com.tzavellas.dyndelegate
Class DynamicDelegateFactory

java.lang.Object
  com.tzavellas.dyndelegate.DynamicDelegateFactory

public class DynamicDelegateFactory
extends Object

A Dynamic Delegate for Session Beans.

This class dynamically creates a Business Delegate for a Session EJB. The delegate will implement the specified interface. When a method is called on the delegate the corresponding method on the client interface of bean will be invoked. Any exception that may be thrown from the invocation will be converted and re-thrown according to the ThrowableConverter of this class.

To use this class your EJBs must implement the Business Interface EJB design pattern (see the EJB Design Patterns book by Floyd Marinescu). In this pattern your EJB's bean class and client interface (local or remote), both implement a common "Business Interface" that defines the business methods.

When creating a dynamic delegate for an EJB, supply as the delegate interface the Business Interface of your bean. The business interface usually does not throw any EJB specific exceptions (like RemoteException and EJBException) and does not have any dependency on the EJB APIs.

This work is based on the "EJB best practices: The dynamic delegate" article by Brett McLaughlin and on the Spring Framework EJB Access classes found at the org.springframework.ejb.access package.

Author:

Spiros Tzavellas

See Also:

ThrowableConverter, EJBHomeFactory, EJB best practices: The dynamic delegate, The Business Interface design pattern, Spring Framework

Constructor Summary

DynamicDelegateFactory()
Construct a DynamicDelegateFactory with an EJBExceptionConverter and a SimpleEJBHomeFactory.

DynamicDelegateFactory(ThrowableConverter exceptionConverter, EJBHomeFactory homeFactory)
Construct a DynamicDelegateFactory using the specified ThrowableConverter and EJBHomeFactory.

Method Summary

protected Object	createDelegate(String jndiName, Class homeInterface, Class businnessInterface, Object[] createArgs, boolean isRemote) Dynamically create a Business Delegate.
Object	createLocalDelegate(String jndiName, Class homeInterface, Class businnessInterface) Dynamically create a Business Delegate for an EJB with local access.
Object	createLocalDelegate(String jndiName, Class homeInterface, Class businnessInterface, Object[] createArgs) Dynamically create a Business Delegate for an EJB with local access.
Object	createRemoteDelegate(String jndiName, Class homeInterface, Class businnessInterface) Dynamically create a Business Delegate for an EJB with remote access.
Object	createRemoteDelegate(String jndiName, Class homeInterface, Class businnessInterface, Object[] createArgs) Dynamically create a Business Delegate for an EJB with remote access.
Object	getBean(Object delegate) Get the EJB that the specified Business Delegate proxies.
void	remove(Object delegate) Remove the EJB behind the specified dynamic delegate object.
void	setExceptionConverter(ThrowableConverter exceptionConverter) Set the ThrowableConverter to use with this factory.
void	setHomeFactory(EJBHomeFactory homeFactory) Set the EJBHomeFactory to use with this factory.

Methods inherited from class java.lang.Object

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

Constructor Detail

DynamicDelegateFactory

public DynamicDelegateFactory(ThrowableConverter exceptionConverter,
                              EJBHomeFactory homeFactory)

Construct a DynamicDelegateFactory using the specified ThrowableConverter and EJBHomeFactory.

See Also:

ThrowableConverter, EJBHomeFactory

DynamicDelegateFactory

public DynamicDelegateFactory()

Construct a DynamicDelegateFactory with an EJBExceptionConverter and a SimpleEJBHomeFactory.

See Also:

EJBExceptionConverter, SimpleEJBHomeFactory

Method Detail

setExceptionConverter

public void setExceptionConverter(ThrowableConverter exceptionConverter)

Set the ThrowableConverter to use with this factory.

setHomeFactory

public void setHomeFactory(EJBHomeFactory homeFactory)

Set the EJBHomeFactory to use with this factory.

createRemoteDelegate

public Object createRemoteDelegate(String jndiName,
                                   Class homeInterface,
                                   Class businnessInterface)

Dynamically create a Business Delegate for an EJB with remote access.

Parameters:

jndiName - the JNDI name to lookup the EJB.

homeInterface - the class of the home interface of the EJB that the created delegate will proxy

businnessInterface - the interface that the created delegate will implement

Returns:

a Business Delegate object for the EJB bound to the specified JNDI name implementing the specified interface.

createRemoteDelegate

public Object createRemoteDelegate(String jndiName,
                                   Class homeInterface,
                                   Class businnessInterface,
                                   Object[] createArgs)

Dynamically create a Business Delegate for an EJB with remote access.

Parameters:

jndiName - the JNDI name to lookup the EJB.

homeInterface - the class of the home interface of the EJB that the created delegate will proxy

businnessInterface - the interface that the created delegate will implement

createArgs - the arguments of the create method in the EJB's home interface

Returns:

a Business Delegate object for the EJB bound to the specified JNDI name implementing the specified interface.

createLocalDelegate

public Object createLocalDelegate(String jndiName,
                                  Class homeInterface,
                                  Class businnessInterface)

Dynamically create a Business Delegate for an EJB with local access.

Parameters:

jndiName - the JNDI name to lookup the EJB.

homeInterface - the class of the home interface of the EJB that the created delegate will proxy

businnessInterface - the interface that the created delegate will implement

Returns:

a Business Delegate object for the EJB bound to the specified JNDI name implementing the specified interface.

createLocalDelegate

public Object createLocalDelegate(String jndiName,
                                  Class homeInterface,
                                  Class businnessInterface,
                                  Object[] createArgs)

Dynamically create a Business Delegate for an EJB with local access.

Parameters:

jndiName - the JNDI name to lookup the EJB.

homeInterface - the class of the home interface of the EJB that the created delegate will proxy

businnessInterface - the interface that the created delegate will implement

createArgs - the arguments of the create method in the EJB's home interface

Returns:

a Business Delegate object for the EJB bound to the specified JNDI name implementing the specified interface.

createDelegate

protected Object createDelegate(String jndiName,
                                Class homeInterface,
                                Class businnessInterface,
                                Object[] createArgs,
                                boolean isRemote)

Dynamically create a Business Delegate.

Parameters:

jndiName - the JNDI name to lookup the EJB.

homeInterface - the class of the home interface of the EJB that the created delegate will proxy

businnessInterface - the interface that the created delegate will implement

createArgs - the arguments of the create method in the EJB's home interface

isRemote - the access of the EJB (remote or local)

Returns:

a Business Delegate object for the EJB bound to the specified JNDI name implementing the specified interface.

getBean

public Object getBean(Object delegate)
               throws IllegalArgumentException

Get the EJB that the specified Business Delegate proxies.

Parameters:

delegate - a dynamic Business Delegate object generated with this class.

Returns:

a reference of the bean's client interface (local or remote).

Throws:

IllegalArgumentException - if the parameter is not a dynamic delegate generated with this class.

remove

public void remove(Object delegate)
            throws IllegalArgumentException

Remove the EJB behind the specified dynamic delegate object.

Since this method calls remove() on the bean's client interface, you cannot invoke methods on the specified delegate object after this method is invoked.

Parameters:

delegate - the delegate that proxies the bean that we want to remove.

Throws:

IllegalArgumentException - if the parameter is not a dynamic delegate generated with this class.