Interface Session
- All Superinterfaces:
AutoCloseable
,EntityManager
,QueryProducer
,Serializable
,SharedSessionContract
- All Known Subinterfaces:
EventSource
,SessionImplementor
- All Known Implementing Classes:
AbstractDelegateSessionImplementor
,SessionDelegatorBaseImpl
,SessionImpl
,SessionLazyDelegator
,ToOneDelegateSessionImplementor
The lifecycle of a Session
is bounded by the beginning and end of the logical
transaction. But a long logical transaction might span several database transactions.
The primary purpose of the Session
is to offer create, read, and delete
operations for instances of mapped entity classes. An instance may be in one of three
states with respect to a given open session:
- transient: never persistent, and not associated with the
Session
, - persistent: currently associated with the
Session
, or - detached: previously persistent, but not currently associated with the
Session
.
At any given time, an instance may be associated with at most one open session.
Any instance returned by get(Class, Object)
, find(Class, Object)
,
or by a query is persistent. A persistent instance might hold references to other
entity instances, and sometimes these references are proxied by an
intermediate object. When an associated entity has not yet been fetched from the
database, references to the unfetched entity are represented by uninitialized
proxies. The state of an unfetched entity is automatically fetched from the
database when a method of its proxy is invoked, if and only if the proxy is
associated with an open session. Otherwise, getReference(Object)
may be
used to trade a proxy belonging to a closed session for a new proxy associated
with the current session.
A transient instance may be made persistent by calling persist(Object)
.
A persistent instance may be made detached by calling detach(Object)
.
A persistent instance may be marked for removal, and eventually made transient, by
calling remove(Object)
.
Persistent instances are held in a managed state by the persistence context. Any
change to the state of a persistent instance is automatically detected and eventually
flushed to the database. This process of automatic change detection is called
dirty checking and can be expensive in some circumstances. Dirty checking
may be disabled by marking an entity as read-only using
setReadOnly(Object, boolean)
or simply by evicting
it from the persistence context. A session may be set to load entities as read-only
by default, or this may be controlled at the
query level.
The state of a transient or detached instance may be made persistent by copying it to
a persistent instance using merge(Object)
. All older operations which moved a
detached instance to the persistent state are now deprecated, and clients should now
migrate to the use of merge()
.
The persistent state of a managed entity may be refreshed from the database, discarding
all modifications to the object held in memory, by calling refresh(Object)
.
From time to time, a flush operation is
triggered, and the session synchronizes state held in memory with persistent state
held in the database by executing SQL insert
, update
, and delete
statements. Note that SQL statements are often not executed synchronously by the methods
of the Session
interface. If synchronous execution of SQL is desired, the
StatelessSession
allows this.
Each managed instance has an associated LockMode
. By default, the session
obtains only LockMode.READ
on an entity instance it reads from the database
and LockMode.WRITE
on an entity instance it writes to the database. This
behavior is appropriate for programs which use optimistic locking.
- A different lock level may be obtained by explicitly specifying the mode using
get(Class, Object, LockMode)
,EntityManager.find(Class, Object, LockModeType)
,refresh(Object, LockMode)
,EntityManager.refresh(Object, LockModeType)
, orSelectionQuery.setLockMode(LockModeType)
. - The lock level of a managed instance already held by the session may be upgraded
to a more restrictive lock level by calling
lock(Object, LockMode)
orEntityManager.lock(Object, LockModeType)
.
A persistence context holds hard references to all its entities and prevents them
from being garbage collected. Therefore, a Session
is a short-lived object,
and must be discarded as soon as a logical transaction ends. In extreme cases,
clear()
and detach(Object)
may be used to control memory usage.
However, for processes which read many entities, a StatelessSession
should
be used.
A session might be associated with a container-managed JTA transaction, or it might be
in control of its own resource-local database transaction. In the case of a
resource-local transaction, the client must demarcate the beginning and end of the
transaction using a Transaction
. A typical resource-local transaction should
use the following idiom:
Session session = factory.openSession(); Transaction tx = null; try { tx = session.beginTransaction(); //do some work ... tx.commit(); } catch (Exception e) { if (tx!=null) tx.rollback(); throw e; } finally { session.close(); }
It's crucially important to appreciate the following restrictions and why they exist:
- If the
Session
throws an exception, the current transaction must be rolled back and the session must be discarded. The internal state of theSession
cannot be expected to be consistent with the database after the exception occurs. - At the end of a logical transaction, the session must be explicitly destroyed, so that all JDBC resources may be released.
- A
Session
is never thread-safe. It contains various different sorts of fragile mutable state. Each thread or transaction must obtain its own dedicated instance from theSessionFactory
.
An easy way to be sure that session and transaction management is being done correctly is to let the factory do it:
sessionFactory.inTransaction(session -> { //do the work ... });
A session may be used to execute JDBC work using its JDBC connection and transaction:
session.doWork(connection -> { try ( PreparedStatement ps = connection.prepareStatement( " ... " ) ) { ps.execute(); } });
A Session
instance is serializable if its entities are serializable.
Every Session
is a JPA EntityManager
. Furthermore, when Hibernate is
acting as the JPA persistence provider, the method EntityManager.unwrap(Class)
may be used to obtain the underlying Session
.
Hibernate, unlike JPA, allows a persistence unit where an entity class is mapped multiple
times, with different entity names, usually to different tables. In this case, the session
needs a way to identify the entity name of a given instance of the entity class. Therefore,
some operations of this interface, including operations inherited from EntityManager
,
are overloaded with a form that accepts an explicit entity name along with the instance. An
alternative solution to this problem is to provide an EntityNameResolver
.
- See Also:
-
Method Summary
Modifier and TypeMethodDescriptionvoid
addEventListeners
(SessionEventListener... listeners) Add one or more listeners to the Session<T> IdentifierLoadAccess<T>
Create anIdentifierLoadAccess
instance to retrieve an instance of the given entity type by its primary key.<T> IdentifierLoadAccess<T>
Create anIdentifierLoadAccess
instance to retrieve an instance of the named entity type by its primary key.<T> MultiIdentifierLoadAccess<T>
byMultipleIds
(Class<T> entityClass) Create aMultiIdentifierLoadAccess
instance to retrieve multiple instances of the given entity type by their primary key values, using batching.<T> MultiIdentifierLoadAccess<T>
byMultipleIds
(String entityName) Create aMultiIdentifierLoadAccess
instance to retrieve multiple instances of the named entity type by their primary key values, using batching.<T> NaturalIdMultiLoadAccess<T>
byMultipleNaturalId
(Class<T> entityClass) Create aMultiIdentifierLoadAccess
instance to retrieve multiple instances of the given entity type by their by natural id values, using batching.<T> NaturalIdMultiLoadAccess<T>
byMultipleNaturalId
(String entityName) Create aMultiIdentifierLoadAccess
instance to retrieve multiple instances of the named entity type by their by natural id values, using batching.<T> NaturalIdLoadAccess<T>
byNaturalId
(Class<T> entityClass) Create aNaturalIdLoadAccess
instance to retrieve an instance of the given entity type by its natural id, which may be a composite natural id.<T> NaturalIdLoadAccess<T>
byNaturalId
(String entityName) Create aNaturalIdLoadAccess
instance to retrieve an instance of the named entity type by its natural id, which may be a composite natural id.<T> SimpleNaturalIdLoadAccess<T>
bySimpleNaturalId
(Class<T> entityClass) Create aSimpleNaturalIdLoadAccess
instance to retrieve an instance of the given entity type by its natural id, which must be a simple (non-composite) value.<T> SimpleNaturalIdLoadAccess<T>
bySimpleNaturalId
(String entityName) Create aSimpleNaturalIdLoadAccess
instance to retrieve an instance of the named entity type by its natural id, which must be a simple (non-composite) value.void
Cancel the execution of the current query.void
clear()
Completely clear the session.boolean
Determine if the given entity is associated with this session.<T> RootGraph<T>
createEntityGraph
(Class<T> rootType) Create a new mutableEntityGraph
with only a root node.RootGraph<?>
createEntityGraph
(String graphName) Create a new mutable copy of the namedEntityGraph
, or returnnull
if there is no graph with the given name.createNamedQuery
(String name) Deprecated.<R> Query<R>
createNamedQuery
(String name, Class<R> resultClass) Create a typedQuery
instance for the given named query.createQuery
(CriteriaDelete deleteQuery) Deprecated.<R> Query<R>
createQuery
(CriteriaQuery<R> criteriaQuery) Create aQuery
for the given JPACriteriaQuery
.createQuery
(CriteriaUpdate updateQuery) Deprecated.<R> Query<R>
createQuery
(TypedQueryReference<R> typedQueryReference) Create a typedQuery
instance for the given typed query reference.createQuery
(String queryString) Deprecated.<R> Query<R>
createQuery
(String queryString, Class<R> resultClass) Create a typedQuery
instance for the given HQL query string and given query result type.void
Remove this instance from the session cache.void
disableFetchProfile
(String name) Disable thefetch profile
with the given name in this session.void
enableFetchProfile
(String name) Enable thefetch profile
with the given name in this session.void
Remove this instance from the session cache.<T> T
Return the persistent instance of the given entity class with the given identifier, or null if there is no such persistent instance.<T> T
Return the persistent instance of the given entity class with the given identifier, or null if there is no such persistent instance.<T> T
find
(Class<T> entityType, Object id, LockOptions lockOptions) Return the persistent instance of the given entity class with the given identifier, or null if there is no such persistent instance.<E> List<E>
findMultiple
(Class<E> entityType, List<Object> ids, FindOption... options) Return the persistent instances of the given entity class with the given identifiers as a list.void
flush()
Force this session to flush.<T> T
Deprecated.Because the semantics of this method may change in a future release.<T> T
Deprecated.The semantics of this method may change in a future release.<T> T
get
(Class<T> entityType, Object id, LockOptions lockOptions) Deprecated.The semantics of this method may change in a future release.Deprecated.The semantics of this method may change in a future release.Deprecated.The semantics of this method may change in a future release.get
(String entityName, Object id, LockOptions lockOptions) Deprecated.The semantics of this method may change in a future release.Get the current cache mode for this session.The JPA-definedCacheRetrieveMode
.The JPA-definedCacheStoreMode
.getCurrentLockMode
(Object object) Determine the currentLockMode
of the given managed instance associated with this session.RootGraph<?>
getEntityGraph
(String graphName) Retrieve the namedEntityGraph
as an immutable graph, or returnnull
if there is no graph with the given name.<T> List<EntityGraph<? super T>>
getEntityGraphs
(Class<T> entityClass) Retrieve all namedEntityGraph
s with the given type.getEntityName
(Object object) Return the entity name for a persistent entity.int
Get the maximum batch size for batch fetching associations by id in this session.Get the current JPA flush mode for this session.Get the current flush mode for this session.getIdentifier
(Object object) Return the identifier value of the given entity associated with this session.<T> T
getReference
(Class<T> entityType, Object id) Return a reference to the persistent instance with the given class and identifier, making the assumption that the instance is still persistent in the database.getReference
(String entityName, Object id) Return a reference to the persistent instance of the given named entity with the given identifier, making the assumption that the instance is still persistent in the database.<T> T
getReference
(T object) Return a reference to the persistent instance with the same identity as the given instance, which might be detached, making the assumption that the instance is still persistent in the database.Get the session factory which created this session.Get the statistics for this session.boolean
Will entities and proxies that are loaded into this session be made read-only by default?boolean
isDirty()
Does this session contain any changes which must be synchronized with the database? In other words, would any DML operations be executed if we flushed this session?boolean
isFetchProfileEnabled
(String name) Is thefetch profile
with the given name enabled in this session?boolean
isReadOnly
(Object entityOrProxy) Is the specified entity or proxy read-only?boolean
Determine if subselect fetching is enabled in this session.void
Read the persistent state associated with the given identifier into the given transient instance.void
Obtain the specified lock level on the given managed instance associated with this session.void
lock
(Object object, LockOptions lockOptions) Obtain a lock on the given managed instance associated with this session, using the given lock options.<T> T
Copy the state of the given object onto the persistent object with the same identifier.<T> T
merge
(T object) Copy the state of the given object onto the persistent object with the same identifier.void
Make a transient instance persistent and mark it for later insertion in the database.void
Make a transient instance persistent and mark it for later insertion in the database.void
Reread the state of the given managed instance associated with this session from the underlying database.void
Reread the state of the given managed instance from the underlying database, obtaining the givenLockMode
.void
refresh
(Object object, LockOptions lockOptions) Reread the state of the given managed instance from the underlying database, obtaining the givenLockMode
.void
Mark a persistence instance associated with this session for removal from the underlying database.void
replicate
(Object object, ReplicationMode replicationMode) Deprecated.With no real replacement.void
replicate
(String entityName, Object object, ReplicationMode replicationMode) Deprecated.With no real replacement.Obtain aSession
builder with the ability to copy certain information from this session.void
setCacheMode
(CacheMode cacheMode) Set the current cache mode for this session.void
setCacheRetrieveMode
(CacheRetrieveMode cacheRetrieveMode) Enable or disable reads from the second-level cache.void
setCacheStoreMode
(CacheStoreMode cacheStoreMode) Enable or disable writes to the second-level cache.void
setDefaultReadOnly
(boolean readOnly) Change the default for entities and proxies loaded into this session from modifiable to read-only mode, or from modifiable to read-only mode.void
setFetchBatchSize
(int batchSize) Set the maximum batch size for batch fetching associations by id in this session.void
setFlushMode
(FlushModeType flushMode) Set the current JPA flush mode for this session.void
setHibernateFlushMode
(FlushMode flushMode) Set the current flush mode for this session.void
setReadOnly
(Object entityOrProxy, boolean readOnly) Set an unmodified persistent object to read-only mode, or a read-only object to modifiable mode.void
setSubselectFetchingEnabled
(boolean enabled) Enable or disable subselect fetching in this session.Methods inherited from interface jakarta.persistence.EntityManager
callWithConnection, close, contains, createNamedStoredProcedureQuery, createNativeQuery, createNativeQuery, createNativeQuery, createQuery, createStoredProcedureQuery, createStoredProcedureQuery, createStoredProcedureQuery, find, find, find, find, find, getCriteriaBuilder, getDelegate, getEntityManagerFactory, getLockMode, getMetamodel, getProperties, getTransaction, isJoinedToTransaction, isOpen, joinTransaction, lock, lock, lock, refresh, refresh, refresh, refresh, runWithConnection, setProperty, unwrap
Methods inherited from interface org.hibernate.query.QueryProducer
createMutationQuery, createMutationQuery, createMutationQuery, createMutationQuery, createMutationQuery, createNamedMutationQuery, createNamedSelectionQuery, createNamedSelectionQuery, createNativeMutationQuery, createNativeQuery, createNativeQuery, createNativeQuery, createNativeQuery, createNativeQuery, createSelectionQuery, createSelectionQuery, createSelectionQuery, getNamedNativeQuery, getNamedNativeQuery, getNamedQuery
Methods inherited from interface org.hibernate.SharedSessionContract
beginTransaction, close, createEntityGraph, createNamedStoredProcedureQuery, createStoredProcedureCall, createStoredProcedureCall, createStoredProcedureCall, createStoredProcedureQuery, createStoredProcedureQuery, createStoredProcedureQuery, disableFilter, doReturningWork, doWork, enableFilter, getCriteriaBuilder, getEnabledFilter, getFactory, getJdbcBatchSize, getNamedProcedureCall, getTenantIdentifier, getTenantIdentifierValue, getTransaction, isConnected, isJoinedToTransaction, isOpen, joinTransaction, setJdbcBatchSize
-
Method Details
-
flush
void flush()Force this session to flush. Must be called at the end of a unit of work, before the transaction is committed. Depending on the current flush mode, the session might automatically flush whenEntityTransaction.commit()
is called, and it is not necessary to call this method directly.Flushing is the process of synchronizing the underlying persistent store with persistable state held in memory.
- Specified by:
flush
in interfaceEntityManager
- Throws:
HibernateException
- if changes could not be synchronized with the database
-
setFlushMode
Set the current JPA flush mode for this session.Flushing is the process of synchronizing the underlying persistent store with persistable state held in memory. The current flush mode determines when the session is automatically flushed.
- Specified by:
setFlushMode
in interfaceEntityManager
- Parameters:
flushMode
- the newFlushModeType
- See Also:
-
setHibernateFlushMode
Set the current flush mode for this session.Flushing is the process of synchronizing the underlying persistent store with persistable state held in memory. The current flush mode determines when the session is automatically flushed.
The default flush mode is sometimes unnecessarily aggressive. For a logically "read only" session, it's reasonable to set the session's flush mode to
FlushMode.MANUAL
at the start of the session in order to avoid some unnecessary work.Note that
FlushMode
defines more options thanFlushModeType
.- Parameters:
flushMode
- the newFlushMode
-
getFlushMode
FlushModeType getFlushMode()Get the current JPA flush mode for this session.- Specified by:
getFlushMode
in interfaceEntityManager
- Returns:
- the
FlushModeType
currently in effect - See Also:
-
getHibernateFlushMode
FlushMode getHibernateFlushMode()Get the current flush mode for this session.- Returns:
- the
FlushMode
currently in effect
-
setCacheMode
Set the current cache mode for this session.The cache mode determines the manner in which this session can interact with the second level cache.
- Parameters:
cacheMode
- the new cache mode
-
getCacheMode
CacheMode getCacheMode()Get the current cache mode for this session.- Returns:
- the current cache mode
-
getCacheStoreMode
CacheStoreMode getCacheStoreMode()The JPA-definedCacheStoreMode
.- Specified by:
getCacheStoreMode
in interfaceEntityManager
- Since:
- 6.2
- See Also:
-
getCacheRetrieveMode
CacheRetrieveMode getCacheRetrieveMode()The JPA-definedCacheRetrieveMode
.- Specified by:
getCacheRetrieveMode
in interfaceEntityManager
- Since:
- 6.2
- See Also:
-
setCacheStoreMode
Enable or disable writes to the second-level cache.- Specified by:
setCacheStoreMode
in interfaceEntityManager
- Parameters:
cacheStoreMode
- a JPA-definedCacheStoreMode
- Since:
- 6.2
- See Also:
-
setCacheRetrieveMode
Enable or disable reads from the second-level cache.- Specified by:
setCacheRetrieveMode
in interfaceEntityManager
- Parameters:
cacheRetrieveMode
- a JPA-definedCacheRetrieveMode
- Since:
- 6.2
- See Also:
-
getFetchBatchSize
int getFetchBatchSize()Get the maximum batch size for batch fetching associations by id in this session.- Since:
- 6.3
-
setFetchBatchSize
void setFetchBatchSize(int batchSize) Set the maximum batch size for batch fetching associations by id in this session. Override the factory-level default controlled by the configuration property "hibernate.default_batch_fetch_size".- If
batchSize>1
, then batch fetching is enabled. - If
batchSize<0
, the batch size is inherited from the factory-level setting. - Otherwise, batch fetching is disabled.
- Parameters:
batchSize
- the maximum batch size for batch fetching- Since:
- 6.3
- See Also:
- If
-
isSubselectFetchingEnabled
boolean isSubselectFetchingEnabled()Determine if subselect fetching is enabled in this session.- Returns:
true
is subselect fetching is enabled- Since:
- 6.3
-
setSubselectFetchingEnabled
void setSubselectFetchingEnabled(boolean enabled) Enable or disable subselect fetching in this session. Override the factory-level default controlled by the configuration property "hibernate.use_subselect_fetch".- Parameters:
enabled
-true
to enable subselect fetching- Since:
- 6.3
- See Also:
-
getSessionFactory
SessionFactory getSessionFactory()Get the session factory which created this session.- Returns:
- the session factory
- See Also:
-
cancelQuery
void cancelQuery()Cancel the execution of the current query.This is the sole method on session which may be safely called from another thread.
- Throws:
HibernateException
- if there was a problem cancelling the query
-
isDirty
boolean isDirty()Does this session contain any changes which must be synchronized with the database? In other words, would any DML operations be executed if we flushed this session?- Returns:
true
if the session contains pending changes;false
otherwise.- Throws:
HibernateException
- could not perform dirtying checking
-
isDefaultReadOnly
boolean isDefaultReadOnly()Will entities and proxies that are loaded into this session be made read-only by default?To determine the read-only/modifiable setting for a particular entity or proxy use
isReadOnly(Object)
.- Returns:
true
, loaded entities/proxies will be made read-only by default;false
, loaded entities/proxies will be made modifiable by default.- See Also:
-
setDefaultReadOnly
void setDefaultReadOnly(boolean readOnly) Change the default for entities and proxies loaded into this session from modifiable to read-only mode, or from modifiable to read-only mode.Read-only entities are not dirty-checked and snapshots of persistent state are not maintained. Read-only entities can be modified, but changes are not persisted.
When a proxy is initialized, the loaded entity will have the same read-only/modifiable setting as the uninitialized proxy has, regardless of the session's current setting.
To change the read-only/modifiable setting for a particular entity or proxy that already belongs to this session use
setReadOnly(Object, boolean)
.To override this session's read-only/modifiable setting for all entities and proxies loaded by a certain
Query
useQuery.setReadOnly(boolean)
.- Parameters:
readOnly
-true
, the default for loaded entities/proxies is read-only;false
, the default for loaded entities/proxies is modifiable- See Also:
-
getIdentifier
Return the identifier value of the given entity associated with this session. An exception is thrown if the given entity instance is transient or detached in relation to this session.- Parameters:
object
- a persistent instance associated with this session- Returns:
- the identifier
- Throws:
TransientObjectException
- if the instance is transient or associated with a different session
-
contains
Determine if the given entity is associated with this session.- Parameters:
entityName
- the entity nameobject
- an instance of a persistent class- Returns:
true
if the given instance is associated with thisSession
-
detach
Remove this instance from the session cache. Changes to the instance will not be synchronized with the database. This operation cascades to associated instances if the association is mapped withCascadeType.DETACH
.- Specified by:
detach
in interfaceEntityManager
- Parameters:
object
- the managed instance to detach
-
evict
Remove this instance from the session cache. Changes to the instance will not be synchronized with the database. This operation cascades to associated instances if the association is mapped withCascadeType.DETACH
.This operation is a synonym for
detach(Object)
.- Parameters:
object
- the managed entity to evict- Throws:
NullPointerException
- if the passed object isnull
IllegalArgumentException
- if the passed object is not mapped as an entity
-
find
Return the persistent instance of the given entity class with the given identifier, or null if there is no such persistent instance. If the instance is already associated with the session, return that instance. This method never returns an uninitialized instance.The object returned by
get()
orfind()
is either an unproxied instance of the given entity class, or a fully-fetched proxy object.This operation requests
LockMode.NONE
, that is, no lock, allowing the object to be retrieved from the cache without the cost of database access. However, if it is necessary to read the state from the database, the object will be returned with the lock modeLockMode.READ
.To bypass the second-level cache, and ensure that the state of the requested instance is read directly from the database, either:
- call
EntityManager.find(Class, Object, FindOption...)
, passingCacheRetrieveMode.BYPASS
as an option, - call
find(Class, Object, LockMode)
with the explicit lock modeLockMode.READ
, or - set the cache mode to
CacheRetrieveMode.BYPASS
before calling this method.
- Specified by:
find
in interfaceEntityManager
- Parameters:
entityType
- the entity typeid
- an identifier- Returns:
- a fully-fetched persistent instance or null
- API Note:
- This operation is very similar to
get(Class, Object)
.
- call
-
find
Return the persistent instance of the given entity class with the given identifier, or null if there is no such persistent instance. If the instance is already associated with the session, return that instance. This method never returns an uninitialized instance. Obtain the specified lock mode if the instance exists.Convenient form of
find(Class, Object, LockOptions)
.- Parameters:
entityType
- the entity typeid
- an identifierlockMode
- the lock mode- Returns:
- a fully-fetched persistent instance or null
- Since:
- 7.0
- See Also:
-
find
Return the persistent instance of the given entity class with the given identifier, or null if there is no such persistent instance. If the instance is already associated with the session, return that instance. This method never returns an uninitialized instance. Obtain the specified lock mode if the instance exists.- Parameters:
entityType
- the entity typeid
- an identifierlockOptions
- the lock mode- Returns:
- a fully-fetched persistent instance or null
- Since:
- 7.0
-
findMultiple
Return the persistent instances of the given entity class with the given identifiers as a list. The position of an instance in the returned list matches the position of its identifier in the given list of identifiers, and the returned list contains a null value if there is no persistent instance matching a given identifier. If an instance is already associated with the session, that instance is returned. This method never returns an uninitialized instance.Every object returned by
findMultiple()
is either an unproxied instance of the given entity class, or a fully-fetched proxy object.This method accepts
BatchSize
as an option, allowing control over the number of records retrieved in a single database request. The performance impact of setting a batch size depends on whether a SQL array may be used to pass the list of identifiers to the database:- for databases which support standard SQL arrays, a smaller batch size might be extremely inefficient compared to a very large batch size or no batching at all, but
- on the other hand, for databases with no SQL array type, a large batch size results in long SQL statements with many JDBC parameters.
For more advanced cases, use
byMultipleIds(Class)
, which returns an instance ofMultiIdentifierLoadAccess
.- Parameters:
entityType
- the entity typeids
- the list of identifiersoptions
- options, if any- Returns:
- an ordered list of persistent instances, with null elements representing missing entities, whose positions in the list match the positions of their ids in the given list of identifiers
- Since:
- 7.0
- See Also:
-
load
Read the persistent state associated with the given identifier into the given transient instance.- Parameters:
object
- a transient instance of an entity classid
- an identifier
-
replicate
Deprecated.With no real replacement. For some use cases tryStatelessSession.upsert(Object)
.Persist the state of the given detached instance, reusing the current identifier value. This operation cascades to associated instances if the association is mapped withCascadeType.REPLICATE
.- Parameters:
object
- a detached instance of a persistent classreplicationMode
- the replication mode to use
-
replicate
@Deprecated(since="6.0") void replicate(String entityName, Object object, ReplicationMode replicationMode) Deprecated.With no real replacement. For some use cases tryStatelessSession.upsert(Object)
.Persist the state of the given detached instance, reusing the current identifier value. This operation cascades to associated instances if the association is mapped withCascadeType.REPLICATE
.- Parameters:
entityName
- the entity nameobject
- a detached instance of a persistent classreplicationMode
- the replication mode to use
-
merge
<T> T merge(T object) Copy the state of the given object onto the persistent object with the same identifier. If there is no persistent instance currently associated with the session, it will be loaded. Return the persistent instance. If the given instance is unsaved, save a copy and return it as a newly persistent instance. The given instance does not become associated with the session. This operation cascades to associated instances if the association is mapped withCascadeType.MERGE
.- Specified by:
merge
in interfaceEntityManager
- Parameters:
object
- a detached instance with state to be copied- Returns:
- an updated persistent instance
-
merge
Copy the state of the given object onto the persistent object with the same identifier. If there is no persistent instance currently associated with the session, it will be loaded. Return the persistent instance. If the given instance is unsaved, save a copy and return it as a newly persistent instance. The given instance does not become associated with the session. This operation cascades to associated instances if the association is mapped withCascadeType.MERGE
.- Parameters:
entityName
- the entity nameobject
- a detached instance with state to be copied- Returns:
- an updated persistent instance
-
persist
Make a transient instance persistent and mark it for later insertion in the database. This operation cascades to associated instances if the association is mapped withCascadeType.PERSIST
.For an entity with a generated id,
persist()
ultimately results in generation of an identifier for the given instance. But this may happen asynchronously, when the session is flushed, depending on the identifier generation strategy.- Specified by:
persist
in interfaceEntityManager
- Parameters:
object
- a transient instance to be made persistent
-
persist
Make a transient instance persistent and mark it for later insertion in the database. This operation cascades to associated instances if the association is mapped withCascadeType.PERSIST
.For entities with a
generated id
,persist()
ultimately results in generation of an identifier for the given instance. But this may happen asynchronously, when the session is flushed, depending on the identifier generation strategy.- Parameters:
entityName
- the entity nameobject
- a transient instance to be made persistent
-
lock
Obtain the specified lock level on the given managed instance associated with this session. This operation may be used to:- perform a version check on an entity read from the second-level cache
by requesting
LockMode.READ
, - schedule a version check at transaction commit by requesting
LockMode.OPTIMISTIC
, - schedule a version increment at transaction commit by requesting
LockMode.OPTIMISTIC_FORCE_INCREMENT
- upgrade to a pessimistic lock with
LockMode.PESSIMISTIC_READ
orLockMode.PESSIMISTIC_WRITE
, or - immediately increment the version of the given instance by requesting
LockMode.PESSIMISTIC_FORCE_INCREMENT
.
If the requested lock mode is already held on the given entity, this operation has no effect.
This operation cascades to associated instances if the association is mapped with
CascadeType.LOCK
.The modes
LockMode.WRITE
andLockMode.UPGRADE_SKIPLOCKED
are not legal arguments tolock()
.- Parameters:
object
- a persistent instance associated with this sessionlockMode
- the lock level
- perform a version check on an entity read from the second-level cache
by requesting
-
lock
Obtain a lock on the given managed instance associated with this session, using the given lock options.This operation cascades to associated instances if the association is mapped with
CascadeType.LOCK
.- Parameters:
object
- a persistent instance associated with this sessionlockOptions
- the lock options- Since:
- 6.2
-
refresh
Reread the state of the given managed instance associated with this session from the underlying database. This may be useful:- when a database trigger alters the object state upon insert or update,
- after executing any HQL update or delete statement,
- after executing a native SQL statement, or
- after inserting a
Blob
orClob
.
This operation cascades to associated instances if the association is mapped with
CascadeType.REFRESH
.This operation requests
LockMode.READ
. To obtain a stronger lock, callrefresh(Object, LockMode)
.- Specified by:
refresh
in interfaceEntityManager
- Parameters:
object
- a persistent instance associated with this session
-
refresh
Reread the state of the given managed instance from the underlying database, obtaining the givenLockMode
.Convenient form of
refresh(Object, LockOptions)
- Parameters:
object
- a persistent instance associated with this sessionlockMode
- the lock mode to use- See Also:
-
refresh
Reread the state of the given managed instance from the underlying database, obtaining the givenLockMode
.- Parameters:
object
- a persistent instance associated with this sessionlockOptions
- contains the lock mode to use
-
remove
Mark a persistence instance associated with this session for removal from the underlying database. Ths operation cascades to associated instances if the association is mappedCascadeType.REMOVE
.Except when operating in fully JPA-compliant mode, this operation does, contrary to the JPA specification, accept a detached entity instance.
- Specified by:
remove
in interfaceEntityManager
- Parameters:
object
- the managed persistent instance to remove, or a detached instance unless operating in fully JPA-compliant mode
-
getCurrentLockMode
Determine the currentLockMode
of the given managed instance associated with this session.- Parameters:
object
- a persistent instance associated with this session- Returns:
- the current lock mode
-
clear
void clear()Completely clear the session. Evict all loaded instances and cancel all pending saves, updates and deletions. Do not close open iterators or instances ofScrollableResults
.- Specified by:
clear
in interfaceEntityManager
-
get
Deprecated.Because the semantics of this method may change in a future release. Usefind(Class, Object)
instead.Return the persistent instance of the given entity class with the given identifier, or null if there is no such persistent instance. If the instance is already associated with the session, return that instance. This method never returns an uninitialized instance.The object returned by
get()
orfind()
is either an unproxied instance of the given entity class, or a fully-fetched proxy object.This operation requests
LockMode.NONE
, that is, no lock, allowing the object to be retrieved from the cache without the cost of database access. However, if it is necessary to read the state from the database, the object will be returned with the lock modeLockMode.READ
.To bypass the second-level cache, and ensure that the state is read from the database, either:
- call
get(Class, Object, LockMode)
with the explicit lock modeLockMode.READ
, or - set the cache mode to
CacheMode.IGNORE
before calling this method.
- Parameters:
entityType
- the entity typeid
- an identifier- Returns:
- a persistent instance or null
- API Note:
- This operation is very similar to
find(Class, Object)
.
- call
-
get
Deprecated.The semantics of this method may change in a future release. Usefind(Class, Object, LockMode)
instead.Return the persistent instance of the given entity class with the given identifier, or null if there is no such persistent instance. If the instance is already associated with the session, return that instance. This method never returns an uninitialized instance. Obtain the specified lock mode if the instance exists.Convenient form of
get(Class, Object, LockOptions)
.- Parameters:
entityType
- the entity typeid
- an identifierlockMode
- the lock mode- Returns:
- a persistent instance or null
- See Also:
- API Note:
- This operation is very similar to
EntityManager.find(Class, Object, LockModeType)
.
-
get
Deprecated.The semantics of this method may change in a future release. Usefind(Class, Object, LockOptions)
instead.Return the persistent instance of the given entity class with the given identifier, or null if there is no such persistent instance. If the instance is already associated with the session, return that instance. This method never returns an uninitialized instance. Obtain the specified lock mode if the instance exists.- Parameters:
entityType
- the entity typeid
- an identifierlockOptions
- the lock mode- Returns:
- a persistent instance or null
-
get
Deprecated.The semantics of this method may change in a future release.Return the persistent instance of the given named entity with the given identifier, or null if there is no such persistent instance. If the instance is already associated with the session, return that instance. This method never returns an uninitialized instance.- Parameters:
entityName
- the entity nameid
- an identifier- Returns:
- a persistent instance or null
-
get
Deprecated.The semantics of this method may change in a future release.Return the persistent instance of the given entity class with the given identifier, or null if there is no such persistent instance. If the instance is already associated with the session, return that instance. This method never returns an uninitialized instance. Obtain the specified lock mode if the instance exists.Convenient form of
get(String, Object, LockOptions)
- Parameters:
entityName
- the entity nameid
- an identifierlockMode
- the lock mode- Returns:
- a persistent instance or null
- See Also:
-
get
Deprecated.The semantics of this method may change in a future release.Return the persistent instance of the given entity class with the given identifier, or null if there is no such persistent instance. If the instance is already associated with the session, return that instance. This method never returns an uninitialized instance. Obtain the specified lock mode if the instance exists.- Parameters:
entityName
- the entity nameid
- an identifierlockOptions
- contains the lock mode- Returns:
- a persistent instance or null
-
getEntityName
Return the entity name for a persistent entity.- Parameters:
object
- a persistent entity associated with this session- Returns:
- the entity name
-
getReference
Return a reference to the persistent instance with the given class and identifier, making the assumption that the instance is still persistent in the database. This method never results in access to the underlying data store, and thus might return a proxy that is initialized on-demand, when a non-identifier method is accessed.Note that
Hibernate.createDetachedProxy(SessionFactory, Class, Object)
may be used to obtain a detached reference.It's sometimes necessary to narrow a reference returned by
getReference()
to a subtype of the given entity type. A direct Java typecast should never be used in this situation. Instead, the methodHibernate.unproxy(Object, Class)
is the recommended way to narrow the type of a proxy object. Alternatively, a new reference may be obtained by simply callinggetReference()
again, passing the subtype. Either way, the narrowed reference will usually not be identical to the original reference, when the references are compared using the==
operator.- Specified by:
getReference
in interfaceEntityManager
- Parameters:
entityType
- the entity typeid
- the identifier of a persistent instance that exists in the database- Returns:
- the persistent instance or proxy
-
getReference
Return a reference to the persistent instance of the given named entity with the given identifier, making the assumption that the instance is still persistent in the database. This method never results in access to the underlying data store, and thus might return a proxy that is initialized on-demand, when a non-identifier method is accessed.- Parameters:
entityName
- the entity nameid
- the identifier of a persistent instance that exists in the database- Returns:
- the persistent instance or proxy
-
getReference
<T> T getReference(T object) Return a reference to the persistent instance with the same identity as the given instance, which might be detached, making the assumption that the instance is still persistent in the database. This method never results in access to the underlying data store, and thus might return a proxy that is initialized on-demand, when a non-identifier method is accessed.- Specified by:
getReference
in interfaceEntityManager
- Parameters:
object
- a detached persistent instance- Returns:
- the persistent instance or proxy
- Since:
- 6.0
-
byId
Create anIdentifierLoadAccess
instance to retrieve an instance of the given entity type by its primary key.- Parameters:
entityClass
- the entity type to be retrieved- Returns:
- an instance of
IdentifierLoadAccess
for executing the lookup - Throws:
HibernateException
- If the given class does not resolve as a mapped entity
-
byId
Create anIdentifierLoadAccess
instance to retrieve an instance of the named entity type by its primary key.- Parameters:
entityName
- the entity name of the entity type to be retrieved- Returns:
- an instance of
IdentifierLoadAccess
for executing the lookup - Throws:
HibernateException
- If the given name does not resolve to a mapped entity
-
byMultipleIds
Create aMultiIdentifierLoadAccess
instance to retrieve multiple instances of the given entity type by their primary key values, using batching.- Parameters:
entityClass
- the entity type to be retrieved- Returns:
- an instance of
MultiIdentifierLoadAccess
for executing the lookup - Throws:
HibernateException
- If the given class does not resolve as a mapped entity- See Also:
-
byMultipleIds
Create aMultiIdentifierLoadAccess
instance to retrieve multiple instances of the named entity type by their primary key values, using batching.- Parameters:
entityName
- the entity name of the entity type to be retrieved- Returns:
- an instance of
MultiIdentifierLoadAccess
for executing the lookup - Throws:
HibernateException
- If the given name does not resolve to a mapped entity
-
byNaturalId
Create aNaturalIdLoadAccess
instance to retrieve an instance of the given entity type by its natural id, which may be a composite natural id. The entity must have at least one attribute annotatedNaturalId
.- Parameters:
entityClass
- the entity type to be retrieved- Returns:
- an instance of
NaturalIdLoadAccess
for executing the lookup - Throws:
HibernateException
- If the given class does not resolve as a mapped entity, or if the entity does not declare a natural id
-
byNaturalId
Create aNaturalIdLoadAccess
instance to retrieve an instance of the named entity type by its natural id, which may be a composite natural id. The entity must have at least one attribute annotatedNaturalId
.- Parameters:
entityName
- the entity name of the entity type to be retrieved- Returns:
- an instance of
NaturalIdLoadAccess
for executing the lookup - Throws:
HibernateException
- If the given name does not resolve to a mapped entity, or if the entity does not declare a natural id
-
bySimpleNaturalId
Create aSimpleNaturalIdLoadAccess
instance to retrieve an instance of the given entity type by its natural id, which must be a simple (non-composite) value. The entity must have exactly one attribute annotatedNaturalId
.- Parameters:
entityClass
- the entity type to be retrieved- Returns:
- an instance of
SimpleNaturalIdLoadAccess
for executing the lookup - Throws:
HibernateException
- If the given class does not resolve as a mapped entity, or if the entity does not declare a natural id
-
bySimpleNaturalId
Create aSimpleNaturalIdLoadAccess
instance to retrieve an instance of the named entity type by its natural id, which must be a simple (non-composite) value. The entity must have exactly one attribute annotatedNaturalId
.- Parameters:
entityName
- the entity name of the entity type to be retrieved- Returns:
- an instance of
SimpleNaturalIdLoadAccess
for executing the lookup - Throws:
HibernateException
- If the given name does not resolve to a mapped entity, or if the entity does not declare a natural id
-
byMultipleNaturalId
Create aMultiIdentifierLoadAccess
instance to retrieve multiple instances of the given entity type by their by natural id values, using batching.- Parameters:
entityClass
- the entity type to be retrieved- Returns:
- an instance of
NaturalIdMultiLoadAccess
for executing the lookup - Throws:
HibernateException
- If the given class does not resolve as a mapped entity, or if the entity does not declare a natural id
-
byMultipleNaturalId
Create aMultiIdentifierLoadAccess
instance to retrieve multiple instances of the named entity type by their by natural id values, using batching.- Parameters:
entityName
- the entity name of the entity type to be retrieved- Returns:
- an instance of
NaturalIdMultiLoadAccess
for executing the lookup - Throws:
HibernateException
- If the given name does not resolve to a mapped entity, or if the entity does not declare a natural id
-
getStatistics
SessionStatistics getStatistics()Get the statistics for this session.- Returns:
- the session statistics being collected for this session
-
isReadOnly
Is the specified entity or proxy read-only?To get the default read-only/modifiable setting used for entities and proxies that are loaded into the session use
isDefaultReadOnly()
- Parameters:
entityOrProxy
- an entity or proxy- Returns:
true
if the entity or proxy is read-only,false
if the entity or proxy is modifiable.- See Also:
-
setReadOnly
Set an unmodified persistent object to read-only mode, or a read-only object to modifiable mode. In read-only mode, no snapshot is maintained, the instance is never dirty checked, and changes are not persisted.If the entity or proxy already has the specified read-only/modifiable setting, then this method does nothing.
To set the default read-only/modifiable setting used for all entities and proxies that are loaded into the session use
setDefaultReadOnly(boolean)
.To override this session's read-only/modifiable setting for entities and proxies loaded by a
Query
useQuery.setReadOnly(boolean)
- Parameters:
entityOrProxy
- an entity or proxyreadOnly
-true
if the entity or proxy should be made read-only;false
if the entity or proxy should be made modifiable- See Also:
-
isFetchProfileEnabled
Is thefetch profile
with the given name enabled in this session?- Parameters:
name
- the name of the profile- Returns:
- True if fetch profile is enabled; false if not.
- Throws:
UnknownProfileException
- Indicates that the given name does not match any known fetch profile names- See Also:
-
enableFetchProfile
Enable thefetch profile
with the given name in this session. If the requested fetch profile is already enabled, the call has no effect.- Parameters:
name
- the name of the fetch profile to be enabled- Throws:
UnknownProfileException
- Indicates that the given name does not match any known fetch profile names- See Also:
-
disableFetchProfile
Disable thefetch profile
with the given name in this session. If the requested fetch profile is not currently enabled, the call has no effect.- Parameters:
name
- the name of the fetch profile to be disabled- Throws:
UnknownProfileException
- Indicates that the given name does not match any known fetch profile names- See Also:
-
getLobHelper
LobHelper getLobHelper()- Returns:
- an instance of
LobHelper
-
sessionWithOptions
SharedSessionBuilder sessionWithOptions()Obtain aSession
builder with the ability to copy certain information from this session.- Returns:
- the session builder
-
addEventListeners
Add one or more listeners to the Session- Parameters:
listeners
- the listener(s) to add
-
createEntityGraph
Description copied from interface:SharedSessionContract
Create a new mutableEntityGraph
with only a root node.- Specified by:
createEntityGraph
in interfaceEntityManager
- Specified by:
createEntityGraph
in interfaceSharedSessionContract
- Parameters:
rootType
- the root entity class of the graph
-
createEntityGraph
Description copied from interface:SharedSessionContract
Create a new mutable copy of the namedEntityGraph
, or returnnull
if there is no graph with the given name.- Specified by:
createEntityGraph
in interfaceEntityManager
- Specified by:
createEntityGraph
in interfaceSharedSessionContract
- Parameters:
graphName
- the name of the graph- See Also:
-
getEntityGraph
Description copied from interface:SharedSessionContract
Retrieve the namedEntityGraph
as an immutable graph, or returnnull
if there is no graph with the given name.- Specified by:
getEntityGraph
in interfaceEntityManager
- Specified by:
getEntityGraph
in interfaceSharedSessionContract
- Parameters:
graphName
- the name of the graph- See Also:
-
getEntityGraphs
Description copied from interface:SharedSessionContract
Retrieve all namedEntityGraph
s with the given type.- Specified by:
getEntityGraphs
in interfaceEntityManager
- Specified by:
getEntityGraphs
in interfaceSharedSessionContract
- See Also:
-
createQuery
Description copied from interface:QueryProducer
Create a typedQuery
instance for the given HQL query string and given query result type.- If the query has a single item in the
select
list, then the select item must be assignable to the given result type. - Otherwise, if there are multiple select items, then the
select items will be packaged into an instance of the
result type. The result type must have an appropriate
constructor with parameter types matching the select items,
or it must be one of the types
Object[]
,List
,Map
, orTuple
.
If a query has no explicit
select
list, the select list is inferred from the given query result type:- if the result type is an entity type, the query must have
exactly one root entity in the
from
clause, it must be assignable to the result type, and the inferred select list will contain just that entity, or - otherwise, the select list contains every root entity and
every non-
fetch
joined entity, and each query result will be packaged into an instance of the result type, just as specified above.
If a query has no explicit
from
clause, and the given result type is an entity type, the root entity is inferred to be the result type.Passing
Object.class
as the query result type is not recommended. In this special case, this method has the same semantics as the overloadQueryProducer.createQuery(String)
.The returned
Query
may be executed by callingQuery.getResultList()
orQuery.getSingleResult()
.- Specified by:
createQuery
in interfaceEntityManager
- Specified by:
createQuery
in interfaceQueryProducer
- Parameters:
queryString
- The HQL queryresultClass
- TheClass
object representing the query result type, which should not beObject.class
- Returns:
- The
Query
instance for manipulation and execution - See Also:
- If the query has a single item in the
-
createQuery
Description copied from interface:QueryProducer
Create a typedQuery
instance for the given typed query reference.- Specified by:
createQuery
in interfaceEntityManager
- Specified by:
createQuery
in interfaceQueryProducer
- Parameters:
typedQueryReference
- the type query reference- Returns:
- The
Query
instance for execution - See Also:
-
createQuery
Deprecated.Description copied from interface:QueryProducer
Create aQuery
instance for the given HQL query, or HQL insert, update, or delete statement.If a query has no explicit
select
list, the select list is inferred:- if there is exactly one root entity in the
from
clause, and it has no non-fetch
joins, then that root entity is the only element of the select list, or - if there is an entity with the alias
this
, then that entity is the only element of the select list, or - otherwise, the query is considered ambiguous, and this
method throws a
SemanticException
.
The query must have an explicit
from
clause, which can never be inferred.- Specified by:
createQuery
in interfaceEntityManager
- Specified by:
createQuery
in interfaceQueryProducer
- Parameters:
queryString
- The HQL query- Returns:
- The
Query
instance for manipulation and execution - See Also:
- if there is exactly one root entity in the
-
createNamedQuery
Description copied from interface:QueryProducer
Create a typedQuery
instance for the given named query. The named query might be defined in HQL or in native SQL.- Specified by:
createNamedQuery
in interfaceEntityManager
- Specified by:
createNamedQuery
in interfaceQueryProducer
- Parameters:
name
- the name of a query defined in metadataresultClass
- the type of the query result- Returns:
- The
Query
instance for manipulation and execution - See Also:
-
createNamedQuery
Deprecated.Description copied from interface:QueryProducer
Create a typedQuery
instance for the given named query. The named query might be defined in HQL or in native SQL.- Specified by:
createNamedQuery
in interfaceEntityManager
- Specified by:
createNamedQuery
in interfaceQueryProducer
- Parameters:
name
- the name of a predefined named query- Returns:
- The
Query
instance for manipulation and execution - See Also:
-
createQuery
Description copied from interface:QueryProducer
Create aQuery
for the given JPACriteriaQuery
.- Specified by:
createQuery
in interfaceEntityManager
- Specified by:
createQuery
in interfaceQueryProducer
-
createQuery
Deprecated.Create aQuery
for the given JPACriteriaDelete
.- Specified by:
createQuery
in interfaceEntityManager
- Specified by:
createQuery
in interfaceQueryProducer
-
createQuery
Deprecated.Create aQuery
for the given JPACriteriaUpdate
.- Specified by:
createQuery
in interfaceEntityManager
- Specified by:
createQuery
in interfaceQueryProducer
-
QueryProducer.createMutationQuery(CriteriaDelete)