Objective

This homework will give you practice designing object-based solutions to problems. In addition, it will allow you to practice arrays of references.

Overview

For this homework you will implement a program that keeps track of customers and cars in a car rental system store. Your program will allow employees to add customers to the database, to add cars, to change the status of a car (from available to rented), etc. You will design and implement all the classes needed to complete this application. More details about the program are provided in the Specifications section. You may want to take a look at the Sample Run section before you read the detailed description.

This homework will be graded as follows:

• 65% - Implementation
• 25% - Design
• 10% - Time log

Specifications

Program Tasks Overview

You will write a program that enables a car rental system employee to complete the following tasks:

• Add a car to the collection of cars (database) available for rent.
• Find information about a car.
• Search for cars in the database with a specific make and/or from a particular year on.
• Add a customer to the collection of customers (database) that can rent cars.
• Find information about a customer.
• Remove a customer from the database.
• Rent a car.
• Return a car.
• Print all the cars in the database.
• Print all the customers in the database.

Assumptions

• Customer' names are unique and consist of a first name and last name (no middle initial).
• Cars' tags are unique.
• A customer rents a cars and immediately pays for it.
• When the program is started there are no customers or cars in the system.

What you must implement, in a nutshell

You must design a solution to the car rental application. The design will describe each of the classes that are part of the application and which methods each one has. We have intentionally only provided the most critical classes. You are expected to design your own classes for representing the basic entities that the program manipulates. You will document your design in the design.txt file, which is part of the code distribution. See the section on design documentation below. After completing your design, you will implement it. The number of classes you decide to use is up to you, however you have to follow a set of restrictions specified below.

Code Distribution

Before you read these specifications, you should access the files associated with this homework by checking out the project named p1. The code distribution provides you with the following:

• Example.java - Illustrates how to access the car rental application via the CarRentalSystem class.
• Tests.java - Java file that test the functionality of the application's driver class (CarRentalSystem.java).
• design.txt - Text file where you will provide a description of your design.
• A time log file.
• Test1Results.txt and Test2Results.txt - Text files used by the Tests.java module to check your results against the expected results.

Database Representation

The database of the car rental application will be represented using two sorted lists:

• Customers list - A list of customers sorted by lastname and firstname.
• Cars list - A list of cars sorted by make.

How you represent these lists is part of your design. You can follow any approach you understand is necessary as long as it adheres to the specifications of the homework. Notice that you will not use any sorting algorithm in this project. You will keep your lists sorted by inserting elements in the appropriate position in the list. 

Required Classes

You must implement and use the following classes:

Customer

This class represents a customer. A customer is identified by a name (firstname and lastname), address, and an array of cars that the customer currently has rented. As long as you defined an array of cars as part of the instance variables of this class you will be okay. We leave it up to you to define the methods you will need.

CarRentalSystem

This class represents the car rental application. Actually, this is the class we will use to test your program. Access to the car rental application is through this class. The methods' prototypes and behaviors are defined next:

• Error Conditions

Several of the methods to be described below generate a set of error conditions identified with the following integer values:

Condition	Integer Value
CORRECT	0 (No error)
INVALID_NAME	1
INVALID_CAR	2
NONZERO_CARS	3
INVALID_CAR_RENTED	4

• Methods (all are public methods)
• addCar: Adds a car to the cars collection. The collection of cars is kept sorted by make. The method prototype is given below:

     boolean addCar(String make, int year, String tag)

The year parameter represents the year the car was released. The make parameter refers to the car's make (e.g., Toyota, Pissan, etc.). This method will return true if the add operation was completed successfully and false if the car is already part of the database. 

• findCar: Returns a String with information about the car or null if the car is not part of the database.
String findCar(String tag)

If the car is not currently rented, the format of the String to return is:

CarString ® Make: "make", Year: year, Tag: tag

where make, year, and tag correspond to the car's make, year and tag. If the car is currently rented then the format is:

CarStringRented ® Make: "make", Year: year, Tag: tag (RENTED)

 

• findCars: Returns a String with those cars that have the specified make (e.g., Noyota, Pissan, etc.) and that were released on or after the specified year.

    String findCars(String make, int year)

If make is null then the make is ignored in the search process. If year is -1 the year value is ignored in the search process. The method will return null if no cars satisfy the search criteria. The format of the String to be returned is a sequence of CarString each on a line by itself. We refer to this list as the CarList.

• addCustomer: Adds to the database the customer whose name and address are specified in the parameters.
boolean addCustomer(String firstName, String lastName, String address)

The collection of customers is kept sorted by customer name. For example Rose Johnson will appear before Albert Smith. The method will return true if the add operation was successful and false if the customer is already part of the database.

• findCustomer: Returns a String with information about a customer or null if the customer is not part of the database.
String findCustomer(String firstName, String lastName)

The format of the String to return is one of the following. If the customer has no rented cars the result is:

CustomerString ®

Name: name
Address: address
No cars rented.

If the customer has rented any cars the result is:

CustomerString ®

Name: name
Address: address
Cars (rented):        
CarList

where the format CarList was given above.

 

• removeCustomer: Removes the specified customer from the database.

 

int removeCustomer(String firstName, String lastName)

The following error conditions can arise while removing a customer from the database. Each of these conditions will be verified in the order to be presented next. Once an error condition has been recognized, the method will return that condition and ignore the rest. For this method the error conditions are:

• INVALID_NAME - No customer with the given name is in the database.
• NONZERO_CARS - The customer still has some rented cars, and so cannot be removed.

If neither of these errors occurs, the value CORRECT should be returned.

• rentACar: A reference to the specified car is added to the array of cars associated with the specified customer.

    int rentACar(String firstName, String lastName, String tag)

The following error conditions can arise as a result of this operation. These conditions must be tested in the following order. Once an error condition has been recognized, the method will return that condition and ignore the rest.

• INVALID_NAME - No customer with the given name is in the database.
• INVALID_CAR - No car with the given tag is in the database.
• INVALID_CAR_RENTED - The specified car is part of the database, but it is currently being rented.

If none of these errors occurs, the value CORRECT should be returned.

• returnACar: Removes the reference to the specified car from the array of cars associated with the customer.

     int returnACar(String firstName, String lastName, String tag)

The following error conditions can arise as a result of this operation. These conditions must be tested in the following order. Once an error condition has been recognized, the method will return that condition and ignore the rest.

• INVALID_NAME - No customer with the given name is in the database.
• INVALID_CAR - No car with the given tag was rented by the customer.

If none of these errors occurs, the value CORRECT should be returned.

• allCars: Returns a String with all the cars in the database.
String allCars()

The format of the string is defined by CarList above. A value of null will be returned if there are no cars in the database.

• allCustomers: Returns a String will all the customers in the database.
String allCustomers()

The format of the String to be returned is a sequence of CustomerString each on a line by itself. We refer to this list as the CustomerList. A value of null will be returned if there are no customers in the database.

• toString: Returns a String with the all the cars in the database followed by all the customers in the database.
  String toString()

  This is just the list of cars followed by the list of customers, that is:
  DatabaseString ®

  CarList
  CustomerList

Additional Classes

As part of your design you will need to define classes in addition to the ones described above. Think carefully about the classes you will need. A good design can simplify dramatically the amount of time you will spend implementing your design. We recommend you implement a class called Name which represents a customer's name. It will have, among other methods, a method that will compare two names so you can insert names in sorted order.

Requirements

• To implement the sorted lists you may not use any of the Java API data structure classes (such as ArrayList), just simple ones like String. The lists must be created using array of references to objects of classes you defined.
• Remember, you must define the classes Customer and CarRentalSystem.
• As mentioned above, you are expected to design your own classes for the various entities used in this project. You will lose a significant number of points if your program only defines the classes Customer and CarRentalSystem.
• As with all programming assignments:
  • You must use meaningful variable names and good indentation.
  • You must avoid code duplication, by calling appropriate methods (rather than cutting and pasting code). You may define your own private utility methods to perform often repeated tasks.
  • Because we are using an automatic testing system, it is important the you adhere closely to the specifications. In particular, please do not change the names of any of the classes you are to implement, and use signatures given above for your methods.
  • Try your best to use the Eclipse/CVS submit option for your submission. If you are having problems with this, please contact us. Use the submit server only as a last resort for submitting your program. If you find it necessary to use the submit server, please see the following page for information on jar creation for submission.

  Because of the difficulty in grading emailed submissions, we will start deducting points unless you submit via the submit option or the submit server.

• To have confidence that your classes have been implemented correctly, execute them using the provided tests (Tests.java). Of course, you should also perform your own testing to be sure.
• Submit your project even if you are not able to complete all the functions. However, for those methods of the CarRentalSystem class that you could not implement provide a shell (empty body) for the method. This will allow us to compile your program and test the components you have implemented.

Design Documentation

The following describes the format of the design.txt file you are expected to provide. Your design file should have two parts:

I. Classes

Lists the classes (just the names) you have chosen as part of your design. Provide a brief (one or two lines) description of each class. You do not need to include the CarRentalSystem class.

II. Methods

For each class, lists the methods (just the names) that you have defined. Provide a one line description for each method.

Sample Run

At the end of this page you will find a class Example.java and the output that it produces. Access to the application is through the CarRentalSystem class, which you will implement. The class Example.java can be found in the code distribution.

Challenge Problem

Remember that you are not required to implement the following problem. Please visit the course web page for information regarding challenge problems. IMPORTANT: If you decide to complete the challenge problem you must provide its implementation in the file called Challenge.java.

The challenge problem consists of defining a GUI for the car rental application. The GUI should allow a user to complete all the tasks associated with the CarRentalSystem class.  Feel free to define your interface as you understand is best, providing any error messages you understand are appropriate.   Remember to define a main method in the Challenge class that allow us to run your program.

Submission

Submit your project using the submit project option associated with Eclipse. Remember to complete your time log before submitting your homework.

Example.java

(This is provided in the code distribution.)

public class Example {
	public static void loadCar(CarRentalSystem carRentalSystem,String make, int year, String tag) {
		System.out.println("Adding car: \"" + make + "\"");
		carRentalSystem.addCar(make, year, tag);
		System.out.println("***Rental Car Database***");  
		System.out.println(carRentalSystem);
		System.out.println();
	}
	

	public static void loadCustomer(CarRentalSystem carRentalSystem, String firstname, String lastname, String address) {
		System.out.println("Adding customer: " + firstname + " " + lastname);
		carRentalSystem.addCustomer(firstname, lastname, address);
		System.out.println("***Rental Car Database***");  
		System.out.println(carRentalSystem);
		System.out.println();
	}
	

	public static void main(String[] args) {        
		String results = "", info;

		CarRentalSystem CarRentalSystem = new CarRentalSystem();

		/* Adding some cars and printing the database status after each add */
		loadCar(CarRentalSystem, "Noyota", 2004, "MD101");
		loadCar(CarRentalSystem, "Tonda", 1989, "VA201");
		loadCar(CarRentalSystem, "Pissan", 1976, "DC301");
		

		/* Adding some customers and printing the database status after each add */
		loadCustomer(CarRentalSystem, "John", "Smith", "8th Street Bethesda CA");
		loadCustomer(CarRentalSystem, "Rose", "Peterson", "101 Road RiverTown CA");
		System.out.println("***All cars***\n" + CarRentalSystem.allCars() + "\n");
		System.out.println("***All customers***\n" + CarRentalSystem.allCustomers());
		

		System.out.println("\n***Looking for all Noyota cars***");
		if ((info = CarRentalSystem.findCars("Noyota", -1)) != null)
			System.out.println(info);
		

		System.out.println("\n***Looking for cars released on or after 1989");
		if ((info = CarRentalSystem.findCars(null, 1989)) != null)
			System.out.println(info);    
		

		System.out.println("\n***John Smith is renting the car with tag \"MD101\"");
		if (CarRentalSystem.rentACar("John", "Smith", "MD101") == 0) 
			System.out.println(CarRentalSystem);
		

		System.out.println("\n***Looking for the car with tag \"DC301\"");
		if ((info = CarRentalSystem.findCar("DC301"))!= null)
			System.out.println(info);
		

		System.out.println("\n***John Smith is returning the car with tag \"DC301\"");
		if (CarRentalSystem.returnACar("John", "Smith", "DC301") == 0)
			System.out.println(CarRentalSystem);
	}
}

Output of Example.java

Adding car: "Noyota"
***Rental Car Database***
Make: "Noyota", Year: 2004, Tag: MD101

Adding car: "Tonda"
***Rental Car Database***
Make: "Noyota", Year: 2004, Tag: MD101
Make: "Tonda", Year: 1989, Tag: VA201

Adding car: "Pissan"
***Rental Car Database***
Make: "Noyota", Year: 2004, Tag: MD101
Make: "Pissan", Year: 1976, Tag: DC301
Make: "Tonda", Year: 1989, Tag: VA201

Adding customer: John Smith
***Rental Car Database***
Make: "Noyota", Year: 2004, Tag: MD101
Make: "Pissan", Year: 1976, Tag: DC301
Make: "Tonda", Year: 1989, Tag: VA201
Name: John Smith
Address: 8th Street Bethesda CA
No cars rented.

Adding customer: Rose Peterson
***Rental Car Database***
Make: "Noyota", Year: 2004, Tag: MD101
Make: "Pissan", Year: 1976, Tag: DC301
Make: "Tonda", Year: 1989, Tag: VA201
Name: Rose Peterson
Address: 101 Road RiverTown CA
No cars rented.
Name: John Smith
Address: 8th Street Bethesda CA
No cars rented.

***All cars***
Make: "Noyota", Year: 2004, Tag: MD101
Make: "Pissan", Year: 1976, Tag: DC301
Make: "Tonda", Year: 1989, Tag: VA201

***All customers***
Name: Rose Peterson
Address: 101 Road RiverTown CA
No cars rented.
Name: John Smith
Address: 8th Street Bethesda CA
No cars rented.

***Looking for all Noyota cars***
Make: "Noyota", Year: 2004, Tag: MD101

***Looking for cars released on or after 1989
Make: "Noyota", Year: 2004, Tag: MD101
Make: "Tonda", Year: 1989, Tag: VA201

***John Smith is renting the car with tag "MD101"
Make: "Noyota", Year: 2004, Tag: MD101
Make: "Pissan", Year: 1976, Tag: DC301
Make: "Tonda", Year: 1989, Tag: VA201
Name: Rose Peterson
Address: 101 Road RiverTown CA
No cars rented.
Name: John Smith
Address: 8th Street Bethesda CA
Cars (rented):
Make: "Noyota", Year: 2004, Tag: MD101

***Looking for the car with tag "DC301"
Make: "Pissan", Year: 1976, Tag: DC301

***John Smith is returning the car with tag "DC301"
 

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