Validate Me (original) (raw)

Daniel Zwolenski zonski at googlemail.com
Mon Feb 20 12:15:02 PST 2012

I started a thread on this a while back with my thoughts on this (which still hold): https://forums.oracle.com/forums/thread.jspa?messageID=10012233&#10012233<https://forums.oracle.com/forums/thread.jspa?messageID=10012233�>

In my first post there is an initial working example: http://zenjava.com/demo/form/forms.html http://code.google.com/p/jfxee/source/browse/trunk/jfxforms/

I've since improved on this code base and am using the improved code in my current project with reasonable success. I'm currently considering if/how to open source this code. I could bundle it into JFX Flow but I'm thinking it might be better in a separate open source project. I'd be more than happy to collaborate with others in this space if there was interest.

I'm a big fan of JSR303 Bean Validation for this as it is very rich, pretty standard and is an active JSR, with some tooling support. It works equally well in UI and server code, which is a definite requirement for me, since when doing a desktop client-server app we need to validate on the client for presentation reasons, but also validate on the server for security reasons (since you can never trust that the client app is your app). My preferred validation framework is basically a JFX based presentation layer on top of JSR303.

This brings us back again to the issue of what is 'core' and what is higher level as it uses a third party library (although it is a JSR, so perhaps that helps). I noticed when I first raised the topic that while JSR303 seems awesome to me, others had some concern about the need to validate a whole 'bean' rather than just simple, individual field validation built into Controls. This would not work for me, but I can see the appeal with a simple API so we once again have more than one 'acceptable' approach. There was also some concern about JSR303 using annotations, the Scala people had trouble with this I think (although I'm personally not sure that's a good reason not to use it). So we hit that question again of whether JFX should provide an out-of-the-box solution or just plumbing that an open source project (or projects) can build upon to provide higher level utilities.

Looking at just the low level plumbing aspects, the things that JFX was lacking that would make my specific validation framework easier to implement are discussed in this thread: http://mail.openjdk.java.net/pipermail/openjfx-dev/2011-December/000048.html

The ability to visually annotate or mark up a node (or control) is the key one for me. This would be useful both for validation frameworks but would also have much wider applications (which is a good test of 'plumbing' in my mind), such as marking up nodes for 'live help' or highlighting nodes when doing a guided walk-through of an application in 'tutorial mode'.

After our discussions in that thread I've personally come to the conclusion that a consistent 'value' property is not actually a strong requirement but that some of the controls (i.e. ChoiceBox) were just lacking a value property and I believe this has been is or is being addressed.

Additionally to the earlier issues, the other big plumbing thing that was not up to the level needed yet was the JFX Tooltip API. The current tooltip mechanism is very simple and I really would have benefited from being able to specify specific tooltip timings and features on a per-control basis (i.e. when a field has an error I want to be able to show the tooltip instantly when the field has focus and keep it visible, but without an error, the tooltip can go back to normal). There is an existing JIRA request for this sort of thing: http://javafx-jira.kenai.com/browse/RT-17324

On Tue, Feb 21, 2012 at 5:07 AM, Jeff McDonald <deep.blue.6802 at gmail.com>wrote:

As part of the App kernel frameworks discussion Richard has discussed the need for a validation frameworks. I'm breaking out the discussion on validation because the topic is broad enough to benefit from a focused discussion.

My random thoughts: - All of Java can benefit from validation, and not just JavaFX. Where should a validation frameworks fit into the Java ecosystem? - Thinking about validation there are two categories that I can think of (1)passive validation - this is the most obvious. A users types in a value and submits it and validation is performed and either the input is bad or it's good. (2) active validation - input is evaluated and validated during the input process. As an example: Let's say you have a field that accepts an email address. With passive validation the user could be informed that they entered an invalid email address. In an active validation system the field could restrict the user from entering invalid characters or stop accepting input once a maximum size is reached. - JavaFX can benefit from both passive and active forms of validation. The important question becomes how to implement validation into the UI. Where to place the hooks and response behavior in the UI code. - What things work great in existing validation frameworks? What sucks? - What libraries do you use? Why did you pick that library? - What is missing from existing validation frameworks? Cheers, Jeff

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