Add documentation

src/main/java/org/warp/commonutils/concurrency/executor/ScheduledTaskLifecycle.java

@@ -15,23 +15,37 @@ public class ScheduledTaskLifecycle {
 		this.lock = new StampedLock();
 	}
 
+	/**
+	 * Register a scheduled task
+	 */
 	public void registerScheduledTask(ScheduledFuture<?> task) {
 		this.tasks.put(task, new Object());
 	}
 
+	/**
+	 * Mark this task as running.
+	 * After calling this method, please call {@method endScheduledTask} inside a finally block!
+	 */
 	public void startScheduledTask() {
 		this.lock.readLock();
 	}
 
+	/**
+	 * Mark this task as ended. Must be called after {@method startScheduledTask}
+	 */
 	public void endScheduledTask() {
 		this.lock.tryUnlockRead();
 	}
 
+	/**
+	 * Cancel all scheduled tasks and wait all running methods to finish
+	 */
 	public void cancelAndWait() {
 		tasks.forEach((task, obj) -> {
 			task.cancel(false);
 		});
 
+		// Acquire a write lock to wait all tasks to end
 		lock.unlockWrite(lock.writeLock());
 	}
 }