PTOLEMY II - CiteSeerX

Custom Applets
Finally, the values of the director and Clock actor parameters are coupled to these top-level parameters
by the lines
director.stopTime.setExpression("stopTime");
clock.period.setExpression("clockPeriod");
The expressions being set here can be much more elaborate. The expression language is documented in
the Data Package chapter. Here, the expressions each contain a single variable reference, referring to
the top-level parameters by name.
In order for the top-level parameters to appear in the controls of an applet, we must configure the
HTML file as shown in figure 8.9. The line
accomplish the objective. The result of invoking the appletviewer on the HTML file in figure 8.9 is
shown in figure 8.10.
8.3.6 Adding Custom Actors
The intent of Ptolemy II is to have a reasonably rich set of actors in the actor libraries. However, it
is anticipated that model builders will often need to define their own, custom actors. This is relatively
easy to do, as discussed in the Designing Actors chapter. By convention, when a specialized actor is
created for a particular applet or application, we store that actor in the same directory with the applet or
application, rather than in the actor libraries. The actor libraries are for generic, reusable actors.
8.3.7 Using Jar Files
A jar file is a Java Archive File that contains multiple .class files. Applets that are being downloaded
over the net will start up more quickly if all the relevant Java .class files are collected together
into one or more jar files. This dramatically reduces the number of HTTP transactions.
Models in the Ptolemy II demo directories typically use three separate jar files:
ptolemy/ptsupport.jar — A jar file containing classes from ptolemy.kernel, ptolemy.actor and
other packages, see $PTII/ptolemy/makefile for a complete list;
\
\
\
No Java Plug-in support for applet, see
http://java.sun.com/products/plugin/
FIGURE 8.9. The HTML that displays model parameters for the applet user to control. This file can be
found in $PTII/doc/tutorial/TutorialApplet3.htm
242 Ptolemy II