* Copyright (c) 2014 IBM Corporation, Oracle and Other Contributors

* 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 implementation in Eclipse Form UI as FormText

*    Martin Donnelly (m2a3@eircom.net) - [145997] FormText::computeTextSize returns incorrect date for horizontal size

*    Ling Hao - adaptation to Sapphire requirements

*    Ling Hao - [284393] Allow FormText to be transparent

*    Konstantin Komissarchik - [357714] Display validation messages for content outline nodes

*******************************************************************************/

* This class is a read-only text control that is capable of rendering wrapped

* text. Text can be rendered as-is or by parsing the formatting XML tags.

* Independently, words that start with http:// can be converted into hyperlinks

* on the fly.

* <p>

* When configured to use formatting XML, the control requires the root element

* <code>form</code> to be used and requires any ampersand (&amp;) characters in the text to

* be replaced by the entity <b>&amp;amp;</b>. The following tags can be children of the

* <code>form</code> element:

* </p>

* <ul>

* <li><b>p </b>- for defining paragraphs. The following attributes are

* allowed:

* <ul>

* <li><b>vspace </b>- if set to 'false', no vertical space will be added

* (default is 'true')</li>

* </ul>

* </li>

* <li><b>li </b>- for defining list items. The following attributes are

* allowed:

* <ul>

* <li><b>vspace </b>- the same as with the <b>p </b> tag</li>

* <li><b>style </b>- could be 'bullet' (default), 'text' and 'image'</li>

* <li><b>value </b>- not used for 'bullet'. For text, it is the value of the

* text that is rendered as a bullet. For image, it is the href of the image to

* be rendered as a bullet.</li>

* <li><b>indent </b>- the number of pixels to indent the text in the list item

* </li>

* <li><b>bindent </b>- the number of pixels to indent the bullet itself</li>

* </ul>

* </li>

* </ul>

* <p>

* Text in paragraphs and list items will be wrapped according to the width of

* the control. The following tags can appear as children of either <b>p </b> or

* <b>li </b> elements:

* <ul>

* <li><b>img </b>- to render an image. Element accepts attribute 'href' that

* is a key to the <code>Image</code> set using 'setImage' method. Vertical

* position of image relative to surrounding text is optionally controlled by

* the attribute <b>align</b> that can have values <b>top</b>, <b>middle</b>

* and <b>bottom</b></li>

* <li><b>a </b>- to render a hyperlink. Element accepts attribute 'href' that

* will be provided to the hyperlink listeners via HyperlinkEvent object. The

* element also accepts 'nowrap' attribute (default is false). When set to

* 'true', the hyperlink will not be wrapped. Hyperlinks automatically created

* when 'http://' is encountered in text are not wrapped.</li>

* <li><b>b </b>- the enclosed text will use bold font.</li>

* <li><b>br </b>- forced line break (no attributes).</li>

* <li><b>span </b>- the enclosed text will have the color and font specified

* in the element attributes. Color is provided using 'color' attribute and is a

* key to the Color object set by 'setColor' method. Font is provided using

* 'font' attribute and is a key to the Font object set by 'setFont' method. As with

* hyperlinks, it is possible to block wrapping by setting 'nowrap' to true

* (false by default).

* </li>

* <li><b>control (new in 3.1)</b> - to place a control that is a child of the

* text control. Element accepts attribute 'href' that is a key to the Control

* object set using 'setControl' method. Optionally, attribute 'fill' can be set

* to <code>true</code> to make the control fill the entire width of the text.

* Form text is not responsible for creating or disposing controls, it only

* places them relative to the surrounding text. Similar to <b>img</b>,

* vertical position of the control can be set using the <b>align</b>

* attribute. In addition, <b>width</b> and <b>height</b> attributes can

* be used to force the dimensions of the control. If not used,

* the preferred control size will be used.

* </ul>

* <p>

* None of the elements can nest. For example, you cannot have <b>b </b> inside

* a <b>span </b>. This was done to keep everything simple and transparent.

* Since 3.1, an exception to this rule has been added to support nesting images

* and text inside the hyperlink tag (<b>a</b>). Image enclosed in the

* hyperlink tag acts as a hyperlink, can be clicked on and can accept and

* render selection focus. When both text and image is enclosed, selection and

* rendering will affect both as a single hyperlink.

* </p>

* <p>

* Since 3.1, it is possible to select text. Text selection can be

* programmatically accessed and also copied to clipboard. Non-textual objects

* (images, controls etc.) in the selection range are ignored.

* <p>

* Care should be taken when using this control. Form text is not an HTML

* browser and should not be treated as such. If you need complex formatting

* capabilities, use Browser widget. If you need editing capabilities and

* font/color styles of text segments is all you need, use StyleText widget.

* Finally, if all you need is to wrap text, use SWT Label widget and create it

* with SWT.WRAP style.

*

* @see org.eclipse.ui.forms.widgets.FormToolkit

* @see org.eclipse.ui.forms.widgets.TableWrapLayout

* @author IBM Corporation

*/

    /**

     * The object ID to be used when registering action to handle URL hyperlinks

     * (those that should result in opening the web browser). Value is

     * "urlHandler".

     */

    public static final String URL_HANDLER_ID = "urlHandler"; //$NON-NLS-1$

    /**

     * Value of the horizontal margin (default is 0).

     */

    public int marginWidth = 0;

    /**

     * Value of tue vertical margin (default is 1).

     */

    public int marginHeight = 1;

    // private fields

    private static final boolean DEBUG_TEXT = false;//"true".equalsIgnoreCase(Platform.getDebugOption(FormUtil.DEBUG_TEXT));

    private static final boolean DEBUG_TEXTSIZE = false;//"true".equalsIgnoreCase(Platform.getDebugOption(FormUtil.DEBUG_TEXTSIZE));

    private static final boolean DEBUG_FOCUS = false;//"true".equalsIgnoreCase(Platform.getDebugOption(FormUtil.DEBUG_FOCUS));   

    private boolean hasFocus;

    private boolean paragraphsSeparated = true;

    private FormTextModel model;

    private ListenerList listeners;

    private Hashtable resourceTable = new Hashtable();

    private IHyperlinkSegment entered;

    private IHyperlinkSegment armed;

    private boolean mouseFocus = false;

    private boolean controlFocusTransfer = false;

    private boolean inSelection = false;

    private SelectionData selData;

   

    private final List<Image> imagesToDispose = new ArrayList<Image>();

   

    private String text;

    private static final String INTERNAL_MENU = "__internal_menu__"; //$NON-NLS-1$

    private static final String CONTROL_KEY = "__segment__"; //$NON-NLS-1$

    private class FormTextLayout extends Layout implements ILayoutExtension {

        public FormTextLayout() {

        }

        public int computeMaximumWidth(Composite parent, boolean changed) {

            return computeSize(parent, SWT.DEFAULT, SWT.DEFAULT, changed).x;

        }

        public int computeMinimumWidth(Composite parent, boolean changed) {

            return computeSize(parent, 5, SWT.DEFAULT, true).x;

        }

        /*

         * @see Layout#computeSize(Composite, int, int, boolean)

         */

        public Point computeSize(Composite composite, int wHint, int hHint,

                boolean changed) {

            long start = 0;

            if (DEBUG_TEXT)

                start = System.currentTimeMillis();

            int innerWidth = wHint;

            if (innerWidth != SWT.DEFAULT)

                innerWidth -= marginWidth * 2;

            Point textSize = computeTextSize(innerWidth);

            int textWidth = textSize.x + 2 * marginWidth;

            int textHeight = textSize.y + 2 * marginHeight;

            Point result = new Point(textWidth, textHeight);

            if (DEBUG_TEXT) {

                long stop = System.currentTimeMillis();

                System.out.println("FormText computeSize: " + (stop - start) //$NON-NLS-1$

                        + "ms"); //$NON-NLS-1$

            }

            if (DEBUG_TEXTSIZE) {

                System.out.println("FormText ("+model.getAccessibleText()+"), computeSize: wHint="+wHint+", result="+result); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$

            }

            return result;

        }

        private Point computeTextSize(int wHint) {

            Paragraph[] paragraphs = model.getParagraphs();

            GC gc = new GC(SapphireFormText.this);

            gc.setFont(getFont());

            Locator loc = new Locator();

            int width = wHint != SWT.DEFAULT ? wHint : 0;

            FontMetrics fm = gc.getFontMetrics();

            int lineHeight = fm.getHeight();

            boolean selectableInTheLastRow = false;

            for (int i = 0; i < paragraphs.length; i++) {

                Paragraph p = paragraphs[i];

                if (i > 0 && getParagraphsSeparated()

                        && p.getAddVerticalSpace())

                    loc.y += getParagraphSpacing(lineHeight);

                loc.rowHeight = 0;

                loc.indent = p.getIndent();

                loc.x = p.getIndent();

                ParagraphSegment[] segments = p.getSegments();

                if (segments.length > 0) {

                    selectableInTheLastRow = false;

                    int pwidth = 0;

                    for (int j = 0; j < segments.length; j++) {

                        ParagraphSegment segment = segments[j];

                        segment.advanceLocator(gc, wHint, loc, resourceTable, false);

                        if (wHint != SWT.DEFAULT) {

                            width = Math.max(width, loc.width);

                        } else {

                            pwidth = Math.max(pwidth, loc.width);

                        }

                        if (segment instanceof IFocusSelectable)

                            selectableInTheLastRow = true;

                    }

                    if (wHint == SWT.DEFAULT)

                        width = Math.max(width, pwidth);

                    loc.y += loc.rowHeight;

                } else {

                    // empty new line

                    loc.y += lineHeight;

                }

            }

            gc.dispose();

            if (selectableInTheLastRow)

                loc.y += 1;

            return new Point(width, loc.y);

        }

        protected void layout(Composite composite, boolean flushCache) {

            long start = 0;

            if (DEBUG_TEXT) {

                start = System.currentTimeMillis();

            }

            selData = null;

            Rectangle carea = composite.getClientArea();

            if (DEBUG_TEXTSIZE) {

                System.out.println("FormText layout ("+model.getAccessibleText()+"), carea="+carea); //$NON-NLS-1$ //$NON-NLS-2$

            }           

            GC gc = new GC(composite);

            gc.setFont(getFont());

            ensureBoldFontPresent(getFont());

            gc.setForeground(getForeground());

            gc.setBackground(getBackground());

            Locator loc = new Locator();

            loc.marginWidth = marginWidth;

            loc.y = marginHeight;

            FontMetrics fm = gc.getFontMetrics();

            int lineHeight = fm.getHeight();

            Paragraph[] paragraphs = model.getParagraphs();

            IHyperlinkSegment selectedLink = getSelectedLink();

            for (int i = 0; i < paragraphs.length; i++) {

                Paragraph p = paragraphs[i];

                if (i > 0 && paragraphsSeparated && p.getAddVerticalSpace())

                    loc.y += getParagraphSpacing(lineHeight);

                loc.indent = p.getIndent();

                loc.resetCaret();

                loc.rowHeight = 0;

                p.layout(gc, carea.width, loc, lineHeight, resourceTable,

                        selectedLink);

            }

            gc.dispose();

            if (DEBUG_TEXT) {

                long stop = System.currentTimeMillis();

                System.out.println("FormText.layout: " + (stop - start) + "ms"); //$NON-NLS-1$ //$NON-NLS-2$

            }

        }

    }

   

    /**

     * Contructs a new form text widget in the provided parent and using the

     * styles.

     * <p>

     * The only valid style bit for <code>FormText</code> is <code>SWT.NO_FOCUS</code>.

     * This will cause the widget to always refuse focus.

     *

     * @param parent

     *            form text parent control

     * @param style

     *            the widget style

     */

    public SapphireFormText(Composite parent, int style) {

        super(parent, SWT.DOUBLE_BUFFERED | SWT.WRAP | style);

        setLayout(new FormTextLayout());

        model = new FormTextModel();

        addDisposeListener(new DisposeListener() {

            public void widgetDisposed(DisposeEvent e) {

                handleDisposeEvent();

            }

        });

        addPaintListener(new PaintListener() {

            public void paintControl(PaintEvent e) {

                paint(e);

            }

        });

        addListener(SWT.KeyDown, new Listener() {

            public void handleEvent(Event e) {

                if (e.character == '\r') {

                    activateSelectedLink();

                    return;

                }

            }

        });

        addListener(SWT.Traverse, new Listener() {

            public void handleEvent(Event e) {

                if (DEBUG_FOCUS)

                    System.out.println("Traversal: " + e); //$NON-NLS-1$

                switch (e.detail) {

                case SWT.TRAVERSE_PAGE_NEXT:

                case SWT.TRAVERSE_PAGE_PREVIOUS:

                case SWT.TRAVERSE_ARROW_NEXT:

                case SWT.TRAVERSE_ARROW_PREVIOUS:

                    e.doit = false;

                    return;

                }

                if (!model.hasFocusSegments()) {

                    e.doit = true;

                    return;

                }

                if (e.detail == SWT.TRAVERSE_TAB_NEXT)

                    e.doit = advance(true);

                else if (e.detail == SWT.TRAVERSE_TAB_PREVIOUS)

                    e.doit = advance(false);

                else if (e.detail != SWT.TRAVERSE_RETURN)

                    e.doit = true;

            }

        });

        addFocusListener(new FocusListener() {

            public void focusGained(FocusEvent e) {

                if (!hasFocus) {

                    hasFocus = true;

                    if (DEBUG_FOCUS) {

                        System.out.println("FormText: focus gained"); //$NON-NLS-1$

                    }

                    if (!mouseFocus && !controlFocusTransfer) {

                        handleFocusChange();

                    }

                }

            }

            public void focusLost(FocusEvent e) {

                if (DEBUG_FOCUS) {

                    System.out.println("FormText: focus lost"); //$NON-NLS-1$

                }

                if (hasFocus) {

                    hasFocus = false;

                    if (!controlFocusTransfer)

                        handleFocusChange();

                }

            }

        });

        addMouseListener(new MouseListener() {

            public void mouseDoubleClick(MouseEvent e) {

            }

            public void mouseDown(MouseEvent e) {

                // select a link

                handleMouseClick(e, true);

            }

            public void mouseUp(MouseEvent e) {

                // activate a link

                handleMouseClick(e, false);

            }

        });

        addMouseTrackListener(new MouseTrackListener() {

            public void mouseEnter(MouseEvent e) {

                handleMouseMove(e);

            }

            public void mouseExit(MouseEvent e) {

                if (entered != null) {

                    exitLink(entered, e.stateMask);

                    paintLinkHover(entered, false);

                    entered = null;

                    setCursor(null);

                }

            }

            public void mouseHover(MouseEvent e) {

                handleMouseHover(e);

            }

        });

        addMouseMoveListener(new MouseMoveListener() {

            public void mouseMove(MouseEvent e) {

                handleMouseMove(e);

            }

        });

        initAccessible();

        ensureBoldFontPresent(getFont());

        createMenu();

        // we will handle traversal of controls, if any

        setTabList(new Control[] {});

    }

    /**

     * Test for focus.

     *

     * @return <samp>true </samp> if the widget has focus.

     */

    public boolean getFocus() {

        return hasFocus;

    }

    /**

     * Test if the widget is currently processing the text it is about to

     * render.

     *

     * @return <samp>true </samp> if the widget is still loading the text,

     *         <samp>false </samp> otherwise.

     * @deprecated not used any more - returns <code>false</code>

     */

    public boolean isLoading() {

        return false;

    }

    /**

     * Returns the text that will be shown in the control while the real content

     * is loading.

     *

     * @return loading text message

     * @deprecated loading text is not used since 3.1

     */

    public String getLoadingText() {

        return null;

    }

    /**

     * Sets the text that will be shown in the control while the real content is

     * loading. This is significant when content to render is loaded from the

     * input stream that was created from a remote URL, and the time to load the

     * entire content is nontrivial.

     *

     * @param loadingText

     *            loading text message

     * @deprecated use setText(loadingText, false, false);

     */

    public void setLoadingText(String loadingText) {

        setText(loadingText, false, false);

    }

    /**

     * If paragraphs are separated, spacing will be added between them.

     * Otherwise, new paragraphs will simply start on a new line with no

     * spacing.

     *

     * @param value

     *            <samp>true </samp> if paragraphs are separated, </samp> false

     *            </samp> otherwise.

     */

    public void setParagraphsSeparated(boolean value) {

        paragraphsSeparated = value;

    }

    /**

     * Tests if there is some inter-paragraph spacing.

     *

     * @return <samp>true </samp> if paragraphs are separated, <samp>false

     *         </samp> otherwise.

     */

    public boolean getParagraphsSeparated() {

        return paragraphsSeparated;

    }

    /**

     * Registers the image referenced by the provided key.

     * <p>

     * For <samp>img </samp> tags, an object of a type <samp>Image </samp> must

     * be registered using the key equivalent to the value of the <samp>href

     * </samp> attribute used in the tag.

     *

     * @param key

     *            unique key that matches the value of the <samp>href </samp>

     *            attribute.

     * @param image

     *            an object of a type <samp>Image </samp>.

     */

    public void setImage(String key, Image image) {

        resourceTable.put("i." + key, image); //$NON-NLS-1$

    }

   

    public void setImage( final String key,

                          final ImageDescriptor imageDescriptor )

    {

        final Image image = imageDescriptor.createImage();

        this.imagesToDispose.add( image );

        setImage( key, image );

    }

   

    public void setImage( final String key,

                          final ImageData imageData )

    {

        setImage( key, SwtUtil.toImageDescriptor( imageData ) );

    }

    /**

     * Registers the color referenced by the provided key.

     * <p>

     * For <samp>span </samp> tags, an object of a type <samp>Color </samp> must

     * be registered using the key equivalent to the value of the <samp>color

     * </samp> attribute.

     *

     * @param key

     *            unique key that matches the value of the <samp>color </samp>

     *            attribute.

     * @param color

     *            an object of the type <samp>Color </samp> or <samp>null</samp>

     *            if the key needs to be cleared.

     */

    public void setColor(String key, Color color) {

        String fullKey = "c." + key; //$NON-NLS-1$

        if (color == null)

            resourceTable.remove(fullKey);

        else

            resourceTable.put(fullKey, color);

    }

    /**

     * Registers the font referenced by the provided key.

     * <p>

     * For <samp>span </samp> tags, an object of a type <samp>Font </samp> must

     * be registered using the key equivalent to the value of the <samp>font

     * </samp> attribute.

     *

     * @param key

     *            unique key that matches the value of the <samp>font </samp>

     *            attribute.

     * @param font

     *            an object of the type <samp>Font </samp> or <samp>null</samp>

     *            if the key needs to be cleared.

     */

    public void setFont(String key, Font font) {

        String fullKey = "f." + key; //$NON-NLS-1$

        if (font == null)

            resourceTable.remove(fullKey);

        else

            resourceTable.put(fullKey, font);

        model.clearCache(fullKey);

    }

    /**

     * Registers the control referenced by the provided key.

     * <p>

     * For <samp>control</samp> tags, an object of a type <samp>Control</samp>

     * must be registered using the key equivalent to the value of the

     * <samp>control</samp> attribute.

     *

     * @param key

     *            unique key that matches the value of the <samp>control</samp>

     *            attribute.

     * @param control

     *            an object of the type <samp>Control</samp> or <samp>null</samp>

     *            if the existing control at the specified key needs to be

     *            removed.

     * @since 3.1

     */

    public void setControl(String key, Control control) {

        String fullKey = "o." + key; //$NON-NLS-1$

        if (control == null)

            resourceTable.remove(fullKey);

        else

            resourceTable.put(fullKey, control);

    }

    /**

     * Sets the font to use to render the default text (text that does not have

     * special font property assigned). Bold font will be constructed from this

     * font.

     *

     * @param font

     *            the default font to use

     */

    public void setFont(Font font) {

        super.setFont(font);

        model.clearCache(null);

        Font boldFont = (Font) resourceTable.get(FormTextModel.BOLD_FONT_ID);

        if (boldFont != null) {

            FormFonts.getInstance().markFinished(boldFont, getDisplay());

            resourceTable.remove(FormTextModel.BOLD_FONT_ID);

        }

        ensureBoldFontPresent(getFont());

    }

    /**

     * Sets the provided text. Text can be rendered as-is, or by parsing the

     * formatting tags. Optionally, sections of text starting with http:// will

     * be converted to hyperlinks.

     *

     * @param text

     *            the text to render

     * @param parseTags

     *            if <samp>true </samp>, formatting tags will be parsed.

     *            Otherwise, text will be rendered as-is.

     * @param expandURLs

     *            if <samp>true </samp>, URLs found in the untagged text will be

     *            converted into hyperlinks.

     */

    public void setText(String text, boolean parseTags, boolean expandURLs) {

        this.text = text;

        disposeResourceTable(false);

        entered = null;

        if (parseTags)

            model.parseTaggedText(text, expandURLs);

        else

            model.parseRegularText(text, expandURLs);

        hookControlSegmentFocus();

        layout();

        redraw();

    }

   

    public String getText()

    {

        return this.text;

    }

    /**

     * Sets the contents of the stream. Optionally, URLs in untagged text can be

     * converted into hyperlinks. The caller is responsible for closing the

     * stream.

     *

     * @param is

     *            stream to render

     * @param expandURLs

     *            if <samp>true </samp>, URLs found in untagged text will be

     *            converted into hyperlinks.

     */

    public void setContents(InputStream is, boolean expandURLs) {

        entered = null;

        disposeResourceTable(false);

        model.parseInputStream(is, expandURLs);

        hookControlSegmentFocus();

        layout();

        redraw();

    }

    private void hookControlSegmentFocus() {

        Paragraph[] paragraphs = model.getParagraphs();

        if (paragraphs == null)

            return;

        Listener listener = new Listener() {

            public void handleEvent(Event e) {

                switch (e.type) {

                case SWT.FocusIn:

                    if (!controlFocusTransfer)

                        syncControlSegmentFocus((Control) e.widget);

                    break;

                case SWT.Traverse:

                    if (DEBUG_FOCUS)

                        System.out.println("Control traversal: " + e); //$NON-NLS-1$

                    switch (e.detail) {

                    case SWT.TRAVERSE_PAGE_NEXT:

                    case SWT.TRAVERSE_PAGE_PREVIOUS:

                    case SWT.TRAVERSE_ARROW_NEXT:

                    case SWT.TRAVERSE_ARROW_PREVIOUS:

                        e.doit = false;

                        return;

                    }

                    Control c = (Control) e.widget;

                    ControlSegment segment = (ControlSegment) c

                            .getData(CONTROL_KEY);

                    if (e.detail == SWT.TRAVERSE_TAB_NEXT)

                        e.doit = advanceControl(c, segment, true);

                    else if (e.detail == SWT.TRAVERSE_TAB_PREVIOUS)

                        e.doit = advanceControl(c, segment, false);

                    if (!e.doit)

                        e.detail = SWT.TRAVERSE_NONE;

                    break;

                }

            }

        };

        for (int i = 0; i < paragraphs.length; i++) {

            Paragraph p = paragraphs[i];

            ParagraphSegment[] segments = p.getSegments();

            for (int j = 0; j < segments.length; j++) {

                if (segments[j] instanceof ControlSegment) {

                    ControlSegment cs = (ControlSegment) segments[j];

                    Control c = cs.getControl(resourceTable);

                    if (c != null) {

                        if (c.getData(CONTROL_KEY) == null) {

                            // first time - hook

                            c.setData(CONTROL_KEY, cs);

                            attachTraverseListener(c, listener);

                        }

                    }

                }

            }

        }

    }

    private void attachTraverseListener(Control c, Listener listener) {

        if (c instanceof Composite) {

            Composite parent = (Composite) c;

            Control[] children = parent.getChildren();

            for (int i = 0; i < children.length; i++) {

                attachTraverseListener(children[i], listener);

            }

            if (c instanceof Canvas) {

                // If Canvas, the control iteself can accept

                // traverse events and should be monitored

                c.addListener(SWT.Traverse, listener);

                c.addListener(SWT.FocusIn, listener);

            }

        } else {

            c.addListener(SWT.Traverse, listener);

            c.addListener(SWT.FocusIn, listener);

        }

    }

    /**

     * If we click on the control randomly, our internal book-keeping will be

     * off. We need to update the model and mark the control segment and

     * currently selected. Hyperlink that may have had focus must also be

     * exited.

     *

     * @param control

     *            the control that got focus

     */

    private void syncControlSegmentFocus(Control control) {

        ControlSegment cs = null;

        while (control != null) {

            cs = (ControlSegment) control.getData(CONTROL_KEY);

            if (cs != null)

                break;

            control = control.getParent();

        }

        if (cs == null)

            return;

        IFocusSelectable current = model.getSelectedSegment();

        // If the model and the control match, all is well

        if (current == cs)

            return;

        IHyperlinkSegment oldLink = null;

        if (current != null && current instanceof IHyperlinkSegment) {

            oldLink = (IHyperlinkSegment) current;

            exitLink(oldLink, SWT.NULL);

        }

        if (DEBUG_FOCUS)

            System.out.println("Sync control: " + cs + ", oldLink=" + oldLink); //$NON-NLS-1$ //$NON-NLS-2$

        model.select(cs);

        if (oldLink != null)

            paintFocusTransfer(oldLink, null);

        // getAccessible().setFocus(model.getSelectedSegmentIndex());

    }

    private boolean advanceControl(Control c, ControlSegment segment,

            boolean next) {

        Composite parent = c.getParent();

        if (parent == this) {

            // segment-level control

            IFocusSelectable nextSegment = model.getNextFocusSegment(next);

            if (nextSegment != null) {

                controlFocusTransfer = true;

                super.forceFocus();

                controlFocusTransfer = false;

                model.select(segment);

                return advance(next);

            }

            // nowhere to go

            return setFocusToNextSibling(this, next);

        }

        if (setFocusToNextSibling(c, next))

            return true;

        // still here - must go one level up

        segment = (ControlSegment) parent.getData(CONTROL_KEY);

        return advanceControl(parent, segment, next);

    }

    private boolean setFocusToNextSibling(Control c, boolean next) {

        Composite parent = c.getParent();

        Control[] children = parent.getTabList();

        for (int i = 0; i < children.length; i++) {

            Control child = children[i];

            if (child == c) {

                // here

                if (next) {

                    for (int j = i + 1; j < children.length; j++) {

                        Control nc = children[j];

                        if (nc.setFocus())

                            return false;

                    }

                } else {

                    for (int j = i - 1; j >= 0; j--) {

                        Control pc = children[j];

                        if (pc.setFocus())

                            return false;

                    }

                }

            }

        }

        return false;

    }

    /**

     * Controls whether whitespace inside paragraph and list items is

     * normalized. Note that the new value will not affect the current text in

     * the control, only subsequent calls to <code>setText</code> or

     * <code>setContents</code>.

     * <p>

     * If normalized:

     * <ul>

     * <li>all white space characters will be condensed into at most one when

     * between words.</li>

     * <li>new line characters will be ignored and replaced with one white

     * space character</li>

     * <li>white space characters after the opening tags and before the closing

     * tags will be trimmed</li>

     *

     * @param value

     *            <code>true</code> if whitespace is normalized,

     *            <code>false</code> otherwise.

     */

    public void setWhitespaceNormalized(boolean value) {

        model.setWhitespaceNormalized(value);

    }

    /**

     * Tests whether whitespace inside paragraph and list item is normalized.

     *

     * @see #setWhitespaceNormalized(boolean)

     * @return <code>true</code> if whitespace is normalized,

     *         <code>false</code> otherwise.

     */

    public boolean isWhitespaceNormalized() {

        return model.isWhitespaceNormalized();

    }

    /**

     * Disposes the internal menu if created and sets the menu provided as a

     * parameter.

     *

     * @param menu

     *            the menu to associate with this text control

     */

    public void setMenu(Menu menu) {

        Menu currentMenu = super.getMenu();

        if (currentMenu != null && INTERNAL_MENU.equals(currentMenu.getData())) {

            // internal menu set

            if (menu != null) {

                currentMenu.dispose();

                super.setMenu(menu);

            }

        } else

            super.setMenu(menu);

    }

    private void createMenu() {

        Menu menu = new Menu(this);

        final MenuItem copyItem = new MenuItem(menu, SWT.PUSH);

        copyItem.setText(Messages.FormText_copy);

        SelectionListener listener = new SelectionAdapter() {

            public void widgetSelected(SelectionEvent e) {

                if (e.widget == copyItem) {

                    copy();

                }

            }

        };

        copyItem.addSelectionListener(listener);

        menu.addMenuListener(new MenuListener() {

            public void menuShown(MenuEvent e) {

                copyItem.setEnabled(canCopy());

            }

            public void menuHidden(MenuEvent e) {

            }

        });

        menu.setData(INTERNAL_MENU);

        super.setMenu(menu);

    }

    /**

     * Returns the hyperlink settings that are in effect for this control.

     *

     * @return current hyperlinks settings

     */

    public HyperlinkSettings getHyperlinkSettings() {

        return model.getHyperlinkSettings();

    }

    /**

     * Sets the hyperlink settings to be used for this control. Settings will

     * affect things like hyperlink color, rendering style, cursor etc.

     *

     * @param settings

     *            hyperlink settings for this control

     */

    public void setHyperlinkSettings(HyperlinkSettings settings) {

        model.setHyperlinkSettings(settings);

    }

    /**

     * Adds a listener that will handle hyperlink events.

     *

     * @param listener

     *            the listener to add

     */

    public void addHyperlinkListener(IHyperlinkListener listener) {

        if (listeners == null)

            listeners = new ListenerList();

        listeners.add(listener);

    }

    /**

     * Removes the hyperlink listener.

     *

     * @param listener

     *            the listener to remove

     */

    public void removeHyperlinkListener(IHyperlinkListener listener) {

        if (listeners == null)

            return;

        listeners.remove(listener);

    }

    /**

     * Adds a selection listener. A Selection event is sent by the widget when

     * the selection has changed.

     * <p>

     * <code>widgetDefaultSelected</code> is not called for FormText.

     * </p>

     *

     * @param listener

     *            the listener

     * @exception org.eclipse.swt.SWTException

     *                <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>

     * @exception IllegalArgumentException

     *                <ul>

     *                <li>ERROR_NULL_ARGUMENT when listener is null</li>

     *                </ul>

     * @since 3.1

     */

    public void addSelectionListener(SelectionListener listener) {

        checkWidget();

        if (listener == null) {

            SWT.error(SWT.ERROR_NULL_ARGUMENT);

        }

        TypedListener typedListener = new TypedListener(listener);

        addListener(SWT.Selection, typedListener);

    }

    /**

     * Removes the specified selection listener.

     * <p>

     *

     * @param listener

     *            the listener

     * @exception org.eclipse.swt.SWTException

     *                <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>

     * @exception IllegalArgumentException

     *                <ul>

     *                <li>ERROR_NULL_ARGUMENT when listener is null</li>

     *                </ul>

     * @since 3.1

     */

    public void removeSelectionListener(SelectionListener listener) {

        checkWidget();

        if (listener == null) {

            SWT.error(SWT.ERROR_NULL_ARGUMENT);

        }

        removeListener(SWT.Selection, listener);

    }

    /**

     * Returns the selected text.

     * <p>

     *

     * @return selected text, or an empty String if there is no selection.

     * @exception org.eclipse.swt.SWTException

     *                <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>

     * @since 3.1

     */

    public String getSelectionText() {

        checkWidget();

        if (selData != null)

            return selData.getSelectionText();

        return ""; //$NON-NLS-1$

    }

    /**

     * Tests if the text is selected and can be copied into the clipboard.

     *

     * @return <code>true</code> if the selected text can be copied into the

     *         clipboard, <code>false</code> otherwise.

     * @since 3.1

     */

    public boolean canCopy() {

        return selData != null && selData.canCopy();

    }

    /**

     * Copies the selected text into the clipboard. Does nothing if no text is

     * selected or the text cannot be copied for any other reason.

     *

     * @since 3.1

     */

    public void copy() {

        if (!canCopy())

            return;

        Clipboard clipboard = new Clipboard(getDisplay());

        Object[] o = new Object[] { getSelectionText() };

        Transfer[] t = new Transfer[] { TextTransfer.getInstance() };

        clipboard.setContents(o, t);

        clipboard.dispose();

    }

    /**

     * Returns the reference of the hyperlink that currently has keyboard focus,

     * or <code>null</code> if there are no hyperlinks in the receiver or no

     * hyperlink has focus at the moment.

     *

     * @return href of the selected hyperlink or <code>null</code> if none

     *         selected.

     * @since 3.1

     */

    public Object getSelectedLinkHref() {

        IHyperlinkSegment link = getSelectedLink();

        return link != null ? link.getHref() : null;

    }

    /**

     * Returns the text of the hyperlink that currently has keyboard focus, or

     * <code>null</code> if there are no hyperlinks in the receiver or no

     * hyperlink has focus at the moment.

     *

     * @return text of the selected hyperlink or <code>null</code> if none

     *         selected.

     * @since 3.1

     */

    public String getSelectedLinkText() {

        IHyperlinkSegment link = getSelectedLink();

        return link != null ? link.getText() : null;

    }

    private IHyperlinkSegment getSelectedLink() {

        IFocusSelectable segment = model.getSelectedSegment();

        if (segment != null && segment instanceof IHyperlinkSegment)

            return (IHyperlinkSegment) segment;

        return null;

    }

    private void initAccessible() {

        Accessible accessible = getAccessible();

        accessible.addAccessibleListener(new AccessibleAdapter() {

            public void getName(AccessibleEvent e) {

                if (e.childID == ACC.CHILDID_SELF)

                    e.result = model.getAccessibleText();

                else {

                    int linkCount = model.getHyperlinkCount();

                    if (e.childID >= 0 && e.childID < linkCount) {

                        IHyperlinkSegment link = model.getHyperlink(e.childID);

                        e.result = link.getText();

                    }

                }

            }

            public void getHelp(AccessibleEvent e) {

                e.result = getToolTipText();

                int linkCount = model.getHyperlinkCount();

                if (e.result == null && e.childID >= 0 && e.childID < linkCount) {

                    IHyperlinkSegment link = model.getHyperlink(e.childID);

                    e.result = link.getText();

                }

            }

        });

        accessible.addAccessibleControlListener(new AccessibleControlAdapter() {

            public void getChildAtPoint(AccessibleControlEvent e) {

                Point pt = toControl(new Point(e.x, e.y));

                IHyperlinkSegment link = model.findHyperlinkAt(pt.x, pt.y);

                if (link != null)

                    e.childID = model.indexOf(link);

                else

                    e.childID = ACC.CHILDID_SELF;

            }

            public void getLocation(AccessibleControlEvent e) {

                Rectangle location = null;

                if (e.childID != ACC.CHILDID_SELF

                        && e.childID != ACC.CHILDID_NONE) {

                    int index = e.childID;

                    IHyperlinkSegment link = model.getHyperlink(index);

                    if (link != null) {

                        location = link.getBounds();

                    }

                }

                if (location == null) {

                    location = getBounds();

                }

                Point pt = toDisplay(new Point(location.x, location.y));

                e.x = pt.x;

                e.y = pt.y;

                e.width = location.width;

                e.height = location.height;

            }

            public void getFocus(AccessibleControlEvent e) {

                int childID = ACC.CHILDID_NONE;

                if (model.hasFocusSegments()) {

                    int selectedIndex = model.getSelectedSegmentIndex();

                    if (selectedIndex != -1) {

                        childID = selectedIndex;

                    }

                }

                e.childID = childID;

            }

           

            public void getDefaultAction (AccessibleControlEvent e) {

                if (model.getHyperlinkCount() > 0) {

                    e.result = SWT.getMessage ("SWT_Press"); //$NON-NLS-1$

                }

            }

            public void getChildCount(AccessibleControlEvent e) {

                e.detail = model.getHyperlinkCount();

            }

            public void getRole(AccessibleControlEvent e) {

                int role = 0;

                int childID = e.childID;

                int linkCount = model.getHyperlinkCount();

                if (childID == ACC.CHILDID_SELF) {

                    if (linkCount > 0) {

                        role = ACC.ROLE_LINK;

                    } else {

                        role = ACC.ROLE_TEXT;

                    }

                } else if (childID >= 0 && childID < linkCount) {

                    role = ACC.ROLE_LINK;

                }

                e.detail = role;

            }

            public void getSelection(AccessibleControlEvent e) {

                int selectedIndex = model.getSelectedSegmentIndex();

                e.childID = (selectedIndex == -1) ? ACC.CHILDID_NONE

                        : selectedIndex;

            }

            public void getState(AccessibleControlEvent e) {

                int linkCount = model.getHyperlinkCount();

                int selectedIndex = model.getSelectedSegmentIndex();

                int state = 0;

                int childID = e.childID;

                if (childID == ACC.CHILDID_SELF) {

                    state = ACC.STATE_NORMAL;

                } else if (childID >= 0 && childID < linkCount) {

                    state = ACC.STATE_SELECTABLE;

                    if (isFocusControl()) {

                        state |= ACC.STATE_FOCUSABLE;

                    }

                    if (selectedIndex == childID) {

                        state |= ACC.STATE_SELECTED;

                        if (isFocusControl()) {

                            state |= ACC.STATE_FOCUSED;

                        }

                    }

                }

                state |= ACC.STATE_READONLY;

                e.detail = state;

            }