Alarm Clock

Mission

Write an application to work as an alarm clock. It displays the current time and the user can set a wakeup time. Once the wakeup time is reached the application sounds an alarm.

Requirements

When the user switches the alarm on, the remaining time until the wakeup time will be displayed. Both current time and remaining time will constantly (every second) be updated.

The user can switch off the count down at any time. The remaining time will then disappear.

When the wakeup time is reached a WAV or MP3 file should be played by the application.

Overview

• System clock tick
  • Update display of current time
  • Update display of remaining time while alarm is switched on
  • Check if wakeup time has been reached
  • Sound alarm if wakeup time has been reached
  • Switched off checking for wakeup time if wakeup time has been reached
• Switch on the alarm
  • Switch on checking for the wakeup time
• Switch off the alarm
  • Switch off checking for the wakeup time

Design

System clock tick

For every tick of the system clock it is checked, if the wakeup time has been reached. Of course this check is only done while the alarm is switched on (see status).

Also, while the alarm is switched on, the remaining time until the wakeup time is calculated. Both current time and remaining time flow to the UI and the alarm bell is rung.

Switch on/off the alarm

Starting the alarm clock means registering the wakeup time and setting the status to "active". Stopping it means setting the status to "inactive."

Class Design