class 21 composition

Author: MartinFiorde

modules/src/main/java/com/platzi/functional_student_practice/_11_composition/C21MathOperations2.java

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+package com.platzi.functional_student_practice._11_composition;
+
+import java.util.function.IntUnaryOperator;
+
+public class C21MathOperations2 {
+    public static void main(String[] args) {
+        System.out.println("////////////////////////////////////////////////////////////////////////////////////");
+        System.out.println("\nCLASS 21\n");
+
+        // 1. We declare 3 functions as variables
+        IntUnaryOperator multiplyBy3 = x -> { // idem: Function<Integer, Integer>
+            System.out.println("Multiplicando x: " + x + " por 3");
+            return x * 3;
+        };
+
+        IntUnaryOperator add1 = x -> {
+            System.out.println("Le agregare 1 a: " + x);
+            return x + 1;
+        };
+
+        IntUnaryOperator square = x -> {
+            System.out.println("Estoy elevando " + x + " al cuadrado");
+            return x * x;
+        };
+
+        // 2. We compose a new function that execute multiplyBy3() AFTER we add1()
+        IntUnaryOperator add1MultiplyBy3 = multiplyBy3.compose(add1); // idem: y -> add1.apply(y) - idem: add1::applyAsInt
+
+        // 3. We compose a new function that execute add1MultiplyBy3() BEFORE we square()
+        IntUnaryOperator andSquare = add1MultiplyBy3.andThen(square); // idem: y -> square.apply(y)
+
+        System.out.println(add1MultiplyBy3.applyAsInt(5));
+        System.out.println(andSquare.applyAsInt(3));
+    }
+}