About Sun Adapter for COM/DCOM

This topic provides conceptual information about COM/DCOM and its Sun Java CAPS Adapter.

About COM/DCOM

The Microsoft^TM Component Object Model (COM) is a component software architecture that allows developers to partition an application into multiple components that can be developed and installed independently of each other. COM is the underlying architecture that forms the foundation for higher-level software services, like those provided by OLE (Object Linking and Embedding). OLE services span various aspects of component software, including compound documents, custom controls, inter-application scripting, data transfer, and other software interactions. Using COM allows software objects to be reused for a variety of applications. Because of its binary standard, COM allows any two components to communicate regardless of the language in which they were written.

The Microsoft Distributed Component Object Model (DCOM) is an extension of COM, and supports communication among objects residing on different computers; LANs, WANs, and the Internet. With DCOM, these software objects can be reused over a distributed Environment.

COM objects or components are individual modular software routines that can be reused within applications. COM objects are reusable compiled binary objects, as opposed to reusable sections of code. Creating an instance of a COM object provides a reference through which you can access the object’s functionality.

The Sun COM/DCOM Adapter

The Sun COM/DCOM Adapter (referred to as the COM/DCOM Adapter through-out this document) allows the Sun Java Composite Application Platform Suite to create an instance of an automation-compatible COM object and access the methods and properties of that object.

One aspect of COM is “automation” based on the COM IDispatch interface. Objects that implement the IDispatch interface are known to be automation-compatible. Automation-compatible components are said to be “scriptable” and/or are capable of being “driven” by an automation client. This is possible because the IDispatch interface is well-known and those components that implement this interface adhere to a strict contract that is based on a “late binding” concept. “Late binding” refers to a programming principle whereby the actual operation invoked is not determined until runtime. Objects that implement the IDispatch interface achieve this through the concept of the Invoke method on the IDispatch interface, which allows the user to call a method by name. The COM/DCOM Adapter is designed to work with automation-compatible components: that is, those that implement the IDispatch interface.

The COM/DCOM Adapter does not support Sun Java CAPS BPEL 1.0 Business Processes.