Stack.java

/* * Stack.java *  * Computer Science S-22, Harvard University */ /* * A generic interface that defines a simple ADT for a stack of * objects of a particular type. */public interface Stack<T> {    /*      * adds the specified item to the top of the stack.  Returns false     * if the list is full, and true otherwise.     */    boolean push(T item);     /*      * removes the item at the top of the stack and returns a     * reference to the removed object.  Returns null is the stack is     * empty.     */    T pop();     /*      * returns a reference to the item at the top of the stack without     * removing it. Returns null is the stack is empty.     */    T peek();     /* returns true if the stack is empty, and false otherwise */    boolean isEmpty();     /* returns true if the stack is full, and false otherwise */    boolean isFull();}