Package org.hibernate

Interface Session

  • All Superinterfaces:
    AutoCloseable, Closeable, EntityManager, QueryProducer, Serializable, SharedSessionContract
    All Known Subinterfaces:
    EventSource, SessionImplementor
    All Known Implementing Classes:
    AbstractDelegateSessionImplementor, SessionDelegatorBaseImpl, SessionImpl, SessionLazyDelegator, ToOneDelegateSessionImplementor

    public interface Session
    extends SharedSessionContract, EntityManager
    The main runtime interface between a Java application and Hibernate. Represents the notion of a persistence context, a set of managed entity instances associated with a logical transaction.

    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), EntityManager.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 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 the Session 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 the SessionFactory.

    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:
    SessionFactory
    • Method Detail

      • 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 when EntityTransaction.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 interface EntityManager
        Throws:
        HibernateException - if changes could not be synchronized with the database
      • setFlushMode

        void setFlushMode​(FlushModeType flushMode)
        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 interface EntityManager
        Parameters:
        flushMode - the new FlushModeType
        See Also:
        for additional options
      • setHibernateFlushMode

        void setHibernateFlushMode​(FlushMode flushMode)
        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 than FlushModeType.

        Parameters:
        flushMode - the new FlushMode
      • getHibernateFlushMode

        FlushMode getHibernateFlushMode()
        Get the current flush mode for this session.
        Returns:
        the FlushMode currently in effect
      • setCacheMode

        void setCacheMode​(CacheMode cacheMode)
        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
      • 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:
        FetchSettings.DEFAULT_BATCH_FETCH_SIZE
      • isSubselectFetchingEnabled

        boolean isSubselectFetchingEnabled()
        Determine if subselect fetching is enabled in this session.
        Returns:
        true is subselect fetching is enabled
        Since:
        6.3
      • getSessionFactory

        SessionFactory getSessionFactory()
        Get the session factory which created this session.
        Returns:
        the session factory
        See Also:
        SessionFactory
      • 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:
        isReadOnly(Object)
      • 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 use Query.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:
        setReadOnly(Object,boolean), Query.setReadOnly(boolean)
      • getIdentifier

        Object getIdentifier​(Object object)
        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

        boolean contains​(String entityName,
                         Object object)
        Determine if the given entity is associated with this session.
        Parameters:
        entityName - the entity name
        object - an instance of a persistent class
        Returns:
        true if the given instance is associated with this Session
      • detach

        void detach​(Object object)
        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 with CascadeType.DETACH.
        Specified by:
        detach in interface EntityManager
        Parameters:
        object - the managed instance to detach
      • evict

        void evict​(Object object)
        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 with CascadeType.DETACH.

        This operation is a synonym for detach(Object).

        Parameters:
        object - the managed entity to evict
        Throws:
        NullPointerException - if the passed object is null
        IllegalArgumentException - if the passed object is not mapped as an entity
      • load

        @Deprecated(since="6.0")
        <T> T load​(Class<T> theClass,
                   Object id,
                   LockOptions lockOptions)
        Return the persistent instance of the given entity class with the given identifier, obtaining the specified lock mode, assuming the instance exists.
        Parameters:
        theClass - a persistent class
        id - a valid identifier of an existing persistent instance of the class
        lockOptions - contains the lock level
        Returns:
        the persistent instance or proxy
      • load

        @Deprecated(since="6.0")
        Object load​(String entityName,
                    Object id,
                    LockOptions lockOptions)
        Return the persistent instance of the given entity class with the given identifier, obtaining the specified lock mode, assuming the instance exists.
        Parameters:
        entityName - the entity name
        id - a valid identifier of an existing persistent instance of the class
        lockOptions - contains the lock level
        Returns:
        the persistent instance or proxy
      • load

        @Deprecated(since="6.0")
        <T> T load​(Class<T> theClass,
                   Object id)
        Return the persistent instance of the given entity class with the given identifier, making the assumption that the instance exists in the database. This method might return a proxied instance that is initialized on-demand, when a non-identifier method is accessed.

        You should not use this method to determine if an instance exists in the database (use get() instead). Use this only to retrieve an instance that you assume exists, where non-existence would be an actual error.

        This operation is very similar to getReference(Class, Object).

        Parameters:
        theClass - a persistent class
        id - a valid identifier of an existing persistent instance of the class
        Returns:
        the persistent instance or proxy
      • load

        @Deprecated(since="6.0")
        Object load​(String entityName,
                    Object id)
        Return the persistent instance of the given entity class with the given identifier, making the assumption that the instance exists in the database. This method might return a proxied instance that is initialized on-demand, when a non-identifier method is accessed.

        You should not use this method to determine if an instance exists in the database (use get() instead). Use this only to retrieve an instance that you assume exists, where non-existence would be an actual error.

        Parameters:
        entityName - the entity name
        id - a valid identifier of an existing persistent instance of the class
        Returns:
        the persistent instance or proxy
      • load

        void load​(Object object,
                  Object id)
        Read the persistent state associated with the given identifier into the given transient instance.
      • replicate

        @Deprecated(since="6.0")
        void replicate​(Object object,
                       ReplicationMode replicationMode)
        Deprecated.
        With no real replacement
        Persist the state of the given detached instance, reusing the current identifier value. This operation cascades to associated instances if the association is mapped with CascadeType.REPLICATE.
        Parameters:
        object - a detached instance of a persistent class
        replicationMode - the replication mode to use
      • replicate

        @Deprecated(since="6.0")
        void replicate​(String entityName,
                       Object object,
                       ReplicationMode replicationMode)
        Deprecated.
        With no real replacement
        Persist the state of the given detached instance, reusing the current identifier value. This operation cascades to associated instances if the association is mapped with CascadeType.REPLICATE.
        Parameters:
        entityName - the entity name
        object - a detached instance of a persistent class
        replicationMode - the replication mode to use
      • save

        @Deprecated(since="6.0")
        Object save​(Object object)
        Deprecated.
        Persist the given transient instance, first assigning a generated identifier. (Or using the current value of the identifier property if the assigned generator is used.) This operation cascades to associated instances if the association is mapped with CascadeType.SAVE_UPDATE.

        This operation is very similar to persist(Object).

        Parameters:
        object - a transient instance of a persistent class
        Returns:
        the generated identifier
      • save

        @Deprecated(since="6.0")
        Object save​(String entityName,
                    Object object)
        Deprecated.
        Persist the given transient instance, first assigning a generated identifier. (Or using the current value of the identifier property if the assigned generator is used.) This operation cascades to associated instances if the association is mapped with CascadeType.SAVE_UPDATE.
        Parameters:
        entityName - the entity name
        object - a transient instance of a persistent class
        Returns:
        the generated identifier
      • update

        @Deprecated(since="6.0")
        void update​(Object object)
        Deprecated.
        Update the persistent instance with the identifier of the given detached instance. If there is a persistent instance with the same identifier, an exception is thrown. This operation cascades to associated instances if the association is mapped with CascadeType.SAVE_UPDATE.
        Parameters:
        object - a detached instance containing updated state
      • update

        @Deprecated(since="6.0")
        void update​(String entityName,
                    Object object)
        Deprecated.
        Update the persistent instance with the identifier of the given detached instance. If there is a persistent instance with the same identifier, an exception is thrown. This operation cascades to associated instances if the association is mapped with CascadeType.SAVE_UPDATE.
        Parameters:
        entityName - the entity name
        object - a detached instance containing updated state
      • 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 with CascadeType.MERGE.
        Specified by:
        merge in interface EntityManager
        Parameters:
        object - a detached instance with state to be copied
        Returns:
        an updated persistent instance
      • merge

        <T> T merge​(String entityName,
                    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 with CascadeType.MERGE.
        Parameters:
        entityName - the entity name
        object - a detached instance with state to be copied
        Returns:
        an updated persistent instance
      • persist

        void persist​(Object object)
        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 with CascadeType.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 interface EntityManager
        Parameters:
        object - a transient instance to be made persistent
      • persist

        void persist​(String entityName,
                     Object object)
        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 with CascadeType.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 name
        object - a transient instance to be made persistent
      • delete

        @Deprecated(since="6.0")
        void delete​(Object object)
        Deprecated.
        Remove a persistent instance from the datastore. The argument may be an instance associated with the receiving Session or a transient instance with an identifier associated with existing persistent state. This operation cascades to associated instances if the association is mapped with CascadeType.REMOVE.
        Parameters:
        object - the instance to be removed
      • delete

        @Deprecated(since="6.0")
        void delete​(String entityName,
                    Object object)
        Deprecated.
        Remove a persistent instance from the datastore. The second argument may be an instance associated with the receiving Session or a transient instance with an identifier associated with existing persistent state. This operation cascades to associated instances if the association is mapped with CascadeType.REMOVE.
        Parameters:
        entityName - the entity name for the instance to be removed.
        object - the instance to be removed
      • lock

        void lock​(Object object,
                  LockMode lockMode)
        Obtain the specified lock level on the given managed instance associated with this session. This may be used to:

        This operation cascades to associated instances if the association is mapped with CascadeType.LOCK.

        Parameters:
        object - a persistent instance
        lockMode - the lock level
      • lock

        void lock​(Object object,
                  LockOptions lockOptions)
        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
        lockOptions - the lock options
        Since:
        6.2
      • lock

        @Deprecated(since="6.2")
        void lock​(String entityName,
                  Object object,
                  LockMode lockMode)
        Deprecated.
        Obtain the specified lock level on the given managed instance associated with this session. This may be used to:

        This operation cascades to associated instances if the association is mapped with CascadeType.LOCK.

        Parameters:
        entityName - the name of the entity
        object - a persistent instance associated with this session
        lockMode - the lock level
      • refresh

        void refresh​(Object object)
        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 or Clob.

        This operation cascades to associated instances if the association is mapped with CascadeType.REFRESH.

        This operation requests LockMode.READ. To obtain a stronger lock, call refresh(Object, LockMode).

        Specified by:
        refresh in interface EntityManager
        Parameters:
        object - a persistent instance associated with this session
      • refresh

        @Deprecated(since="6.0")
        void refresh​(String entityName,
                     Object object)
        Deprecated.
        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 or Clob.

        This operation cascades to associated instances if the association is mapped with CascadeType.REFRESH.

        Parameters:
        entityName - the name of the entity
        object - a persistent instance associated with this session
      • refresh

        void refresh​(Object object,
                     LockOptions lockOptions)
        Reread the state of the given managed instance from the underlying database, obtaining the given LockMode.
        Parameters:
        object - a persistent instance associated with this session
        lockOptions - contains the lock mode to use
      • refresh

        @Deprecated(since="6.0")
        void refresh​(String entityName,
                     Object object,
                     LockOptions lockOptions)
        Reread the state of the given managed instance from the underlying database, obtaining the given LockMode.
        Parameters:
        entityName - the name of the entity
        object - a persistent instance associated with this session
        lockOptions - contains the lock mode to use
      • remove

        void remove​(Object object)
        Mark a persistence instance associated with this session for removal from the underlying database. Ths operation cascades to associated instances if the association is mapped CascadeType.REMOVE.
        Specified by:
        remove in interface EntityManager
        Parameters:
        object - the managed persistent instance to remove
      • getCurrentLockMode

        LockMode getCurrentLockMode​(Object object)
        Determine the current LockMode 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 of ScrollableResults.
        Specified by:
        clear in interface EntityManager
      • get

        <T> T get​(Class<T> entityType,
                  Object id)
        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.

        This operation is very similar to EntityManager.find(Class, Object).

        The object returned by get() or find() is either an unproxied instance of the given entity class, of 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 mode LockMode.READ.

        To bypass the second-level cache, and ensure that the state is read from the database, either:

        Parameters:
        entityType - the entity type
        id - an identifier
        Returns:
        a persistent instance or null
      • get

        <T> T get​(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. 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 type
        id - an identifier
        lockOptions - the lock mode
        Returns:
        a persistent instance or null
      • get

        Object get​(String entityName,
                   Object id)
        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 name
        id - an identifier
        Returns:
        a persistent instance or null
      • get

        Object get​(String entityName,
                   Object id,
                   LockMode lockMode)
        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 name
        id - an identifier
        lockMode - the lock mode
        Returns:
        a persistent instance or null
        See Also:
        get(String, Object, LockOptions)
      • get

        Object get​(String entityName,
                   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. 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 name
        id - an identifier
        lockOptions - contains the lock mode
        Returns:
        a persistent instance or null
      • getEntityName

        String getEntityName​(Object object)
        Return the entity name for a persistent entity.
        Parameters:
        object - a persistent entity associated with this session
        Returns:
        the entity name
      • getReference

        <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. 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 method Hibernate.unproxy(Object, Class) is the recommended way to narrow the type of a proxy object. Alternatively, a new reference may be obtained by simply calling getReference() 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 interface EntityManager
        Parameters:
        entityType - the entity type
        id - the identifier of a persistent instance that exists in the database
        Returns:
        the persistent instance or proxy
      • getReference

        Object 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. 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 name
        id - 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.
        Parameters:
        object - a detached persistent instance
        Returns:
        the persistent instance or proxy
        Since:
        6.0
      • byNaturalId

        <T> NaturalIdLoadAccess<T> byNaturalId​(Class<T> entityClass)
        Create a NaturalIdLoadAccess 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 annotated NaturalId.
        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

        <T> NaturalIdLoadAccess<T> byNaturalId​(String entityName)
        Create a NaturalIdLoadAccess 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 annotated NaturalId.
        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

        <T> SimpleNaturalIdLoadAccess<T> bySimpleNaturalId​(Class<T> entityClass)
        Create a SimpleNaturalIdLoadAccess 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 annotated NaturalId.
        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

        <T> SimpleNaturalIdLoadAccess<T> bySimpleNaturalId​(String entityName)
        Create a SimpleNaturalIdLoadAccess 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 annotated NaturalId.
        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
      • enableFilter

        Filter enableFilter​(String filterName)
        Description copied from interface: SharedSessionContract
        Enable the named filter for this current session.

        The returned Filter object must be used to bind arguments to parameters of the filter, and every parameter must be set before any other operation of this session is called.

        Specified by:
        enableFilter in interface SharedSessionContract
        Parameters:
        filterName - the name of the filter to be enabled.
        Returns:
        the Filter instance representing the enabled filter.
        See Also:
        FilterDef
      • getStatistics

        SessionStatistics getStatistics()
        Get the statistics for this session.
        Returns:
        the session statistics being collected for this session
      • isReadOnly

        boolean isReadOnly​(Object entityOrProxy)
        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:
        isDefaultReadOnly()
      • setReadOnly

        void setReadOnly​(Object entityOrProxy,
                         boolean readOnly)
        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 use Query.setReadOnly(boolean)

        Parameters:
        entityOrProxy - an entity or proxy
        readOnly - true if the entity or proxy should be made read-only; false if the entity or proxy should be made modifiable
        See Also:
        setDefaultReadOnly(boolean), Query.setReadOnly(boolean), IdentifierLoadAccess.withReadOnly(boolean)
      • isFetchProfileEnabled

        boolean isFetchProfileEnabled​(String name)
                               throws UnknownProfileException
        Is the fetch 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:
        FetchProfile
      • enableFetchProfile

        void enableFetchProfile​(String name)
                         throws UnknownProfileException
        Enable the fetch 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:
        FetchProfile
      • disableFetchProfile

        void disableFetchProfile​(String name)
                          throws UnknownProfileException
        Disable the fetch 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:
        FetchProfile
      • sessionWithOptions

        SharedSessionBuilder sessionWithOptions()
        Obtain a Session builder with the ability to copy certain information from this session.
        Returns:
        the session builder
      • addEventListeners

        void addEventListeners​(SessionEventListener... listeners)
        Add one or more listeners to the Session
        Parameters:
        listeners - the listener(s) to add
      • createQuery

        <R> Query<R> createQuery​(String queryString,
                                 Class<R> resultClass)
        Description copied from interface: QueryProducer
        Create a typed Query 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, or Tuple.

        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.

        The returned Query may be executed by calling Query.getResultList() or Query.getSingleResult().

        Specified by:
        createQuery in interface EntityManager
        Specified by:
        createQuery in interface QueryProducer
        Parameters:
        queryString - The HQL query
        resultClass - The type of the query result
        Returns:
        The Query instance for manipulation and execution
        See Also:
        EntityManager.createQuery(String,Class)
      • createQuery

        @Deprecated
        Query createQuery​(String queryString)
        Deprecated.
        Description copied from interface: QueryProducer
        Create a Query 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, then that root entity is the only element of the select list, or
        • otherwise, if there are multiple root entities in the from clause, then the select list contains every root entity and every non-fetch joined entity.
        Specified by:
        createQuery in interface EntityManager
        Specified by:
        createQuery in interface QueryProducer
        Parameters:
        queryString - The HQL query
        Returns:
        The Query instance for manipulation and execution
        See Also:
        EntityManager.createQuery(String)