Meyer's Implementation inheritance in java

Question

Can someone give an example of Meyers Implementation inheritance in Java, the book in the link is about eiffel, but i need a java example.

I know java doesn't support multiple inheritance, so can we call it implementation inheritance if I implement an interface and extend a class?

Also does it have to have two parents to be a case of implementation inheritance?

Answer 1

The definitions from the book go over this here:

Definition: implementation inheritance Structural inheritance applies if B obtains from A a set of features (other than constant attributes and once functions) necessary to the implementation of the abstraction associated with B. Both A and B must be effective.

The classes A and B must not be deferred. That is the case when extending a non-abstract Java class A by a non-abstract class B.

Definition: reification inheritance Reification inheritance applies if A represents a general kind of data structures, and B represents a partial or complete choice of implementation for that data structure. A is deferred; B may still be deferred, leaving room for further reification through its own heirs, or it may be effective.

The class A is deferred, so this would be the case when implementing a Java interface A or extending a Java interface A (the new interface would then be B)

The case you specify (implementing an interface and extending a non-abstract class in Java) is a combination of these two. The text makes it quite clear here:

A common case is what will be called the "marriage of convenience", based on multiple inheritance, where one parent provides the specification (reification inheritance) and the other the implementation (implementation inheritance).