Work on improved Bridge example

Author: iluwatar

bridge/etc/bridge.png

@@ -22,40 +22,42 @@
  */
 package com.iluwatar.bridge;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 /**
  * 
- * The Bridge pattern can also be thought of as two layers of abstraction. With Bridge, you can
- * decouple an abstraction from its implementation so that the two can vary independently.
+ * Composition over inheritance. The Bridge pattern can also be thought of as two layers of abstraction.
+ * With Bridge, you can decouple an abstraction from its implementation so that the two can vary independently.
  * <p>
- * In Bridge pattern both abstraction ({@link MagicWeapon}) and implementation (
- * {@link MagicWeaponImpl}) have their own class hierarchies. The interface of the implementations
+ * In Bridge pattern both abstraction ({@link Weapon}) and implementation (
+ * {@link Enchantment}) have their own class hierarchies. The interface of the implementations
  * can be changed without affecting the clients.
+ * <p>
+ * In this example we have two class hierarchies. One of weapons and another one of enchantments. We can easily
+ * combine any weapon with any enchantment using composition instead of creating deep class hierarchy.
  * 
  */
 public class App {
 
+  private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
+
   /**
    * Program entry point
    * 
    * @param args command line args
    */
   public static void main(String[] args) {
-    BlindingMagicWeapon blindingMagicWeapon = new BlindingMagicWeapon(new Excalibur());
-    blindingMagicWeapon.wield();
-    blindingMagicWeapon.blind();
-    blindingMagicWeapon.swing();
-    blindingMagicWeapon.unwield();
-
-    FlyingMagicWeapon flyingMagicWeapon = new FlyingMagicWeapon(new Mjollnir());
-    flyingMagicWeapon.wield();
-    flyingMagicWeapon.fly();
-    flyingMagicWeapon.swing();
-    flyingMagicWeapon.unwield();
+    LOGGER.info("The knight receives an enchanted sword.");
+    Sword enchantedSword = new Sword(new SoulEatingEnchantment());
+    enchantedSword.wield();
+    enchantedSword.swing();
+    enchantedSword.unwield();
 
-    SoulEatingMagicWeapon soulEatingMagicWeapon = new SoulEatingMagicWeapon(new Stormbringer());
-    soulEatingMagicWeapon.wield();
-    soulEatingMagicWeapon.swing();
-    soulEatingMagicWeapon.eatSoul();
-    soulEatingMagicWeapon.unwield();
+    LOGGER.info("The valkyrie receives an enchanted hammer.");
+    Hammer hammer = new Hammer(new FlyingEnchantment());
+    hammer.wield();
+    hammer.swing();
+    hammer.unwield();
   }
 }

bridge/etc/bridge.ucls

@@ -24,11 +24,14 @@
 
 /**
  * 
- * FlyingMagicWeaponImpl
- *
+ * Enchantment
+ * 
  */
-public abstract class FlyingMagicWeaponImpl extends MagicWeaponImpl {
+public interface Enchantment {
+
+  void onActivate();
 
-  public abstract void flyImp();
+  void apply();
 
+  void onDeactivate();
 }