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Middleware

What is middleware?

Software layer that lies between the operating system and the application on each site of the system

Middleware Functions:

Hiding distribution

Make of many part running in distributed location

Hiding the heterogeneity of various hardware components, operating system and communication protocol

Provide uniform, standard, high level interface to the application developer and integrator

Application can easily be composed, versed, ported and made to interoperate

Supply set of common service

Perform various general purpose functions such as

  • Avoid duplicating effort
  • Facilitate collaboration between application

What is ORB?

ORB is Object Request Broker.

It is a middleware that uses CORBA specification. It take care of all the details involve in routing a request from client to object, and routing response to its destination.

ORB is the custodian of the Interface Repository (IFR), an OMG standardized distributed database containing IDL interface definition.

On the client side:

  • ORB provide interface definition from the IFR
  • Construct invocations for use with the Dynamic Invocation Interface (DII),
  • Convert Object References between session and stringifield format
  • Convert URL-format corbaloc and corbaname object references to session references.

On the server side:

  • Same as above process. Plus,
  • ORB deactivates inactive objects.
  • Re-activates  object whenever request come in.
  • Activate and De-activates in the way that uses resources best.

ORB, wow!