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AccessibleContext.javaAPI DocJava SE 5 API27303Fri Aug 26 14:57:28 BST 2005javax.accessibility

AccessibleContext

public abstract class AccessibleContext extends Object
AccessibleContext represents the minimum information all accessible objects return. This information includes the accessible name, description, role, and state of the object, as well as information about its parent and children. AccessibleContext also contains methods for obtaining more specific accessibility information about a component. If the component supports them, these methods will return an object that implements one or more of the following interfaces:

  • {@link AccessibleAction} - the object can perform one or more actions. This interface provides the standard mechanism for an assistive technology to determine what those actions are and tell the object to perform them. Any object that can be manipulated should support this interface.
  • {@link AccessibleComponent} - the object has a graphical representation. This interface provides the standard mechanism for an assistive technology to determine and set the graphical representation of the object. Any object that is rendered on the screen should support this interface.
  • {@link AccessibleSelection} - the object allows its children to be selected. This interface provides the standard mechanism for an assistive technology to determine the currently selected children of the object as well as modify its selection set. Any object that has children that can be selected should support this interface.
  • {@link AccessibleText} - the object presents editable textual information on the display. This interface provides the standard mechanism for an assistive technology to access that text via its content, attributes, and spatial location. Any object that contains editable text should support this interface.
  • {@link AccessibleValue} - the object supports a numerical value. This interface provides the standard mechanism for an assistive technology to determine and set the current value of the object, as well as obtain its minimum and maximum values. Any object that supports a numerical value should support this interface.
beaninfo
attribute: isContainer false description: Minimal information that all accessible objects return
version
1.43 04/02/04
author
Peter Korn
author
Hans Muller
author
Willie Walker
author
Lynn Monsanto

Fields Summary
public static final String
ACCESSIBLE_NAME_PROPERTY
Constant used to determine when the accessibleName property has changed. The old value in the PropertyChangeEvent will be the old accessibleName and the new value will be the new accessibleName.
public static final String
ACCESSIBLE_DESCRIPTION_PROPERTY
Constant used to determine when the accessibleDescription property has changed. The old value in the PropertyChangeEvent will be the old accessibleDescription and the new value will be the new accessibleDescription.
public static final String
ACCESSIBLE_STATE_PROPERTY
Constant used to determine when the accessibleStateSet property has changed. The old value will be the old AccessibleState and the new value will be the new AccessibleState in the accessibleStateSet. For example, if a component that supports the vertical and horizontal states changes its orientation from vertical to horizontal, the old value will be AccessibleState.VERTICAL and the new value will be AccessibleState.HORIZONTAL. Please note that either value can also be null. For example, when a component changes from being enabled to disabled, the old value will be AccessibleState.ENABLED and the new value will be null.
public static final String
ACCESSIBLE_VALUE_PROPERTY
Constant used to determine when the accessibleValue property has changed. The old value in the PropertyChangeEvent will be a Number representing the old value and the new value will be a Number representing the new value
public static final String
ACCESSIBLE_SELECTION_PROPERTY
Constant used to determine when the accessibleSelection has changed. The old and new values in the PropertyChangeEvent are currently reserved for future use.
public static final String
ACCESSIBLE_CARET_PROPERTY
Constant used to determine when the accessibleText caret has changed. The old value in the PropertyChangeEvent will be an integer representing the old caret position, and the new value will be an integer representing the new/current caret position.
public static final String
ACCESSIBLE_VISIBLE_DATA_PROPERTY
Constant used to determine when the visual appearance of the object has changed. The old and new values in the PropertyChangeEvent are currently reserved for future use.
public static final String
ACCESSIBLE_CHILD_PROPERTY
Constant used to determine when Accessible children are added/removed from the object. If an Accessible child is being added, the old value will be null and the new value will be the Accessible child. If an Accessible child is being removed, the old value will be the Accessible child, and the new value will be null.
public static final String
ACCESSIBLE_ACTIVE_DESCENDANT_PROPERTY
Constant used to determine when the active descendant of a component has changed. The active descendant is used for objects such as list, tree, and table, which may have transient children. When the active descendant has changed, the old value of the property change event will be the Accessible representing the previous active child, and the new value will be the Accessible representing the current active child.
public static final String
ACCESSIBLE_TABLE_CAPTION_CHANGED
Constant used to indicate that the table caption has changed The old value in the PropertyChangeEvent will be an Accessible representing the previous table caption and the new value will be an Accessible representing the new table caption.
public static final String
ACCESSIBLE_TABLE_SUMMARY_CHANGED
Constant used to indicate that the table summary has changed The old value in the PropertyChangeEvent will be an Accessible representing the previous table summary and the new value will be an Accessible representing the new table summary.
public static final String
ACCESSIBLE_TABLE_MODEL_CHANGED
Constant used to indicate that table data has changed. The old value in the PropertyChangeEvent will be null and the new value will be an AccessibleTableModelChange representing the table change.
public static final String
ACCESSIBLE_TABLE_ROW_HEADER_CHANGED
Constant used to indicate that the row header has changed The old value in the PropertyChangeEvent will be null and the new value will be an AccessibleTableModelChange representing the header change.
public static final String
ACCESSIBLE_TABLE_ROW_DESCRIPTION_CHANGED
Constant used to indicate that the row description has changed The old value in the PropertyChangeEvent will be null and the new value will be an Integer representing the row index.
public static final String
ACCESSIBLE_TABLE_COLUMN_HEADER_CHANGED
Constant used to indicate that the column header has changed The old value in the PropertyChangeEvent will be null and the new value will be an AccessibleTableModelChange representing the header change.
public static final String
ACCESSIBLE_TABLE_COLUMN_DESCRIPTION_CHANGED
Constant used to indicate that the column description has changed The old value in the PropertyChangeEvent will be null and the new value will be an Integer representing the column index.
public static final String
ACCESSIBLE_ACTION_PROPERTY
Constant used to indicate that the supported set of actions has changed. The old value in the PropertyChangeEvent will be an Integer representing the old number of actions supported and the new value will be an Integer representing the new number of actions supported.
public static final String
ACCESSIBLE_HYPERTEXT_OFFSET
Constant used to indicate that a hypertext element has received focus. The old value in the PropertyChangeEvent will be an Integer representing the start index in the document of the previous element that had focus and the new value will be an Integer representing the start index in the document of the current element that has focus. A value of -1 indicates that an element does not or did not have focus.
public static final String
ACCESSIBLE_TEXT_PROPERTY
PropertyChangeEvent which indicates that text has changed.
For text insertion, the oldValue is null and the newValue is an AccessibleTextSequence specifying the text that was inserted.
For text deletion, the oldValue is an AccessibleTextSequence specifying the text that was deleted and the newValue is null.
For text replacement, the oldValue is an AccessibleTextSequence specifying the old text and the newValue is an AccessibleTextSequence specifying the new text.
public static final String
ACCESSIBLE_INVALIDATE_CHILDREN
PropertyChangeEvent which indicates that a significant change has occurred to the children of a component like a tree or text. This change notifies the event listener that it needs to reacquire the state of the subcomponents. The oldValue is null and the newValue is the component whose children have become invalid.
public static final String
ACCESSIBLE_TEXT_ATTRIBUTES_CHANGED
PropertyChangeEvent which indicates that text attributes have changed.
For attribute insertion, the oldValue is null and the newValue is an AccessibleAttributeSequence specifying the attributes that were inserted.
For attribute deletion, the oldValue is an AccessibleAttributeSequence specifying the attributes that were deleted and the newValue is null.
For attribute replacement, the oldValue is an AccessibleAttributeSequence specifying the old attributes and the newValue is an AccessibleAttributeSequence specifying the new attributes.
public static final String
ACCESSIBLE_COMPONENT_BOUNDS_CHANGED
PropertyChangeEvent which indicates that a change has occurred in a component's bounds. The oldValue is the old component bounds and the newValue is the new component bounds.
protected Accessible
accessibleParent
The accessible parent of this object.
protected String
accessibleName
A localized String containing the name of the object.
protected String
accessibleDescription
A localized String containing the description of the object.
private PropertyChangeSupport
accessibleChangeSupport
Used to handle the listener list for property change events.
private AccessibleRelationSet
relationSet
Used to represent the context's relation set
Constructors Summary
Methods Summary
public voidaddPropertyChangeListener(java.beans.PropertyChangeListener listener)
Adds a PropertyChangeListener to the listener list. The listener is registered for all Accessible properties and will be called when those properties change.

see
#ACCESSIBLE_NAME_PROPERTY
see
#ACCESSIBLE_DESCRIPTION_PROPERTY
see
#ACCESSIBLE_STATE_PROPERTY
see
#ACCESSIBLE_VALUE_PROPERTY
see
#ACCESSIBLE_SELECTION_PROPERTY
see
#ACCESSIBLE_TEXT_PROPERTY
see
#ACCESSIBLE_VISIBLE_DATA_PROPERTY
param
listener The PropertyChangeListener to be added

        if (accessibleChangeSupport == null) {
            accessibleChangeSupport = new PropertyChangeSupport(this);
        }
        accessibleChangeSupport.addPropertyChangeListener(listener);
    
public voidfirePropertyChange(java.lang.String propertyName, java.lang.Object oldValue, java.lang.Object newValue)
Support for reporting bound property changes. If oldValue and newValue are not equal and the PropertyChangeEvent listener list is not empty, then fire a PropertyChange event to each listener. In general, this is for use by the Accessible objects themselves and should not be called by an application program.

param
propertyName The programmatic name of the property that was changed.
param
oldValue The old value of the property.
param
newValue The new value of the property.
see
java.beans.PropertyChangeSupport
see
#addPropertyChangeListener
see
#removePropertyChangeListener
see
#ACCESSIBLE_NAME_PROPERTY
see
#ACCESSIBLE_DESCRIPTION_PROPERTY
see
#ACCESSIBLE_STATE_PROPERTY
see
#ACCESSIBLE_VALUE_PROPERTY
see
#ACCESSIBLE_SELECTION_PROPERTY
see
#ACCESSIBLE_TEXT_PROPERTY
see
#ACCESSIBLE_VISIBLE_DATA_PROPERTY

        if (accessibleChangeSupport != null) {
	    if (newValue instanceof PropertyChangeEvent) {
		PropertyChangeEvent pce = (PropertyChangeEvent)newValue;
		accessibleChangeSupport.firePropertyChange(pce);
	    } else {
		accessibleChangeSupport.firePropertyChange(propertyName, 
							   oldValue, 
							   newValue);
	    }
	}
    
public javax.accessibility.AccessibleActiongetAccessibleAction()
Gets the AccessibleAction associated with this object that supports one or more actions.

return
AccessibleAction if supported by object; else return null
see
AccessibleAction

	return null;
    
public abstract javax.accessibility.AccessiblegetAccessibleChild(int i)
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 abstract intgetAccessibleChildrenCount()
Returns the number of accessible children of the object.

return
the number of accessible children of the object.

public javax.accessibility.AccessibleComponentgetAccessibleComponent()
Gets the AccessibleComponent associated with this object that has a graphical representation.

return
AccessibleComponent if supported by object; else return null
see
AccessibleComponent

	return null;
    
public java.lang.StringgetAccessibleDescription()
Gets the accessibleDescription property of this object. The accessibleDescription property of this object is a short localized phrase describing the purpose of the object. For example, in the case of a 'Cancel' button, the accessibleDescription could be 'Ignore changes and close dialog box.'

return
the localized description of the object; null if this object does not have a description
see
#setAccessibleDescription

	return accessibleDescription;
    
public javax.accessibility.AccessibleEditableTextgetAccessibleEditableText()
Gets the AccessibleEditableText associated with this object presenting editable text on the display.

return
AccessibleEditableText if supported by object; else return null
see
AccessibleEditableText

	return null;
    
public javax.accessibility.AccessibleIcon[]getAccessibleIcon()
Gets the AccessibleIcons associated with an object that has one or more associated icons

return
an array of AccessibleIcon if supported by object; otherwise return null
see
AccessibleIcon

	return null;
    
public abstract intgetAccessibleIndexInParent()
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 java.lang.StringgetAccessibleName()
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


                                                                                                                       
       
	return accessibleName;
    
public javax.accessibility.AccessiblegetAccessibleParent()
Gets the Accessible parent of this object.

return
the Accessible parent of this object; null if this object does not have an Accessible parent

	return accessibleParent;
    
public javax.accessibility.AccessibleRelationSetgetAccessibleRelationSet()
Gets the AccessibleRelationSet associated with an object

return
an AccessibleRelationSet if supported by object; otherwise return null
see
AccessibleRelationSet

	return relationSet;
    
public abstract javax.accessibility.AccessibleRolegetAccessibleRole()
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 sublasses that behave differently (e.g., AccessibleRole.CHECK_BOX for check boxes and AccessibleRole.RADIO_BUTTON for radio buttons).

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 javax.accessibility.AccessibleSelectiongetAccessibleSelection()
Gets the AccessibleSelection associated with this object which allows its Accessible children to be selected.

return
AccessibleSelection if supported by object; else return null
see
AccessibleSelection

	return null;
    
public abstract javax.accessibility.AccessibleStateSetgetAccessibleStateSet()
Gets the state set of this object. The AccessibleStateSet of an object is composed of a set of unique AccessibleStates. A change in the AccessibleStateSet of an object will cause a PropertyChangeEvent to be fired for the ACCESSIBLE_STATE_PROPERTY property.

return
an instance of AccessibleStateSet containing the current state set of the object
see
AccessibleStateSet
see
AccessibleState
see
#addPropertyChangeListener

public javax.accessibility.AccessibleTablegetAccessibleTable()
Gets the AccessibleTable associated with an object

return
an AccessibleTable if supported by object; otherwise return null
see
AccessibleTable

	return null;
    
public javax.accessibility.AccessibleTextgetAccessibleText()
Gets the AccessibleText associated with this object presenting text on the display.

return
AccessibleText if supported by object; else return null
see
AccessibleText

	return null;
    
public javax.accessibility.AccessibleValuegetAccessibleValue()
Gets the AccessibleValue associated with this object that supports a Numerical value.

return
AccessibleValue if supported by object; else return null
see
AccessibleValue

	return null;
    
public abstract java.util.LocalegetLocale()
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 voidremovePropertyChangeListener(java.beans.PropertyChangeListener listener)
Removes a PropertyChangeListener from the listener list. This removes a PropertyChangeListener that was registered for all properties.

param
listener The PropertyChangeListener to be removed

        if (accessibleChangeSupport != null) {
            accessibleChangeSupport.removePropertyChangeListener(listener);
        }
    
public voidsetAccessibleDescription(java.lang.String s)
Sets the accessible description of this object. Changing the name will cause a PropertyChangeEvent to be fired for the ACCESSIBLE_DESCRIPTION_PROPERTY property.

param
s the new localized description of the object
see
#setAccessibleName
see
#addPropertyChangeListener
beaninfo
preferred: true description: Sets the accessible description for the component.

	String oldDescription = accessibleDescription;
	accessibleDescription = s;
	firePropertyChange(ACCESSIBLE_DESCRIPTION_PROPERTY,
			   oldDescription,accessibleDescription);
    
public voidsetAccessibleName(java.lang.String s)
Sets the localized accessible name of this object. Changing the name will cause a PropertyChangeEvent to be fired for the ACCESSIBLE_NAME_PROPERTY property.

param
s the new localized name of the object.
see
#getAccessibleName
see
#addPropertyChangeListener
beaninfo
preferred: true description: Sets the accessible name for the component.

	String oldName = accessibleName;
	accessibleName = s;
	firePropertyChange(ACCESSIBLE_NAME_PROPERTY,oldName,accessibleName);
    
public voidsetAccessibleParent(javax.accessibility.Accessible a)
Sets the Accessible parent of this object. This is meant to be used only in the situations where the actual component's parent should not be treated as the component's accessible parent and is a method that should only be called by the parent of the accessible child.

param
a - Accessible to be set as the parent

        accessibleParent = a;