Category: Uncategorized

JSF Submit-on-Enter forms

It’s not (so far as I know) officially required anywhere, but it’s a generally accepted principle that a form on a web page containing one text field and one submit button should submit itself when you type in text and press the ENTER key. A classic example of this is Google .

In actuality, it isn’t quite that simple. For totally unknown reasons, Microsoft Internet Explorer requires at least two text fields and this apparently goes all the way up to and including IE8 (at least when you upgrade from IE6). Fortunately, the “spare” text field can be invisible and ignored by the application.

JSF is more complicated, and AJAX-aware JSF such as RichFaces compounds the issue even more. Here’s a solution that seems to work for me:

  <h:panelGroup>
     <h:inputText style="visibility:hidden;display:none;"
        disabled="disabled" required="false" />
     <a4j:commandButton id="ask"
        type="submit" styleClass="button1"
        action="#{forgotPassword.doAskQuestion}"
        reRender="pnl1,fpMsg" value="Submit" />
 </h:panelGroup>

I am indebted to Lincoln Baxter for this particular hidden field definition (it’s quite touchy). He’s the person behind the JSF PrettyFaces product (ocpsoft.com).

Note that this is only a kludge, and may not always work. Additionally, it causes the RichFaces a4j:commandButton oncomplete action to misbehave under both IE and Firefox (though in different ways), as of RichFaces 3.4.

OpenJPA, Tomcat6, Spring and Hibernate

Getting all of the above to play together can be tricky. I knocked myself offline for nearly 2 days after the latest upgrade.

Broken Tomcat/Eclipse

The sysdeo Tomcat plugin no longer works when my testapp is installed – the log says the WebAppClassLoader (todo: check name) cannot be found. Something’s messed up the core Tomcat classpath. Fortunately the stand-alone remote debug option still works.

Annotations and Weaving

The test app is using Java 5 annotations on the persistent classes. Persistent classes are “magic”. Before they can actually be used, they have to be re-written to add the additional properties that aid the persistency manager. In the Old Days, that would have meant using some sort of utility that added additional source text to the persistent classes before they were compiled. In our new, more transparent era, this means that after the java source is compiled into classes, the extra embellishments are added to the binary class definition.

There’s 2 ways to do that:

  1. Permanently modify the class binary file
  2. Piggyback the embellishments onto the class as it’s being loaded into the JVM.

When I used JDO – and in early OpenJPA, option 1 was used courtesy of a utility known as the enhancer.

Since about October 2007 (give or take), OpenJPA has had the ability to do on-the-fly enhancement, which is option 2 or some facsimile thereof. But there’s a catch.

In order to