// generics/GenericCast.java

// (c)2017 MindView LLC: see Copyright.txt

// We make no guarantees that this code is fit for any purpose.

// Visit http://OnJava8.com for more book information.

import java.util.*;

import java.util.stream.*;

class FixedSizeStack<T> {

private final int size;

private Object[] storage;

private int index = 0;

FixedSizeStack(int size) {

this.size = size;

storage = new Object[size];

}

public void push(T item) {

if(index < size)

storage[index++] = item;

}

@SuppressWarnings("unchecked")

public T pop() {

return index == 0 ? null : (T)storage[--index];

}

@SuppressWarnings("unchecked")

Stream<T> stream() {

return (Stream<T>)Arrays.stream(storage);

}

}

public class GenericCast {

static String[] letters =

"ABCDEFGHIJKLMNOPQRS".split("");

public static void main(String[] args) {

FixedSizeStack<String> strings =

new FixedSizeStack<>(letters.length);

Arrays.stream("ABCDEFGHIJKLMNOPQRS".split(""))

.forEach(strings::push);

System.out.println(strings.pop());

strings.stream()

.map(s -> s + " ")

.forEach(System.out::print);

}

}

/* Output:

S

A B C D E F G H I J K L M N O P Q R S

*/