June 2018 Update

Task/History-variables/Java/history-variables-2.java

@@ -0,0 +1,25 @@
+public class TestIntegerWithHistory {
+
+    public static void main(String[] args) {
+
+        //creating and setting three different values
+        IntegerWithHistory i = new IntegerWithHistory(3);
+        i.set(42);
+        i.set(7);
+
+        //looking at current value and history
+        System.out.println("The current value of i is :" + i.get());
+        System.out.println("The history of i is :" + i.getHistory());
+
+        //demonstrating rollback
+        System.out.println("Rolling back:");
+        System.out.println("returns what was the current value: " + i.rollback());
+        System.out.println("after rollback: " + i.get());
+        System.out.println("returns what was the current value: " + i.rollback());
+        System.out.println("after rollback: " + i.get());
+        System.out.println("Rolling back only works to the original value: " + i.rollback());
+        System.out.println("Rolling back only works to the original value: " + i.rollback());
+        System.out.println("So there is no way to 'null' the variable: " + i.get());
+
+    }
+}