In MySearchTree
the K
of the base type is Course
. So K
must “extend” Comparable<Keyable<Course>> & Keyable<Course>
. But it doesn’t, it extends Comparable<Keyable<DataElement>> & Keyable<DataElement>
.
I guess DataElement
should be generified in a similar manner to Comparable
or Enum
.
public interface Keyable <T> {public String getKey();}
public interface DataElement<THIS extends DataElement<THIS>> extends Comparable<Keyable<THIS>>, Keyable<THIS>, Serializable {...}
public class Course implements DataElement<Course> {...}
public interface SearchTree<K extends Comparable<Keyable<K>> & Keyable<K>> extends Serializable {...}
public class MySearchTree implements SearchTree<Course> {