(Novice) Java generics: Comparable

Question

I have a class called Generic . I am assigned to create a boolean method called matches() that receives another Generic as a parameter and returns true if the two stored values can be found in the current Generic . Order of the values is not important.

public class Generic<T extends Comparable<? super T>> {
    ...
    public boolean matches(Class Generic){
    return this.valueA = that.valueA && this.valueB = that.valueB): } 
    ... 
}

I am scrabbling to figure out how the class is able to store multiple values for valueA and valueB and distinguish this.valueA from the other one. Should I refer to the concept called reflection for more info?

Answer 1

If the purpose of type parameter T is for fields valueA and valueB to be of that type, and that matches() should use the fact that they are Comparable (since T extends Comparable ), this is how:

public class Generic<T extends Comparable<? super T>> {
    private T valueA;
    private T valueB;
    public boolean matches(Generic<T> that){
        return (this.valueA.compareTo(that.valueA) == 0 &&
                this.valueB.compareTo(that.valueB) == 0);
    }
}

Of course, assuming that the referenced type enforces that Comparable is consistent with equals , then you don't really need Comparable at all:

public class Generic<T> {
    private T valueA;
    private T valueB;
    public boolean matches(Generic<T> that){
        return (this.valueA.equals(that.valueA) &&
                this.valueB.equals(that.valueB));
    }
}

Be aware that neither of these two examples can handle null values for valueA and valueB .