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Question about design pattern

Renato Carauta
Greenhorn

Joined: Jun 21, 2012
Posts: 8

I don't understand the question bellow

Which design pattern, when used, may introduce stale business data in the presentation tier?

A) Business Delegate

B) Transfer Object

F) Front Controller

The right answer is letter B. I don't understand this design pattern.

The source of this question is this mock exam OCEWCD (Java EE 6 Web Component) Training Lab
Sanjay Singh
Ranch Hand

Joined: Mar 02, 2006
Posts: 37

The Transfer Object is the copy of remote entity so during the time we data is send to view layer over the network it might be altered by some other program. So Transfer Object might have the stale state. E.g. the view requests for Employee details. The employee data is sent to view in a Transfer Object EmployeeDTO object. While the view gets it and process it some other program can update the Employee data and hence stale state of EmployeeDTO. I hope this helps.


Regards, Sanjay Singh
SCJP-1.6, OCEWCD 6
Renato Carauta
Greenhorn

Joined: Jun 21, 2012
Posts: 8

I understand you can have a stale state when you using a Transfer Object. Thank you for your answer.
 
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subject: Question about design pattern
 
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