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Desktop Java: JDNC Released as Open Source Project

Desktop Java: JDNC Released as Open Source Project

  • Java Trends - Exclusive Interview with Amy Fowler

    In her extensive "Java Trends" interview with JDJ last month, Sun's Amy Fowler - technical lead of the Java Desktop Network Component (JDNC) project - said that the JDNC API "is targeted at Java developers who aren't necessarily Swing literate" and spoke of her "current fever to make rich Java clients easier to build."

    Now in her latest blog Fowler turns up the heat under the JDNC project, inviting developers to read up about it in her latest article, visit the project site, "and join in on making it happen."

    "After all,": Fowler adds, "who knows better than you [i.e., the developer] what would make your development life easier."

    The article she refers to, published at javadesktop.org, the java.net community for developers of apps with rich client interfaces, confirms that  JDNC has been released as an open source project.

    Fowler explains:

    "This enables us to make the technology available to you early enough so that you can directly shape the vision, the feature set, and even the code. There is still a lot of work to do — the JDNC feature set is far from complete and there remain rough edges, especially in the API, which has not had extensive usage outside of unit testing and markup-driven use-cases. But, that is exactly why we need your involvement."

    "Work with us as we make the technology marry better with tools." she continues, "File bugs and requests for enhancements. Submit code changes. Submit new components. We are anxious to engage directly with you to make Java desktop client development as productive and satisfying as we all know it can be."

    In her article, Fowler writes explains that the need for JDNC was inspired by the realization that, although applications rarely fit neatly into a cookie-cutter mold, many of the apps which enterprise developers need to build do share a common cross-section of functionality.

    "In developing JDNC," she writes,  "we are creating shortcuts for these common features so that developers can get applications up very quickly and then easily enhance them over time. Central to these "shortcuts" is a suite of very high level user-interface (UI) components which leverage Swing, but provide common functionality in a simpler JavaBeans component API."

    "Although these components are indeed the project's namesake, they are only part of the solution," Fowler adds.

    "The most central feature shared by what we call "data-centric, enterprise desktop clients" is connecting users with data — loading it, viewing it, filtering it, editing it, validating it, saving it, and so on. And these days that data is usually tied to a network data source, such as an SQL database, HTTP servlet, or WebService, bringing with it the complexity of networking. JDNC does the heavy lifting here, by providing built-in support for dealing with these network data sources, including multithreaded support (so the UI doesn't block during network operations) and incremental loading — hence, the "Network" in "JDesktop Network Components".

    The application model for a data-centric enterprise client boils down to the life cycle of its data. JDNC promotes this notion by supporting the pattern of clearly separating the data from the UI, but making it very easy to bind the two together. Application data is encapsulated in one or more client-side, UI-independent data models, such as a JDBC RowSet or a JavaBeans component. The data-model interface should be easy to understand and easily configurable from tools, with simple properties to configure its data source, metadata, edit constraints, validation logic, etc., and simple actions for common operations such as load, insert, modify, cache locally (for off-line use), and update (back to server). The UI components are then bound to that local data model (or models) with a simple syntax. From a tool the binding might be created by drawing a line between graphical representations of the two objects. The connection between the UI and the local data model is handled by JDNC's binding mechanism, which automatically handles input validation, type conversion, pushing and pulling values to/from the model, and reporting errors to the user. This frees the developer to focus on their data and how it should be presented in the UI, rather than on the plumbing which glues the two together."

    As JDNC is a work in progress, Fowler concedes that those involved have not yet implemented all the functionality required to realize this vision.

    For example, she notes that support for disconnected RowSets (JSR 114) will be included in the release following 0.5.

    "However, 0.5 does include an experimental version of a data-binding framework for Swing components which, being central to our purpose, should evolve substantially over the course of the project."
    Anyone interested can view JDNC's Feature Summary for detailed information about current and planned features, Fowler adds. 

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    Most Recent Comments
    Will 07/06/04 01:56:27 AM EDT

    Interested in a better alternative to JDNC?
    - more mature
    - more features
    - production stable

    Take a look at JForm!
    http://jform.coderight.nl

    Will

    Greg Leisner 06/25/04 08:42:40 AM EDT

    I'm reworking a legacy Java app that uses a very hacked-up version of SUN's original JTreeTable. Replacing those classes is on my todo list. I'm looking forward to adding this library to the app and cleaning it up alot!

    Since the modified class has been in use for 5 years, I hope to be able to provide useful feedback.

    Thanks to all who worked on this.

    Gerald Bauer 06/24/04 11:31:45 PM EDT

    Just to let you know I've started a JDNC mailinglist over at Yahoo! Groups. If anyone is interested in JDNC I invite you to join the discussion and ask questions or share tips and tricks about Sun's new Java Desktop Network Components initiative.

    Find out more @ http://groups.yahoo.com/group/jdnc

    - Gerald