From a37f8801d4db0ce08eaab38fa8c42e481c415153 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Dyda?= <pawel.dyda@amu.edu.pl>
Date: Sat, 12 Nov 2022 20:25:28 +0100
Subject: [PATCH] Same example expressed functionally.

---
 .../amu/edu/demo/primes/FunctionalPrimes.java | 30 +++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 demo/03/src/main/java/pl/amu/edu/demo/primes/FunctionalPrimes.java

diff --git a/demo/03/src/main/java/pl/amu/edu/demo/primes/FunctionalPrimes.java b/demo/03/src/main/java/pl/amu/edu/demo/primes/FunctionalPrimes.java
new file mode 100644
index 0000000..da859d9
--- /dev/null
+++ b/demo/03/src/main/java/pl/amu/edu/demo/primes/FunctionalPrimes.java
@@ -0,0 +1,30 @@
+package pl.amu.edu.demo.primes;
+
+import lombok.NoArgsConstructor;
+
+import java.util.function.IntPredicate;
+import java.util.stream.IntStream;
+
+@NoArgsConstructor
+public class FunctionalPrimes {
+
+    public static void main(String[] args) {
+        new FunctionalPrimes().printPrimes();
+    }
+
+    public void printPrimes() {
+        IntStream.range(0, 121)
+                .filter(this::isPrime)
+                .forEach(i -> System.out.printf("%d is prime\n", i));
+    }
+
+    private boolean isPrime(int number) {
+        if (number <= 0) {
+            return false;
+        }
+        IntPredicate isDivisible = (int divisor) -> number % divisor == 0;
+        return IntStream.rangeClosed(2, (int) Math.sqrt(number))
+                .noneMatch(isDivisible);
+    }
+
+}