package lists;

/*
 * A Stack is a "first-in, last-out" (FILO) structure where new
 * elements are inserted in such a way that the element that can
 * be removed is the one that was added last.
 * 
 * A stack supports the following methods:
 * 
 *  isEmpty  - returns true if stack is empty
 *  isFull   - returns true if stack is full
 *  getSize  - returns the number of nodes in the stack
 *  push     - adds an object to the top of a stack
 *  pop      - returns top element from the stack and removes it
 *  peek     - returns top element from stack without removing it
 */
public interface ADTStack
{
    /*
     * 
     */
    public abstract boolean isEmpty();
    /*
     * 
     */
    public abstract boolean isFull();
    /*
     * 
     */
    public abstract int getSize();
    /*
     * 
     */
    public abstract void push(Object obj);
    /*
     * 
     */
    public abstract Object pop();
    /*
     * 
     */
    public abstract Object peek();
}