package effect.java.generics.item31;

import java.util.Arrays;

import java.util.Collection;

import java.util.EmptyStackException;

public class Stack<E> {

private E[] elements;

private int size = 0;

private static final int DEFAULT_INITIAL_CAPACITY = 16;

@SuppressWarnings("unchecked")

public Stack() {

elements = (E[])new Object[DEFAULT_INITIAL_CAPACITY];

}

public void push(E e) {

ensureCapacity();

elements[size++] = e;

}

public E pop() {

if (size ==0) {

throw new EmptyStackException();

}

E result = elements[--size];

elements[size] = null;

return result;

}

private void ensureCapacity() {

if(elements.length == size) {

elements = Arrays.copyOf(elements, 2 * size + 1);

}

}

public boolean isEmpty() {

return size == 0;

}

public void pushAll(Iterable<? extends E> src) {

for(E e: src) {

push(e);

}

}

public void popAll(Collection<? super E> dst) {

while(!isEmpty()) {

dst.add(pop());

}

}

public static void main(String[] args) {

Stack <Number> numberStack = new Stack<>();

Iterable<Integer> integers = null;

numberStack.pushAll(integers);

Collection<Object> objects = null;

numberStack.popAll(objects);

}

}