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BODY BGCOLOR="#FFFFFF">
0N/ADefines a contract between user-interface components and an assistive technology
0N/Athat provides access to those components. If a Java application fully supports
0N/Athe Java Accessibility API, then it should be compatible with, and friendly
0N/Atoward, assistive technologies such as screen readers, screen magnifiers,
0N/Aetc. With a Java application that fully supports the Java Accessibility
0N/AAPI, no screen reader off screen model would be necessary because the API
0N/Aprovides all of the information normally contained in an off screen model.
0N/A<
P>The Java Accessibility API package consists of 8 Java programming language
0N/Ainterfaces, and 6 Java programming language classes. These are described
0N/Aof the Java Accessibility API. All components that support the Java Accessibility
0N/AAPI must implement this interface. It contains a single method, <
TT>getAccessibleContext</
TT>,
0N/Athat returns an instance of the class <
A HREF="#AccessibleContext">AccessibleContext</
A>.
Sun thinks that implementing this interface is the absolute minimum requirement
of every object that is part of the user interface of a Java application,
if that program is to be compatible with assistive technologies.
AccessibleContext</
A></
H3>
information all accessible objects return and is obtained by calling the
<
TT>getAccessibleContext</
TT> method on an object that implements the <
A HREF="#Accessible">Accessible</
A>
interface. This information includes the accessible name, description,
<
A HREF="#AccessibleRole">role</
A>, and <
A HREF="#AccessibleState">state</
A>
of the object, as well as information about the parent and children of
the object. In addition, JavaBeans <
SUP><
FONT SIZE=-
2>TM</
FONT></
SUP>
property change support is also included to allow assisitive technologies
learn when the values of the accessible properties change. AccessibleContext
also contains methods for obtaining more specific accessibility information
about a component. If the component supports it, these methods will return
an object that implements one or more of the following interfaces:
<
B><
A HREF="#AccessibleAction">AccessibleAction</
A></
B> - 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 those actions. Any object that can be manipulated
should return an object that implements this interface when the <
TT>getAccessibleAction</
TT>
method is called on an AccessibleContext.</
LI>
<
B><
A HREF="#AccessibleComponent">AccessibleComponent</
A></
B> - 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 return
an object that implements this interface when the <
TT>getAccessibleComponent</
TT>
method is called on an AccessibleContext.</
LI>
<
B><
A HREF="#AccessibleSelection">AccessibleSelection</
A></
B> - the object
allows its children to be selected. This interface provides the standard
mechanism for an assistive technology to determine the currently selected
children as well as modify the selection set. Any object that has children
that can be selected should return an object that implements this interface
when the <
TT>getAccessibleSelection</
TT> method is called on an AccessibleContext.</
LI>
<
B><
A HREF="#AccessibleText">AccessibleText</
A></
B> - 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 return an object that implements this interface when
the <
TT>getAccessibleText</
TT> method is called on an AccessibleContext.</
LI>
<
B><
A HREF="#AccessibleHypertext">AccessibleHypertext</
A></
B> - the object
presents hypertext information on the display. This interface provides
the standard mechanism for an assistive technology to access that hypertext
via its content, attributes, and spatial location. Any object that contains
hypertext should return an object that implements this interface when the
<
TT>getAccessibleText</
TT> method is called on an AccessibleContext.</
LI>
<
B><
A HREF="#AccessibleValue">AccessibleValue</
A></
B> - 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 the minimum and maximum values. Any object that supports a numerical
value should return an object that implements this interface when the <
TT>getAccessibleValue</
TT>
method is called on an AccessibleContext.</
LI>
This class encapsulates the Accessible object's role in the user interface
and is obtained by calling the <
TT>getAccessibleRole</
TT> method on an
<
A HREF="#AccessibleContext">AccessibleContext</
A>. Accessible roles include
"Check box", "Menu Item", "Panel", etc. These roles are identified by the
a strongly typed enumeration of common object roles. A public constructor
for this class has been purposely omitted and applications should use one
of the constants from this class. Although this class pre-defines a large
list of standard roles, it is extensible so additional programmer-defined
roles can be added in the future without needing to modify the base class.
This class encapsulates a particular state of the Accessible object. Accessible
states include things like "Armed", "Busy", "Checked", "Focused", etc.
The sum of all the states of an Accessible object is called the <
A HREF="#AccessibleStateSet">AccessibleStateSet</
A>,
and can be obtained by calling the <
TT>getAccessibleStateSet</
TT> method
on an <
A HREF="#AccessibleContext">AccessibleContext</
A>.
<
P>The constants in this class present a strongly typed enumeration of
common object roles. A public constructor for this class has been purposely
omitted and applications should use one of the constants from this class.
Although this class pre-defines a large list of standard roles, it is extensible
so additional, programmer-defined roles can be added in the future without
needing to modify the base class.
AccessibleStateSet</
A></
H3>
This class encapsulates a collection of states of the Accessible object
and is obtained by calling the <
TT>getAccessibleStateSet</
TT> method on
an <
A HREF="#AccessibleContext">AccessibleContext</
A>. Since an object
might have multiple states (
e.g. it might be both "Checked" and "Focused"),
this class is needed to encapsulate a collection of these states. Methods
in the class provide for retrieving the individual <
A HREF="#AccessibleState">AccessibleStates</
A>
This class is used to maintain a strongly typed enumeration. It is the
super class of both the <
A HREF="#AccessibleRole">AccessibleRole</
A> and
<
A HREF="#AccessibleState">AccessibleState</
A> classes. Programmers normally
do not interact with this class directly, but will instead use the <
A HREF="#AccessibleRole">AccessibleRole</
A>
and <
A HREF="#AccessibleState">AccessibleState</
A> classes.
AccessibleAction</
A></
H3>
be supported by any object that can perform one or more actions. This interface
provides the standard mechanism for an assistive technology to determine
what those actions are as well as tell the object to perform those actions.
Any object that can be manipulated should support this interface.
<
P>Applications can determine if an object supports the AccessibleAction
interface by first obtaining its <
A HREF="#AccessibleContext">AccessibleContext</
A>
(see <
A HREF="#Accessible">Accessible</
A>) and then calling the <
TT>getAccessibleAction</
TT>
method of <
A HREF="#AccessibleContext">AccessibleContext</
A>. If the return
value is not null, the object supports this interface.
AccessibleComponent</
A></
H3>
should be supported by any object that is rendered on the screen. This
interface provides the standard mechanism for an assistive technology to
determine and set the graphical representation of an object.
<
P>Applications can determine if an object supports the AccessibleComponent
interface by first obtaining its <
A HREF="#AccessibleContext">AccessibleContext</
A>
(see <
A HREF="#Accessible">Accessible</
A>) and then calling the <
TT>getAccessibleComponent</
TT>
method of <
A HREF="#AccessibleContext">AccessibleContext</
A>. If the return
value is not null, the object supports this interface.
AccessibleSelection</
A></
H3>
provides the standard mechanism for an assistive technology to determine
what the current selected children are, as well as modify the selection
set. Any object that has children that can be selected should support this
the AccessibleSelection interface.
<
P>Applications can determine if an object supports the AccessibleSelection
interface by first obtaining its <
A HREF="#AccessibleContext">AccessibleContext</
A>
(see <
A HREF="#Accessible">Accessible</
A>) and then calling the <
TT>getAccessibleSelection</
TT>
method of <
A HREF="#AccessibleContext">AccessibleContext</
A>. If the return
value is not null, the object supports this interface.
for making rich, editable text Accessible. Not all text displayed on the
screen is rich and editable (
e.g. text contained in buttons, labels, menus,
etc., which users aren't expected to manipulate). However, objects containing
editable text must implement interface AccessibleText if they are to interoperate
with assistive technologies.
<
P>This interface provides support for going between pixel coordinates
and the text at a given pixel coordinate, for retrieving the letter, word,
and sentence at, before, or after a given position in the text. This interface
provides support for retrieving the attributes of the character at a given
position in the text (font, font size, style, etc.), as well as getting
the selected text (if any), the length of the text, and the location of
<
P>Applications can determine if an object supports the AccessibleText
interface by first obtaining its <
A HREF="#AccessibleContext">AccessibleContext</
A>
(see <
A HREF="#Accessible">Accessible</
A>) and then calling the <
TT>getAccessibleText</
TT>
method of <
A HREF="#AccessibleContext">AccessibleContext</
A>. If the return
value is not null, the object supports this interface.
<
H3><
A NAME="AccessibleHypertext"></
A>
should be supported by any object that presents hypertext 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. It also provides standard mechanisms for manipulating <
A HREF="#AccessibleHyperlink">hyperlinks</
A>.
Applications can determine if an object supports the AccessibleHypertext
interface by first obtaining its <
A HREF="#AccessibleContext">AccessibleContext</
A>
method of <
A HREF="#AccessibleContext">AccessibleContext</
A>. If the return
value is a class which extends AccessibleHypertext, then that object supports
AccessibleHyperlink</
A></
H3>
interface. An object that implements this interface will be returned
by calling the getLink method on an <
A HREF="#AccessibleHypertext">AccessibleHypertext</
A>
be supported by any object that supports a numerical value (
e.g., a scroll
bar). This interface provides the standard mechanism for an assistive technology
to determine and set the numerical value as well as get the minimum and
<
P>Applications can determine if an object supports the AccessibleValue
interface by first obtaining its <
A HREF="#AccessibleContext">AccessibleContext</
A>
(see <
A HREF="#Accessible">Accessible</
A>) and then calling the <
TT>getAccessibleValue</
TT>
method of <
A HREF="#AccessibleContext">AccessibleContext</
A>. If the return
value is not null, the object supports this interface.