Proxy pattern: Improve the example

proxy/src/main/java/com/iluwatar/proxy/App.java

@@ -35,7 +35,7 @@ package com.iluwatar.proxy;
  * functionality to the object of interest without changing the object's code.
  * <p>
  * In this example the proxy ({@link WizardTowerProxy}) controls access to the actual object (
- * {@link WizardTower}).
+ * {@link IvoryTower}).
  * 
  */
 public class App {
@@ -45,12 +45,12 @@ public class App {
    */
   public static void main(String[] args) {
 
-    WizardTowerProxy tower = new WizardTowerProxy();
-    tower.enter(new Wizard("Red wizard"));
-    tower.enter(new Wizard("White wizard"));
-    tower.enter(new Wizard("Black wizard"));
-    tower.enter(new Wizard("Green wizard"));
-    tower.enter(new Wizard("Brown wizard"));
+    WizardTowerProxy proxy = new WizardTowerProxy(new IvoryTower());
+    proxy.enter(new Wizard("Red wizard"));
+    proxy.enter(new Wizard("White wizard"));
+    proxy.enter(new Wizard("Black wizard"));
+    proxy.enter(new Wizard("Green wizard"));
+    proxy.enter(new Wizard("Brown wizard"));
 
   }
 }

proxy/src/main/java/com/iluwatar/proxy/IvoryTower.java

@@ -0,0 +1,41 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.proxy;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * 
+ * The object to be proxyed.
+ * 
+ */
+public class IvoryTower implements WizardTower {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(IvoryTower.class);
+
+  public void enter(Wizard wizard) {
+    LOGGER.info("{} enters the tower.", wizard);
+  }
+
+}

proxy/src/main/java/com/iluwatar/proxy/Wizard.java

@@ -29,7 +29,7 @@ package com.iluwatar.proxy;
  */
 public class Wizard {
 
-  private String name;
+  private final String name;
 
   public Wizard(String name) {
     this.name = name;

proxy/src/main/java/com/iluwatar/proxy/WizardTower.java

@@ -1,41 +1,9 @@
-/**
- * The MIT License
- * Copyright (c) 2014 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-package com.iluwatar.proxy;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-/**
- * 
- * The object to be proxyed.
- * 
- */
-public class WizardTower {
-
-  private static final Logger LOGGER = LoggerFactory.getLogger(WizardTower.class);
-
-  public void enter(Wizard wizard) {
-    LOGGER.info("{} enters the tower.", wizard);
-  }
-
-}
+package com.iluwatar.proxy;
+
+/**
+ * WizardTower interface
+ */
+public interface WizardTower {
+
+  void enter(Wizard wizard);
+}

proxy/src/main/java/com/iluwatar/proxy/WizardTowerProxy.java

@@ -27,10 +27,10 @@ import org.slf4j.LoggerFactory;
 
 /**
  * 
- * The proxy controlling access to the {@link WizardTower}.
+ * The proxy controlling access to the {@link IvoryTower}.
  * 
  */
-public class WizardTowerProxy extends WizardTower {
+public class WizardTowerProxy implements WizardTower {
 
   private static final Logger LOGGER = LoggerFactory.getLogger(WizardTowerProxy.class);
 
@@ -38,10 +38,16 @@ public class WizardTowerProxy extends WizardTower {
 
   private int numWizards;
 
+  private final WizardTower tower;
+
+  public WizardTowerProxy(WizardTower tower) {
+    this.tower = tower;
+  }
+
   @Override
   public void enter(Wizard wizard) {
     if (numWizards < NUM_WIZARDS_ALLOWED) {
-      super.enter(wizard);
+      tower.enter(wizard);
       numWizards++;
     } else {
       LOGGER.info("{} is not allowed to enter!", wizard);