XPages: Running Google’s Chrome V8 Javascript Engine

After answering a question on Stackoverflow.com about the Prototype problematic in the XPages SSJS engine, I thought of running another Javascript engine on top of Domino.

While you can use the JavaScripting API JSR223, I choosed the jav8 project for a test how this can be realized. So I downloaded the Windows binaries to get the required DLL and imported it into a new database. I also imported the source files of the lu.fler.script package to recompile all required classes.

Then, I registered the factory service by creating a javax.script.ScriptEngineFactory file in the /META-INF/services folder and added the line lu.flier.script.V8ScriptEngineFactory.

The package explorer looked like this:

To prevent collisions, I commented out some names in the V8ScriptEngineFactory class:

For a simple test, I decided to invoke the engine manually when clicking on a button on a XPage. To do this, I created a simple ActionListener in Java which loads the JavaScript Engine and evals a simple “ var i = 1+1″. The Javascript variable is then accessed and printed out to the server console.

package ch.hasselba.xpages.jav8;

import javax.faces.event.AbortProcessingException;
import javax.faces.event.ActionEvent;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;

public class JAV8Test implements javax.faces.event.ActionListener {

    static ScriptEngineManager factory = new ScriptEngineManager();
    static ScriptEngine engine = factory.getEngineByName("jav8");

    public void processAction(ActionEvent actionEvent)
            throws AbortProcessingException {
        try {
            System.out.println( engine.getClass().getCanonicalName() );
            engine.eval("var i=1+1;");
            System.out.println( "i = " + engine.get("i") );
        } catch (ScriptException ex) {
            ex.printStackTrace();
        }
    }
}

The XPage to test the ActionListener is rather simple too:

<?xml version="1.0" encoding="UTF-8"?>
<xp:view xmlns:xp="http://www.ibm.com/xsp/core">

    <xp:button
        value="Click Me!"
        id="buttonClickMe">
        <xp:eventHandler
            event="onclick"
            submit="true"
            refreshMode="complete">
            <xp:this.actionListeners>
                <xp:actionListener type="ch.hasselba.xpages.jav8.JAV8Test" />
            </xp:this.actionListeners>
        </xp:eventHandler>
    </xp:button>
    
</xp:view>

When the button is clicked, the V8 engine works as it should:

But now comes a hard problems: It works only once! After doing this, my test server crashes completly. During playing with it, I was able to run it as it should, but I have no idea anymore how I did it. I think it is the DLL and static classes, but I am currently to busy to investigate the problem further. The @Override notations added to the methods (which must removed before the code can be compiled) do not override exitisting ones (I checked the bundled javax.script JAR of the binary package), this does not seem to be the problem. Maybe someone else has an idea?

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