Java example source code file (AccessibleHTML.java)
The AccessibleHTML.java Java example source code
/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package javax.swing.text.html;
import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import javax.accessibility.*;
import java.text.BreakIterator;
/*
* The AccessibleHTML class provide information about the contents
* of a HTML document to assistive technologies.
*
* @author Lynn Monsanto
*/
class AccessibleHTML implements Accessible {
/**
* The editor.
*/
private JEditorPane editor;
/**
* Current model.
*/
private Document model;
/**
* DocumentListener installed on the current model.
*/
private DocumentListener docListener;
/**
* PropertyChangeListener installed on the editor
*/
private PropertyChangeListener propChangeListener;
/**
* The root ElementInfo for the document
*/
private ElementInfo rootElementInfo;
/*
* The root accessible context for the document
*/
private RootHTMLAccessibleContext rootHTMLAccessibleContext;
public AccessibleHTML(JEditorPane pane) {
editor = pane;
propChangeListener = new PropertyChangeHandler();
setDocument(editor.getDocument());
docListener = new DocumentHandler();
}
/**
* Sets the document.
*/
private void setDocument(Document document) {
if (model != null) {
model.removeDocumentListener(docListener);
}
if (editor != null) {
editor.removePropertyChangeListener(propChangeListener);
}
this.model = document;
if (model != null) {
if (rootElementInfo != null) {
rootElementInfo.invalidate(false);
}
buildInfo();
model.addDocumentListener(docListener);
}
else {
rootElementInfo = null;
}
if (editor != null) {
editor.addPropertyChangeListener(propChangeListener);
}
}
/**
* Returns the Document currently presenting information for.
*/
private Document getDocument() {
return model;
}
/**
* Returns the JEditorPane providing information for.
*/
private JEditorPane getTextComponent() {
return editor;
}
/**
* Returns the ElementInfo representing the root Element.
*/
private ElementInfo getRootInfo() {
return rootElementInfo;
}
/**
* Returns the root <code>View associated with the current text
* component.
*/
private View getRootView() {
return getTextComponent().getUI().getRootView(getTextComponent());
}
/**
* Returns the bounds the root View will be rendered in.
*/
private Rectangle getRootEditorRect() {
Rectangle alloc = getTextComponent().getBounds();
if ((alloc.width > 0) && (alloc.height > 0)) {
alloc.x = alloc.y = 0;
Insets insets = editor.getInsets();
alloc.x += insets.left;
alloc.y += insets.top;
alloc.width -= insets.left + insets.right;
alloc.height -= insets.top + insets.bottom;
return alloc;
}
return null;
}
/**
* If possible acquires a lock on the Document. If a lock has been
* obtained a key will be retured that should be passed to
* <code>unlock.
*/
private Object lock() {
Document document = getDocument();
if (document instanceof AbstractDocument) {
((AbstractDocument)document).readLock();
return document;
}
return null;
}
/**
* Releases a lock previously obtained via <code>lock.
*/
private void unlock(Object key) {
if (key != null) {
((AbstractDocument)key).readUnlock();
}
}
/**
* Rebuilds the information from the current info.
*/
private void buildInfo() {
Object lock = lock();
try {
Document doc = getDocument();
Element root = doc.getDefaultRootElement();
rootElementInfo = new ElementInfo(root);
rootElementInfo.validate();
} finally {
unlock(lock);
}
}
/*
* Create an ElementInfo subclass based on the passed in Element.
*/
ElementInfo createElementInfo(Element e, ElementInfo parent) {
AttributeSet attrs = e.getAttributes();
if (attrs != null) {
Object name = attrs.getAttribute(StyleConstants.NameAttribute);
if (name == HTML.Tag.IMG) {
return new IconElementInfo(e, parent);
}
else if (name == HTML.Tag.CONTENT || name == HTML.Tag.CAPTION) {
return new TextElementInfo(e, parent);
}
else if (name == HTML.Tag.TABLE) {
return new TableElementInfo(e, parent);
}
}
return null;
}
/**
* Returns the root AccessibleContext for the document
*/
public AccessibleContext getAccessibleContext() {
if (rootHTMLAccessibleContext == null) {
rootHTMLAccessibleContext =
new RootHTMLAccessibleContext(rootElementInfo);
}
return rootHTMLAccessibleContext;
}
/*
* The roow AccessibleContext for the document
*/
private class RootHTMLAccessibleContext extends HTMLAccessibleContext {
public RootHTMLAccessibleContext(ElementInfo elementInfo) {
super(elementInfo);
}
/**
* Gets the accessibleName property of this object. The accessibleName
* property of an object is a localized String that designates the purpose
* of the object. For example, the accessibleName property of a label
* or button might be the text of the label or button itself. In the
* case of an object that doesn't display its name, the accessibleName
* should still be set. For example, in the case of a text field used
* to enter the name of a city, the accessibleName for the en_US locale
* could be 'city.'
*
* @return the localized name of the object; null if this
* object does not have a name
*
* @see #setAccessibleName
*/
public String getAccessibleName() {
if (model != null) {
return (String)model.getProperty(Document.TitleProperty);
} else {
return null;
}
}
/**
* Gets the accessibleDescription property of this object. If this
* property isn't set, returns the content type of this
* <code>JEditorPane instead (e.g. "plain/text", "html/text").
*
* @return the localized description of the object; <code>null
* if this object does not have a description
*
* @see #setAccessibleName
*/
public String getAccessibleDescription() {
return editor.getContentType();
}
/**
* Gets the role of this object. The role of the object is the generic
* purpose or use of the class of this object. For example, the role
* of a push button is AccessibleRole.PUSH_BUTTON. The roles in
* AccessibleRole are provided so component developers can pick from
* a set of predefined roles. This enables assistive technologies to
* provide a consistent interface to various tweaked subclasses of
* components (e.g., use AccessibleRole.PUSH_BUTTON for all components
* that act like a push button) as well as distinguish between subclasses
* that behave differently (e.g., AccessibleRole.CHECK_BOX for check boxes
* and AccessibleRole.RADIO_BUTTON for radio buttons).
* <p>Note that the AccessibleRole class is also extensible, so
* custom component developers can define their own AccessibleRole's
* if the set of predefined roles is inadequate.
*
* @return an instance of AccessibleRole describing the role of the object
* @see AccessibleRole
*/
public AccessibleRole getAccessibleRole() {
return AccessibleRole.TEXT;
}
}
/*
* Base AccessibleContext class for HTML elements
*/
protected abstract class HTMLAccessibleContext extends AccessibleContext
implements Accessible, AccessibleComponent {
protected ElementInfo elementInfo;
public HTMLAccessibleContext(ElementInfo elementInfo) {
this.elementInfo = elementInfo;
}
// begin AccessibleContext implementation ...
public AccessibleContext getAccessibleContext() {
return this;
}
/**
* Gets the state set of this object.
*
* @return an instance of AccessibleStateSet describing the states
* of the object
* @see AccessibleStateSet
*/
public AccessibleStateSet getAccessibleStateSet() {
AccessibleStateSet states = new AccessibleStateSet();
Component comp = getTextComponent();
if (comp.isEnabled()) {
states.add(AccessibleState.ENABLED);
}
if (comp instanceof JTextComponent &&
((JTextComponent)comp).isEditable()) {
states.add(AccessibleState.EDITABLE);
states.add(AccessibleState.FOCUSABLE);
}
if (comp.isVisible()) {
states.add(AccessibleState.VISIBLE);
}
if (comp.isShowing()) {
states.add(AccessibleState.SHOWING);
}
return states;
}
/**
* Gets the 0-based index of this object in its accessible parent.
*
* @return the 0-based index of this object in its parent; -1 if this
* object does not have an accessible parent.
*
* @see #getAccessibleParent
* @see #getAccessibleChildrenCount
* @see #getAccessibleChild
*/
public int getAccessibleIndexInParent() {
return elementInfo.getIndexInParent();
}
/**
* Returns the number of accessible children of the object.
*
* @return the number of accessible children of the object.
*/
public int getAccessibleChildrenCount() {
return elementInfo.getChildCount();
}
/**
* Returns the specified Accessible child of the object. The Accessible
* children of an Accessible object are zero-based, so the first child
* of an Accessible child is at index 0, the second child is at index 1,
* and so on.
*
* @param i zero-based index of child
* @return the Accessible child of the object
* @see #getAccessibleChildrenCount
*/
public Accessible getAccessibleChild(int i) {
ElementInfo childInfo = elementInfo.getChild(i);
if (childInfo != null && childInfo instanceof Accessible) {
return (Accessible)childInfo;
} else {
return null;
}
}
/**
* Gets the locale of the component. If the component does not have a
* locale, then the locale of its parent is returned.
*
* @return this component's locale. If this component does not have
* a locale, the locale of its parent is returned.
*
* @exception IllegalComponentStateException
* If the Component does not have its own locale and has not yet been
* added to a containment hierarchy such that the locale can be
* determined from the containing parent.
*/
public Locale getLocale() throws IllegalComponentStateException {
return editor.getLocale();
}
// ... end AccessibleContext implementation
// begin AccessibleComponent implementation ...
public AccessibleComponent getAccessibleComponent() {
return this;
}
/**
* Gets the background color of this object.
*
* @return the background color, if supported, of the object;
* otherwise, null
* @see #setBackground
*/
public Color getBackground() {
return getTextComponent().getBackground();
}
/**
* Sets the background color of this object.
*
* @param c the new Color for the background
* @see #setBackground
*/
public void setBackground(Color c) {
getTextComponent().setBackground(c);
}
/**
* Gets the foreground color of this object.
*
* @return the foreground color, if supported, of the object;
* otherwise, null
* @see #setForeground
*/
public Color getForeground() {
return getTextComponent().getForeground();
}
/**
* Sets the foreground color of this object.
*
* @param c the new Color for the foreground
* @see #getForeground
*/
public void setForeground(Color c) {
getTextComponent().setForeground(c);
}
/**
* Gets the Cursor of this object.
*
* @return the Cursor, if supported, of the object; otherwise, null
* @see #setCursor
*/
public Cursor getCursor() {
return getTextComponent().getCursor();
}
/**
* Sets the Cursor of this object.
*
* @param cursor the new Cursor for the object
* @see #getCursor
*/
public void setCursor(Cursor cursor) {
getTextComponent().setCursor(cursor);
}
/**
* Gets the Font of this object.
*
* @return the Font,if supported, for the object; otherwise, null
* @see #setFont
*/
public Font getFont() {
return getTextComponent().getFont();
}
/**
* Sets the Font of this object.
*
* @param f the new Font for the object
* @see #getFont
*/
public void setFont(Font f) {
getTextComponent().setFont(f);
}
/**
* Gets the FontMetrics of this object.
*
* @param f the Font
* @return the FontMetrics, if supported, the object; otherwise, null
* @see #getFont
*/
public FontMetrics getFontMetrics(Font f) {
return getTextComponent().getFontMetrics(f);
}
/**
* Determines if the object is enabled. Objects that are enabled
* will also have the AccessibleState.ENABLED state set in their
* AccessibleStateSets.
*
* @return true if object is enabled; otherwise, false
* @see #setEnabled
* @see AccessibleContext#getAccessibleStateSet
* @see AccessibleState#ENABLED
* @see AccessibleStateSet
*/
public boolean isEnabled() {
return getTextComponent().isEnabled();
}
/**
* Sets the enabled state of the object.
*
* @param b if true, enables this object; otherwise, disables it
* @see #isEnabled
*/
public void setEnabled(boolean b) {
getTextComponent().setEnabled(b);
}
/**
* Determines if the object is visible. Note: this means that the
* object intends to be visible; however, it may not be
* showing on the screen because one of the objects that this object
* is contained by is currently not visible. To determine if an object
* is showing on the screen, use isShowing().
* <p>Objects that are visible will also have the
* AccessibleState.VISIBLE state set in their AccessibleStateSets.
*
* @return true if object is visible; otherwise, false
* @see #setVisible
* @see AccessibleContext#getAccessibleStateSet
* @see AccessibleState#VISIBLE
* @see AccessibleStateSet
*/
public boolean isVisible() {
return getTextComponent().isVisible();
}
/**
* Sets the visible state of the object.
*
* @param b if true, shows this object; otherwise, hides it
* @see #isVisible
*/
public void setVisible(boolean b) {
getTextComponent().setVisible(b);
}
/**
* Determines if the object is showing. This is determined by checking
* the visibility of the object and its ancestors.
* Note: this
* will return true even if the object is obscured by another (for
* example, it is underneath a menu that was pulled down).
*
* @return true if object is showing; otherwise, false
*/
public boolean isShowing() {
return getTextComponent().isShowing();
}
/**
* Checks whether the specified point is within this object's bounds,
* where the point's x and y coordinates are defined to be relative
* to the coordinate system of the object.
*
* @param p the Point relative to the coordinate system of the object
* @return true if object contains Point; otherwise false
* @see #getBounds
*/
public boolean contains(Point p) {
Rectangle r = getBounds();
if (r != null) {
return r.contains(p.x, p.y);
} else {
return false;
}
}
/**
* Returns the location of the object on the screen.
*
* @return the location of the object on screen; null if this object
* is not on the screen
* @see #getBounds
* @see #getLocation
*/
public Point getLocationOnScreen() {
Point editorLocation = getTextComponent().getLocationOnScreen();
Rectangle r = getBounds();
if (r != null) {
return new Point(editorLocation.x + r.x,
editorLocation.y + r.y);
} else {
return null;
}
}
/**
* Gets the location of the object relative to the parent in the form
* of a point specifying the object's top-left corner in the screen's
* coordinate space.
*
* @return An instance of Point representing the top-left corner of the
* object's bounds in the coordinate space of the screen; null if
* this object or its parent are not on the screen
* @see #getBounds
* @see #getLocationOnScreen
*/
public Point getLocation() {
Rectangle r = getBounds();
if (r != null) {
return new Point(r.x, r.y);
} else {
return null;
}
}
/**
* Sets the location of the object relative to the parent.
* @param p the new position for the top-left corner
* @see #getLocation
*/
public void setLocation(Point p) {
}
/**
* Gets the bounds of this object in the form of a Rectangle object.
* The bounds specify this object's width, height, and location
* relative to its parent.
*
* @return A rectangle indicating this component's bounds; null if
* this object is not on the screen.
* @see #contains
*/
public Rectangle getBounds() {
return elementInfo.getBounds();
}
/**
* Sets the bounds of this object in the form of a Rectangle object.
* The bounds specify this object's width, height, and location
* relative to its parent.
*
* @param r rectangle indicating this component's bounds
* @see #getBounds
*/
public void setBounds(Rectangle r) {
}
/**
* Returns the size of this object in the form of a Dimension object.
* The height field of the Dimension object contains this object's
* height, and the width field of the Dimension object contains this
* object's width.
*
* @return A Dimension object that indicates the size of this component;
* null if this object is not on the screen
* @see #setSize
*/
public Dimension getSize() {
Rectangle r = getBounds();
if (r != null) {
return new Dimension(r.width, r.height);
} else {
return null;
}
}
/**
* Resizes this object so that it has width and height.
*
* @param d The dimension specifying the new size of the object.
* @see #getSize
*/
public void setSize(Dimension d) {
Component comp = getTextComponent();
comp.setSize(d);
}
/**
* Returns the Accessible child, if one exists, contained at the local
* coordinate Point.
*
* @param p The point relative to the coordinate system of this object.
* @return the Accessible, if it exists, at the specified location;
* otherwise null
*/
public Accessible getAccessibleAt(Point p) {
ElementInfo innerMostElement = getElementInfoAt(rootElementInfo, p);
if (innerMostElement instanceof Accessible) {
return (Accessible)innerMostElement;
} else {
return null;
}
}
private ElementInfo getElementInfoAt(ElementInfo elementInfo, Point p) {
if (elementInfo.getBounds() == null) {
return null;
}
if (elementInfo.getChildCount() == 0 &&
elementInfo.getBounds().contains(p)) {
return elementInfo;
} else {
if (elementInfo instanceof TableElementInfo) {
// Handle table caption as a special case since it's the
// only table child that is not a table row.
ElementInfo captionInfo =
((TableElementInfo)elementInfo).getCaptionInfo();
if (captionInfo != null) {
Rectangle bounds = captionInfo.getBounds();
if (bounds != null && bounds.contains(p)) {
return captionInfo;
}
}
}
for (int i = 0; i < elementInfo.getChildCount(); i++)
{
ElementInfo childInfo = elementInfo.getChild(i);
ElementInfo retValue = getElementInfoAt(childInfo, p);
if (retValue != null) {
return retValue;
}
}
}
return null;
}
/**
* Returns whether this object can accept focus or not. Objects that
* can accept focus will also have the AccessibleState.FOCUSABLE state
* set in their AccessibleStateSets.
*
* @return true if object can accept focus; otherwise false
* @see AccessibleContext#getAccessibleStateSet
* @see AccessibleState#FOCUSABLE
* @see AccessibleState#FOCUSED
* @see AccessibleStateSet
*/
public boolean isFocusTraversable() {
Component comp = getTextComponent();
if (comp instanceof JTextComponent) {
if (((JTextComponent)comp).isEditable()) {
return true;
}
}
return false;
}
/**
* Requests focus for this object. If this object cannot accept focus,
* nothing will happen. Otherwise, the object will attempt to take
* focus.
* @see #isFocusTraversable
*/
public void requestFocus() {
// TIGER - 4856191
if (! isFocusTraversable()) {
return;
}
Component comp = getTextComponent();
if (comp instanceof JTextComponent) {
comp.requestFocusInWindow();
try {
if (elementInfo.validateIfNecessary()) {
// set the caret position to the start of this component
Element elem = elementInfo.getElement();
((JTextComponent)comp).setCaretPosition(elem.getStartOffset());
// fire a AccessibleState.FOCUSED property change event
AccessibleContext ac = editor.getAccessibleContext();
PropertyChangeEvent pce = new PropertyChangeEvent(this,
AccessibleContext.ACCESSIBLE_STATE_PROPERTY,
null, AccessibleState.FOCUSED);
ac.firePropertyChange(
AccessibleContext.ACCESSIBLE_STATE_PROPERTY,
null, pce);
}
} catch (IllegalArgumentException e) {
// don't fire property change event
}
}
}
/**
* Adds the specified focus listener to receive focus events from this
* component.
*
* @param l the focus listener
* @see #removeFocusListener
*/
public void addFocusListener(FocusListener l) {
getTextComponent().addFocusListener(l);
}
/**
* Removes the specified focus listener so it no longer receives focus
* events from this component.
*
* @param l the focus listener
* @see #addFocusListener
*/
public void removeFocusListener(FocusListener l) {
getTextComponent().removeFocusListener(l);
}
// ... end AccessibleComponent implementation
} // ... end HTMLAccessibleContext
/*
* ElementInfo for text
*/
class TextElementInfo extends ElementInfo implements Accessible {
TextElementInfo(Element element, ElementInfo parent) {
super(element, parent);
}
// begin AccessibleText implementation ...
private AccessibleContext accessibleContext;
public AccessibleContext getAccessibleContext() {
if (accessibleContext == null) {
accessibleContext = new TextAccessibleContext(this);
}
return accessibleContext;
}
/*
* AccessibleContext for text elements
*/
public class TextAccessibleContext extends HTMLAccessibleContext
implements AccessibleText {
public TextAccessibleContext(ElementInfo elementInfo) {
super(elementInfo);
}
public AccessibleText getAccessibleText() {
return this;
}
/**
* Gets the accessibleName property of this object. The accessibleName
* property of an object is a localized String that designates the purpose
* of the object. For example, the accessibleName property of a label
* or button might be the text of the label or button itself. In the
* case of an object that doesn't display its name, the accessibleName
* should still be set. For example, in the case of a text field used
* to enter the name of a city, the accessibleName for the en_US locale
* could be 'city.'
*
* @return the localized name of the object; null if this
* object does not have a name
*
* @see #setAccessibleName
*/
public String getAccessibleName() {
if (model != null) {
return (String)model.getProperty(Document.TitleProperty);
} else {
return null;
}
}
/**
* Gets the accessibleDescription property of this object. If this
* property isn't set, returns the content type of this
* <code>JEditorPane instead (e.g. "plain/text", "html/text").
*
* @return the localized description of the object; <code>null
* if this object does not have a description
*
* @see #setAccessibleName
*/
public String getAccessibleDescription() {
return editor.getContentType();
}
/**
* Gets the role of this object. The role of the object is the generic
* purpose or use of the class of this object. For example, the role
* of a push button is AccessibleRole.PUSH_BUTTON. The roles in
* AccessibleRole are provided so component developers can pick from
* a set of predefined roles. This enables assistive technologies to
* provide a consistent interface to various tweaked subclasses of
* components (e.g., use AccessibleRole.PUSH_BUTTON for all components
* that act like a push button) as well as distinguish between subclasses
* that behave differently (e.g., AccessibleRole.CHECK_BOX for check boxes
* and AccessibleRole.RADIO_BUTTON for radio buttons).
* <p>Note that the AccessibleRole class is also extensible, so
* custom component developers can define their own AccessibleRole's
* if the set of predefined roles is inadequate.
*
* @return an instance of AccessibleRole describing the role of the object
* @see AccessibleRole
*/
public AccessibleRole getAccessibleRole() {
return AccessibleRole.TEXT;
}
/**
* Given a point in local coordinates, return the zero-based index
* of the character under that Point. If the point is invalid,
* this method returns -1.
*
* @param p the Point in local coordinates
* @return the zero-based index of the character under Point p; if
* Point is invalid returns -1.
*/
public int getIndexAtPoint(Point p) {
View v = getView();
if (v != null) {
return v.viewToModel(p.x, p.y, getBounds());
} else {
return -1;
}
}
/**
* Determine the bounding box of the character at the given
* index into the string. The bounds are returned in local
* coordinates. If the index is invalid an empty rectangle is
* returned.
*
* @param i the index into the String
* @return the screen coordinates of the character's the bounding box,
* if index is invalid returns an empty rectangle.
*/
public Rectangle getCharacterBounds(int i) {
try {
return editor.getUI().modelToView(editor, i);
} catch (BadLocationException e) {
return null;
}
}
/**
* Return the number of characters (valid indicies)
*
* @return the number of characters
*/
public int getCharCount() {
if (validateIfNecessary()) {
Element elem = elementInfo.getElement();
return elem.getEndOffset() - elem.getStartOffset();
}
return 0;
}
/**
* Return the zero-based offset of the caret.
*
* Note: That to the right of the caret will have the same index
* value as the offset (the caret is between two characters).
* @return the zero-based offset of the caret.
*/
public int getCaretPosition() {
View v = getView();
if (v == null) {
return -1;
}
Container c = v.getContainer();
if (c == null) {
return -1;
}
if (c instanceof JTextComponent) {
return ((JTextComponent)c).getCaretPosition();
} else {
return -1;
}
}
/**
* IndexedSegment extends Segment adding the offset into the
* the model the <code>Segment was asked for.
*/
private class IndexedSegment extends Segment {
/**
* Offset into the model that the position represents.
*/
public int modelOffset;
}
public String getAtIndex(int part, int index) {
return getAtIndex(part, index, 0);
}
public String getAfterIndex(int part, int index) {
return getAtIndex(part, index, 1);
}
public String getBeforeIndex(int part, int index) {
return getAtIndex(part, index, -1);
}
/**
* Gets the word, sentence, or character at <code>index.
* If <code>direction is non-null this will find the
* next/previous word/sentence/character.
*/
private String getAtIndex(int part, int index, int direction) {
if (model instanceof AbstractDocument) {
((AbstractDocument)model).readLock();
}
try {
if (index < 0 || index >= model.getLength()) {
return null;
}
switch (part) {
case AccessibleText.CHARACTER:
if (index + direction < model.getLength() &&
index + direction >= 0) {
return model.getText(index + direction, 1);
}
break;
case AccessibleText.WORD:
case AccessibleText.SENTENCE:
IndexedSegment seg = getSegmentAt(part, index);
if (seg != null) {
if (direction != 0) {
int next;
if (direction < 0) {
next = seg.modelOffset - 1;
}
else {
next = seg.modelOffset + direction * seg.count;
}
if (next >= 0 && next <= model.getLength()) {
seg = getSegmentAt(part, next);
}
else {
seg = null;
}
}
if (seg != null) {
return new String(seg.array, seg.offset,
seg.count);
}
}
break;
default:
break;
}
} catch (BadLocationException e) {
} finally {
if (model instanceof AbstractDocument) {
((AbstractDocument)model).readUnlock();
}
}
return null;
}
/*
* Returns the paragraph element for the specified index.
*/
private Element getParagraphElement(int index) {
if (model instanceof PlainDocument ) {
PlainDocument sdoc = (PlainDocument)model;
return sdoc.getParagraphElement(index);
} else if (model instanceof StyledDocument) {
StyledDocument sdoc = (StyledDocument)model;
return sdoc.getParagraphElement(index);
} else {
Element para;
for (para = model.getDefaultRootElement(); ! para.isLeaf(); ) {
int pos = para.getElementIndex(index);
para = para.getElement(pos);
}
if (para == null) {
return null;
}
return para.getParentElement();
}
}
/*
* Returns a <code>Segment containing the paragraph text
* at <code>index, or null if
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