Chapter 7 - Object Adapters

Abstract

This chapter provides an overview of the functionality of object adapters. Object adapter is defined as a design pattern to achieve a reusable class that cooperates with unrelated or unforeseen classes. According to this definition, an object adapter receives a client's request and translates it into a request that is understood by the “adaptee.” An object adapter's primary task is of dispatching incoming client's requests—that the object adapter is handed by its client, the Object Request Broker (ORB) kernel—to the adaptee, a servant. In the process, the request must be translated; the object request—which arrives from the ORB as a blob of binary data—must be demarshalled into the method parameters that the servant expects. An object adapter's functionality can be segmented into five categories: management of servants, management of objects, generation and interpretation of object references, mapping objects to servants, and method invocation. The premise of request unmarshalling and dispatching must be supplemented with some associated functionality.