Java Applet<-->JavaScript communication (Firefox 3).

[Daniel Pitts]

I only need to support Firefox 3 at the moment, so any advice can be
specific to that.

I have a Java Applet, lets call it HelperApplet.

It has one method of importance:
public Object doHelp(JSObject callback) {
System.out.prin tln(callback + "\n" + callback.getMem ber("foo"));
callback.call(" helped", new Object[] {callback.getMe mber("foo")});
return callback;
}

I have javascript that does this:

myCallback = documents.apple ts[0].doHelp({
foo: "bar",
helped: function(result ) {
alert(result);
}
});

Unfortunately, the callback doesn't get called. It appears the the
JSObject callback doesn't contain any members in Java land. Although, I
can access the returned object, eg myCallback.help ed("Broken Java") works.

Any advice? Work-arounds? Are my attempts probably going to be futile?

Thanks,
Daniel.

--
Daniel Pitts' Tech Blog: <http://virtualinfinity .net/wordpress/>

[Daniel Pitts]

Daniel Pitts wrote:

I only need to support Firefox 3 at the moment, so any advice can be
specific to that.

I have a Java Applet, lets call it HelperApplet.

It has one method of importance:
public Object doHelp(JSObject callback) {
System.out.prin tln(callback + "\n" + callback.getMem ber("foo"));
callback.call(" helped", new Object[] {callback.getMe mber("foo")});
return callback;
}

I have javascript that does this:

myCallback = documents.apple ts[0].doHelp({
foo: "bar",
helped: function(result ) {
alert(result);
}
});

Unfortunately, the callback doesn't get called. It appears the the
JSObject callback doesn't contain any members in Java land. Although, I
can access the returned object, eg myCallback.help ed("Broken Java") works.

Any advice? Work-arounds? Are my attempts probably going to be futile?

Thanks,
Daniel.

I figured out a work around, not pretty, but it does the trick:

public class MyApplet extends JApplet {
private JSObject appletTmp;

public JSObject resolveObject(O bject o) {
final int hashCode = System.identity HashCode(o);
appletTmp.setMe mber("toResolve " + hashCode, o);
return (JSObject) appletTmp.getMe mber("toResolve " + hashCode);
}

public void init() {
if (appletTmp == null) {
final JSObject window = JSObject.getWin dow(this);
final String tmpName = "_AppletTmp " +
System.identity HashCode(this);
window.eval("va r "+ tmpName +" = {}");
appletTmp = (JSObject)windo w.getMember(tmp Name);
}
}

public Object doHelp(Object o) {
JSObject callback = resolveObject(o );
System.out.prin tln(callback + "\n" + callback.getMem ber("foo"));
callback.call(" helped", new Object[] {callback.getMe mber("foo")});
return callback;
}
}

--
Daniel Pitts' Tech Blog: <http://virtualinfinity .net/wordpress/>