first version of pattern without Tests

extension-objects/src/main/java/units/CommanderUnit.java

@@ -0,0 +1,30 @@
+package units;
+
+import abstractextensions.CommanderExtension;
+import abstractextensions.UnitExtension;
+import concreteextensions.Commander;
+
+/**
+ * Created by Srdjan on 27-Apr-17.
+ */
+public class CommanderUnit extends Unit {
+
+  private CommanderExtension commanderExtension;
+
+  public CommanderUnit(String name) {
+    super(name);
+  }
+
+  @Override
+  public UnitExtension getUnitExtension(String extensionName) {
+
+    if (extensionName.equals("CommanderExtension")) {
+      if (commanderExtension == null) {
+        commanderExtension = new Commander(this);
+      }
+      return commanderExtension;
+    }
+
+    return super.getUnitExtension(extensionName);
+  }
+}