The WatchDogService is a Sakai Service that is used to send event information from Sakai to the CANS Server. This version of the WatchDogService will not work with Sakai 2.2.x or later, but should work for you if you're using an older version of Sakai.
You can find the new material by clicking on this link or by going to the 'Sakai Tools and Services' section in 'Download and Resources'.