Chapter 2. Client View of a Session Bean

This page discusses - Chapter 2. Client View of a Session Bean

Ads

Tutorials   
Chapter 5. Client View of an Entity Identify correct and incorrect statements about the Application Assembler's responsibilities, including the use of deployment descriptor elements related to transactions and the identifica Given a list of responsibilities, identify whose which are the Container's with respect to transactions, including the handling of getRollbackOnly, setRollbackOnly, getUserTransacti EJB Transactional Attributes Chapter 11. Transactions Given a list of scenarios, identify which will result in an ejbRemove method not being called on a bean instance. Given a list of responsibilities related to session beans, identify those which are the responsibility of the session bean provider and those which are the responsibility of the EJB contai Given a list of methods for a stateful or stateless session bean class, define which of the following operations can be performed from each of those methods: SessionContext interface metho Chapter 4. Session Bean Life Cycle Identify correct and incorrect statements or examples about the client view of a session bean's local and remote component interfaces. Identify the interface and method for each of the following: retrieve the session bean's remote home interface, retrieve the session bean's local component interface, determine if the sessio Match the correct description about purpose and function to which session bean type they apply: stateless, stateful, or both. Chapter 14. Security Management Given a security-related deployment descriptor tag, identify correct and incorrect statements and code related to that tag. Given a list of responsibilities, identify which belong to the deployer, bean provider, application assembler, container provider, system administrator, or any combination. From a list of responsibilities, identify which belong to the application assembler, bean provider, deployer, container provider, or system administrator. Part I. Exam Objectives Preface Identify the interfaces and methods a JMS message-driven bean must implement. Identify the use and behavior of the MessageDrivenContext interface methods. SCBCD Study Guide Given a list of responsibilities related to exceptions, identify those which are the bean provider's, and those which are the responsibility of the container provider. Be prepared to recog Given a particular method condition, identify the following: whether an exception will be thrown, the type of exception thrown, the container's action, and the client's view. Identify correct and incorrect statements or examples about application exceptions and system exceptions in entity beans, session beans, and message-driven beans. Identify correct and incorrect statements or examples about the client's view of exceptions received from an enterprise bean invocation. Identify correct and incorrect statements or examples about an entity bean's primary key and object identity. Identify the use, syntax, and behavior of, the following entity bean home method types, for Container-Managed Persistence (CMP); finder methods, create methods, remove methods, and home me Chapter 8. Entity Beans Chapter 13. Enterprise Bean Environment Chapter 2. Client View of a Session Bean Match EJB roles with the corresponding description of the role's responsibilities, where the description may include deployment descriptor information. Given a list, identify which are requirements for an EJB-jar file. Identify correct and incorrect statements or examples about the client view of a entity bean's remote component interface (EJBObject). Identify correct and incorrect conditional expressions, BETWEEN expressions, IN expressions, LIKE expressions, and comparison expressions. Identify correct and incorrect statements or examples about the purpose and use of EJB QL. Chapter 9. EJB-QL Identify correct and incorrect statements or examples about EJB programming restrictions. Chapter 1. EJB Overview Identify EJB 2.0 container requirements. Identify correct and incorrect statements or examples about the client view of an entity bean's local component interface (EJBLocalObject).

Chapter 2. Client View of a Session Bean

Identify correct and incorrect statements or examples about the client view of a session bean's local and remote home interfaces, including the code used by a client to locate a session bean's home interface.

A client locates a session bean’s home interface using JNDI. For example, the remote home interface for the Cart session bean can be located using the following code segment:

				
Context initialContext = new InitialContext(); 
CartHome cartHome = (CartHome)javax.rmi.PortableRemoteObject.narrow(
	initialContext.lookup(?java:comp/env/ejb/cart?),
	CartHome.class);
				

If the Cart session bean provides a local client view instead of a remote client view and CartHome is a local home interface, this lookup might be as follows:

				
Context initialContext = new InitialContext();
CartHome cartHome = (CartHome)
	initialContext.lookup(?java:comp/env/ejb/cart?);
				

A client can pass a remote home object reference to another application. The receiving application can use the home interface in the same way that it would use a remote home object reference obtained via JNDI.

A client can pass a local home object reference to another application through its local interface. A local home object reference cannot be passed as an argument or result of a method on an enterprise bean’s remote home or remote interface.

The REMOTE HOME interface allows a client to do the following:

  • Create a new session object.

  • Remove a session object (using bean's HANDLE).

  • Get the javax.ejb.EJBMetaData interface for the session bean. The javax.ejb.EJBMetaData interface is intended to allow application assembly tools to discover information about the session bean, and to allow loose client/server binding and client-side scripting.

  • Obtain a handle for the REMOTE home interface. The home handle can be SERIALIZED and written to stable storage. Later, possibly in a different JVM, the handle can be deserialized from stable storage and used to obtain back a reference of the remote home interface.

public interface EJBHome extends Remote {
	EJBMetaData getEJBMetaData() throws RemoteException;
	HomeHandle getHomeHandle() throws RemoteException;
	void remove(Handle handle) throws RemoteException, 
		RemoveException;
	void remove(Object primaryKey) throws RemoteException, 
		RemoveException; // only Entity EJB !!!
}	
					

The LOCAL HOME interface allows a local client to do the following:

  • Create a new session object.

public interface EJBLocalHome {
	void remove(Object primaryKey) throws RemoveException, 
			EJBException;  // only Entity EJB !!!
}					
					

EJBMetaData and HomeHandle are ONLY accessible for REMOTE HOME interfaces.

EJBHome interface extends Remote (marker) interface.

Session bean can be removed ONLY using it's handle (remote view ONLY), since it does not have primary key.

Visit http://java.boot.by  for the updates.

Advertisements

Ads
Share on Google+Share on Google+

Chapter 2. Client View of a Session Bean

Posted on: April 18, 2011 If you enjoyed this post then why not add us on Google+? Add us to your Circles

Advertisements

 

Discuss: Chapter 2. Client View of a Session Bean  

Post your Comment


Your Name (*) :
Your Email :
Subject (*):
Your Comment (*):
  Reload Image
 
 
Comments:0

Ads

 

Ads