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Enthuware doubt : Buisness Delegate

 
avi sinha
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Google Web Toolkit Hibernate Java
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This question is from Enthware JWeb v4 Test-2
Question 59 of 69 (Answered Wrong)



What are the benefits of using Business Delegate pattern?

Select 3 correct options

a> It shields the clients from the business rule changes.

b> It allows the clients to access the business services using any technology like EJB, CORBA or RMI.

c> It shields the clients from changes in the implementation of the business services.

d> It provides a uniform interface to the clients.

e> It improves performance by caching the data.

Answer: c,d,e

General Comments

Business Delegate : It is used to abstract out the back end implementation so that changes in the back end do not affect the front ends. All the client requests are taken by the business delegate on the server which internally delegates the tasks to appropriate implementations.
Use a Business Delegate to reduce coupling between presentation-tier clients and business services. The Business Delegate hides the underlying implementation details of the business service, such as lookup and access details of the EJB architecture.



is it correct?? i had chosen a,b,c . doesn't it shields the client from business rule changes & platforms??? also its for the first time i have seen caching in buisness Delegate . strange.

avi sinha

 
Lucas Smith
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Cashing is in ServiceLocator for sure.
 
Chinmaya Chowdary
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Hi, Avi.
a> It shields the clients from the business rule changes.


I think here 'business rule change' means, changing the logic of the code. If the rule changes it will reflect to the client. If the backend implementation changes, like previously if we use 'MySQL' and now if we implement with 'Oracle', that implementation change will not reflect to the client. It seems option A is invalid.
 
avi sinha
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Chinmaya Chowdary wrote:Hi, Avi.
a> It shields the clients from the business rule changes.


I think here 'business rule change' means, changing the logic of the code. If the rule changes it will reflect to the client. If the backend implementation changes, like previously if we use 'MySQL' and now if we implement with 'Oracle', that implementation change will not reflect to the client. It seems option A is invalid.


i am not satisfied with your answer.well i have never seen a Buisness Delegate. what i know is that it shields the client from the complexity of remote access or methods.
can it be a Buisness Delegate :



if yes then A will be invalid. i don't know if there are rules for buisness delegate or not but i have implemented the above in my project.the shielding can be done like this.
i am very much confused now.

avi sinha
 
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