org.springframework.ejb.support
Class AbstractStatelessSessionBean

java.lang.Object
  org.springframework.ejb.support.AbstractStatelessSessionBean

All Implemented Interfaces:

Serializable, EnterpriseBean, SessionBean, SmartSessionBean

public abstract class AbstractStatelessSessionBean
extends Object

Convenient superclass for stateless session beans (SLSBs), minimizing the work involved in implementing an SLSB and preventing common errors. Note that SLSBs are the most useful kind of EJB.

As the ejbActivate() and ejbPassivate() methods cannot be invoked on SLSBs, these methods are implemented to throw an exception and should not be overriden by subclasses. (Unfortunately the EJB specification forbids enforcing this by making EJB lifecycle methods final.)

There should be no need to override the setSessionContext() or ejbCreate() lifecycle methods.

Subclasses are left to implement the onEjbCreate() method to do whatever initialization they wish to do after their BeanFactory has already been loaded, and is available from the getBeanFactory() method.

This class provides the no-arg ejbCreate() method required by the EJB specification, but not the SessionBean interface, eliminating a common cause of EJB deployment failure.

Author:

Rod Johnson

See Also:

Serialized Form

Field Summary

static String	BEAN_FACTORY_PATH_ENVIRONMENT_KEY
protected Log	logger Logger available to subclasses

Constructor Summary

AbstractStatelessSessionBean()

Method Summary

void	ejbActivate()
void	ejbCreate() This implementation loads the BeanFactory.
void	ejbPassivate()
void	ejbRemove() EJB lifecycle method, implemented to invoke onEjbRemote and unload the BeanFactory afterwards.
protected BeanFactory	getBeanFactory() May be called after ejbCreate().
SessionContext	getSessionContext() Convenience method for subclasses.
protected abstract void	onEjbCreate() Subclasses must implement this method to do any initialization they would otherwise have done in an ejbCreate() method.
protected void	onEjbRemove() Subclasses must implement this method to do any initialization they would otherwise have done in an ejbRemove() method.
void	setBeanFactoryLocator(BeanFactoryLocator beanFactoryLocator) Set the BeanFactoryLocator to use for this EJB.
void	setBeanFactoryLocatorKey(String factoryKey) Set the bean factory locator key.
void	setSessionContext(SessionContext sessionContext) Set the session context.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface javax.ejb.SessionBean

ejbRemove

Field Detail

logger

protected final Log logger

Logger available to subclasses

BEAN_FACTORY_PATH_ENVIRONMENT_KEY

public static final String BEAN_FACTORY_PATH_ENVIRONMENT_KEY

See Also:

Constant Field Values

Constructor Detail

AbstractStatelessSessionBean

public AbstractStatelessSessionBean()

Method Detail

ejbCreate

public void ejbCreate()
               throws CreateException

This implementation loads the BeanFactory. A BeansException thrown by loadBeanFactory will simply get propagated, as it is a runtime exception.

Don't override it (although it can't be made final): code your own initialization in onEjbCreate(), which is called when the BeanFactory is available.

Unfortunately we can't load the BeanFactory in setSessionContext(), as resource manager access isn't permitted there - but the BeanFactory may require it.

Throws:

CreateException

onEjbCreate

protected abstract void onEjbCreate()
                             throws CreateException

Subclasses must implement this method to do any initialization they would otherwise have done in an ejbCreate() method. In contrast to ejbCreate, the BeanFactory will have been loaded here.

The same restrictions apply to the work of this method as to an ejbCreate() method.

Throws:

CreateException

ejbActivate

public void ejbActivate()
                 throws EJBException

Throws:

EJBException

See Also:

This method always throws an exception, as it should not be invoked by the EJB container.

ejbPassivate

public void ejbPassivate()
                  throws EJBException

Throws:

EJBException

See Also:

This method always throws an exception, as it should not be invoked by the EJB container.

setSessionContext

public void setSessionContext(SessionContext sessionContext)

Set the session context.

If overriding this method, be sure to invoke this form of it first.

Specified by:

setSessionContext in interface SessionBean

Parameters:

sessionContext - the SessionContext for this EJB

getSessionContext

public final SessionContext getSessionContext()

Convenience method for subclasses. Return the EJB context saved on initialization.

Specified by:

getSessionContext in interface SmartSessionBean

Returns:

the SessionContext saved on initialization by this class's implementation of the setSessionContext method

setBeanFactoryLocator

public void setBeanFactoryLocator(BeanFactoryLocator beanFactoryLocator)

Set the BeanFactoryLocator to use for this EJB. Default is a ContextJndiBeanFactoryLocator.

Can be invoked before loadBeanFactory, for example in constructor or setSessionContext if you want to override the default locator.

Note that the BeanFactory is automatically loaded by the ejbCreate implementations of AbstractStatelessSessionBean and AbstractMessageDriverBean but needs to be explicitly loaded in custom AbstractStatefulSessionBean ejbCreate methods.

See Also:

ejbCreate(), AbstractMessageDrivenBean.ejbCreate(), AbstractStatefulSessionBean.loadBeanFactory(), ContextJndiBeanFactoryLocator

setBeanFactoryLocatorKey

public void setBeanFactoryLocatorKey(String factoryKey)

Set the bean factory locator key.

In case of the default BeanFactoryLocator implementation, ContextJndiBeanFactoryLocator, this is the JNDI path. The default value of this property is "java:comp/env/ejb/BeanFactoryPath".

Can be invoked before loadBeanFactory, for example in constructor or setSessionContext if you want to override the default locator key.

See Also:

BEAN_FACTORY_PATH_ENVIRONMENT_KEY

getBeanFactory

protected BeanFactory getBeanFactory()

May be called after ejbCreate().

Returns:

the bean factory

ejbRemove

public void ejbRemove()

EJB lifecycle method, implemented to invoke onEjbRemote and unload the BeanFactory afterwards.

Don't override it (although it can't be made final): code your shutdown in onEjbRemove.

See Also:

onEjbRemove()

onEjbRemove

protected void onEjbRemove()

Subclasses must implement this method to do any initialization they would otherwise have done in an ejbRemove() method. The BeanFactory will be unloaded afterwards.

This implementation is empty, to be overridden in subclasses. The same restrictions apply to the work of this method as to an ejbRemove() method.