Changed Scheduler class to be a enum and modified the way how Singlet…

…on instance is implemented

.project

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <projectDescription>
- <name>JavaTaskScheduler</name>
+ <name>Java-TaskScheduler</name>
  <comment></comment>
  <projects>
  </projects>

bin/.gitignore

@@ -1,4 +1,3 @@
+/scheduler/
 /factory/
 /main/
-/scheduler/
-/task/

src/factory/Task.java

@@ -51,7 +51,7 @@ private void executeMethod() throws Exception {
  print_task.append(this.getClass().getSimpleName()).append("-ID:").append(id).append("]");
 
  print_task = sFather.append(print_task);
- System.out.println(Util.getCurrentHour() + " S " + print_task.toString() + " started -> CPU: " + Util.getProcessCPU() + " (Queue Size: " + Scheduler.getInstance().getQueueSize() + ")");
+ System.out.println(Util.getCurrentHour() + " S " + print_task.toString() + " started -> CPU: " + Util.getProcessCPU() + " (Queue Size: " + Scheduler.INSTANCE.getQueueSize() + ")");
  long start = System.currentTimeMillis();
  String future = (String) execute(this);
  long end = System.currentTimeMillis();
@@ -61,7 +61,7 @@ private void executeMethod() throws Exception {
  Thread.sleep(delay);
 
  for (Task dependecy : queuedDependecy) {
- Scheduler.getInstance().addQueue(dependecy);
+ Scheduler.INSTANCE.addQueue(dependecy);
  }
  }
 
@@ -188,7 +188,7 @@ public void run() {
  try {
 
  Thread.sleep(task.getFixedRate());
- Scheduler.getInstance().addQueue(task);
+ Scheduler.INSTANCE.addQueue(task);
 
  } catch (InterruptedException e) {
  bstop = true;

src/main/MainScheduler.java

@@ -17,14 +17,20 @@ public static void main(String args[]) throws InterruptedException {
 
  Util.loadProperties();
  //Starting the Scheduler thread
- new Thread(Scheduler.getInstance(), "shceduler_thread").start();
+ Runnable runScheduler = new Runnable() {
+ @Override
+ public void run() {
+ Scheduler.INSTANCE.run();
+ }
+ };
+ new Thread(runScheduler, "scheduler_thread").start();
 
  //create tasks
  for(String name : Util.tasks){
  try {
  Task t = TaskFactory.create(name);
  if (t != null)
- Scheduler.getInstance().addQueue(t);
+ Scheduler.INSTANCE.addQueue(t);
 
  } catch (Exception e) {
  System.err.println("Some problem while creating tasks. Exception message: " + e.getMessage());

src/scheduler/Scheduler.java

@@ -13,27 +13,18 @@
 import factory.Task;
 import factory.Util;
 
-final public class Scheduler implements Runnable {
+/**
+ * Singleton class using enum
+ *
+ */
+public enum Scheduler {
+ INSTANCE;
 
  private static int taskID = 0;
 
  private Queue<Task> queue;
  private boolean bStop;
 
- /**
- * SINGLETON -----------------------------------------------------
- */
- private static class SchedulerSingleton {
- private static final Scheduler INSTANCE = new Scheduler();
- }
-
- public static Scheduler getInstance() {
- return SchedulerSingleton.INSTANCE;
- }
- /**
- * ----------------------------------------------------------------
- */
-
  private Scheduler() {
  queue = new LinkedList<Task>();
  bStop = false;
@@ -50,7 +41,6 @@ public void addQueue(Task task) throws InterruptedException {
  }
  }
 
- @Override
  public void run() {
 
  try {