Processing 1.0 - Processing Discourse - Call Java function from Javascript

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Index › Programming Questions & Help › Integration › Call Java function from Javascript

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Call Java function from Javascript (Read 1817 times)

benst

Call Java function from Javascript
Aug 8^th, 2007, 3:48am

Hello to you all,

this should be rather simple but I don't get it.
I want to my Javascript to call a Java function like

<script>
function snd()
{
document.sketch_070808b_container.doSmthng("test");
}
</script>

This is the sketch code:

import netscape.javascript.*;

public MyClass test;

void setup()
{
test = new MyClass( this );
test.doSmthng("hello world");
}

public class MyClass {
PApplet papplet;
MyClass ( PApplet _p )
{
papplet = _p;
}

void doSmthng (String str) {
papplet.println(str);
}
}

It prints "hello world" on setup(), but it never reaches doSmthng() when called by the Javascript.

What am I doing wrong?

Cheers,
Ben

fjen

Re: Call Java function from Javascript
Reply #1 - Aug 8^th, 2007, 8:59am

the method you are calling is inside a class, it needs to be on a global scope:

Code:


void setup() { .... }
void draw() { .... }

void doSmthng () { .... }

class MyClass { .... }

you can try to call document.sketch_070808b_container.test.doSmthng() too. be aware that javascript to java communication is rather unreliable .. and make sure your exported html has "mayscript" enabled (should already be set when you export with processing).

F

benst

Re: Call Java function from Javascript
Reply #2 - Aug 8^th, 2007, 12:36pm

Found it. Scriptable is set by default, but the code Processing generates doesn't create a DOM object for the applet. You can reproduce it if you generate any sketch and check with Firefox and Firebug that the element with name *_container is null. I tried to set an param id inside the applet's object, but no go.

So in short, this works (other than below the element here is known as "applet_one" not as *_container, but that doesn't change anything):

<applet id="applet_one" code="sketch_070808b" archive="sketch_070808b.jar" width="400" height="100" MAYSCRIPT="TRUE"></applet>

And this lengthy code produced by Processing doesn't work (sketch_070808b_container unknown, setting an param id inside the object won't help either):

Greets from Germany,
Ben

<div id="sketch_070808b_container">


<object classid="java:sketch_070808b.class"
type="application/x-java-applet"
archive="sketch_070808b.jar"
width="100" height="100"
standby="Loading Processing software..." >

<param name="archive" value="sketch_070808b.jar" />

<param name="mayscript" value="true" />
<param name="scriptable" value="true" />

<param name="image" value="loading.gif" />
<param name="boxmessage" value="Loading Processing software..." />
<param name="boxbgcolor" value="#FFFFFF" />

<param name="test_string" value="outer" />


<object classid="clsid:8AD9C840-044E-11D1-B3E9-00805F499D93"
codebase="http://java.sun.com/update/1.4.2/jinstall-1_4_2_12-windows-i586.cab"
width="100" height="100"
standby="Loading Processing software..." >

<param name="code" value="sketch_070808b" />
<param name="archive" value="sketch_070808b.jar" />

<param name="mayscript" value="true" />
<param name="scriptable" value="true" />

<param name="image" value="loading.gif" />
<param name="boxmessage" value="Loading Processing software..." />
<param name="boxbgcolor" value="#FFFFFF" />

fjen God Member Offline Posts: 965	Re: Call Java function from Javascript Reply #3 - Aug 8^th, 2007, 5:00pm hmm .. i'm pretty sure the code produced by processing is ok. i think you have to go for document.applets[0] (applets array). did you check that? i'm looking into the DOM problem as soon as i can. here's a bug for that: http://dev.processing.org/bugs/show_bug.cgi?id=608 F

fjen

Re: Call Java function from Javascript
Reply #4 - Aug 19^th, 2007, 9:41am

here's a test for FF to show it's working:

Code:


<!-- add this right after <body> -->
<script type="application/x-javascript" >
// add id="applet_outer"
// to first <object>
var pinit = function ( event )
{
var applet = document.getElementById( "applet_outer" );
console.log( applet.parentNode );
};
addEventListener( 'load', pinit, false );
</script>

the problem with your code is that you tried to call the functions on the container, which is a DIV not the actual applet (<OBJECT>).

here's some code that will list all nodes in the container, including the applet (OBJECT) and it's functions that are available to javascript:

Code:



// console.log() is firebug-addon for firefox
// you will need that ...

var container = document.getElementById( "sketch_070819a_container" );

for ( var num in container.childNodes )
{
  console.log( " ---------------------------------- " );
  console.log( container.childNodes[num] );
  var node = container.childNodes[num].nodeName;

  for ( var attr in container.childNodes[num] )
  {
    console.log( node + " " + attr + " " + container.childNodes[num][attr] );
  };
};

benst

Re: Call Java function from Javascript
Reply #5 - Aug 19^th, 2007, 1:54pm

Yes, that was the problem. I found it myself later, I'm sorry that I didn't share it. It works with all browser I've tested (IE6, IE7, FF2, FF1.5, Konqueror) but Opera. But that's most propably because of it's limited Javascript engine, I tested with applet and object tag.

Maybe Processing could generate an id for the object by itself.

~Ben

fjen God Member Offline Posts: 965	Re: Call Java function from Javascript Reply #6 - Aug 19^th, 2007, 2:09pm yeah i have the ID on my list .. have to update the templates for the next release. can you post a link to what you've done? thanks F

benst

Re: Call Java function from Javascript
Reply #7 - Aug 19^th, 2007, 2:27pm

Sure,

http://estudy-portal.de/~wa-soziomat/applet/java.htm
http://estudy-portal.de/~wa-soziomat/test/java.html

The first uses the applet tag, the latter the object tag. Opera can't deal with the applet.
This is a GPL project. I can put the sources online if you like.

~Ben

fjen wrote on Aug 19^th, 2007, 2:09pm:

yeah i have the ID on my list .. have to update the templates for the next release.

can you post a link to what you've done

thanks
F

fjen

Re: Call Java function from Javascript
Reply #8 - Aug 19^th, 2007, 2:40pm

super. danke.

i don't need to see the sources, was just interessted in your javascript code. i think you have to define the onclick handler as:

onclick="snd1(); return false;"

a return value is assumed by the specs ... returning false will keep it from "bubbling up".

btw, on safari 2.x the <applet> version is not working

best
F

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