Re: inter-applet communication problems

"Andrew Thompson" <>
2 Aug 2006 00:30:47 -0700
Eric Capps wrote:

Andrew Thompson wrote:

It sounds like your IDE might be enforcing the type
of 'sand-box' that faces an untrusted applet on the internet.

One thing I forgot to mention is that I am not debugging this with
something like the Sun Applet Viewer, I am embedding it in HTML, loading
the page in my web browser, and using eclipse to connect to it & debug

Thank you. That fills in some details.

Where are all your resources (your applet, the
JMol applet, and any data files) coming from?

I'm not sure I understand the question. Could you be a bit more clear?

Your answer suggests you made a pretty good guess..

If you are asking where they are actually physically located,

...or URLs would be superb, but..

...the Jmol
applet is in a .jar file, my applet (the second one embedded in the
page) is in a series of .class files,

....hmm. That is interesting. While I've run plain old
class files in applets off the local disks & the web,
it is not something I'd recommend, as it can lead to
'unexpected' results.

It *might* have something to do with this problem,
though I strongly doubt it.

..and both applets and all data
files can be considered to be in the same directory on a webserver.

Yep - OK.

To get to the point you seem to have worked out..

If all the files are effectively 'in the same place', then no
security exception should result. That is apparently
*not* the problem.

I think something that may be causing this error is the method by which
I make the code in my applet aware of the code in Jmol, something I'm
doing because I want to call actual Jmol methods from within my applet.


Again, within eclipse: I have downloaded the source for Jmol (I've made
some modifications) and made it into a project in eclipse. The second
applet (mine) is also a separate eclipse project. In this project, I
have added the Jmol project to the build path. This allows me to import
classes declared in Jmol, for example, the JmolApplet class.

There is a little too much faith being placed in the IDE,
for my tastes. For instance, which classpath has precedence,
the one defined within eclipse, or the one defined in the HTML
used to launch the applet? Is that 'applet HTML' generated by
Eclipse - have you examined it?

What would help you most? To be able to see the actual execution of the
applet? Or the source, or the HTML that embeds it?

An URL that points to a page that embeds the applet and
links to the rest. It would be *best* if..
 - the applet does not require acceptance of code signatures
 - is a 'small'ish total download.
 - the demo code should be as absolutely simple as is
 practical to generate the errors you are seeing in eclipse,
 make sure it doesn not silently 'swallow' any exceptions,
 but instead dump the stack traces.

Here is one I prepared recently to investigate a problem
with dialogs, you might take some pointers off that.

One of the advantages of putting it up on the net is
that sometimes an applet that fails for you works fine
for others. That can help us figure out what is happening.

Oh, and if your going ahead with putting it up on the net,
can you 'jar' your classes up first? In fact, you might as
well test again locally once you've done that. It probably
is not part of the problem, but then again..


Andrew T.

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