Problem with initializing a class object

From:
"phillip.s.powell@gmail.com" <phillip.s.powell@gmail.com>
Newsgroups:
comp.lang.java.help
Date:
7 Feb 2007 11:59:24 -0800
Message-ID:
<1170878364.002322.321550@a75g2000cwd.googlegroups.com>
I am trying to write a more modified version of the infamous
SimpleBrowser by allowing for the WebBrowser object property to
receive a given java.net.URL object.

[code]
private final WebBrowser webBrowser = new WebBrowser();

    /**
     * Perform setup
     */
    private void setupSimpleBrowser() {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                initObjects();
                initComponents();
            }
        });
    }

    /**
     * Initialize objects
     */
    private void initObjects() {
        WebBrowser.setDebug(true); // SET TO TRUE TO SEE trace() DEBUG
STATEMENTS
    }

    /**
     * Initialize components
     */
    private void initComponents() {
        setTitle(myName);
        generateWebBrowser();
        webAddressTextField = new JTextField(51);
        generateJButton();
        p1 = new JPanel();
        p2 = new JPanel();
        addToPanel();
        forceTFFocus();
        addToFrame();
        showFrame();
    }

    /**
     * Generate {@link #webBrowser}
     */
    private void generateWebBrowser() {

        //Use below code to check the status of the navigation
process,
        //or register a listener for the notification events.
        webBrowser.addWebBrowserListener(
                new WebBrowserListener() {
            boolean isFirstPage = true;

            public void downloadStarted(WebBrowserEvent event) {;}
            public void downloadCompleted(WebBrowserEvent event) {;}
            public void downloadProgress(WebBrowserEvent event) {;}
            public void downloadError(WebBrowserEvent event) {;}
            public void documentCompleted(WebBrowserEvent event) {
                // Uncomment below code to test getContent()/
setContent()/
                // executeScript() APIs.
                // As the setContent() call will invoke this event,
which falls
                // into a loop, so check if this event is fired by the
first
                // loaded page.
                /*
                if (isFirstPage) {
                    testDOMAPI(webBrowser);
                    isFirstPage = false;
                }
                 */
            }
            public void titleChange(WebBrowserEvent event) {;}
            public void statusTextChange(WebBrowserEvent event) {;}
            public void windowClose(WebBrowserEvent event) {;}
            public void initializationCompleted(WebBrowserEvent event)
{;}
        });

        setWebBrowserURL();
        System.out.println(webBrowser.getURL().toString());
    }

    /**
     * Set {@link #webBrowser} with either instantiable {@link
java.net.URL} or with {@link #DEFAULT_URL_PATH}
     */
    private void setWebBrowserURL() {
        try {
            URL url = getURL();
            System.out.println("url = " + url);
            String urlPath = getURLPath();
            System.out.println("urlPath = " + urlPath);
            if (url != null) {
                webBrowser.setURL(url);
            } else if (urlPath != null && !urlPath.equals("")) {
                webBrowser.setURL(new URL(urlPath));
            } else {
                System.out.println("setting webBrowser with " +
DEFAULT_URL_PATH);
                webBrowser.setURL(new URL(DEFAULT_URL_PATH));
                System.out.println("set up initial homepage of " +
DEFAULT_URL_PATH);
            }
        } catch (Exception e) {
            try {
                System.out.println("oops! setting webBrowser with " +
DEFAULT_URL_PATH);
                webBrowser.setURL(new URL(DEFAULT_URL_PATH));
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
    }
[/code]

However, the moment you leave setWebBrowserURL(), or somehow, within
the Thread that is running between setWebBrowserURL() and the
System.out.println() line, this happens:

[code]
url = null
urlPath = null
setting webBrowser with http://java.net
set up initial homepage of http://java.net
*** Jtrace: You can't call this method before WebBrowser is
initialized!
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
        at
com.ppowell.tools.ObjectTools.SimpleBrowser.generateWebBrowser(SimpleBrowser.java:
349)
        at
com.ppowell.tools.ObjectTools.SimpleBrowser.initComponents(SimpleBrowser.java:
384)
        at com.ppowell.tools.ObjectTools.SimpleBrowser.access
$600(SimpleBrowser.java:42)
        at com.ppowell.tools.ObjectTools.SimpleBrowser
$4.run(SimpleBrowser.java:447)
        at
java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
        at
java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:
273)
        at
java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:
183)
        at
java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:
173)
        at
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
        at
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:
121)
*** Jtrace: Process event to native browser: -1, 0,
*** Jtrace: Send data to socket: -1,0,</html><body></html>

[/code]

I can't figure out why webBrowser will not allow for me to determine
the given java.net.URL object parameter which will allow for the
display of the given URL.

This is based upon http://www.koders.com/java/
fidC1435DC25F674DBFCB9C50BE409180D2CAD108E1.aspx

Thanx
Phil

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