SurveyDatabase

The SurveyDatabase class is a mockup of a database for storing Surveys, it has methods such as addSurvey() and getAllSurveys(). To emulate a database, it even allocates primary keys for surveys. Additionally, when surveys are added to the database, they are copied and when surveys are retrieved from the database, they are copied (that is, modifying a Survey instance after adding it to, or retrieving it from, the database doesn't affect the persistently stored Surveys within the database ... just as if they were in external storage).