Object broker

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An object broker is an object-oriented form of middleware , namely an RPC -based system with reference to object-oriented programming. The traditional RPC was developed at a time when imperative programming languages were still predominant. With the advent of object-oriented languages, there was a need for platforms that support access to remote objects ; the development of such platforms resulted in object brokers.

Property brokers first appeared in the early 1990s. The main purpose of an object broker is the same as in classic RPC-based systems, namely to hide the complexity of remote calls - in terms of implementation, there is hardly any difference between object brokers and classic RPC systems. The difference is that the client does not call procedures , but rather methods of objects. Since the object-oriented programming model also includes concepts such as inheritance and polymorphism , the function that the server-side object performs depends on which class the object belongs to - different objects may therefore perform the same method differently. This means that the object broker must be able to connect a client to specific objects and manage interactions between objects.

Over time, this main functionality has been supplemented by capabilities that go beyond simple interoperability of objects, for example location transparency , sophisticated techniques for handling dynamic binding , object lifecycle management and persistence .

The best-known representative of object brokers is CORBA - an architecture and specification for the management of object-oriented applications in a distributed environment, which represents an abstraction of object brokers, the so-called Object Request Broker . CORBA was developed by the Object Management Group (OMG) in the early 1990s . The best-known non-CORBA object brokers are the Distributed Component Object Model (DCOM) and its successor COM + , developed by the US company Microsoft .

See also

literature

  • Gustavo Alonso, F. Casati, H. Kuno, V. Machiraju: Web Services. Springer, Berlin 2003, ISBN 3-540-44008-9 (English)