New Java Plugin applet experiment

[vash]

Hi,
I have modified the "Javascript Location-marks Applet" example using JNLP built-in support available in the new Java Plugin included in the Java SE 6 Update 10.

The applet starts really fast now with this new plugin and it is more stable .

It can be tested here (Firefox 3 or IE 7 and Java SE update 10 is required, you can find it here)

What i have modified :

html code :

...
<applet id="wwjApplet" name="wwjApplet" mayscript code="gov.nasa.worldwind.examples.applet.WWJApplet" width=100% height=70% >
<param name="jnlp_href" value="wwjapplet.jnlp">
</applet>
...

jnlp code :

<?xml version="1.0" encoding="utf-8"?>
<jnlp href="wwjapplet.jnlp">
    <information>
        <title>World Wind Java New Plugin Applet Demo</title>
        <vendor>NASA</vendor>
        <homepage href="http://worldwind.arc.nasa.gov"/>
        <description>World Wind Java New Plugin Applet Demo</description>
        <description kind="short">World Wind Java New Plugin Applet Demo</description>
        <offline-allowed/>
    </information>
    <security>
        <all-permissions/>
    </security>

    <resources>
        <j2se href="http://java.sun.com/products/autodl/j2se" version="1.5+" initial-heap-size="512m"
              max-heap-size="512m"/>
        <property name="sun.java2d.noddraw" value="true"/>
        <jar href="http://worldwind.arc.nasa.gov/java/demos/WWJApplet.jar" main="false"/>
        <jar href="http://worldwind.arc.nasa.gov/java/demos/worldwind.jar" main="false"/>
        <extension name="jogl"
                   href="http://download.java.net/media/jogl/builds/archive/jsr-231-webstart-current/jogl.jnlp"/>
    </resources>
     <applet-desc 
         name="My Applet"
         main-class="gov.nasa.worldwind.examples.applet.WWJApplet"
         width="300"
         height="300">
     <param name="MAYSCRIPT" value="true"/>
     </applet-desc>
</jnlp>

Now you can manage the memory allocated to the applet using the same system than in JNLP :

...
<j2se href="http://java.sun.com/products/autodl/j2se" version="1.5+" initial-heap-size="512m"
              max-heap-size="512m"/>
...

Moreover the built-in JNLP support avoids WWJ applets from using applet-launcher anymore.
The side effect of this modification is that the javascript code that calls the applet have to be rewritten from :

document.getElementById('wwjApplet').getSubApplet().method(params);

to

document.getElementById('wwjApplet').method(params);

[patmurris]

Thanks Nicolas, this is a nice run down of the new Java plugin features. I'll have to look into it

[vash]

Java 6 update 10 is available now. You could download it on the java se website

[patmurris]

BTW: is there an html version using the OBJECT tag instead of the APPLET one which is deprecated?

[TomServo]

Originally Posted by vash

Java 6 update 10 is available now. You could download it on the java se website

FINALLY!

Now, to make my website visitors update so I can use the better code.

[patmurris]

Here are some notes from Sun's Ken Russell about the new plugin:

The Cascade Mountains WWJ applet example converted to a new-style applet is here:

https://jdk6.dev.java.net/plugin2/#DEMOS

and described in detail here:

https://jdk6.dev.java.net/plugin2/jn...PLES_WORLDWIND

Basically, this eliminates the need for the JNLPAppletLauncher, and is a much more
robust technique in general. You can use all of the JNLP APIs you might otherwise
use in a Java Web Start application.

Note that the getWWJApplet() function on that web page caches the applet via

var theApplet = null;

function getWWJApplet() {
  if (theApplet == null) {
     theApplet = document.getElementById('wwjApplet');
  }
  return theApplet;
}

You can actually have an old-style and a new-style applet in the same applet tag,
for backward compatibility, so:

<applet archive="..." code="...JNLPAppletLauncher">
   <param ...> <!-- Parameters for JNLPAppletLauncher -->
   <param name="jnlp_href" value="WWJApplet.jnlp">  <!-- Picked up by the new Java Plug-In -->
</applet>

so the JNLPAppletLauncher will be used if the old Java Plug-In is in use, and
the WWJApplet.jnlp will be used if the new Java Plug-In is in use. You can then
make the JavaScript portable with a technique like

function getWWJApplet() {
  if (theApplet == null) {
     theApplet = document.getElementById('wwjApplet');
  }
  // See if we're using the old Java Plug-In and the JNLPAppletLauncher
  try {
     theApplet = theApplet.getSubApplet();
  } catch (e) {
     // Using new-style applet -- ignore
  }
  return theApplet;
}