Merge pull request #9760 from umangbudhwar/master

BAEL-4329: Set field value with reflection

core-java-modules/core-java-reflection-2/src/test/java/com/baeldung/reflection/set/fields/SetFieldsUsingReflectionUnitTest.java

@@ -0,0 +1,183 @@
+package com.baeldung.reflection.set.fields;
+
+import java.lang.reflect.Field;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import com.baeldung.reflection.access.privatefields.Person;
+
+public class SetFieldsUsingReflectionUnitTest {
+
+    @Test
+    public void whenSetIntegerFields_thenSuccess() throws Exception {
+        Person person = new Person();
+
+        Field ageField = person.getClass()
+            .getDeclaredField("age");
+        ageField.setAccessible(true);
+
+        byte age = 26;
+        ageField.setByte(person, age);
+        Assertions.assertEquals(age, person.getAge());
+
+        Field uidNumberField = person.getClass()
+            .getDeclaredField("uidNumber");
+        uidNumberField.setAccessible(true);
+
+        short uidNumber = 5555;
+        uidNumberField.setShort(person, uidNumber);
+        Assertions.assertEquals(uidNumber, person.getUidNumber());
+
+        Field pinCodeField = person.getClass()
+            .getDeclaredField("pinCode");
+        pinCodeField.setAccessible(true);
+
+        int pinCode = 411057;
+        pinCodeField.setInt(person, pinCode);
+        Assertions.assertEquals(pinCode, person.getPinCode());
+
+        Field contactNumberField = person.getClass()
+            .getDeclaredField("contactNumber");
+        contactNumberField.setAccessible(true);
+
+        long contactNumber = 123456789L;
+        contactNumberField.setLong(person, contactNumber);
+        Assertions.assertEquals(contactNumber, person.getContactNumber());
+
+    }
+
+    @Test
+    public void whenDoUnboxing_thenSuccess() throws Exception {
+        Person person = new Person();
+
+        Field pinCodeField = person.getClass()
+            .getDeclaredField("pinCode");
+        pinCodeField.setAccessible(true);
+
+        Integer pinCode = 411057;
+        pinCodeField.setInt(person, pinCode);
+        Assertions.assertEquals(pinCode, person.getPinCode());
+    }
+
+    @Test
+    public void whenDoNarrowing_thenSuccess() throws Exception {
+        Person person = new Person();
+
+        Field pinCodeField = person.getClass()
+            .getDeclaredField("pinCode");
+        pinCodeField.setAccessible(true);
+
+        short pinCode = 4110;
+        pinCodeField.setInt(person, pinCode);
+        Assertions.assertEquals(pinCode, person.getPinCode());
+    }
+
+    @Test
+    public void whenSetFloatingTypeFields_thenSuccess() throws Exception {
+        Person person = new Person();
+
+        Field heightField = person.getClass()
+            .getDeclaredField("height");
+        heightField.setAccessible(true);
+
+        float height = 6.1242f;
+        heightField.setFloat(person, height);
+        Assertions.assertEquals(height, person.getHeight());
+
+        Field weightField = person.getClass()
+            .getDeclaredField("weight");
+        weightField.setAccessible(true);
+
+        double weight = 75.2564;
+        weightField.setDouble(person, weight);
+        Assertions.assertEquals(weight, person.getWeight());
+    }
+
+    @Test
+    public void whenSetCharacterFields_thenSuccess() throws Exception {
+        Person person = new Person();
+
+        Field genderField = person.getClass()
+            .getDeclaredField("gender");
+        genderField.setAccessible(true);
+
+        char gender = 'M';
+        genderField.setChar(person, gender);
+        Assertions.assertEquals(gender, person.getGender());
+    }
+
+    @Test
+    public void whenSetBooleanFields_thenSuccess() throws Exception {
+        Person person = new Person();
+
+        Field activeField = person.getClass()
+            .getDeclaredField("active");
+        activeField.setAccessible(true);
+
+        activeField.setBoolean(person, true);
+        Assertions.assertTrue(person.isActive());
+    }
+
+    @Test
+    public void whenSetObjectFields_thenSuccess() throws Exception {
+        Person person = new Person();
+
+        Field nameField = person.getClass()
+            .getDeclaredField("name");
+        nameField.setAccessible(true);
+
+        String name = "Umang Budhwar";
+        nameField.set(person, name);
+        Assertions.assertEquals(name, person.getName());
+    }
+
+    @Test
+    public void givenInt_whenSetStringField_thenIllegalArgumentException() throws Exception {
+        Person person = new Person();
+        Field nameField = person.getClass()
+            .getDeclaredField("name");
+        nameField.setAccessible(true);
+
+        Assertions.assertThrows(IllegalArgumentException.class, () -> nameField.setInt(person, 26));
+    }
+
+    @Test
+    public void givenInt_whenSetLongField_thenIllegalArgumentException() throws Exception {
+        Person person = new Person();
+
+        Field pinCodeField = person.getClass()
+            .getDeclaredField("pinCode");
+        pinCodeField.setAccessible(true);
+
+        long pinCode = 411057L;
+
+        Assertions.assertThrows(IllegalArgumentException.class, () -> pinCodeField.setLong(person, pinCode));
+    }
+
+    @Test
+    public void whenFieldNotSetAccessible_thenIllegalAccessException() throws Exception {
+        Person person = new Person();
+        Field nameField = person.getClass()
+            .getDeclaredField("name");
+
+        Assertions.assertThrows(IllegalAccessException.class, () -> nameField.set(person, "Umang Budhwar"));
+    }
+
+    @Test
+    public void whenAccessingWrongProperty_thenNoSuchFieldException() throws Exception {
+        Person person = new Person();
+
+        Assertions.assertThrows(NoSuchFieldException.class, () -> person.getClass()
+            .getDeclaredField("firstName"));
+    }
+
+    @Test
+    public void whenAccessingNullProperty_thenNullPointerException() throws Exception {
+        Person person = new Person();
+
+        Assertions.assertThrows(NullPointerException.class, () -> person.getClass()
+            .getDeclaredField(null));
+    }
+
+}