OnJava8-Examples/generics/Fibonacci.java

// generics/Fibonacci.java
// (c)2021 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.
// Generate a Fibonacci sequence
import java.util.function.*;
import java.util.stream.*;

public class Fibonacci implements Supplier<Integer> {
  private int count = 0;
  @Override
  public Integer get() { return fib(count++); }
  private int fib(int n) {
    if(n < 2) return 1;
    return fib(n-2) + fib(n-1);
  }
  public static void main(String[] args) {
    Stream.generate(new Fibonacci())
      .limit(18)
      .map(n -> n + " ")
      .forEach(System.out::print);
  }
}
/* Output:
1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597
2584
*/