Basically, an applet is a Java™
application
(a rich client) running inside a Web browser. The main noticeable
differences between applets and applications are:
Applets do not have the same kind of
top-level container (like a JFrame
, for
example). Your Java code is not responsible for creating the main
window, and your applets have to live within the limits of the provided ContentPane
.
The code of the applet is usually invoked
by a Web page downloaded from a remote website and executed on demand.
Unless your application is signed or
your Java security policy has been extended, your applets have limited
access to local resources, such as files, printers, and so on. This
requires particular attention for dealing with security exceptions.
Most of the time applet classes and
resources need to be packaged as JAR files and need to have a very
clean access to their data, such as images or resource files.
Like other Java programs, a JViews application needs
some particular attention to packaging and use as an applet. If possible,
we recommend you use the IlvDiagrammerApplication
class,
which is already able to manage applets or applications. Most samples
available in the JViews Diagrammer distribution are packaged so they
can work transparently as applets or applications. If you decide to
use lower-level containers, such as IlvDiagrammer
,
you will need to take more care in the integration with the top-level
containers.
Creating an applet
The
IlvDiagrammer instance and its associated beans can be used in
applets in exactly the same way as in Swing applications. The only
limitations are the restricted permissions in applets, for example,
it is not possible to save data files from an applet.
The
IlvDiagrammerApplication class extends the Swing
JApplet
class,
so it can be used directly in an HTML applet tag. You can pass the
command-line parameters as applet parameters: the names of the parameters
are the same, without the "-" prefix.