete(String entityName, Object entity);
/**
* Use a SQL {@code merge into} statement to perform an upsert,
* that is, to insert the record if it does not exist, or update
* it if it already exists.
*
* This method never performs id generation, and does not accept
* an entity instance with a null identifier. When id generation
* is required, use {@link #insert(Object)}.
*
* On the other hand, {@code upsert()} does accept an entity
* instance with an assigned identifier value, even if the entity
* {@code @Id} field is declared to be generated, for example, if
* it is annotated {@code @GeneratedId}. Thus, this method may be
* used to import data from an external source.
*
* @param entity a detached entity instance, or a new instance
* with an assigned identifier
* @throws TransientObjectException is the entity has a null id
*
* @since 6.3
*/
@Incubating
void upsert(Object entity);
/**
* Use a SQL {@code merge into} statement to perform an upsert.
*
* @param entityName The entityName for the entity to be merged
* @param entity a detached entity instance
* @throws TransientObjectException is the entity has a null id
*
* @since 6.3
*/
@Incubating
void upsert(String entityName, Object entity);
/**
* Retrieve a record.
*
* @param entityName The name of the entity to retrieve
* @param id The id of the entity to retrieve
*
* @return a detached entity instance
*/
Object get(String entityName, Object id);
/**
* Retrieve a record.
*
* @param entityClass The class of the entity to retrieve
* @param id The id of the entity to retrieve
*
* @return a detached entity instance
*/
T get(Class entityClass, Object id);
/**
* Retrieve a record, obtaining the specified lock mode.
*
* @param entityName The name of the entity to retrieve
* @param id The id of the entity to retrieve
* @param lockMode The lock mode to apply to the entity
*
* @return a detached entity instance
*/
Object get(String entityName, Object id, LockMode lockMode);
/**
* Retrieve a record, obtaining the specified lock mode.
*
* @param entityClass The class of the entity to retrieve
* @param id The id of the entity to retrieve
* @param lockMode The lock mode to apply to the entity
*
* @return a detached entity instance
*/
T get(Class entityClass, Object id, LockMode lockMode);
/**
* Retrieve a record, fetching associations specified by the
* given {@link EntityGraph}.
*
* @param graph The {@link EntityGraph}
* @param graphSemantic a {@link GraphSemantic} specifying
* how the graph should be interpreted
* @param id The id of the entity to retrieve
*
* @return a detached entity instance
*
* @since 6.3
*/
T get(EntityGraph graph, GraphSemantic graphSemantic, Object id);
/**
* Retrieve a record, fetching associations specified by the
* given {@link EntityGraph}, and obtaining the specified
* lock mode.
*
* @param graph The {@link EntityGraph}
* @param graphSemantic a {@link GraphSemantic} specifying
* how the graph should be interpreted
* @param id The id of the entity to retrieve
* @param lockMode The lock mode to apply to the entity
*
* @return a detached entity instance
*
* @since 6.3
*/
T get(EntityGraph graph, GraphSemantic graphSemantic, Object id, LockMode lockMode);
/**
* Refresh the entity instance state from the database.
*
* @param entity The entity to be refreshed.
*/
void refresh(Object entity);
/**
* Refresh the entity instance state from the database.
*
* @param entityName The entityName for the entity to be refreshed.
* @param entity The entity to be refreshed.
*/
void refresh(String entityName, Object entity);
/**
* Refresh the entity instance state from the database.
*
* @param entity The entity to be refreshed.
* @param lockMode The LockMode to be applied.
*/
void refresh(Object entity, LockMode lockMode);
/**
* Refresh the entity instance state from the database.
*
* @param entityName The entityName for the entity to be refreshed.
* @param entity The entity to be refreshed.
* @param lockMode The LockMode to be applied.
*/
void refresh(String entityName, Object entity, LockMode lockMode);
/**
* Fetch an association or collection that's configured for lazy loading.
*
* Book book = session.get(Book.class, isbn); // book is immediately detached
* session.fetch(book.getAuthors()); // fetch the associated authors
* book.getAuthors().forEach(author -> ... ); // iterate the collection
*
*
* Warning: this operation in a stateless session is quite sensitive
* to data aliasing effects and should be used with great care. It's
* usually better to fetch associations using eager join fetching.
*
* @param association a lazy-loaded association
*
* @see org.hibernate.Hibernate#initialize(Object)
*
* @since 6.0
*/
void fetch(Object association);
/**
* Return the identifier value of the given entity, which may be detached.
*
* @param entity a persistent instance associated with this session
*
* @return the identifier
*
* @since 6.6
*/
Object getIdentifier(Object entity);
}