Add exception handling for instance ids

src/main/java/instanceids/AddressId.java

@@ -3,7 +3,7 @@
 public class AddressId extends Identifiable {
 
     private AddressId(Integer id) {
-        super(id);
+        super(id , AddressId.class.getSimpleName());
     }
 
     public static AddressId get(Integer id) {

src/main/java/instanceids/Identifiable.java

@@ -1,11 +1,28 @@
 package instanceids;
 
+
 public abstract class Identifiable {
 
-    private Integer id;
+    private final Integer id;
+    private final String className;
 
-    public Identifiable(Integer id) {
+    public Identifiable(Integer id, String className){
         this.id = id;
+        this.className = className;
+        checkValue();
+    }
+
+    private void throwException()  {
+        throw new IllegalArgumentException(String.format("Invalid value %s for class %s" , id , className));
+    }
+
+    private void checkValue()  {
+        if(id == null){
+            throwException();
+        }
+        if(id != null && id <= 0 ){
+            throwException();
+        }
     }
 
     public Integer getValue() {

src/main/java/instanceids/PersonId.java

@@ -3,7 +3,7 @@
 public class PersonId extends Identifiable {
 
     private PersonId(Integer id) {
-        super(id);
+        super(id , PersonId.class.getSimpleName());
     }
 
     public static PersonId get(Integer id) {

src/test/java/instanceids/InstanceIdInputterTest.java

@@ -1,15 +1,27 @@
 package instanceids;
 
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.ExpectedException;
 
 import static org.junit.Assert.assertEquals;
 
 public class InstanceIdInputterTest {
 
     @Test
-    public void test_ThrowsExceptionIfNullInput() {
+    public void test_ValidInput() {
         InstanceIdInputter inputter = new InstanceIdInputter(PersonId.get(1), AddressId.get(2));
         assertEquals(new Integer(1), inputter.getPersonId());
         assertEquals(new Integer(2), inputter.getAddressId());
     }
+
+    @Test(expected=IllegalArgumentException.class)
+    public void test_ThrowsExceptionIfInvalidInteger() {
+        InstanceIdInputter inputter = new InstanceIdInputter(PersonId.get(0), AddressId.get(0));
+    }
+
+    @Test(expected=IllegalArgumentException.class)
+    public void test_ThrowsExceptionIfNullInput() {
+        InstanceIdInputter inputter = new InstanceIdInputter(PersonId.get(null), AddressId.get(null));
+    }
 }