Oracle Forms

Where I work we have some Oracle Forms applications and, in one of them, we need to embed a webpage which will itself contain an applet... Pretty much the only solution I found to achieve this in Java 6+ is the SWT Browser component.

I have made a proof of concept embedding the SWT Browser component inside a JApplet and everything works fine! But when we replace the top JApplet with a VBean and we embed it in our Forms application, it gives this error :

java.lang.IllegalArgumentException: Argument not valid [peer not created] 
at org.eclipse.swt.SWT.error(Unknown Source) 
at org.eclipse.swt.awt.SWT_AWT.new_Shell(Unknown Source) 
at xx.xxxxx.forms.utils.webbrowser.BrowserCanvas$1.run(BrowserCanvas.java:65)

I found some posts about this error on the net but nothing helped! The tests are done on a Windows 64bits machine. The Java version is JRE 1.6.0_12-b04 Java HotSpot(TM) Client VM.

Here's the code (heavily based on this article) :

SwtWebBrowser (the VBean) :

import java.awt.BorderLayout;
import javax.swing.JPanel;
import oracle.forms.handler.IHandler;
import oracle.forms.ui.VBean;
import org.eclipse.swt.browser.Browser;

//public class SwtWebBrowser extends JApplet {
public class SwtWebBrowser extends VBean {
    private static final long serialVersionUID = 1L;

    private JPanel panel;
    private BrowserCanvas browserCanvas;

    @Override
    //public void init() {
    public void init(IHandler handler) {
        // Required for Linux systems
        // https://bugs.eclipse.org/bugs/show_bug.cgi?id=161911
        try {
            System.setProperty("sun.awt.xembedserver", "true");
        } catch (Exception ex) {
            // ok on Windows
        }

        this.browserCanvas = new BrowserCanvas();
        this.panel = new JPanel(new BorderLayout());
        this.panel.setPreferredSize(this.getPreferredSize());
        this.panel.add(this.browserCanvas, BorderLayout.CENTER);
        add(this.panel);

        // This is VERY important: Make the frame visible BEFORE
        // connecting the SWT Shell and starting the event loop!
        setVisible(true);

        this.browserCanvas.connect();

        setURL("http://google.com");
    }

    protected Browser getBrowser() {
        return this.browserCanvas.getBrowser();
    }

    protected JPanel getPanel() {
        return this.panel;
    }

    protected void executeInBrowser(Runnable runnable) {
        getBrowser().getDisplay().asyncExec(runnable);   
    }

    public void setURL(final String url) {
        executeInBrowser(new Runnable() {
            @Override
            public void run() {
                getBrowser().setUrl(url);
            }
       });        
    }
}

BrowserCanvas :

import java.awt.Canvas;
import org.eclipse.swt.SWT;
import org.eclipse.swt.awt.SWT_AWT;
import org.eclipse.swt.browser.Browser;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class BrowserCanvas extends Canvas {
    private static final long serialVersionUID = 1L;

    private Thread swtThread;
    private Browser swtBrowser;

    /**
     * Connect this canvas to a SWT shell with a Browser component and
     * starts a background thread to handle SWT events. This method waits
     * until the browser component is ready.
     */
    public void connect() {
        if (this.swtThread == null) {
            final Canvas canvas = this;
            this.swtThread = new Thread() {

                @Override
                public void run() {
                    try {
                        Display display = new Display();

                        // The exception is here :
                        Shell shell = SWT_AWT.new_Shell(display, canvas);
                        shell.setLayout(new FillLayout());

                        synchronized (this) {
                            BrowserCanvas.this.swtBrowser = new Browser(shell, SWT.NONE);
                            this.notifyAll();
                        }

                        shell.open();
                        while (!isInterrupted() && !shell.isDisposed()) {
                            if (!display.readAndDispatch()) {
                                display.sleep();
                            }
                        }
                        shell.dispose();
                        display.dispose();
                    } catch (Exception e) {
                        interrupt();
                    }
                }
            };
            this.swtThread.start();
        }

        // Wait for the Browser instance to become ready
        synchronized (this.swtThread) {
            while (this.swtBrowser == null) {
                try {
                    this.swtThread.wait(100);
                } catch (InterruptedException e) {
                    this.swtBrowser = null;
                    this.swtThread = null;
                    break;
                }
            }
        }
    }

    /**
     * Returns the Browser instance. Will return "null" before "connect()"
     * or after "disconnect()" has been called.
     */
    public Browser getBrowser() {
        return this.swtBrowser;
    }

    /**
     * Stops the swt background thread.
     */
    public void disconnect() {
        if (this.swtThread != null) {
            this.swtBrowser = null;
            this.swtThread.interrupt();
            this.swtThread = null;
        }
    }

    /**
     * Ensures that the SWT background thread is stopped if this canvas is
     * removed from it's parent component (e.g. because the frame has been
     * disposed).
     */
    @Override
    public void removeNotify() {
        super.removeNotify();
        disconnect();
    }
}

Any idea on how to make it work would be really appreciated! Or in fact any other ideas on how to embed a webpage that contains an applet.