org.hibernate.proxy

Interface LazyInitializer

All Known Implementing Classes:

AbstractLazyInitializer, BasicLazyInitializer, JavassistLazyInitializer, MapLazyInitializer

public interface LazyInitializer

Handles fetching of the underlying entity for a proxy

Author:

Gavin King, Steve Ebersole

Method Summary

Modifier and Type	Method and Description
String	getEntityName() The entity-name of the entity our owning proxy represents.
Serializable	getIdentifier() Retrieve the identifier value for the entity our owning proxy represents.
Object	getImplementation() Return the underlying persistent object, initializing if necessary
Object	getImplementation(SessionImplementor session) Return the underlying persistent object in the given session, or null if not contained in this session's persistence context.
Class	getPersistentClass() Get the actual class of the entity.
SessionImplementor	getSession() Get the session to which this proxy is associated, or null if it is not attached.
void	initialize() Initialize the proxy, fetching the target entity if necessary.
boolean	isReadOnly() Is the proxy read-only?.
boolean	isReadOnlySettingAvailable() Is the proxy's read-only/modifiable setting available?
boolean	isUninitialized() Is the proxy uninitialzed?
boolean	isUnwrap()
void	setIdentifier(Serializable id) Set the identifier value for the entity our owning proxy represents.
void	setImplementation(Object target) Initialize the proxy manually by injecting its target.
void	setReadOnly(boolean readOnly) Set an associated modifiable proxy to read-only mode, or a read-only proxy to modifiable mode.
void	setSession(SessionImplementor session) Associate the proxy with the given session.
void	setUnwrap(boolean unwrap)
void	unsetSession() Unset this initializer's reference to session.

Method Detail

initialize

void initialize()
         throws HibernateException

Initialize the proxy, fetching the target entity if necessary.

Throws:

HibernateException - Indicates a problem initializing the proxy.

getIdentifier

Serializable getIdentifier()

Retrieve the identifier value for the entity our owning proxy represents.

Returns:

The identifier value.

setIdentifier

void setIdentifier(Serializable id)

Set the identifier value for the entity our owning proxy represents.

Parameters:

id - The identifier value.

getEntityName

String getEntityName()

The entity-name of the entity our owning proxy represents.

Returns:

The entity-name.

getPersistentClass

Class getPersistentClass()

Get the actual class of the entity. Generally, getEntityName() should be used instead.

Returns:

The actual entity class.

isUninitialized

boolean isUninitialized()

Is the proxy uninitialzed?

Returns:

True if uninitialized; false otherwise.

getImplementation

Object getImplementation()

Return the underlying persistent object, initializing if necessary

Returns:

The underlying target entity.

getImplementation

Object getImplementation(SessionImplementor session)
                  throws HibernateException

Return the underlying persistent object in the given session, or null if not contained in this session's persistence context.

Parameters:

session - The session to check

Returns:

The target, or null.

Throws:

HibernateException - Indicates problem locating the target.

setImplementation

void setImplementation(Object target)

Initialize the proxy manually by injecting its target.

Parameters:

target - The proxy target (the actual entity being proxied).

isReadOnlySettingAvailable

boolean isReadOnlySettingAvailable()

Is the proxy's read-only/modifiable setting available?

Returns:

true, if the setting is available false, if the proxy is detached or its associated session is closed

isReadOnly

boolean isReadOnly()

Is the proxy read-only?. The read-only/modifiable setting is not available when the proxy is detached or its associated session is closed. To check if the read-only/modifiable setting is available:

Returns:

true, if this proxy is read-only; false, otherwise

Throws:

TransientObjectException - if the proxy is detached (getSession() == null)

SessionException - if the proxy is associated with a sesssion that is closed

See Also:

isReadOnlySettingAvailable(), Session.isReadOnly(Object entityOrProxy)

setReadOnly

void setReadOnly(boolean readOnly)

Set an associated modifiable proxy to read-only mode, or a read-only proxy to modifiable mode. If the proxy is currently initialized, its implementation will be set to the same mode; otherwise, when the proxy is initialized, its implementation will have the same read-only/ modifiable setting as the proxy. In read-only mode, no snapshot is maintained and the instance is never dirty checked. If the associated proxy already has the specified read-only/modifiable setting, then this method does nothing.

Parameters:

readOnly - if true, the associated proxy is made read-only; if false, the associated proxy is made modifiable.

Throws:

TransientObjectException - if the proxy is not association with a session

SessionException - if the proxy is associated with a session that is closed

See Also:

Session.setReadOnly(Object entityOrProxy, boolean readOnly)

getSession

SessionImplementor getSession()

Get the session to which this proxy is associated, or null if it is not attached.

Returns:

The associated session.

setSession

void setSession(SessionImplementor session)
         throws HibernateException

Associate the proxy with the given session.

Care should be given to make certain that the proxy is added to the session's persistence context as well to maintain the symetry of the association. That must be done seperately as this method simply sets an internal reference. We do also check that if there is already an associated session that the proxy reference was removed from that previous session's persistence contet.

Parameters:

session - The session

Throws:

HibernateException - Indicates that the proxy was still contained in the persistence context of the "previous session".

unsetSession

void unsetSession()

Unset this initializer's reference to session. It is assumed that the caller is also taking care or cleaning up the owning proxy's reference in the persistence context.

Generally speaking this is intended to be called only during Session.evict(java.lang.Object) and Session.clear() processing; most other use-cases should call setSession(org.hibernate.engine.spi.SessionImplementor) instead.

setUnwrap

void setUnwrap(boolean unwrap)

isUnwrap

boolean isUnwrap()