chromeos/dbus/system_clock_client.h

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROMEOS_DBUS_SYSTEM_CLOCK_CLIENT_H_
   6 #define CHROMEOS_DBUS_SYSTEM_CLOCK_CLIENT_H_
   7
   8 #include "base/observer_list.h"
   9 #include "chromeos/chromeos_export.h"
  10 #include "chromeos/dbus/dbus_client.h"
  11
  12 namespace chromeos {
  13
  14 // SystemClockClient is used to communicate with the system clock.
  15 class CHROMEOS_EXPORT SystemClockClient : public DBusClient {
  16  public:
  17   // Interface for observing changes from the system clock.
  18   class Observer {
  19    public:
  20     // Called when the status is updated.
  21     virtual void SystemClockUpdated() {}
  22    protected:
  23     virtual ~Observer() {}
  24   };
  25
  26   virtual ~SystemClockClient();
  27
  28   // Adds and removes the observer.
  29   virtual void AddObserver(Observer* observer) = 0;
  30   virtual void RemoveObserver(Observer* observer) = 0;
  31   // Returns true if this object has the given observer.
  32   virtual bool HasObserver(Observer* observer) = 0;
  33
  34   // Creates the instance.
  35   static SystemClockClient* Create();
  36
  37  protected:
  38   // Create() should be used instead.
  39   SystemClockClient();
  40
  41  private:
  42   DISALLOW_COPY_AND_ASSIGN(SystemClockClient);
  43 };
  44
  45 }  // namespace chromeos
  46
  47 #endif  // CHROMEOS_DBUS_SYSTEM_CLOCK_CLIENT_H_