Yes, an abstract class can have constructors. An abstract class may have instance variables and non-abstract methods (common to all concrete subclasses) that operate on those variables. A constructor could be used to initialize the instance variables. A constructor of a concrete subclass would invoke the superclass constructor to initialize the variables of the abstract superclass.
Joined: Mar 05, 2003
Graph is part of a framework. It supplies nearly all of the methods to support a generic graph editor. SimpleGraph is a client-defined extension that supplies the geometric shapes of the nodes and edges to be used in the graph.
Graph is an abstract class. It needs a constructor to initialize the variables to do its work.
(From Cay Horstmann�s Object Oriented Design & Patterns) [ May 27, 2003: Message edited by: Marlene Miller ]