Guidelines

Note: In on get/set hooks for an attribute implementation, only use attributes that are modeled as ‘used attributes’ for that attribute implementation!

Note that you cannot have both an on set hook and an on get hook on the same attribute implementation.

An attribute implementation value can be filled (or changed) only in the following cases:

In case of an on set hook, if it is the attribute implementation that contains the on set hook.
In case of an on get hook, if it is the attribute implementation that contains the on get hook.

An attribute implementation value can be used only in the following cases:

In case of an on set hook, if it is one of the attribute implementations listed in the used attributes of the attribute implementation containing the on set hook.
In case of an on get hook, if it is one of the attribute implementations listed in the used attributes of the attribute implementation containing the on get hook.