Real easy question about defining objects in java

Question

hey guys here is my problem. I am trying to implement an insert() method for my binary tree. i have my node class defined to contain
public T element() {
          return _data;
and then my actual tree class has an instance of this declared to be called runner.
BTreeNode runner;
runner = _root;
The problem occurs when i try to compare what i am inserting (obj) with what i have (runner.element) The actual line of code is
( obj.compareTo(runner.element) < 0 )
i get an error that says "runner.element cannot be resolved or is not a field".
I believe the error comes because i didnt adequately define runner but im not sure how to take care of that. Any suggestions would be most appreciated.
-peter

Answer 1

this is all of the code that has a relation to the error I am getting. The error is found in the BasicBTree class and says
"The method compareTo(T) in the type Comparable<T> is not applicable for the arguments
(Comparable)"
Basic Binary Tree Node class
public class BTreeNode<T extends Comparable<T>> implements Position<T> {
     private BTreeNode<T> _left;
     private BTreeNode<T> _right;
     private BTreeNode<T> _parent;
     private T            _data;
     public T element() {
          return _data;
     }Basic Binary Tree class
public class BasicBTree<T extends Comparable<T>> implements BinaryTree<T> {
public void insert(T obj) {
          BTreeNode runner;
          runner = _root;
          if (obj.compareTo (runner.element()) = null) { // ERROR OCCURS HERE
               _root = new BTreeNode(obj);
          return;   
}the interface posistion
public interface Position<T> {
     public T element();
}