TransactionAwareSessionAdapter (Spring Framework) - Spring Framework 1.2.9 API 文档英文版
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org.springframework.orm.toplink.support
Class TransactionAwareSessionAdapter
java.lang.Objectorg.springframework.orm.toplink.support.TransactionAwareSessionAdapter
- All Implemented Interfaces:
- FactoryBean
public class TransactionAwareSessionAdapter
- extends Object
- implements FactoryBean
- extends Object
This adapter FactoryBean takes a TopLink SessionFactory and exposes a corresponding transaction-aware TopLink Session as bean reference.
This adapter bean will usually be defined in front of a Spring
LocalSessionFactoryBean, to allow for passing Session references to DAOs
that expect to work on a raw TopLink Session. Your DAOs can then,
for example, access the currently active Session and UnitOfWork via
Session.getActiveSession() and
Session.getActiveUnitOfWork(), respectively.
The main advantage of this proxy is that it allows DAOs to work with a plain TopLink Session reference, while still participating in Spring's (or a J2EE server's) resource and transaction management. DAOs will only rely on the TopLink API in such a scenario, without any Spring dependencies.
It is usually preferable to write your TopLink-based DAOs with Spring's TopLinkTemplate, offering benefits such as consistent data access exceptions instead of TopLinkExceptions at the DAO layer. However, Spring's resource and transaction management (and Dependency Injection) will work for DAOs written against the plain TopLink API too.
Of course, you can still access the target TopLink SessionFactory even when your DAOs go through this adapter, by defining a bean reference that points directly at your target SessionFactory bean.
Note that the actual creation of a transaction-aware TopLink Session is available on the TopLink SessionFactory itself. This adapter FactoryBean is just a convenient way to expose such a Session in a declarative fashion.
- Since:
- 1.2
- Author:
- Juergen Hoeller
- See Also:
LocalSessionFactoryBean,SessionFactory.createTransactionAwareSession(),Session.getActiveSession(),Session.getActiveUnitOfWork()
| Constructor Summary | |
|---|---|
TransactionAwareSessionAdapter()
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|
| Method Summary | |
|---|---|
Object |
getObject()
Return an instance (possibly shared or independent) of the object managed by this factory. |
Class |
getObjectType()
Return the type of object that this FactoryBean creates, or null
if not known in advance. |
boolean |
isSingleton()
Is the bean managed by this factory a singleton or a prototype? |
void |
setSessionFactory(SessionFactory sessionFactory)
Set the SessionFactory that this adapter is supposed to expose a transaction-aware TopLink Session for. |
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
|---|
TransactionAwareSessionAdapter
public TransactionAwareSessionAdapter()
| Method Detail |
|---|
setSessionFactory
public void setSessionFactory(SessionFactory sessionFactory)
- Set the SessionFactory that this adapter is supposed to expose a
transaction-aware TopLink Session for. This should be the raw
SessionFactory, as accessed by TopLinkTransactionManager.
- See Also:
TopLinkTransactionManager
getObject
public Object getObject()
- Description copied from interface:
FactoryBean - Return an instance (possibly shared or independent) of the object
managed by this factory. As with a BeanFactory, this allows
support for both the Singleton and Prototype design pattern.
If this method returns
null, the factory will consider the FactoryBean as not fully initialized and throw a corresponding FactoryBeanNotInitializedException.- Specified by:
getObjectin interfaceFactoryBean
- Returns:
- an instance of the bean (should not be
null; anullvalue will be considered as an indication of incomplete initialization) - See Also:
FactoryBeanNotInitializedException
getObjectType
public Class getObjectType()
- Description copied from interface:
FactoryBean - Return the type of object that this FactoryBean creates, or
nullif not known in advance. This allows to check for specific types of beans without instantiating objects, for example on autowiring.For a singleton, this should try to avoid singleton creation as far as possible; it should rather estimate the type in advance. For prototypes, returning a meaningful type here is advisable too.
This method can be called before this FactoryBean has been fully initialized. It must not rely on state created during initialization; of course, it can still use such state if available.
NOTE: Autowiring will simply ignore FactoryBeans that return
nullhere. Therefore it is highly recommended to implement this method properly, using the current state of the FactoryBean.- Specified by:
getObjectTypein interfaceFactoryBean
- Returns:
- the type of object that this FactoryBean creates,
or
nullif not known at the time of the call - See Also:
ListableBeanFactory.getBeansOfType(java.lang.Class)
isSingleton
public boolean isSingleton()
- Description copied from interface:
FactoryBean - Is the bean managed by this factory a singleton or a prototype?
That is, will
getObject()always return the same object (a reference that can be cached)?NOTE: If a FactoryBean indicates to hold a singleton object, the object returned from
getObject()might get cached by the owning BeanFactory. Hence, do not returntrueunless the FactoryBean always exposes the same reference.The singleton status of the FactoryBean itself will generally be provided by the owning BeanFactory; usually, it has to be defined as singleton there.
- Specified by:
isSingletonin interfaceFactoryBean
- Returns:
- if this bean is a singleton
- See Also:
FactoryBean.getObject()
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