/*******************************************************************************
 * Copyright (c) 2003, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     
 * Port to the D programming language:
 *     Jacob Carlborg <doob@me.com>
 *******************************************************************************/
module dwt.browser.Browser;

import tango.core.Thread;

import dwt.DWT;
import dwt.DWTError;
import dwt.DWTException;
import dwt.widgets.Composite;
import dwt.widgets.Display;
import dwt.widgets.Widget;

import dwt.browser.LocationListener;
import dwt.browser.WebBrowser;
import dwt.browser.CloseWindowListener;
import dwt.browser.OpenWindowListener;
import dwt.browser.ProgressListener;
import dwt.browser.StatusTextListener;
import dwt.browser.TitleListener;
import dwt.browser.VisibilityWindowListener;

import dwt.dwthelper.utils;

/**
 * Instances of this class implement the browser user interface
 * metaphor.  It allows the user to visualize and navigate through
 * HTML documents.
 * <p>
 * Note that although this class is a subclass of <code>Composite</code>,
 * it does not make sense to set a layout on it.
 * </p>
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>MOZILLA</dd>
 * <dt><b>Events:</b></dt>
 * <dd>CloseWindowListener, LocationListener, OpenWindowListener, ProgressListener, StatusTextListener, TitleListener, VisibilityWindowListener</dd>
 * </dl>
 * <p>
 * IMPORTANT: This class is <em>not</em> intended to be subclassed.
 * </p>
 * 
 * @see <a href="http://www.eclipse.org/swt/snippets/#browser">Browser snippets</a>
 * @see <a href="http://www.eclipse.org/swt/examples.php">DWT Examples: ControlExample, BrowserExample</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 *
 * @since 3.0
 */

public class Browser : Composite {
    WebBrowser webBrowser;
    int userStyle;

    static final String PACKAGE_PREFIX = "dwt.browser."; //$NON-NLS-1$
    static final String NO_INPUT_METHOD = "dwt.internal.gtk.noInputMethod"; //$NON-NLS-1$

    /**
     * Constructs a new instance of this class given its parent
     * and a style value describing its behavior and appearance.
     * <p>
     * The style value is either one of the style constants defined in
     * class <code>DWT</code> which is applicable to instances of this
     * class, or must be built by <em>bitwise OR</em>'ing together 
     * (that is, using the <code>int</code> "|" operator) two or more
     * of those <code>DWT</code> style constants. The class description
     * lists the style constants that are applicable to the class.
     * Style bits are also inherited from superclasses.
     * </p>
     *
     * @param parent a widget which will be the parent of the new instance (cannot be null)
     * @param style the style of widget to construct
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
     * </ul>
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
     * </ul>
     * @exception DWTError <ul>
     *    <li>ERROR_NO_HANDLES if a handle could not be obtained for browser creation</li>
     * </ul>
     * 
     * @see Widget#getStyle
     * 
     * @since 3.0
     */
    public this (Composite parent, int style) {
        super(checkParent(parent), checkStyle(style));
        userStyle = style;

        String platform = DWT.getPlatform();
        Display display = parent.getDisplay();
        if ("gtk".opEquals(platform))
            display.setData(NO_INPUT_METHOD, null); //$NON-NLS-1$
        String className = null;
        if ((style & DWT.MOZILLA) !is 0) {
            className = "dwt.browser.Mozilla"; //$NON-NLS-1$
        }
        else {
            if ("win32".opEquals(platform) || "wpf".opEquals(platform)) { //$NON-NLS-1$ $NON-NLS-2$
                className = "dwt.browser.IE"; //$NON-NLS-1$
            }
            else if ("motif".opEquals(platform)) { //$NON-NLS-1$
                className = "dwt.browser.Mozilla"; //$NON-NLS-1$
            }
            else if ("gtk".opEquals(platform)) { //$NON-NLS-1$
                className = "dwt.browser.Mozilla"; //$NON-NLS-1$
            }
            else if ("carbon".opEquals(platform) || "cocoa".opEquals(platform)) { //$NON-NLS-1$
                className = "dwt.browser.Safari"; //$NON-NLS-1$
            }
            else if ("photon".opEquals(platform)) { //$NON-NLS-1$
                className = "dwt.browser.Voyager"; //$NON-NLS-1$
            }
            else {
                dispose();
                DWT.error(DWT.ERROR_NO_HANDLES);
            }
        }

        try {
            Class clazz = Class.forName(className);
            webBrowser = cast(WebBrowser) clazz.newInstance();
        }
        catch (ClassNotFoundException e) {
        } catch (IllegalAccessException e) {
        } catch (InstantiationException e) {
        }
        if (webBrowser is null) {
            dispose();
            DWT.error(DWT.ERROR_NO_HANDLES);
        }

        webBrowser.setBrowser(this);
        webBrowser.create(parent, style);
    }

    static Composite checkParent (Composite parent) {
        String platform = DWT.getPlatform();
        if (!"gtk".opEquals(platform))
            return parent; //$NON-NLS-1$

        /*
         * Note.  Mozilla provides all IM support needed for text input in web pages.
         * If DWT creates another input method context for the widget it will cause
         * indeterminate results to happen (hangs and crashes). The fix is to prevent 
         * DWT from creating an input method context for the  Browser widget.
         */
        if (parent !is null && !parent.isDisposed()) {
            Display display = parent.getDisplay();
            if (display !is null) {
                if (display.getThread() is Thread.currentThread()) {
                    display.setData(NO_INPUT_METHOD, "true"); //$NON-NLS-1$
                }
            }
        }
        return parent;
    }

    static int checkStyle (int style) {
        String platform = DWT.getPlatform();
        if ((style & DWT.MOZILLA) !is 0) {
            if ("carbon".opEquals(platform))
                return style | DWT.EMBEDDED; //$NON-NLS-1$
            if ("motif".opEquals(platform))
                return style | DWT.EMBEDDED; //$NON-NLS-1$
            return style;
        }

        if ("win32".opEquals(platform)) { //$NON-NLS-1$
            /*
             * For IE on win32 the border is supplied by the embedded browser, so remove
             * the style so that the parent Composite will not draw a second border.
             */
            return style & ~DWT.BORDER;
        }
        else if ("motif".opEquals(platform)) { //$NON-NLS-1$
            return style | DWT.EMBEDDED;
        }
        return style;
    }

    /**
     * Clears all session cookies from all current Browser instances.
     * 
     * @since 3.2
     */
    public static void clearSessions () {
        WebBrowser.clearSessions();
    }

    /**  
     * Adds the listener to the collection of listeners who will be
     * notified when the window hosting the receiver should be closed.
     * <p>
     * This notification occurs when a javascript command such as
     * <code>window.close</code> gets executed by a <code>Browser</code>.
     * </p>
     *
     * @param listener the listener which should be notified
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     *
     * @since 3.0
     */
    public void addCloseWindowListener (CloseWindowListener listener) {
        checkWidget();
        if (listener is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        webBrowser.addCloseWindowListener(listener);
    }

    /**  
     * Adds the listener to the collection of listeners who will be
     * notified when the current location has changed or is about to change.
     * <p>
     * This notification typically occurs when the application navigates
     * to a new location with {@link #setUrl(String)} or when the user
     * activates a hyperlink.
     * </p>
     *
     * @param listener the listener which should be notified
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     *
     * @since 3.0
     */
    public void addLocationListener (LocationListener listener) {
        checkWidget();
        if (listener is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        webBrowser.addLocationListener(listener);
    }

    /**  
     * Adds the listener to the collection of listeners who will be
     * notified when a new window needs to be created.
     * <p>
     * This notification occurs when a javascript command such as
     * <code>window.open</code> gets executed by a <code>Browser</code>.
     * </p>
     *
     * @param listener the listener which should be notified
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     *
     * @since 3.0
     */
    public void addOpenWindowListener (OpenWindowListener listener) {
        checkWidget();
        if (listener is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        webBrowser.addOpenWindowListener(listener);
    }

    /**  
     * Adds the listener to the collection of listeners who will be
     * notified when a progress is made during the loading of the current 
     * URL or when the loading of the current URL has been completed.
     *
     * @param listener the listener which should be notified
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     *
     * @since 3.0
     */
    public void addProgressListener (ProgressListener listener) {
        checkWidget();
        if (listener is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        webBrowser.addProgressListener(listener);
    }

    /**  
     * Adds the listener to the collection of listeners who will be
     * notified when the status text is changed.
     * <p>
     * The status text is typically displayed in the status bar of
     * a browser application.
     * </p>
     *
     * @param listener the listener which should be notified
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     *
     * @since 3.0
     */
    public void addStatusTextListener (StatusTextListener listener) {
        checkWidget();
        if (listener is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        webBrowser.addStatusTextListener(listener);
    }

    /**  
     * Adds the listener to the collection of listeners who will be
     * notified when the title of the current document is available
     * or has changed.
     *
     * @param listener the listener which should be notified
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     *
     * @since 3.0
     */
    public void addTitleListener (TitleListener listener) {
        checkWidget();
        if (listener is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        webBrowser.addTitleListener(listener);
    }

    /**  
     * Adds the listener to the collection of listeners who will be
     * notified when a window hosting the receiver needs to be displayed
     * or hidden.
     *
     * @param listener the listener which should be notified
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     *
     * @since 3.0
     */
    public void addVisibilityWindowListener (VisibilityWindowListener listener) {
        checkWidget();
        if (listener is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        webBrowser.addVisibilityWindowListener(listener);
    }

    /**
     * Navigate to the previous session history item.
     *
     * @return <code>true</code> if the operation was successful and <code>false</code> otherwise
     *
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     *
     * @see #forward
     * 
     * @since 3.0
     */
    public bool back () {
        checkWidget();
        return webBrowser.back();
    }

    protected void checkSubclass () {
        String name = getClass().getName();
        int index = name.lastIndexOf('.');
        if (!name.substring(0, index + 1).opEquals(PACKAGE_PREFIX)) {
            DWT.error(DWT.ERROR_INVALID_SUBCLASS);
        }
    }

    /**
     * Execute the specified script.
     *
     * <p>
     * Execute a script containing javascript commands in the context of the current document. 
     * 
     * @param script the script with javascript commands
     *  
     * @return <code>true</code> if the operation was successful and <code>false</code> otherwise
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the script is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     *
     * @since 3.1
     */
    public bool execute (String script) {
        checkWidget();
        if (script is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        return webBrowser.execute(script);
    }

    /**
     * Navigate to the next session history item.
     *
     * @return <code>true</code> if the operation was successful and <code>false</code> otherwise
     *
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     * 
     * @see #back
     * 
     * @since 3.0
     */
    public bool forward () {
        checkWidget();
        return webBrowser.forward();
}

/**
 * Returns the type of native browser being used by this instance.
 * Examples: "mozilla", "ie", "safari", "voyager"
 *
 * @return the type of the native browser
 * 
 * @since 3.5
 */
public String getBrowserType () {
    checkWidget();
    return webBrowser.getBrowserType ();
    }

    public int getStyle () {
        /*
         * If DWT.BORDER was specified at creation time then getStyle() should answer
         * it even though it is removed for IE on win32 in checkStyle().
         */
        return super.getStyle() | (userStyle & DWT.BORDER);
    }

    /**
     * Returns a String with HTML that represents the content of the current page.
     *
     * @return HTML representing the current page or an empty <code>String</code>
     * if this is empty
     *
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     *
     * @since 3.4
     */
    public String getText () {
        checkWidget();
        return webBrowser.getText();
    }

    /**
     * Returns the current URL.
     *
     * @return the current URL or an empty <code>String</code> if there is no current URL
     *
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     *
     * @see #setUrl
     * 
     * @since 3.0
     */
    public String getUrl () {
        checkWidget();
        return webBrowser.getUrl();
    }

    /**
     * Returns the JavaXPCOM <code>nsIWebBrowser</code> for the receiver, or <code>null</code>
     * if it is not available.  In order for an <code>nsIWebBrowser</code> to be returned all
     * of the following must be true: <ul>
     *    <li>the receiver's style must be <code>DWT.MOZILLA</code></li>
     *    <li>the classes from JavaXPCOM &gt;= 1.8.1.2 must be resolvable at runtime</li>
     *    <li>the version of the underlying XULRunner must be &gt;= 1.8.1.2</li>
     * </ul> 
     *
     * @return the receiver's JavaXPCOM <code>nsIWebBrowser</code> or <code>null</code>
     * 
     * @since 3.3
     */
    public Object getWebBrowser () {
        checkWidget();
        return webBrowser.getWebBrowser();
    }

    /**
     * Returns <code>true</code> if the receiver can navigate to the 
     * previous session history item, and <code>false</code> otherwise.
     *
     * @return the receiver's back command enabled state
     *
     * @exception DWTException <ul>
     *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
     * </ul>
     * 
     * @see #back
     */
    public bool isBackEnabled () {
        checkWidget();
        return webBrowser.isBackEnabled();
    }

    public bool isFocusControl () {
        checkWidget();
        if (webBrowser.isFocusControl())
            return true;
        return super.isFocusControl();
    }

    /**
     * Returns <code>true</code> if the receiver can navigate to the 
     * next session history item, and <code>false</code> otherwise.
     *
     * @return the receiver's forward command enabled state
     *
     * @exception DWTException <ul>
     *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
     *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
     * </ul>
     * 
     * @see #forward
     */
    public bool isForwardEnabled () {
        checkWidget();
        return webBrowser.isForwardEnabled();
    }

    /**
     * Refresh the current page.
     *
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     *
     * @since 3.0
     */
    public void refresh () {
        checkWidget();
        webBrowser.refresh();
    }

    /**  
     * Removes the listener from the collection of listeners who will
     * be notified when the window hosting the receiver should be closed.
     *
     * @param listener the listener which should no longer be notified
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     * 
     * @since 3.0
     */
    public void removeCloseWindowListener (CloseWindowListener listener) {
        checkWidget();
        if (listener is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        webBrowser.removeCloseWindowListener(listener);
    }

    /**  
     * Removes the listener from the collection of listeners who will
     * be notified when the current location is changed or about to be changed.
     *
     * @param listener the listener which should no longer be notified
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     * 
     * @since 3.0
     */
    public void removeLocationListener (LocationListener listener) {
        checkWidget();
        if (listener is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        webBrowser.removeLocationListener(listener);
    }

    /**  
     * Removes the listener from the collection of listeners who will
     * be notified when a new window needs to be created.
     *
     * @param listener the listener which should no longer be notified
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     * 
     * @since 3.0
     */
    public void removeOpenWindowListener (OpenWindowListener listener) {
        checkWidget();
        if (listener is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        webBrowser.removeOpenWindowListener(listener);
    }

    /**  
     * Removes the listener from the collection of listeners who will
     * be notified when a progress is made during the loading of the current 
     * URL or when the loading of the current URL has been completed.
     *
     * @param listener the listener which should no longer be notified
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     * 
     * @since 3.0
     */
    public void removeProgressListener (ProgressListener listener) {
        checkWidget();
        if (listener is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        webBrowser.removeProgressListener(listener);
    }

    /**  
     * Removes the listener from the collection of listeners who will
     * be notified when the status text is changed.
     *
     * @param listener the listener which should no longer be notified
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     * 
     * @since 3.0
     */
    public void removeStatusTextListener (StatusTextListener listener) {
        checkWidget();
        if (listener is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        webBrowser.removeStatusTextListener(listener);
    }

    /**  
     * Removes the listener from the collection of listeners who will
     * be notified when the title of the current document is available
     * or has changed.
     *
     * @param listener the listener which should no longer be notified
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     * 
     * @since 3.0
     */
    public void removeTitleListener (TitleListener listener) {
        checkWidget();
        if (listener is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        webBrowser.removeTitleListener(listener);
    }

    /**  
     * Removes the listener from the collection of listeners who will
     * be notified when a window hosting the receiver needs to be displayed
     * or hidden.
     *
     * @param listener the listener which should no longer be notified
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     * 
     * @since 3.0
     */
    public void removeVisibilityWindowListener (VisibilityWindowListener listener) {
        checkWidget();
        if (listener is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        webBrowser.removeVisibilityWindowListener(listener);
    }

    /**
     * Renders HTML.
     * 
     * <p>
     * The html parameter is Unicode encoded since it is a java <code>String</code>.
     * As a result, the HTML meta tag charset should not be set. The charset is implied
     * by the <code>String</code> itself.
     * 
     * @param html the HTML content to be rendered
     *
     * @return true if the operation was successful and false otherwise.
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the html is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     *  
     * @see #setUrl
     * 
     * @since 3.0
     */
    public bool setText (String html) {
        checkWidget();
        if (html is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        return webBrowser.setText(html);
    }

    /**
     * Loads a URL.
     * 
     * @param url the URL to be loaded
     *
     * @return true if the operation was successful and false otherwise.
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the url is null</li>
     * </ul>
     * 
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     *  
     * @see #getUrl
     * 
     * @since 3.0
     */
    public bool setUrl (String url) {
        checkWidget();
        if (url is null)
            DWT.error(DWT.ERROR_NULL_ARGUMENT);
        return webBrowser.setUrl(url);
    }

    /**
     * Stop any loading and rendering activity.
     *
     * @exception DWTException <ul>
     *    <li>ERROR_THREAD_INVALID_ACCESS when called from the wrong thread</li>
     *    <li>ERROR_WIDGET_DISPOSED when the widget has been disposed</li>
     * </ul>
     *
     * @since 3.0
     */
    public void stop () {
        checkWidget();
        webBrowser.stop();
    }
}