Hello,
I've encountered the same problem recently and I've also figured out the
reason. It's because the method setProperties() is called twice. Usually
you wouldn't notice this behaviour as most properties just will be
overridden but that's not the case for a ValueChangeListener (or an
ActionListener). For a better understanding of this issue, I'll describe
the call hierachy (somewhat simplified):
///
//
myfaces/core/branches/1_2_1/api/javax/faces/webapp/UIComponentClassicTagBase.java
protected UIComponent findComponent(FacesContext context)
{
// ...
// around line 1097
_componentInstance = findComponent(parent,id);
if (_componentInstance == null)
{
_componentInstance = createComponent(context, id);
_created = true;
setProperties(_componentInstance); // << here is the
"first" call
// ....
\\\
///
// myfaces/core/branches/1_2_1/api/javax/faces/webapp/UIComponentELTag.java
protected UIComponent createComponent(FacesContext context, String newId)
{
// ...
// around line 98
component.setId(newId);
setProperties(component); // << her is the "second" call (it's
actually the first, but it's the one I would omit)
return component;
}
\\\
I'll create a JIRA issue (including the appropriate patch) in a few
hours, or maybe anyone else might be taking a look in the meantime.
regards,
Bernhard
Fan Shao wrote:
Hi,
When trying to trace down the problem I posted a few days ago
(http://www.nabble.com/Button-must-be-clicked-once-before-it-could-actually-do-something-tf4297733.html#a12234990)
I found some of the events are fired twice, where they are supposed to be
fired only once.
The screen contains a datatable, and a dropdown box. When the user selects a
value of the dropdown box, the form is submitted using this.form.submit(),
and the datatable is reloaded according to user's selection. Everytime the
datatable is reloaded its associated handler is called twice.
Anyone has any idea about this?
Many thanks!
Fan
