السلام عليكم ورحمة الله وبركاته
أرجو من الأعضاء الكرام مساعدتي في حل سؤال class diagram
السؤال هذا هو:
For security reasons , expensive computer equipment in a university department is kept in rooms in a single corridor. The doors at the ends of the corridor are locked and can only be opened by means of a card which is swiped through a card key system . Authorised students may obtain a card from a computer officer by giving a deposit of f2. A list of the possessors of each card is maintained on the Departmental file system by the computer officer
The card key system consists consists of a card reader, a lock and is controlled by a simple processor with main memory , but no file . The card reader can read the number on a card . A corridor door is unlocked by swiping a current card though the card reader . The door automatically locks again after 20 seconds . The card key lock system has a list of authorised card numbers and also maintains a list of card uses in the last 48 hours .
There is a two-way link between the Department`s computer system and the card key lock system by which :
- the card key system can by given a list of authorised card numbers,
- the list can be updated by adding or removing card numbers,
-the list of card uses in the last 48 hours can be obtained
There is no other communication between the two systems .
The computer officer can :
-create a user list and add or delete users from the Departmental system,
- initiate the transfer of card number information to the card key lock system and
- get a list of users in the last 48 hours .