Adaptors

The CORBA standard describes a number of object adapters; with the task of interfacing an object's implementation with its ORB. The OMG provides three sample object adapters: The Basic Object Adapter (BOA), which is the most used one, the Library Object Adapter, and the Object-Oriented Database Adapter. The last two adaptors are mainly used for accessing objects in persistent storage.

The BOA provides CORBA objects with a set of methods for accessing functions defined in ORB. These functions range from user authentication to object activation to object persistence. The BOA is the CORBA object's interface to the ORB. BOA plays a slightly different role in the server application compared to the role it plays in the client application. In the server implementation, BOA informs the ORB when objects are ready to receive incoming requests. In the client application, BOA is the component of ORB that makes sure that the reference or the proxy reaches the real object located in the server. The next two sections will provide examples of the use of adaptors in server and client applications. According to the CORBA specification, the BOA should be available in every ORB implementation, and this seems to be the case with most CORBA products available in the market.

In the next sections we will present a simple example of implementation of a CORBA soil server and a soil client.

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