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Thread: implementing generic compareTo()

  1. #1
    Junior Member pyler's Avatar
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    Default implementing generic compareTo()

    I have a generic class that contains a compareTo() method
    I'm getting an error on the method it'self that goes something like;

    Name clash: the method compareTo(T) of type twos<T N> has the same erasure as compareTo(T) of type Compareable<T> but does not override it.
    How do I fix it?

    here's my class
    public class twos<P,N> implements Comparable<twos<P,N>>{
    private P a;
    private N b;
    public twos(P puu, N paa ){
    public P getP(){
    return a;}
    public N getN(){
    return b;}
    public compareTo(P bee){
    int num1 = ((Comparable<twos<P, N>>) this.a).compareTo( (twos<P, N>) bee.b );
    			if (num1 != 0)
    				return num1;
    			if (this.a < bee.a) return -1;
    			if (this.a > bee.a) return 1;
    			return 0;
    }//end of class

    Any help is appreciated

  2. #2
    Member andbin's Avatar
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    Default Re: implementing generic compareTo()

    Quote Originally Posted by pyler View Post
    I have a generic class that contains a compareTo() method
    I'm getting an error on the method it'self that goes something like;
    Firstly, if the Comparable is Comparable<twos<P,N>>, then the compareTo must be:

    public int compareTo(twos<P,N> other)

    Secondly, 'a' and 'b' are of type P and N (type variables). They are not numbers (by itself), so you can't do this.a < something.
    Andrea, www.andbin.net SCJP 5 (91%) SCWCD 5 (94%)

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  3. The Following User Says Thank You to andbin For This Useful Post:

    GregBrannon (December 5th, 2013)

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