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JavaBeans and ActiveX go head to head

Don't choose until you've considered these 5 issues crucial to developers

By Merlin Hughes, JavaWorld.com, 03/01/97

One area of intense software investment is in the creation of rapid-application-development (or RAD) packages. A RAD package consists of a programming language, a component model for connecting together interaction elements (called "controls"), and a customization environment (called "resource editors"). One of the most successful RADs on the PC has been Borland's Delphi; however, the first RAD to see widespread use was Microsoft's Visual Basic. Borland's product used a proprietary version of Pascal (Object Pascal) and Microsoft's product used a proprietary version of Basic. Because of Java's strengths as a robust, secure programming language, it seems a natural fit as the base language for a killer RAD environment; until now, however, Java has lacked a fundamental technology: components.

Software components are simply a convention for writing user-interface controls so that the application development tools and runtime environment can manipulate them. Visual Basic's component model, "VBX" (for Visual Basic eXtensions), is a variation of Microsoft's DLL (dynamic-link libraries) architecture. Delphi defined a component architecture around Borland's "OWL" (Object Window Library) architecture.

Not content to sit idly by and watch the action, JavaSoft has thrown its hat into the ring with a component architecture called JavaBeans.

You might think that this is simply the tale of three different RAD environments, each with their own language. You'd be right in one sense, but you know as well as I do that nothing is quite so simple. The Java language has injected a significant kink into the way programmers are taught to think. That kink was felt most strongly at Microsoft, which saw another competitor to its Visual Basic on the horizon. It was with this in mind that Microsoft took some existing work on generalizing VBXs for its other programming languages and created ActiveX -- a component architecture allegedly suitable for all languages. To reinforce this point, Microsoft has provided support in its newest development tools to invoke ActiveX controls from Java and to invoke Java from ActiveX controls.

Software component models

Let's begin with a simple definition: A software component model is a specification for how to develop reusable software components and how these component objects can communicate with each other.

With that said, we can now focus on how component models work in a general sense.

Developers of software components must deal with the low-level details of implementing a component and its associated classes. Users of software components (developers in their own right) can then simply hook together existing components in a visual development environment. This is what we call rapid application development -- existing codebase can be easily reused (or purchased from an independent vendor) and integrated in a third-party development environment. Component developers also benefit from this type of environment: They can reuse existing components, obtaining a consistent object-interface to many standard system facilities during the development of their own components.

 

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