Added comments in the code. modified index.md

value-object/src/main/java/com/iluwatar/value/object/App.java

@@ -1,12 +1,19 @@
 package com.iluwatar.value.object;
 
 /**
- * Hello world!.
+ * App Class.
  *
  */
 public class App {
+  /**
+   * main method.
+   */
   public static void main(String[] args) {
-    HeroStat stat = HeroStat.valueOf(10, 5, 0);
-    System.out.println(stat.toString());
+    HeroStat statA = HeroStat.valueOf(10, 5, 0);
+    HeroStat statB = HeroStat.valueOf(5, 1, 8);
+
+    System.out.println(statA.toString());
+    // When using Value Objects do not use ==, only compare using equals().
+    System.out.println("is statA and statB equal : " + statA.equals(statB));
   }
 }

value-object/src/main/java/com/iluwatar/value/object/HeroStat.java

@@ -1,13 +1,20 @@
 package com.iluwatar.value.object;
 
 /**
- * The Discount Coupon only discounts by percentage.
- *
+ * HeroStat is a Value Object. following rules are from Stephen Colebourne's term VALJO(not the
+ * entire rule set) from : http://blog.joda.org/2014/03/valjos-value-java-objects.html<br>
+ * Value Objects must override equals(), hashCode() to check the equality with values. <br>
+ * Value Objects should be immutable so declare members final. Obtain instances by static factory
+ * methods. <br>
+ * The elements of the state must be other values, including primitive types.<br>
+ * Provide methods, typically simple getters, to get the elements of the state.<br>
+ * 
+ * {@link http://docs.oracle.com/javase/8/docs/api/java/lang/doc-files/ValueBased.html}
  */
 public class HeroStat {
 
 
-  // stats for a hero
+  // Stats for a hero
 
   private final int strength;
   private final int intelligence;
@@ -22,6 +29,7 @@ public class HeroStat {
     this.luck = luck;
   }
 
+  // Static factory method to create new instances.
   public static HeroStat valueOf(int strength, int intelligence, int luck) {
     return new HeroStat(strength, intelligence, luck);
   }
@@ -39,7 +47,7 @@ public class HeroStat {
   }
 
   /*
-   * recommended to provide a static factory method capable of creating an instance from the formal
+   * Recommended to provide a static factory method capable of creating an instance from the formal
    * string representation declared like this. public static Juice parse(String string) {}
    */
 
@@ -86,6 +94,6 @@ public class HeroStat {
   }
 
 
-  // the clone() method should not be public
+  // The clone() method should not be public
 
 }

value-object/src/test/java/com/iluwatar/value/object/HeroStatTest.java

@@ -1,5 +1,10 @@
 package com.iluwatar.value.object;
 
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.CoreMatchers.not;
+
+import static org.junit.Assert.assertThat;
+
 import com.google.common.testing.EqualsTester;
 
 import org.junit.Test;
@@ -11,6 +16,7 @@ public class HeroStatTest {
 
   /**
    * Tester for equals() and hashCode() methods of a class.
+   * 
    * @see http://www.javadoc.io/doc/com.google.guava/guava-testlib/19.0
    */
   @Test
@@ -20,4 +26,21 @@ public class HeroStatTest {
     new EqualsTester().addEqualityGroup(heroStatA, heroStatB).testEquals();
   }
 
+  /**
+   * The toString() for two equal values must be the same. For two non-equal values it must be
+   * different.
+   */
+  @Test
+  public void testToString() {
+
+    HeroStat heroStatA = HeroStat.valueOf(3, 9, 2);
+    HeroStat heroStatB = HeroStat.valueOf(3, 9, 2);
+    HeroStat heroStatC = HeroStat.valueOf(3, 9, 8);
+
+    assertThat(heroStatA.toString(), is(heroStatB.toString()));
+    assertThat(heroStatA.toString(), is(not(heroStatC.toString())));
+
+
+  }
+
 }