Inner class of JComponent used to provide default support for
accessibility. This class is not meant to be used directly by
application developers, but is instead meant only to be
subclassed by component developers.
Warning:
Serialized objects of this class will not be compatible with
future Swing releases. The current serialization support is
appropriate for short term storage or RMI between applications running
the same version of Swing. As of 1.4, support for long term storage
of all JavaBeansTM
has been added to the java.beans
package.
Please see java.beans.XMLEncoder
.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Constant used to determine when the accessibleSelection has changed.
The old and new values in the PropertyChangeEvent are currently
reserved for future use.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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
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.
Adds the specified focus listener to receive focus events from this
component.
Adds a PropertyChangeListener to the listener list.
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.
Indicates whether some other object is "equal to" this one.
The equals
method implements an equivalence relation
on non-null object references:
- It is reflexive: for any non-null reference value
x
, x.equals(x)
should return
true
.
- It is symmetric: for any non-null reference values
x
and y
, x.equals(y)
should return true
if and only if
y.equals(x)
returns true
.
- It is transitive: for any non-null reference values
x
, y
, and z
, if
x.equals(y)
returns true
and
y.equals(z)
returns true
, then
x.equals(z)
should return true
.
- It is consistent: for any non-null reference values
x
and y
, multiple invocations of
x.equals(y) consistently return true
or consistently return false
, provided no
information used in equals
comparisons on the
objects is modified.
- For any non-null reference value
x
,
x.equals(null)
should return false
.
The equals method for class Object
implements
the most discriminating possible equivalence relation on objects;
that is, for any non-null reference values x
and
y
, this method returns true
if and only
if x
and y
refer to the same object
(x == y
has the value true
).
Note that it is generally necessary to override the hashCode
method whenever this method is overridden, so as to maintain the
general contract for the hashCode method, which states
that equal objects must have equal hash codes.
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.
Gets the AccessibleAction associated with this object that supports
one or more actions.
Returns the Accessible
child, if one exists,
contained at the local coordinate Point
.
Returns the nth Accessible child of the object.
Returns the number of accessible children in the object. If all
of the children of this object implement Accessible, than this
method should return the number of children of this object.
Gets the AccessibleComponent
associated
with this object if one exists.
Otherwise return null
.
Gets the accessible description of this object. This should be
a concise, localized description of what this object is - what
is its meaning to the user. If the object has a tooltip, the
tooltip text may be an appropriate string to return, assuming
it contains a concise description of the object (instead of just
the name of the object - for example a "Save" icon on a toolbar that
had "save" as the tooltip text shouldn't return the tooltip
text as the description, but something like "Saves the current
text document" instead).
Gets the AccessibleEditableText associated with this object
presenting editable text on the display.
Gets the AccessibleIcons associated with an object that has
one or more associated icons
Gets the index of this object in its accessible parent.
Returns key bindings associated with this object
Gets the accessible name of this object. This should almost never
return java.awt.Component.getName(), as that generally isn't
a localized name, and doesn't have meaning for the user. If the
object is fundamentally a text object (such as a menu item), the
accessible name should be the text of the object (for example,
"save").
If the object has a tooltip, the tooltip text may also be an
appropriate String to return.
Gets the Accessible
parent of this object.
If the parent of this object implements Accessible
,
this method should simply return getParent
.
Gets the AccessibleRelationSet associated with an object
Gets the role of this object.
Gets the AccessibleSelection associated with this object which allows its
Accessible children to be selected.
Gets the state of this object.
Gets the AccessibleTable associated with an object
Gets the AccessibleText associated with this object presenting
text on the display.
Gets the AccessibleValue associated with this object that supports a
Numerical value.
Gets the background color of this object.
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.
Returns the runtime class of an object. That Class
object is the object that is locked by static synchronized
methods of the represented class.
Gets the Cursor
of this object.
Gets the Font
of this object.
Gets the FontMetrics
of this object.
Gets the foreground color of this object.
Returns the locale of this object.
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.
Returns the location of the object on the screen.
Returns the size of this object in the form of a
Dimension
object. The height field of the
Dimension
object contains this objects's
height, and the width field of the Dimension
object contains this object's width.
Returns the titled border text
Returns the tool tip text
Returns a hash code value for the object. This method is
supported for the benefit of hashtables such as those provided by
java.util.Hashtable
.
The general contract of hashCode
is:
- Whenever it is invoked on the same object more than once during
an execution of a Java application, the hashCode method
must consistently return the same integer, provided no information
used in equals comparisons on the object is modified.
This integer need not remain consistent from one execution of an
application to another execution of the same application.
- If two objects are equal according to the equals(Object)
method, then calling the
hashCode
method on each of
the two objects must produce the same integer result.
- It is not required that if two objects are unequal
according to the
method, then calling the hashCode method on each of the
two objects must produce distinct integer results. However, the
programmer should be aware that producing distinct integer results
for unequal objects may improve the performance of hashtables.
As much as is reasonably practical, the hashCode method defined by
class Object does return distinct integers for distinct
objects. (This is typically implemented by converting the internal
address of the object into an integer, but this implementation
technique is not required by the
JavaTM programming language.)
Determines if the object is enabled.
Returns whether this object can accept focus or not.
Determines if the object is showing. This is determined by checking
the visibility of the object and ancestors of the object. Note:
this will return true even if the object is obscured by another
(for example, it happens to be underneath a menu that was pulled
down).
Determines if the object is visible. Note: this means that the
object intends to be visible; however, it may not in fact be
showing on the screen because one of the objects that this object
is contained by is not visible. To determine if an object is
showing on the screen, use isShowing
.
Wakes up a single thread that is waiting on this object's
monitor. If any threads are waiting on this object, one of them
is chosen to be awakened. The choice is arbitrary and occurs at
the discretion of the implementation. A thread waits on an object's
monitor by calling one of the
wait
methods.
The awakened thread will not be able to proceed until the current
thread relinquishes the lock on this object. The awakened thread will
compete in the usual manner with any other threads that might be
actively competing to synchronize on this object; for example, the
awakened thread enjoys no reliable privilege or disadvantage in being
the next thread to lock this object.
This method should only be called by a thread that is the owner
of this object's monitor. A thread becomes the owner of the
object's monitor in one of three ways:
- By executing a synchronized instance method of that object.
- By executing the body of a
synchronized
statement
that synchronizes on the object.
- For objects of type
Class,
by executing a
synchronized static method of that class.
Only one thread at a time can own an object's monitor.
Wakes up all threads that are waiting on this object's monitor. A
thread waits on an object's monitor by calling one of the
wait
methods.
The awakened threads will not be able to proceed until the current
thread relinquishes the lock on this object. The awakened threads
will compete in the usual manner with any other threads that might
be actively competing to synchronize on this object; for example,
the awakened threads enjoy no reliable privilege or disadvantage in
being the next thread to lock this object.
This method should only be called by a thread that is the owner
of this object's monitor. See the notify
method for a
description of the ways in which a thread can become the owner of
a monitor.
Removes the specified focus listener so it no longer receives focus
events from this component.
Removes a PropertyChangeListener from the listener list.
This removes a PropertyChangeListener that was registered
for all properties.
Requests focus for this object.
Sets the accessible description of this object. Changing the
name will cause a PropertyChangeEvent to be fired for the
ACCESSIBLE_DESCRIPTION_PROPERTY property.
Sets the localized accessible name of this object. Changing the
name will cause a PropertyChangeEvent to be fired for the
ACCESSIBLE_NAME_PROPERTY property.
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.
Sets the background color of this object.
(For transparency, see isOpaque
.)
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.
Sets the Cursor
of this object.
Sets the enabled state of the object.
Sets the Font
of this object.
Sets the foreground color of this object.
Sets the location of the object relative to the parent.
Resizes this object so that it has width width and height.
Sets the visible state of the object.
Returns a string representation of the object. In general, the
toString
method returns a string that
"textually represents" this object. The result should
be a concise but informative representation that is easy for a
person to read.
It is recommended that all subclasses override this method.
The toString
method for class Object
returns a string consisting of the name of the class of which the
object is an instance, the at-sign character `@
', and
the unsigned hexadecimal representation of the hash code of the
object. In other words, this method returns a string equal to the
value of:
getClass().getName() + '@' + Integer.toHexString(hashCode())
Causes current thread to wait until another thread invokes the
method or the
method for this object.
In other words, this method behaves exactly as if it simply
performs the call
wait(0).
The current thread must own this object's monitor. The thread
releases ownership of this monitor and waits until another thread
notifies threads waiting on this object's monitor to wake up
either through a call to the notify
method or the
notifyAll
method. The thread then waits until it can
re-obtain ownership of the monitor and resumes execution.
As in the one argument version, interrupts and spurious wakeups are
possible, and this method should always be used in a loop:
synchronized (obj) {
while (<condition does not hold>)
obj.wait();
... // Perform action appropriate to condition
}
This method should only be called by a thread that is the owner
of this object's monitor. See the
notify
method for a
description of the ways in which a thread can become the owner of
a monitor.
Causes current thread to wait until either another thread invokes the
method or the
method for this object, or a
specified amount of time has elapsed.
The current thread must own this object's monitor.
This method causes the current thread (call it T) to
place itself in the wait set for this object and then to relinquish
any and all synchronization claims on this object. Thread T
becomes disabled for thread scheduling purposes and lies dormant
until one of four things happens:
- Some other thread invokes the notify method for this
object and thread T happens to be arbitrarily chosen as
the thread to be awakened.
- Some other thread invokes the notifyAll method for this
object.
- Some other thread interrupts
thread T.
- The specified amount of real time has elapsed, more or less. If
timeout is zero, however, then real time is not taken into
consideration and the thread simply waits until notified.
The thread
T is then removed from the wait set for this
object and re-enabled for thread scheduling. It then competes in the
usual manner with other threads for the right to synchronize on the
object; once it has gained control of the object, all its
synchronization claims on the object are restored to the status quo
ante - that is, to the situation as of the time that the
wait
method was invoked. Thread
T then returns from the
invocation of the
wait method. Thus, on return from the
wait method, the synchronization state of the object and of
thread
T is exactly as it was when the
wait method
was invoked.
A thread can also wake up without being notified, interrupted, or
timing out, a so-called spurious wakeup. While this will rarely
occur in practice, applications must guard against it by testing for
the condition that should have caused the thread to be awakened, and
continuing to wait if the condition is not satisfied. In other words,
waits should always occur in loops, like this one:
synchronized (obj) {
while (<condition does not hold>)
obj.wait(timeout);
... // Perform action appropriate to condition
}
(For more information on this topic, see Section 3.2.3 in Doug Lea's
"Concurrent Programming in Java (Second Edition)" (Addison-Wesley,
2000), or Item 50 in Joshua Bloch's "Effective Java Programming
Language Guide" (Addison-Wesley, 2001).
If the current thread is
interrupted
by another thread
while it is waiting, then an InterruptedException is thrown.
This exception is not thrown until the lock status of this object has
been restored as described above.
Note that the wait method, as it places the current thread
into the wait set for this object, unlocks only this object; any
other objects on which the current thread may be synchronized remain
locked while the thread waits.
This method should only be called by a thread that is the owner
of this object's monitor. See the notify
method for a
description of the ways in which a thread can become the owner of
a monitor.
Causes current thread to wait until another thread invokes the
method or the
method for this object, or
some other thread interrupts the current thread, or a certain
amount of real time has elapsed.
This method is similar to the wait
method of one
argument, but it allows finer control over the amount of time to
wait for a notification before giving up. The amount of real time,
measured in nanoseconds, is given by:
1000000*timeout+nanos
In all other respects, this method does the same thing as the
method
of one argument. In particular,
wait(0, 0) means the same thing as wait(0).
The current thread must own this object's monitor. The thread
releases ownership of this monitor and waits until either of the
following two conditions has occurred:
- Another thread notifies threads waiting on this object's monitor
to wake up either through a call to the
notify
method
or the notifyAll
method.
- The timeout period, specified by
timeout
milliseconds plus nanos
nanoseconds arguments, has
elapsed.
The thread then waits until it can re-obtain ownership of the
monitor and resumes execution.
As in the one argument version, interrupts and spurious wakeups are
possible, and this method should always be used in a loop:
synchronized (obj) {
while (<condition does not hold>)
obj.wait(timeout, nanos);
... // Perform action appropriate to condition
}
This method should only be called by a thread that is the owner
of this object's monitor. See the
notify
method for a
description of the ways in which a thread can become the owner of
a monitor.