Iterator design pattern - BEFORE CODE for Face book friends project

premaseem · premaseem · commit a74324464682 · 2018-03-01T23:27:53.000-06:00
diff --git a/pattern/src/com/premaseem/Client.java b/pattern/src/com/premaseem/Client.java
@@ -1,13 +1,46 @@
 package com.premaseem;
 
+import java.util.List;
+
 /*
 @author: Aseem Jain
 @title: Design Patterns with Java 9
 @link: https://premaseem.wordpress.com/category/computers/design-patterns/
-@copyright: 2018 Packt Publication
 */
 public class Client {
     public static void main (String[] args) {
-        System.out.println("Singleton cook example ");
+        System.out.println("Iterator Pattern BEFORE CODE");
+
+        FaceBook faceBook = new FaceBook();
+
+        // Data structure is exposed
+        List<String> friendsList = faceBook.getFriendsList();
+
+        // print friends with normal conventional loop
+        for (int i = 0; i < friendsList.size(); i++) {
+            System.out.println(friendsList.get(i));
+        }
+
+        // Un intentional addition of data
+        friendsList.add("Lady gaga");
+
+        // print friends with normal conventional loop
+        for (int i = 0; i < friendsList.size(); i++) {
+            System.out.println(friendsList.get(i));
+        }
+
+        // Clients can accidentally or maliciously trash data structure.
+        friendsList.clear();
+
+        // print friends with normal conventional loop
+        for (int i = 0; i < friendsList.size(); i++) {
+            System.out.println(friendsList.get(i));
+        }
+
+        // Lesson Learned
+        // 1. Underlying Data structure is exposed
+        // 2. Data can be manipulated
+        // 3. Data can be get trashed accidentally
+        // 4. Data traversal is not easy or uniform
     }
 }
diff --git a/pattern/src/com/premaseem/FaceBook.java b/pattern/src/com/premaseem/FaceBook.java
@@ -0,0 +1,26 @@
+package com.premaseem;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/*
+@author: Aseem Jain
+@title: Design Patterns with Java 9
+@link: https://premaseem.wordpress.com/category/computers/design-patterns/
+*/
+public class FaceBook {
+
+    List<String> friendsList = new ArrayList<>();
+
+    public FaceBook () {
+        // initialize with seed data
+        friendsList.add("Aseem Jain");
+        friendsList.add("James Bond");
+        friendsList.add("Spider Man");
+        friendsList.add("Super Man");
+    }
+
+    public List<String> getFriendsList () {
+        return friendsList;
+    }
+}
