//----------------------------------------------------------------------------
// BSTInterface.java            by Dale/Joyce/Weems                  Chapter 8
//
// Interface for a class that implements a binary search tree (BST).
//
// The trees are unbounded and allow duplicate elements, but do not allow null
// elements. As a general precondition, null elements are not passed as
// arguments to any of the methods.
//
// The tree supports iteration through its elements in INORDER, PREORDER,
// and POSTORDER.
//
// ajg version: Only support one active iteration; not one per order-type
//
//----------------------------------------------------------------------------

package ch08.trees;

public interface BSTInterface<T extends Comparable<T>> {
    // used to specify traversal order
    public static final int INORDER = 1;
    public static final int PREORDER = 2;
    public final int POSTORDER = 3;

    boolean isEmpty();

    int size();

    boolean contains (T element);
    // Returns true if this BST contains an element e such that
    // e.compareTo(element) == 0; otherwise, returns false.

    boolean remove (T element);
    // Removes an element e from this BST such that e.compareTo(element) == 0
    // and returns true; if no such element exists, returns false.

    T get(T element);
    // Returns an element e from this BST such that e.compareTo(element) == 0;
    // if no such element exists, returns null.

    void add (T element);
    // Adds element to this BST. The tree retains its BST property.

    int reset(int orderType);
    // Initializes current position for an iteration in the given order.
    // Returns current number of nodes in the BST.

    T getNext ();
    // Preconditions: The BST is not empty
    //                The BST has been reset.
    //                The BST has not been modified since the most recent reset
    //                The end of the iteration
    //
    // Returns the element at the current position on this BST
    // and advances the value of the current position.
}
// Local Variables:
// compile-command: "cd ../..; javac ch08/trees/BSTInterface.java"
// End: