[ale] ActiveX for LINUX?

R I Feigenblatt docdtv at peachlink.com
Wed Mar 5 15:29:36 EST 1997


At 06:49 PM 3/3/97 -0500, Jim wrote:
>No one has explained yet what ActiveX is supposed to do on a
>non-Microsoft platform.

The obvious answer: the same as on Microsoft platforms; expose
COM's binary, language-independent, object interface standards.
(The networked version of this, DCOM, uses RPC for transport.)

COM is at the heart of what Microsoft has called OLE these many years,
and as time has passed there has been semantic erosion of their distinction.
ActiveX controls are the successor to OLE controls (*.OCX), which are
the successor to Visual Basic (*.VBX) controls. Such controls are the
bread-and-butter of contemporary corporate PC software development,
as well as the business of a thriving industry of third-party control makers,
not the least of which is Marietta's MicroHelp, recently acquired by an
ambitious Internet firm.

COM objects are semantically equivalent to Java classes, but also
provide the ability to discover what interfaces exist at run time,
via QueryInterface. This important feature is being introduced to Java
through the JavaBeans Spec 1.0, via the BeanInfo class ("introspection").
To quote Microsoft, (May 23, 1996 Draft) 
	"The integration of Java and COM can be achieved by just making 
	changes to the Java VM, and not adding any new keywords or
	constructs to the Java language."
Visual  J++ 1.1 includes Wizards that allow you to use ActiveX objects as
Java classes and vice-versa.

However, COM objects are instantiated with native code, not
on a "platform-independent" Java Virtual Machine. Cross-platform
congruence or differentiation depends on the implementation
of the object on each platform, rather than on the implementation
of the Java Virtual Machine on each platform. In this aspect, one might
compare ActiveX objects to Netscape plug-ins, rather than Java classes.

Ron Feigenblatt
 






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