From 2b28336cd6f7709d1751a2d5f1838017e69b8266 Mon Sep 17 00:00:00 2001
From: Andrey Shcherbakov <veontomo@users.noreply.github.com>
Date: Fri, 15 Mar 2019 23:45:56 +0100
Subject: [PATCH] Add the code for article "Kotlin Annotations" (BAEL-2579)
 (#6540)

---
 .../com/baeldung/annotations/Annotations.kt   |  7 ++++
 .../kotlin/com/baeldung/annotations/Item.kt   |  3 ++
 .../kotlin/com/baeldung/annotations/Main.kt   |  7 ++++
 .../com/baeldung/annotations/Validator.kt     | 38 +++++++++++++++++
 .../annotations/ValidationUnitTest.kt         | 42 +++++++++++++++++++
 5 files changed, 97 insertions(+)
 create mode 100644 core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Annotations.kt
 create mode 100644 core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Item.kt
 create mode 100644 core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Main.kt
 create mode 100644 core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Validator.kt
 create mode 100644 core-kotlin-2/src/test/kotlin/com/baeldung/annotations/ValidationUnitTest.kt

diff --git a/core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Annotations.kt b/core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Annotations.kt
new file mode 100644
index 0000000000..a8f83446dc
--- /dev/null
+++ b/core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Annotations.kt
@@ -0,0 +1,7 @@
+package com.baeldung.annotations
+
+@Target(AnnotationTarget.FIELD)
+annotation class Positive
+
+@Target(AnnotationTarget.FIELD)
+annotation class AllowedNames(val names: Array<String>)
diff --git a/core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Item.kt b/core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Item.kt
new file mode 100644
index 0000000000..6864fe416e
--- /dev/null
+++ b/core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Item.kt
@@ -0,0 +1,3 @@
+package com.baeldung.annotations
+
+class Item(@Positive val amount: Float, @AllowedNames(["Alice", "Bob"]) val name: String)
\ No newline at end of file
diff --git a/core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Main.kt b/core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Main.kt
new file mode 100644
index 0000000000..2b7f2c5590
--- /dev/null
+++ b/core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Main.kt
@@ -0,0 +1,7 @@
+package com.baeldung.annotations
+
+fun main(args: Array<String>) {
+    val item = Item(amount = 1.0f, name = "Bob")
+    val validator = Validator()
+    println("Is instance valid? ${validator.isValid(item)}")
+}
diff --git a/core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Validator.kt b/core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Validator.kt
new file mode 100644
index 0000000000..40139048ab
--- /dev/null
+++ b/core-kotlin-2/src/main/kotlin/com/baeldung/annotations/Validator.kt
@@ -0,0 +1,38 @@
+package com.baeldung.annotations
+
+/**
+ * Naive annotation-based validator.
+ * @author A.Shcherbakov
+ */
+class Validator() {
+
+    /**
+     * Return true if every item's property annotated with @Positive is positive and if
+     * every item's property annotated with @AllowedNames has a value specified in that annotation.
+     */
+    fun isValid(item: Item): Boolean {
+        val fields = item::class.java.declaredFields
+        for (field in fields) {
+            field.isAccessible = true
+            for (annotation in field.annotations) {
+                val value = field.get(item)
+                if (field.isAnnotationPresent(Positive::class.java)) {
+                    val amount = value as Float
+                    if (amount < 0) {
+                        return false
+                    }
+                }
+                if (field.isAnnotationPresent(AllowedNames::class.java)) {
+                    val allowedNames = field.getAnnotation(AllowedNames::class.java)?.names
+                    val name = value as String
+                    allowedNames?.let {
+                        if (!it.contains(name)) {
+                            return false
+                        }
+                    }
+                }
+            }
+        }
+        return true
+    }
+}
\ No newline at end of file
diff --git a/core-kotlin-2/src/test/kotlin/com/baeldung/annotations/ValidationUnitTest.kt b/core-kotlin-2/src/test/kotlin/com/baeldung/annotations/ValidationUnitTest.kt
new file mode 100644
index 0000000000..506b7a24b5
--- /dev/null
+++ b/core-kotlin-2/src/test/kotlin/com/baeldung/annotations/ValidationUnitTest.kt
@@ -0,0 +1,42 @@
+package com.baeldung.annotations
+
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Assertions.assertFalse
+import org.junit.jupiter.api.Test
+
+
+class ValidationUnitTest {
+
+    @Test
+    fun whenAmountIsOneAndNameIsAlice_thenTrue() {
+        assertTrue(Validator().isValid(Item(1f, "Alice")))
+    }
+
+    @Test
+    fun whenAmountIsOneAndNameIsBob_thenTrue() {
+        assertTrue(Validator().isValid(Item(1f, "Bob")))
+    }
+
+
+    @Test
+    fun whenAmountIsMinusOneAndNameIsAlice_thenFalse() {
+        assertFalse(Validator().isValid(Item(-1f, "Alice")))
+    }
+
+    @Test
+    fun whenAmountIsMinusOneAndNameIsBob_thenFalse() {
+        assertFalse(Validator().isValid(Item(-1f, "Bob")))
+    }
+
+    @Test
+    fun whenAmountIsOneAndNameIsTom_thenFalse() {
+        assertFalse(Validator().isValid(Item(1f, "Tom")))
+    }
+
+    @Test
+    fun whenAmountIsMinusOneAndNameIsTom_thenFalse() {
+        assertFalse(Validator().isValid(Item(-1f, "Tom")))
+    }
+
+
+}
\ No newline at end of file