Green Street Car Park - CRC cards

In order to decrement spaces, the CarPark class must receive a message from entrance Barrier object. To increment spaces, the CarPark class must receive a message from the exit Barrier.


The FullSign object executes the switchOn method when a message is received from the CarPark object so say that capacity == spaces. The sign is switched off when spaces < capacity. The entrance barrier is raised when the cardreader returns the card after validation.


The entrance barrier is raised when it receives a message saying the cardreader has returned the card and lowered when the sensor no longer detects that there is a car present.
The exit barrier is raised when it detects a car is present and is lowered when a car is no longer present.


The cardreader validates the card on receiving a message from reception that the cards number id indeed on the valid cards list.