Programming and Problem Solving with Java

CASE STUDY^307

What are the responsibilities of the driver? To create instances of the class Entryand
write them to a file.Entryhas a responsibility that writes itself to a file, so that respon-
sibility is implemented by sending a message to Entry. We have two possibilities for cre-
ating instances of the class: We can use the nonparameterized version of the
constructor for Entryand let it be responsible for instantiating Name,Address, and Phone,
or we can let the driver input the values and use Entry’s parameterized constructor.
Because this is a special-purpose driver whose only function is to create entries, let’s
centralize the input for the fields of Entryin the driver. We should also use the parame-
terized constructors for Nameand Address.Phonedoesn’t have a nonparameterized
constructor, so there is no choice. Here, then, is the CRC card for the driver:

Class Name: AddressDr Superclass: Subclasses:

Responsibilities Collaborations

Prepare input file BufferedReader

Prepare output file PrintWriter

Process entries Name, Address, Phone, Entry

Close files BufferedReader, PrintWriter

Class Name: Address Superclass: Subclasses:

Responsibilities Collaborations

Create (street, city, state, zip) String

Create( ) String. BufferedReader

Know street None

return String

Know city None

return String

return String

Know state None

Know zip None

return String