Lab 2: Designing Classes

Part A: Getting Started

Download Lab2Point.exe, extract it, open the project.

In this part you will add test cases to an existing class and its test suite.

The handout has the code for the Class ManhattanPoint and its test suite ManhattanPointTest.

1. Define aManhattanPoint with coordinates x = 29 and y = 17.
2. Add test for the method distanceTo0()
3. Add test for the method isWithin(...)
4. Add test for the method isCloserThan(...)
5. Add test for the method getCloserPoint(...)
6. Save and print the results of your tests, and the source code for your extended test suite.

Part B: Designing-Building a Class

Download Lab2Book.exe, extract it, open the project.

1. Define the class Book which contains as member data the name of the author, the title of the book, the book id, the year published.
2. Build the skeleton of the test suite for this class.
3. Define the constructor for this class.
4. Define the toString method for this class and test the constructor.
5. Develop the method howOld() which determines how old is the book.

Part C: Class Composition

1. Design-Build the class LibRecord which contains lending record for a book in the library. The record contains a boolean value available, the day it is due (make it just an integer), and the reference to a Book object. Add it to your project.
2. Develop a method takeOut, which records that the book has been taken out for three weeks.
3. Develop the method returnBook, which records the return of the book.
4. Draw UML diagram of this collection of classes.

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Appendix A: Rules for writing the toString method for a class (thanks aLJaFP):

· if the class doe not contain any member data fields, use

public String toString(){

return "new" + getClass().getName() + "()"; }

· if the class has one member data field, say x, use

public String toString(){

return "new" + getClass().getName() + "(" + x + ")"; }

· if the class has two member data fields, say x and y, use

public String toString(){

return "new" + getClass().getName() + "(" + x + ", " + y + ")"; }

To define an object to experiment with:

SomeClass y = new SomeClass(.....);

println(y);

expected(...);

actual(y.methodName());

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Appendix B: Building Your Own Project to Design a Class MyClass

In File menu select New

1. Select Java2SE Stationery
2. Type in the name for your project and hit return
3. Expand the Generic item and select Java Application
4. When the project opens, right-click next to its name and select MDI child

This gives you more space to work with - the project floats in the window.

5. In the Project menu select Create Group and name it CodeBase
6. In Project menu select Add Files and select the file jpt.jar and jpfalt.jar
7. The window asks where to add files - select Java Application Release only
8. Expand the Sources tab in the project file list.
9. Delete TrivialApplication.
10. In File menu select New
11. Select File tab, then Text File - make sure you see where is it stored.
12. Give the file the name of the class you will write: MyClass.java for Class MyClass .
13. Now you can develop your class.
14. Copy the skeleton of the test class (e.g. BookTest.java) and re-name it MyClassTest.java.
15. In three places change the BookTest to MyClassTest.
16. In Edit menu select Java Application Release Settings near the bottom
17. On the left select Java Target and replace TrivialApplication with the name of your test class MyClassTest.
18. On the left select Java Output and replace TrivialApplication with the name of your test class MyClassTest.
19. Make sure the output type is again Java Application
20. Develop the test suite and run your program