Components are reusable modules of code that combine related tasks (methods) into a well-defined interface. EJB Server components are installed on an EJB Server and contain the methods that execute business logic and access data sources. You or your administrator install the component’s executable code on the EJB Server. Components can be distributed to Adaptive Server databases residing on the same host. Once installed, components can be used by any number of independent applications.
Since EJB Server components reside on the server, components do not contain methods to display graphics or user interfaces—that is, EJB Server components are inherently nonvisual.
User-interface developers or other component developers can browse a component’s interface in the Adaptive Server plug-in for Sybase Central; in their code, they use a client stub or proxy to invoke the component’s methods. The stub or proxy acts as a local surrogate for the remote component, providing the same method signatures as the component and hiding the details of server communication.
EJB Server’s server-side component support and client-side stub or proxy support are independent. Any EJB Server client can execute any component. Additionally, since EJB Server uses standard CORBA IIOP as its core network protocol, you can use CORBA client runtimes from other vendors to invoke components installed on an EJB Server.
All clients and components share a common interface repository. Component interfaces are stored in standard CORBA Interface Definition Language (IDL). Interfaces can be defined by importing compiled Java classes or standard-format EJB-JAR files.
