Introducing
JDIC
Desktop Integration for Java Applications
June
1, 2004
Sun has launched the JDesktop
Integration Components (JDIC) project on javadesktop.org.
JDIC will enable applications written for the Java™
platform (Java applications) to integrate more
seamlessly with their native desktop environment. Initially
the project supports features such as embedding the native
HTML browser, programmatically opening the native mail
tool, using registered file-type viewers, and packaging
JNLP applications as RPM, SVR4, and MSI installer packages.
As a bonus, an SDK for developing platform-independent
screensavers is included.
This article has the following sections:
Many factors — including the rapidly growing market
share of Linux on the desktop and the desire to close the
usability gap of browser-based applications vs. rich desktop
applications — have made the Java platform an increasingly
popular choice for non-browser-based desktop applications:
Developers have adopted Java
Web Start technology to build applications that can
be deployed at the click of a link while providing the same
rich user experience that has traditionally been the domain
of full-featured desktop applications. The Sun
Java Desktop System has made the Java platform its native
development platform for desktop applications.
Unlike many desktop applications, Web pages are traditionally
designed to have a platform-independent appearance that
looks the same in each browser they're displayed in. Often
they break with the paradigms of the desktop, using different
GUI elements and styles. Developers favor this approach
because it minimizes development and testing work. Outside
of the browser, however, most users expect applications
to seamlessly integrate into the desktop and follow its
user interface guidelines.
The Java platform has enabled this level of seamless desktop
integration with functionality such as its native look and
feels (XP, GTK, Aqua), drag and drop, and clipboard support.
Java Web Start comes with features to place application
shortcuts into the start menu and on the desktop. The 1.5
release of the Java 2 Platform, Standard Edition (J2SE™
platform) will further enhance desktop integration,
enabling applications deployed using Java Web Start to be
registered with file types and enabling the native look
and feel for all dialogs provided by the Java platform (for
example, the Java control panel).
Developers who want to go beyond what already exists in
the Java platform, however, have limited choices. Many developers
resort to using JNI to implement the enhancements they need,
an approach that often leads to platform dependence and
decreasing the market potential for the application. Projects
like java-gnome provide direct bindings to the native APIs
of a platform, but these suffer from the same problem and
limit use of the application to one platform.
To enable better native platform integration, Sun is launching
the JDesktop Integration Components (JDIC) project, an open-source
project hosted on javadesktop.org. Its mission is to take
cross-platform Java desktop integration to the next level.
JDIC is a set of cross-platform APIs that abstract the
contracts between an application and the desktop it runs
on. JDIC-based applications will run on any platform JDIC
is ported to and will realize the behavior associated with
these contracts in a way that's suitable for each particular
desktop environment.
The JDIC approach is possible because many desktop concepts,
such as an HTML rendering engine, are implemented across
all environments. Additionally some desktop services, such
as the icon tray, are an enhancement to an application rather
than necessary to its operation. Such features can be left
unimplemented on platforms where the service is not available.
Sun is seeding the JDIC project with a number of interesting
integration components that are already implemented on Microsoft
Windows, Linux, and Solaris. These components have been
selected by customer demand and by considering what will
happen as developers move from pure HTML-based applications
to rich clients.
As developers move to rich clients, they will need to replace
functionality that was provided by the browser. In addition
to the many features that the Java platform provides, an
HTML browser supports the following:
- Embedding HTML content
- Starting desktop file viewers on content unknown to
the browser
- Sending e-mail using the desktop mailer via mailto:
URLs
- Dispatching URLs into new browser instances
JDIC currently supports all of the above features for Java
applications. JDIC also comes with a tool to package JNLP
applications as RPM, SVR4, or MSI files. Finally the SaverBeans
Screensaver SDK incubator project is included in JDIC, providing
an SDK to create write-one-run-anywhere (WORA) screensavers
for Microsoft Windows, Linux, and Solaris.
A guiding principle in the design of the JDIC APIs has
been simplicity. The emphasis is on making the most common
use cases easy to code, rather than exposing more advanced
functionality for special cases. As an example the browser-embedding
API allows you to very easily embed an HTML page in your
application, but it wouldn't be suitable for writing a complete
Web browser.
JDIC is an exploratory project. While you're welcome to
use JDIC in your products, be aware that all current
APIs are subject to change. JDIC components will be
considered for inclusion into the J2SE platform when they
have matured adequately.
Join us in identifying
the desktop integration functionality most needed in modern
desktop applications, and work with us on their design and
implementation!
The demonstration programs pictured in this section show
some of JDIC's capabilities. You can run the demos with
Java
Web Start by clicking the [Run Demo] links. For
more information about the demos, see the Demos
section of the JDIC
home page.
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Desktop [Run
Demo]
This demo shows the functionality in the
org.jdesktop.jdic.desktop
package. The items in the popup menu — Open, Edit, Print,
Browse, and Mail to... — correspond to methods in the
Desktop
class.
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