Validation with Either

rucek · rucek · commit a87f9bf723c3 · 2022-06-21T15:02:15.000+02:00
diff --git a/src/main/java/org/kunicki/functional_java/Validation.java b/src/main/java/org/kunicki/functional_java/Validation.java
@@ -1,5 +1,7 @@
 package org.kunicki.functional_java;
 
+import io.vavr.control.Either;
+
 record Person(String name, int age) {
 }
 
@@ -18,6 +20,21 @@ default boolean isAgeValid(int age) {
 
 class FailingFast implements PersonValidator {
 
+    private Either<String, String> validateName(String name) {
+        return isNameValid(name) ? Either.right(name) : Either.left("Invalid name");
+    }
+
+    private Either<String, Integer> validateAge(int age) {
+        return isAgeValid(age) ? Either.right(age) : Either.left("Invalid age");
+    }
+
+    public Either<String, Person> validate(String name, int age) {
+        return validateName(name).flatMap(n ->
+            validateAge(age).map(a ->
+                new Person(n, a)
+            )
+        );
+    }
 }
 
 class Accumulating implements PersonValidator {
