Due: Wednesday, Sept 17th by 11:59 PM
Getting Started
Download CS201_Assign02.zip and import it into your Eclipse workspace (File→Import→General→Existing projects into workspace→Archive file.)
You should see a project called CS201_Assign02 in the Package Explorer.
Your Task
You have two tasks:
- Complete the implementation of the Point, Circle and Rectangle classes.
- Improve the JUnit tests for each of the above classes.
Implementing Point, Circle, and Rectangle
The Point, Circle, and Rectangle classes represent points and shapes in the x/y coordinate plane.
Important: in these classes, y values increase in the down direction, and decrease in the up direction:
Each of the three classes is partially specified. Each class has a number of methods, but each method has a body containing the statement
throw new UnsupportedOperationException("TODO - implement");
which indicates that the method has not been implemented. You will need to replace each such statement with an actual method body that carries out the behavior described by the method's documentation comment.
In addition, none of the classes defines any fields. You will need to add fields as necessary to store the data that is needed by each object. For example, the Point class will need fields to store the values of the x and y coordinates.
Improving the JUnit tests
In the junit source directory are three JUnit test classes, PointTest, CircleTest, and RectangleTest. The PointTest class is fairly complete. The CircleTest and RectangleTest classes are somewhat incomplete.
You will need to add test fixture objects and test methods to CircleTest and RectangleTest so that they are more complete.
One measure of the completeness of a test class is that each method in the class being tested should be tested at least once. For example, the PointTest class satisfies this measure of completeness. The Point class has four methods (a constructor, getX, getY, and distanceTo), and the PointTest class tests all of them.
Hints
The geometric distance between two points is
sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1))
where (x1,y1) and (x2,y2) are the coordinates of the points.
You can use the Math.sqrt method to compute the square root of a double value.
You will need to think carefully about how to implement the overlaps method in the Rectangle class. Here is a sketch of a possible approach:
- If the center of the circle is inside the rectangle, then there is definitely overlap.
- If the center of the circle is directly above, below, to the left, or to the right of the rectangle, and the distance between the center of the circle and the closest edge is less than the radius of the circle, then there is overlap.
- If the center of the circle is in one of the corner regions, and the distance from the center of the circle to the closest corner of the rectangle is less than the radius of the circle, then there is overlap.
- Otherwise, there is no overlap.
When you write tests, you may need to test whether a Point object has expected x and y coordinate values. There are two ways you can do this:
- Add an equals method to the Point class (see Lecture 9)
Use separate assertions for the x and y coordinates. For example, to check the coordinates of the center of a Circle object:
Point center = someCircle.getCenter(); assertEquals(5.0, center.getX(), DELTA); assertEquals(6.0, center.getY(), DELTA);
Grading
Your grade will be determined as follows:
- Point class: 20%
- Circle class: 20%
- Rectangle class: 20%
- CircleTest test class: 20%
- RectangleTest test class: 20%
I expect that you will use good coding style (comments, consistent indentation, meaningful names for variables and methods.) I may deduct points for poor coding style.
Submitting
When you are done, submit the lab to the Marmoset server using either of the methods below.
Important: after you submit, log into the submission server and verify that the correct files were uploaded. You are responsible for ensuring that you upload the correct files. I may assign a grade of 0 for an incorrectly submitted assignment.
From Eclipse
If you have the Simple Marmoset Uploader Plugin installed, select the project (CS201_Assign02) in the package explorer and then press the blue up arrow button in the toolbar. Enter your Marmoset username and password when prompted.
From a web browser
Save the project (CS201_Assign02) to a zip file by right-clicking it and choosing
Export...→Archive File
Upload the saved zip file to the Marmoset server as assign02. The server URL is
