lab-03:

- Define custom exception class that extends IlleglArg and add a 'value' property
	- Throw different Ex for the 2 problems
	- Print the exception class in output for information

lab-03/src/Factorials.java

@@ -14,8 +14,8 @@ public class Factorials{
             try {
                 System.out.println("Factorial(" + val + ") = " + factorial(val));
             }
-            catch (IllegalArgumentException ex){
-                System.out.println(ex.getMessage() + String.format(" (%d)", val));
+            catch (IllegalArgumentException ex){ //use of polymorphism since 'ex' can be an instance of one of two classes
+                System.out.println(ex.getMessage() + String.format(" (%d) (%s)", val, ex.getClass()));
             }
 
             System.out.print("Another factorial? (y/n) ");
@@ -24,11 +24,30 @@ public class Factorials{
     }
 
     private static int factorial(int value) throws IllegalArgumentException {
-        if (value < 0) throw new IllegalArgumentException("Can not calculate a negative factorial");
+        if (value < 0) throw new IllegalFactorialException("Can not calculate a negative factorial", value);
         if (value > 16) throw  new IllegalArgumentException("Can not calculate factorials for value over 16");
         for (int i = value - 1; i > 0; i--){
             value *= i;
         }
         return value;
     }
+
+    private static class IllegalFactorialException extends IllegalArgumentException {
+
+        private int value;
+
+        public IllegalFactorialException(String s, int value) {
+            super(s);
+            this.value = value;
+        }
+
+        public IllegalFactorialException(int value) {
+            this(null, value);
+        }
+
+        public int getIllegalValue() {
+            return value;
+        }
+
+    }
 }