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/*
* SPDX-License-Identifier: Apache-2.0
* Copyright Red Hat Inc. and Hibernate Authors
*/
package org.hibernate;
import jakarta.persistence.EntityGraph;
import org.hibernate.graph.GraphSemantic;
import java.util.List;
/**
* 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 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.
*
*
* Since version 7, the configuration property
* {@value org.hibernate.cfg.BatchSettings#STATEMENT_BATCH_SIZE} has no effect
* on a stateless session. Automatic batching may be enabled by explicitly
* {@linkplain #setJdbcBatchSize setting the batch size}. However, automatic
* batching has the side effect of delaying execution of the batched operation,
* thus undermining the synchronous nature of operations performed through a
* stateless session. A preferred approach is to explicitly batch operations via
* {@link #insertMultiple}, {@link #updateMultiple}, or {@link #deleteMultiple}.
*
* Since version 7, a stateless session makes use of the second-level cache by
* default. To bypass the second-level cache, call {@link #setCacheMode(CacheMode)},
* passing {@link CacheMode#IGNORE}, or set the configuration properties
* {@value org.hibernate.cfg.CacheSettings#JAKARTA_SHARED_CACHE_RETRIEVE_MODE}
* and {@value org.hibernate.cfg.CacheSettings#JAKARTA_SHARED_CACHE_STORE_MODE}
* to {@code BYPASS}.
*
* @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 @GeneratedValue}, 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 multiple records.
*
* @param entities a list of transient instances to be inserted
*
* @since 7.0
*/
@Incubating
void insertMultiple(List entities);
/**
* 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 multiple records.
*
* @param entities a list of detached instances to be updated
*
* @since 7.0
*/
@Incubating
void updateMultiple(List entities);
/**
* 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 multiple records.
*
* @param entities a list of detached instances to be deleted
*
* @since 7.0
*/
@Incubating
void deleteMultiple(List entities);
/**
* 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 @GeneratedValue}. 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);
/**
* Perform an upsert, that is, to insert the record if it does
* not exist, or update the record if it already exists, for
* each given record.
*
* @param entities a list of detached instances and new
* instances with assigned identifiers
*
* @since 7.0
*/
@Incubating
void upsertMultiple(List entities);
/**
* 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);
/**
* Retrieve multiple rows, returning entity instances in a
* list where the position of an instance in the list matches
* the position of its identifier in the given array, and the
* list contains a null value if there is no persistent
* instance matching a given identifier.
*
* @param entityClass The class of the entity to retrieve
* @param ids The ids of the entities to retrieve
* @return an ordered list of detached entity instances, with
* null elements representing missing entities
* @since 7.0
*/
List getMultiple(Class entityClass, List