Dirty Flag pattern #560

dirty-flag/src/main/java/com/iluwatar/dirtyflag/World.java

@@ -0,0 +1,47 @@
+package com.iluwatar.dirtyflag;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 
+ * A middle-layer app that calls/passes along data from the back-end.
+ * 
+ * @author swaisuan
+ *
+ */
+public class World {
+
+  private static World world;
+  private static List<String> countries = new ArrayList<String>();
+
+  private World() {
+  }
+
+  /**
+   * Init.
+   * 
+   * @return World instance
+   */
+  public static World getInstance() {
+    if (world == null) {
+      world = new World();
+    }
+    return world;
+  }
+
+  /**
+   * 
+   * Calls {@link DataFetcher} to fetch data from back-end.
+   * 
+   * @return List of strings
+   */
+  public List<String> fetch() {
+    DataFetcher df = DataFetcher.getInstance();
+    List<String> data = df.fetch();
+
+    countries = data == null ? countries : data;
+
+    return countries;
+  }
+}