Hello,
I think I have found a bug, but rather than open an issue I prefer to ask it
here first.
I'm writing a custom version of UIData component extending the default UIData
class. I want to register a DataModelListener in order to be notified on row
index changes.
I have overridden the setValue(Object) method to register the DataModelListener
whenever a new value is set to the component:
@Override
public void setValue(Object value) {
super.setValue(value);
getDataModel().addDataModelListener(new MyDataModelListener());
}
But MyDataModelListener is not notified the very first time the UIData's row
index changes from -1 to 0.
Looking through the code, this is caused because when getDataModel() is first
called, it calls createDataModel() and then a new instance is created using the
one-argument constructor. This one-argument constructor in all variants of
DataModel concrete classes calls the method setWrappedData() and as say the
specification of this method:
"If data is non-null, the currently selected row index must be
set to zero, and a
DataModelEvent<http://javaserverfaces.java.net/nonav/docs/2.1/javadocs/javax/faces/model/DataModelEvent.html>
must be sent to the rowSelected() method of all registered
DataModelListener<http://javaserverfaces.java.net/nonav/docs/2.1/javadocs/javax/faces/model/DataModelListener.html>s
indicating that this row is now selected."
But this DataModelEvent will never be sent to any listeners, because this is
triggered from the constructor and so, it is impossible to have any listener
registered.
So, I have had to refactor my code to workaround this bug, this way:
@Override
public void setValue(Object value) {
super.setValue(value);
DataModel<?> dm = getDataModel();
dm.setRowIndex(-1); // FIXME reset rowIndex due to bug
dm.addDataModelListener(new MyDataModelListener());
}
To solve this, and to be compliant with the spec, I think that the one-argument
constructor of the DataModel classes shouldn't call setWrappedData(), but
instead assign its internal variable directly.
What do you think?
Un saludo,
Jesús Pérez Alcaide
Lab. Banksphere - Runtime
Tlf: 91 470 5223
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