Allow typing a prefix of the role to specify the role

docs/UserGuide.md

@@ -73,7 +73,7 @@ Shows a message listing out all the available commands and their purpose.
 Format: `help`
 
 For more information regarding the comamnd formats and examples, press `F1` to open up a help window (as shown in the picture below).
-To close the help window, you can simply press `esc` on your keyboard (other methods such as `alt`+`F4` and clicking on 
+To close the help window, you can simply press `esc` on your keyboard (other methods such as `alt`+`F4` and clicking on
 the red `X` button on the top right corner of the window also works).
 
 ![help message](images/helpMessage.png)
@@ -91,13 +91,17 @@ A person can have any number of tags (including 0)
 </div>
 
 Examples:
-* `add n/John Doe p/98765432 e/[email protected] r/STUDENT a/PGPR c/CS2101`
+* `add n/John Doe p/98765432 e/[email protected] r/student a/PGPR c/CS2101`
 * `add n/Betsy Crowe t/friend e/[email protected] r/TA a/COM2-0102 c/ST2334`
 
 Unlike the `edit` command, `t/` with an empty tag is not supported.
 If you want to not include any tag, leave out `t/TAG` entirely.
 Similarly, `p/` without any phone number is not supported, if you want to not specify the phone number, leave out `p/PHONE` entirely.
 
+The allowed roles are `Student`, `TA`, or `Professor`.
+The input is case-insensitive, and you can type an unambiguous prefix to specify the role.
+For example, you can type `r/s` instead of `r/student` as shown above.
+
 ### Listing all persons : `list`
 
 Shows a list of all persons in the address book.

src/main/java/seedu/address/logic/parser/ParserUtil.java

@@ -27,6 +27,8 @@ public class ParserUtil {
 
     public static final String MESSAGE_INVALID_INDEX = "Index is not a non-zero unsigned integer.";
     public static final String MESSAGE_DUPLICATE_INDEX = "There is a duplicate Index listed.";
+    public static final String MESSAGE_ROLE_CONSTRAINTS =
+            "Roles should be either 'STUDENT', 'TA', or 'PROFESSOR', or an unambiguous prefix of it.";
 
     /**
      * Parses {@code oneBasedIndex} into an {@code Index} and returns it. Leading and trailing whitespaces will be
@@ -168,18 +170,20 @@ public static Course parseCourse(String course) throws ParseException {
     }
 
     /**
-     * Parses a {@code String role} into a {@code Role}.
+     * Parses a {@code String role} from user input into a {@code Role}.
      * Leading and trailing whitespaces will be trimmed.
+     * Allows specifying a role case-insensitively, and matching by an unambiguous prefix.
      *
      * @throws ParseException if the given {@code role} is invalid.
      */
     public static Role parseRole(String role) throws ParseException {
         requireNonNull(role);
-        String trimmedRole = role.trim();
-        if (!Role.isValidRole(trimmedRole)) {
-            throw new ParseException(Role.MESSAGE_CONSTRAINTS);
+        List<String> matchedRoles = ParserUtil.filterByPrefix(role.trim().toUpperCase(), Role.getAllRoles());
+        if (matchedRoles.size() == 1) {
+            return Role.valueOf(matchedRoles.get(0));
+        } else {
+            throw new ParseException(MESSAGE_ROLE_CONSTRAINTS);
         }
-        return Role.valueOf(trimmedRole);
     }
 
     /**

src/main/java/seedu/address/model/person/Role.java

@@ -1,5 +1,7 @@
 package seedu.address.model.person;
 
+import java.util.Arrays;
+
 /**
  * Represents a Person's role in the address book.
  * Guarantees: immutable; is valid as declared in {@link #isValidRole(String)}
@@ -12,6 +14,13 @@ public enum Role {
     public static final String MESSAGE_CONSTRAINTS =
             "Roles should be either 'STUDENT', 'TA', or 'PROFESSOR'.";
 
+    /**
+     * Returns an array of strings containing all roles.
+     */
+    public static String[] getAllRoles() {
+        return Arrays.stream(Role.values()).map(Role::name).toArray(size -> new String[size]);
+    }
+
     /**
      * Returns true if a given string is a valid role.
      */

src/test/java/seedu/address/logic/parser/ParserUtilTest.java

@@ -20,6 +20,7 @@
 import seedu.address.model.person.Email;
 import seedu.address.model.person.Name;
 import seedu.address.model.person.Phone;
+import seedu.address.model.person.Role;
 import seedu.address.model.tag.Tag;
 
 public class ParserUtilTest {
@@ -231,6 +232,30 @@ public void parseTags_collectionWithValidTags_returnsTagSet() throws Exception {
         assertEquals(expectedTagSet, actualTagSet);
     }
 
+    @Test
+    public void parseRole_null_throwsNullPointerException() {
+        assertThrows(NullPointerException.class, () -> ParserUtil.parseRole(null));
+    }
+
+    @Test
+    public void parseRole_invalidValue_throwsParseException() {
+        assertThrows(ParseException.class, () -> ParserUtil.parseRole("")); // empty string
+        assertThrows(ParseException.class, () -> ParserUtil.parseRole(" ")); // spaces only
+        assertThrows(ParseException.class, () -> ParserUtil.parseRole("STUDENT123"));
+        assertThrows(ParseException.class, () -> ParserUtil.parseRole("STUDENT-"));
+    }
+
+    @Test
+    public void parseRole_validValue_returnsRole() throws Exception {
+        assertEquals(ParserUtil.parseRole("STUDENT "), Role.STUDENT);
+        assertEquals(ParserUtil.parseRole(" STUDENT"), Role.STUDENT);
+        assertEquals(ParserUtil.parseRole("student"), Role.STUDENT);
+        assertEquals(ParserUtil.parseRole("student"), Role.STUDENT);
+        assertEquals(ParserUtil.parseRole(" s "), Role.STUDENT);
+        assertEquals(ParserUtil.parseRole("t"), Role.TA);
+        assertEquals(ParserUtil.parseRole("pro"), Role.PROFESSOR);
+    }
+
     @Test
     public void filterByPrefix_emptyPrefix_returnsFullList() {
         String[] words = {"Hello", "World", "Bye", "Life"};

src/test/java/seedu/address/model/person/RoleTest.java

@@ -0,0 +1,80 @@
+package seedu.address.model.person;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static seedu.address.testutil.Assert.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+public class RoleTest {
+
+    @Test
+    public void valueOf_null_throwsNullPointerException() {
+        assertThrows(NullPointerException.class, () -> Role.valueOf(null));
+    }
+
+    @Test
+    public void valueOf_invalidRole_throwsIllegalArgumentException() {
+        String invalidRole = "";
+        assertThrows(IllegalArgumentException.class, () -> Role.valueOf(invalidRole));
+    }
+
+    @Test
+    public void valueOf_validRole_success() {
+        String validRole = "STUDENT";
+        assertEquals(Role.valueOf(validRole), Role.STUDENT);
+    }
+
+    @Test
+    public void isValidRole() {
+        // null role
+        assertThrows(NullPointerException.class, () -> Role.isValidRole(null));
+
+        // invalid roles
+        assertFalse(Role.isValidRole("")); // empty string
+        assertFalse(Role.isValidRole(" ")); // spaces only
+        assertFalse(Role.isValidRole("professor")); // non-uppercase
+        assertFalse(Role.isValidRole("STUDENT ")); // spaces at the end
+        assertFalse(Role.isValidRole(" STUDENT")); // spaces at the front
+        assertFalse(Role.isValidRole("STUDENT123")); // numbers within characters
+        assertFalse(Role.isValidRole("STUDENT-")); // special characters
+
+        // valid roles
+        assertTrue(Role.isValidRole("STUDENT"));
+        assertTrue(Role.isValidRole("PROFESSOR"));
+        assertTrue(Role.isValidRole("TA"));
+    }
+
+    @Test
+    public void equals() {
+        Role role = Role.STUDENT;
+
+        // same values -> returns true
+        assertTrue(role.equals(Role.STUDENT));
+
+        // same object -> returns true
+        assertTrue(role.equals(role));
+
+        // null -> returns false
+        assertFalse(role.equals(null));
+
+        // different types -> returns false
+        assertFalse(role.equals(5.0f));
+
+        // different values -> returns false
+        assertFalse(role.equals(Role.PROFESSOR));
+    }
+
+    @Test
+    public void hashcode() {
+        Role role = Role.STUDENT;
+
+        // same values -> returns same hash code
+        assertEquals(role.hashCode(), Role.STUDENT.hashCode());
+
+        // different values -> returns different hash code
+        assertNotEquals(role.hashCode(), Role.PROFESSOR.hashCode());
+    }
+}