// excerpts from http://code.google.com/p/muduo/
 //
 // Use of this source code is governed by a BSD-style license
 // that can be found in the License file.
 //
 // Author: Shuo Chen (chenshuo at chenshuo dot com)
 
 #ifndef MUDUO_NET_TIMER_H
 #define MUDUO_NET_TIMER_H
 
 #include <boost/noncopyable.hpp>
 
 #include "datetime/Timestamp.h"
+#include "thread/Atomic.h"
 #include "Callbacks.h"
 
 namespace muduo
 {
 
 ///
 /// Internal class for timer event.
 ///
 class Timer : boost::noncopyable
 {
  public:
   Timer(const TimerCallback& cb, Timestamp when, double interval)
     : callback_(cb),
       expiration_(when),
       interval_(interval),
-      repeat_(interval > 0.0)
-  { }
+      repeat_(interval > 0.0),
+      sequence_(s_numCreated_.incrementAndGet())
+  {
+  }
 
   void run() const
   {
     callback_();
   }
 
   Timestamp expiration() const  { return expiration_; }
   bool repeat() const { return repeat_; }
+  int64_t sequence() const { return sequence_; }
 
   void restart(Timestamp now);
 
  private:
   const TimerCallback callback_;
   Timestamp expiration_;
   const double interval_;
   const bool repeat_;
+  const int64_t sequence_;
+
+  static AtomicInt64 s_numCreated_;
 };
 
 }
 #endif  // MUDUO_NET_TIMER_H