Verse Of The Day

Tuesday, March 03, 2009

An Overzealous SEAM Validation

I am using the Jboss SEAM framework for the project I am currently working on. The first thing that really bit me was a validation on single character fields that seems a bit "too stringent". I'm sure I'm not the first to run into this. In fact it may be fixed by now in a newer version of SEAM, but figured it's worth a post anyways.

When you use Jboss Developer Studio (JBDS) to reverse engineer your database (I imagine the seam-gen tools do the same since JBDS uses them), the getter method on the EJB looks something like this...

@Column(name = "DEFAULT_REMAP_IND", length = 1)
@Length(max = 1)
public Character getDefaultRemapInd() {
return this.defaultRemapInd;
Looks fine, looks reasonable. Single character fields are often used for flags or indicators, as this one above is -- it's a simple Y/N field. So in my XHTML I use a radio button control instead of a free form text field.

<h:selectOneRadio id="defaultRemapInd" value="#{ocamCustTypeDfltHome.instance.defaultRemapInd}" required="true">
<f:selectItem itemValue="Y" itemLabel="Yes" />
<f:selectItem itemValue="N" itemLabel="No" />
<a:support event="onblur" reRender="defaultRemapIndDecoration"/>

The SEAM framework will use that @Length annotation to perform some field validations for you automagically, which is pretty cool as it can be a real time-saver. But the funny thing is that when this "max length of 1" validation fires, you get the lovely message shown in this partial screen shot ....

Not sure how to get a single character with a length greater than 0 but less than 1, but I do know that the easiest thing to do in this case is remove the @Length annotation for that field. I had to do that for a few different tables. Luckily they were all flags that could be replaced with radio buttons, but in the case where you had to allow free input, you might have to get more creative (you can always put a max length on the input text field).

For reference, I am using Jboss 4.2.2, SEAM 1.2GA, Jboss's EJB3 implementation (which is Hibernate under the hood), XHTML and Facelets for the views. Like I said, this might be fixed in a later release of SEAM.

1 comment:

Chuck said...

Reading this made me think of "Charlie Brown" your text was like the teachers "Waa wa waa wa waa" to me as I know nothing about programming (although I could type up some killer sprites with my Commodore 128/64 back in the day!)Yet the greater than 0 less than 1 part of your post made me laugh hystarically and to think there are people who worry about computers taking over the world - not with that kind of intellect!