12-10-2010, 04:48 PM
Distributed Objects and Remote Invocation.ppt (Size: 205 KB / Downloads: 48)
Distributed Objects and Remote Invocation
Introduction.
Distributed Applications: Applications that are designed to have cooperating programs that run in several different processes.
Several familiar programming models that have been extended to distributed programs:
Move from conventional procedure call to Remote Procedure Call (in different processes).
Remote Method Invocations: allows different objects to call each others.
Objects receive notification if other objects have been changed by some external events.
Visibility: Object B is Visible to Object A if and only if A can invoke Methods defined in Object B.
Types of visibility:
Object B is a parameter to some function in object A.
Object B is defined as a member variable in Object A.
Object B is declared globally for Object A.
Object B is defined in some function in Object A.
RPC is the same of RMI in the case of using objects environment.
Middleware:
It is a software that provides programming model above the basic building blocks of processes and messages passing between objects.
An important aspect in middleware is the location transparency.
There is an independency from the details of communication protocol, OS, and HW.