JAVA ACCESSIBILITY
Overview of the Java Accessibility Features
Version 1.3
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Overview of the Java Accessibility Features
Introduction
Java Accessibility is currently broken into two separate packages:
the Java Accessibility API and the Java Accessibility Utilities.
This release represents the Java Accessibility Utilities and contains classes
designed to help assistive technologies take advantage of the Java Accessibility
API. The Java Accessibility API is a cross platform, toolkit independent
API designed to give assistive technologies direct access to the information
in user interface objects, and is part of the JavaTM
Foundation Classes.
There are four areas in which Sun is currently building Accessibility
support into the Java platform. The four sections below give
a brief overview of the four areas of support for Java Accessibility that
Sun is currently developing.
The Java Accessibility API defines a contract between individual user-interface
components that make up a Java application and an assistive technology
that is providing access to that Java application. If a Java application
fully supports the Java Accessibility API, then it should be compatible
with, and friendly toward, assistive technologies such as screen readers,
screen magnifiers, etc. With a Java application that fully supports
the Java Accessibility API, no off screen model would be necessary because
the API provides all of the information normally contained in an off screen
model.
In order to provide access to a Java application, an assistive technology
requires more than the Java Accessibility API: it also requires support
in locating the objects that implement the API as well as support for being
loaded into the Java virtual machine, tracking events, etc. The Java
Accessibility utility classes provide this assistance.
Java applications run on a wide variety of host operating systems,
many of which already have assistive technologies available for them (e.g.
Macintosh, OS/2, Windows). In order for these existing assistive
technologies to provide access to programs written in the Java programming
language, they need a bridge between themselves in their native environment(s)
and the Java Accessibility support that is available from within the Java
virtual machine (or Java VM). This bridge, by virtue of the fact
that it has one end in the Java VM and the other on the native platform,
will be slightly different for each platform it bridges to. Sun is
currently developing both the Java programming language side of this bridge,
and the Win32 side. In cooperation with assistive technology vendors
and the various platform vendors, Sun intends to make similar bridges available
for other platforms over time.
The Java Foundation Classes
(or JFC) are a collection of technologies that represent a new foundation
upon which to build Java applications. The JFC is a core part of
JDK1.2 and later releases, and is also available as a separate package
for JDK1.1.
The Java Accessibility API is one of the technologies of the JFC.
Another is the "Swing" set of user-interface components, which is built
using a Pluggable Look and Feel architecture. This architecture separates
the implementation of the user-interface components from their presentation.
On a component-by-component basis, the presentation is programmatically
determined and can be chosen by the user. Instead of a visual presentation,
a user could instead choose an audio presentation, or a tactile (e.g. Braille)
presentation, or a combination of the two. With this support, a user
wouldn't need a separate assistive technology product interpreting the
visual presentation of the program on the screen. Instead, the user
would have direct access to that program because it would interact with
the user in his/her desired modality.
The Road Ahead
We are not finished with Java Accessibility, and are continuing to improve
our current offerings as well as investigate new areas. The road
ahead will tell you more about our plans for the future.
Copyright©
1995-99
Sun
Microsystems, Inc. All Rights Reserved.
To submit comments or suggestions about Java
Accessibility, please send mail to access@sun.com.