Merge branch 'master' into change-tag-colour

src/main/java/seedu/address/model/loan/Nric.java

@@ -0,0 +1,83 @@
+package seedu.address.model.loan;
+
+import static java.util.Objects.requireNonNull;
+import static seedu.address.commons.util.AppUtil.checkArgument;
+
+/**
+ * Class that stores the NRIC of a person.
+ */
+public class Nric {
+
+    public static final String MESSAGE_NRIC_CONSTRAINTS =
+            "NRIC should be Singapore issued. It may be blank. ";
+
+    public static final String NRIC_VALIDATION_REGEX = "^[ST]\\d{7}[A-JZ]|[FG]\\d{7}[K-NPQRTUWX]$";
+
+    public final String nric;
+
+    /**
+     * Constructs a {@code Nric}.
+     *
+     * @param ic A valid nric.
+     */
+    public Nric(String ic) {
+        requireNonNull(ic);
+        ic = ic.toUpperCase();
+        checkArgument(isValidNric(ic), MESSAGE_NRIC_CONSTRAINTS);
+        nric = ic;
+    }
+
+    /**
+     * Returns true if a given string is a valid nric.
+     * Precondition: test is not null.
+     */
+    public static boolean isValidNric(String test) {
+        String ic = test.toUpperCase();
+
+        if (!ic.matches(NRIC_VALIDATION_REGEX)) {
+            return false;
+        }
+
+        String prefix = String.valueOf(ic.charAt(0));
+        String checksum = String.valueOf(ic.charAt(8));
+        String digits = ic.substring(1, 8);
+
+        int[] weights = {2, 7, 6, 5, 4, 3, 2};
+        int sum = 0;
+
+        // Generate checksum
+        for (int i = 0; i < digits.length(); i++) {
+            sum += Integer.parseInt(String.valueOf(digits.charAt(i))) * weights[i];
+        }
+
+        // Add 4 to IC issued in 21th century. This rule was designed by the Singapore government.
+        if ("G".equals(prefix) || "T".equals(prefix)) {
+            sum += 4;
+        }
+
+        if ("S".equals(prefix) || "T".equals(prefix)) {
+            String[] nricCheckDigits = {"J", "Z", "I", "H", "G", "F", "E", "D", "C", "B", "A"};
+            return nricCheckDigits[sum % 11].equals(checksum);
+        } else {
+            String[] finCheckDigits = {"X", "W", "U", "T", "R", "Q", "P", "N", "M", "L", "K"};
+            return finCheckDigits[sum % 11].equals(checksum);
+        }
+    }
+
+    @Override
+    public String toString() {
+        return nric;
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        return other == this // short circuit if same object
+                || (other instanceof Nric // instanceof handles nulls
+                && nric.equals(((Nric) other).nric)); // state check
+    }
+
+    @Override
+    public int hashCode() {
+        return nric.hashCode();
+    }
+}

src/test/java/seedu/address/model/loan/NricTest.java

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+package seedu.address.model.loan;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+import seedu.address.testutil.Assert;
+
+public class NricTest {
+    @Test
+    public void constructor_null_throwsNullPointerException() {
+        Assert.assertThrows(NullPointerException.class, () -> new Nric(null));
+    }
+
+    @Test
+    public void constructor_invalidNric_throwsIllegalArgumentException() {
+        String invalidNric = "";
+        Assert.assertThrows(IllegalArgumentException.class, () -> new Nric(invalidNric));
+    }
+
+    @Test
+    public void isValidNric() {
+        // null nric
+        Assert.assertThrows(NullPointerException.class, () -> Nric.isValidNric(null));
+
+        // invalid nric
+        assertFalse(Nric.isValidNric("")); // empty string
+        assertFalse(Nric.isValidNric(" ")); // spaces only
+        assertFalse(Nric.isValidNric("^")); // only non-alphanumeric characters
+        assertFalse(Nric.isValidNric("njkakjsdnfa")); // contains random alphanumeric characters
+
+        // Wrong checksum
+        assertFalse(Nric.isValidNric("S1234567Z"));
+        assertFalse(Nric.isValidNric("T1234567Z"));
+        assertFalse(Nric.isValidNric("F1234567Z"));
+        assertFalse(Nric.isValidNric("G1234567Z"));
+
+        // valid nric
+        assertTrue(Nric.isValidNric("S1234567D")); // IC for citizens born in 20th century
+        assertTrue(Nric.isValidNric("T1234567J")); // IC for citizens born in 21th century
+        assertTrue(Nric.isValidNric("F1234567N")); // Foreign IC F
+        assertTrue(Nric.isValidNric("G1234567X")); // Foreign IC G
+
+        // Inconsistant case
+        assertTrue(Nric.isValidNric("s1234567d"));
+        assertTrue(Nric.isValidNric("t1234567j"));
+        assertTrue(Nric.isValidNric("f1234567N"));
+        assertTrue(Nric.isValidNric("G1234567x"));
+    }
+}