package chapter11;

import java.util.Optional;

class Resource

{

static int count = 3;

public Resource()

{

count--;

System.out.println("Resource consumed, " + count

+ " remaining.");

}

}

public class Sect7_Ex5

{

public static void main(String[] args)

{

Optional.of(new Resource()) // Resource.count = 2

.filter(x -> x.count > 0)

.map(x -> new Resource()) // Resource.count = 1

.filter(x -> x.count > 0)

.map(x -> new Resource()) // Resource.count = 0

.filter(x -> x.count > 0) // Optional(null)

.map(x -> new Resource()); // doesn't execute

}

}