About custom components...

Question

Hello everybody (and sorry for my bad english ( it could be my sign on sun forums :) ) )
I am actually working on my custom JSF components. I can't understand the interest of the saveState and restoreState functions on a class extending UIComponentBase.
I have readen things about this (and even on this forum), but without result. Effectively, it is generally said that it allows to save and restore the state of a component!!! Don't help a lot :) .
What state are we speaking about:
attributes of a component between two requests for the same user? (but it is generally the backing bean that contains informations needed for a component, no?). i can admit some component attributes have to be saved, but in this case, I don't understad exactly the meaning of the following code:
public Object saveState(FacesContext context) {
  Object values[] = new Object[2];
  values[0] = super.saveState(context);
  values[1] = this.attribute;
return values;
public void restoreState(FacesContext context, Object state) {
  Object values[] = (Object[]) state;
  super.restoreState(context, values[0]);
  this.attribute = (Integer)values[1];
}More particularly, if you save the state of the current object by calling super.saveState, what is the goal of values[1]. Why don't do in restore state:
public Object saveState(FacesContext context){
  return super.saveState(context);
public void restoreState(FacesContext context, Object state){
  CurrentClassExtendingUIComponentBase object= (CurrentClassExtendingUIComponentBase) state;
  super.restoreState( context, object);
  this.attribute= object.getAttribute();
} I am not really sure of what happens with these methods,
Thank you by advance.

Answer 1

Finally, by reading the sources, I can see that UIComponentBase does the same thing in its saveState method and put its attributes in an object array.