Modify Faculty to use enums

Restrict the valid input values to currently existing NUS faculties. Change the test class.

src/main/java/staffconnect/model/person/Faculty.java

@@ -1,5 +1,8 @@
 package staffconnect.model.person;
 
+import java.lang.reflect.Array;
+import java.util.Arrays;
+
 import static java.util.Objects.requireNonNull;
 import static staffconnect.commons.util.AppUtil.checkArgument;
 
@@ -9,13 +12,47 @@
  * {@link #isValidFaculty(String)}
  */
 public class Faculty {
-    public static final String MESSAGE_CONSTRAINTS = "This can be any non-blank String content.";
+    public static final String MESSAGE_CONSTRAINTS =
+            "The content should be a String representing a real faculty of NUS";
     /*
-     * The first character of the faculty must not be a whitespace,
-     * otherwise " " (a blank string) becomes a valid input.
+     * For this version, a valid faculty value should match exactly the full name of the facult,
+     * or the value is invalid
      */
-    public static final String VALIDATION_REGEX = "[^\\s].*";
-    private final String value;
+    public enum NUSFaculty {
+        ARTS_AND_SOCIAL_SCIENCES("Arts and Social Sciences"),
+        BUSINESS("Business"),
+        COMPUTING("Computing"),
+        CONTINUING_AND_LIFELONG_EDUCATION("Continuing and Lifelong Education"),
+        DENTISTRY("Dentistry"),
+        DESIGN_AND_ENVIRONMENT("Design and Environment"),
+        DUKE_NUS_MEDICAL_SCHOOL("Duke-NUS Medical School"),
+        ENGINEERING("Engineering"),
+        INTEGRATIVE_SCIENCES_AND_ENGINEERING("Integrative Sciences and Engineering"),
+        LAW("Law"),
+        MEDICINE("Medicine"),
+        MUSIC("Music"),
+        PUBLIC_HEALTH("Public Health"),
+        PUBLIC_POLICY("Public Policy"),
+        SCIENCE("Science"),
+        UNIVERSITY_SCHOLARS_PROGRAMME("University Scholars Programme"),
+        YALE_NUS_COLLEGE("Yale-NUS College");
+
+        private final String facultyName;
+
+        NUSFaculty(String facultyName) {
+            this.facultyName = facultyName;
+        }
+
+        /**
+         * Links enum member to its name.
+         *
+         * @return name of the faculty
+         */
+        public String getFacultyName() {
+            return facultyName;
+        }
+    }
+    private final NUSFaculty value;
 
     /**
      * Constructs a {@code Faculty}.
@@ -25,16 +62,28 @@ public class Faculty {
     public Faculty(String faculty) {
         requireNonNull(faculty);
         checkArgument(isValidFaculty(faculty), MESSAGE_CONSTRAINTS);
-        value = faculty;
+        value = fromString(faculty);
     }
 
     public static boolean isValidFaculty(String test) {
-        return test.matches(VALIDATION_REGEX);
+        requireNonNull(test, "faculty cannot be null");
+
+        return Arrays.stream(NUSFaculty.values())
+                .anyMatch(faculty -> faculty.getFacultyName().equalsIgnoreCase(test));
+    }
+
+    private static NUSFaculty fromString(String name) {
+        for (NUSFaculty faculty : NUSFaculty.values()) {
+            if (faculty.getFacultyName().equalsIgnoreCase(name)) {
+                return faculty;
+            }
+        }
+        throw new IllegalArgumentException("No enum constant matches the provided name: " + name);
     }
 
     @Override
     public String toString() {
-        return value;
+        return value.getFacultyName();
     }
 
     @Override

src/test/java/staffconnect/model/person/FacultyTest.java

@@ -30,17 +30,17 @@ public void isValidFaculty() {
         assertFalse(Faculty.isValidFaculty(" ")); // spaces only
 
         // valid Faculties
-        assertTrue(Faculty.isValidFaculty("~")); // one character
-        assertTrue(Faculty.isValidFaculty("School of Computing")); // long faculty
-        assertTrue(Faculty.isValidFaculty("abcdefg"));
+        assertTrue(Faculty.isValidFaculty("science")); // ignore capitals
+        assertTrue(Faculty.isValidFaculty("Computing"));
+        assertTrue(Faculty.isValidFaculty("Arts and Social Sciences")); // long faculty
     }
 
     @Test
     public void equals() {
-        Faculty faculty = new Faculty("a faculty");
+        Faculty faculty = new Faculty("Computing");
 
         // same values -> returns true
-        assertEquals(faculty, new Faculty("a faculty"));
+        assertEquals(faculty, new Faculty("Computing"));
 
         // same object -> returns true
         assertEquals(faculty, faculty);
@@ -52,6 +52,6 @@ public void equals() {
         assertFalse(faculty.equals(5.0f));
 
         // different values -> returns false
-        assertNotEquals(faculty, new Faculty("Other Faculty"));
+        assertNotEquals(faculty, new Faculty("Science"));
     }
 }