Chapter 1: Introducing EAServer

Component support

Components are reusable modules of code that combine related tasks (methods) into a well-defined interface. EAServer components are installed on an EAServer application 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 server. Components can be distributed throughout a network, including the Internet or an intranet, on different servers. Installed components can be used by any number of independent applications.

Since EAServer components reside on the server, components do not contain methods to display graphics or user interfaces—that is, EAServer components are inherently nonvisual.

User-interface developers or other component developers can browse a component’s interface in EAServer Manager; 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 remote server communication.

The EAServer server-side component support and client-side stub or proxy support are independent. Any EAServer client can execute any type of component. A component of any model can execute components of another model using intercomponent calls without the use of additional gateway software. Additionally, since EAServer uses standard CORBA IIOP as its core network protocol, you can use CORBA client runtimes from other vendors to invoke components installed on EAServer.

All clients and components share a common interface repository. Component interfaces are stored in standard CORBA interface definition language (IDL). Component developers can define, edit, and browse interfaces in EAServer Manager, which allows you to edit interfaces graphically or as raw IDL. You can also define interfaces by importing compiled Java classes, standard-format EJB-JAR files, or ActiveX type libraries.

For more information about the component models that EAServer supports, see Chapter 3, “EAServer Components.”