JBossDeveloper

Its done in CVS

Does anyone have an example of this ? I'm trying to create my own @SelectItems and @SelectItemsSelection and I can't get the DataSelector implementation to fire.

So I have a couple of questions:

1) What do I put in the value attribute of a <h:selectOneMenu/> tag ? Should it be just a regular bijected field of the same type as the Entity that is used in the List that I have marked up with @SelectItemsSelection ?

2) Do I need - as Peter Muir has suggested above - to re-read the List from the EntityManager ? This seems wasteful to me. Should I get the List from the Seam context ? Essentially - how do I convert the value from the <h:selectOneMenu/> in JSF into the selected Entity value ?

Thanks in advance,

Thanks Jim.

This helps a lot - it confirms what I understood, but thought that I didn't and you provided me with a critical bit of information (SelectOneMenu doesn't actually set a selection on the SelectItems).

I thought I was 'missing a trick' - the first approach seems sufficient for most purposes. My only concern here is that it introduces 'binding and conversion' code into my action - which doesn't feel like business logic.

I can give the second approach a go this weekend also - I think that it will work and it gives me a chance to learn more about annotations.

I do wonder if there is a third attack on this problem, which is a not annotation based at all. A JSF component - essentially a UIDataModel based component that renders an HTML Select and sets the selected state on the appropriate item. It would be a single action element (tag) that takes DataModel EL expression and another EL expression that resolves the Label. It could do more than this (multi value binding ?). Maybe this is another item for my weekend.

This may obviate the need for @SelectItems and @SelectItemsSelection - allowing @DataModel and @DataModelSelection to work.

Thanks again,

Hello,

Is it possible to use this approach to select multiple items?

Regards,

Sergey

Jim,

Could you please post a complete example (WAR) at seam wiki. It will be very helpful.

Regards,

Sergey

In response to many requests I've decided to post my @SelectItems DataBinder to the Seam Wiki.

Thank you a lot!

I tweaked your wrap method to add some extra functionality.

I added the following annotation property to SelectItems.

 /**
 * If specified along with Strategy.OBJECT, and new
 * object with the specified empty lable will be added.
 *
 * @return The method to call for a custom disabled value.
 */
 String emptyValueLabel() default "";

 public List<SelectItem> wrap(SelectItems ann, List list)
 {
 if (list != null)
 {
 WrappingArrayList<SelectItem> selectItems = new WrappingArrayList<SelectItem>();
 selectItems.setWrappedData(list);

 if (ann.emptyValueLabel().length() > 0 && ann.valueStrategy() == SelectItems.Strategy.OBJECT)
 {
 try
 {
 // Get an new instance of the type of the first object in the list.
 // If there is a problem do nothing.
 Object obj = list.get(0).getClass().newInstance();
 selectItems.add(new SelectItem(obj, ann.emptyValueLabel()));
 } catch (Exception e) { }
 }
 for (int i = 0; i < list.size(); i++)
 {
 selectItems.add(convertToSelectItem(String.valueOf(i), list.get(i), ann));
 }
 return selectItems;
 } else
 {
 return null;
 }
 }

 @SelectItems(valueStrategy = SelectItems.Strategy.OBJECT,
 labelMethod = "getGrade",
 emptyValueLabel = "Any")
 private List gradeSelectItems;