Windchill System Administrator's Guide

Java Applets
Many simple accesses to the system may use only HTML presentation, with
HTML form data serving as input. However, the typical client session requires
that applet tags (used to carry out complex user interactions involving complex
data), be embedded in these HTML responses.
Java applets are downloaded from Windchill servers and executed within the
address space of the client browser. They provide sophisticated graphical user
interface functionality, allowing for complex interactions with the user.
Once running, the applets communicate directly with Windchill servers via Java
RMI. This avoids the additional overhead of communicating indirectly through
the HTTP server and allows for very complex data to be passed easily between
client and server.
If it is necessary to get through firewalls by using an HTTP proxy, Java RMI
communication is automatically layered on HTTP. However, this results in
greater performance degradation than a direct connection to a Windchill server.
Applet classes loaded from the same Windchill system communicate with one
another to use the browser windows and frames, presenting a seamless system
image.
Applet classes loaded from federated Windchill systems (coming from separate
HTTP servers) cannot communicate directly with one another for security
reasons. Intersystem links are therefore accomplished using HTTP URLs, given to
the browser for loading into HTML windows. The resulting HTML pages contain
JavaScript/JScript and applet tags that use windows and frames to present a
seamless system image.
Interactive applets can present feedback on behalf of long-running server
transactions. This feedback can take the form of progress indicators and, in some
cases, provides the ability to cancel the operation.
Windchill Runtime Environment A-5