Leaf is an abstract base class for leaf nodes in the
instance tree. FIXME: The content value is actually handled in the
child classes, and needs to be unified into this class.
author: Jens-S. Vöckler author: Yong Zhao version: $Revision: 50 $ See Also:Text See Also:Use See Also:LFN
Accessor method. Sets the attribute of same name to a new value.
Parameters: value - is the new value to overwrite the current state with. See Also:Leaf.getValue()