Description
Overview: You will write a program this week that is composed of three classes: the first class
defines Icosahedron objects, the second class defines IcosahedronList objects, and the third,
IcosahedronListApp, reads in a file name entered by the user then reads the list name and Icosahedron
data from the file, creates Icosahedron objects and stores them in an ArrayList, creates a
IcosahedronList object with the list name and ArrayList, prints the IcosahedronList object, and then
prints summary information about the IcosahedronList object.
An Icosahedron has 20 equilateral triangle faces, 12 vertices, and 30 edges as depicted below. The
formulas are provided to assist you in computing return values for the respective methods in the
Icosahedron class described in this project.
Surface Area (A)
Volume (V)
Edge length (a)
Surface/Volume ratio (A/V)
Project: Icosahedron List App Page 2 of 7
Page 2 of 7
• Icosahedron.java (assuming that you successfully created this class in Project 4, just copy
the file to your new Project 5 folder and go on to IcosahedronList.java on page 4.
Otherwise, you will need to create Icosahedron.java as part of this project.)
Requirements: Create an Icosahedron class that stores the label, color, and edge (i.e., length of
an edge, which must be greater than zero). The Icosahedron class also includes methods to set
and get each of these fields, as well as methods to calculate the surface area, volume, and surface
to volume ratio of an Icosahedron object, and a method to provide a String value of an
Icosahedron object (i.e., a class instance).
Design: The Icosahedron class has fields, a constructor, and methods as outlined below.
(1) Fields (instance variables): label of type String, color of type String, and edge of type double.
Initialize the Strings to “” and the double to 0 in their respective declarations. These instance
variables should be private so that they are not directly accessible from outside of the
Icosahedron class, and these should be the only instance variables in the class.
(2) Constructor: Your Icosahedron class must contain a public constructor that accepts three
parameters (see types of above) representing the label, color, and edge. Instead of assigning
the parameters directly to the fields, the respective set method for each field (described
below) should be called. For example, instead of the statement label = labelIn; use
the statement setLabel(labelIn); Below are examples of how the constructor could
be used to create Icosahedron objects. Note that although String and numeric literals are used
for the actual parameters (or arguments) in these examples, variables of the required type
could have been used instead of the literals.
Icosahedron example1 = new Icosahedron(“Small”, “blue”, 0.01);
Icosahedron example2 = new Icosahedron(” Medium “, “orange”, 12.3);
Icosahedron example3 = new Icosahedron(“Large”, ” white “, 123.4);
(3) Methods: Usually a class provides methods to access and modify each of its instance
variables (known as get and set methods) along with any other required methods. The
methods for Icosahedron, which should each be public, are described below. See formulas in
Code and Test below.
o getLabel: Accepts no parameters and returns a String representing the label field.
o setLabel: Takes a String parameter and returns a boolean. If the string parameter is
not null, then the “trimmed” String is set to the label field and the method returns true.
Otherwise, the method returns false and the label is not set.
o getColor: Accepts no parameters and returns a String representing the color field.
o setColor: Takes a String parameter and returns a boolean. If the string parameter is
not null, then the “trimmed” String is set to the color field and the method returns true.
Otherwise, the method returns false and the label is not set.
o getEdge: Accepts no parameters and returns a double representing the edge field.
Project: Icosahedron List App Page 3 of 7
Page 3 of 7
o setEdge: Accepts a double parameter and returns a boolean as follows. If the edge is
greater than zero, sets the edge field to the double passed in and returns true. Otherwise,
the method returns false and the edge is not set.
o surfaceArea: Accepts no parameters and returns the double value for the total
surface area calculated using the value for edge.
o volume: Accepts no parameters and returns the double value for the volume calculated
using the value for edge.
o surfaceToVolumeRatio: Accepts no parameters and returns the double value
calculated by dividing the total surface area by the volume.
o toString: Returns a String containing the information about the Icosahedron object
formatted as shown below, including decimal formatting (“#,##0.0#####”) for the
double values. Newline and tab escape sequences should be used to achieve the proper
layout. In addition to the field values (or corresponding “get” methods), the following
methods should be used to compute appropriate values in the toString method:
surfaceArea(), volume(), and surfaceToVolumeRatio(). Each line should have
no trailing spaces (e.g., there should be no spaces before a newline (\n) character). The
toString value for example1, example2, and example3 respectively are shown
below (the blank lines are not part of the toString values).
Icosahedron “Small” is “blue” with 30 edges of length 0.01 units.
surface area = 0.000866 square units
volume = 0.000002 cubic units
surface/volume ratio = 396.950723
Icosahedron “Medium” is “orange” with 30 edges of length 12.3 units.
surface area = 1,310.209833 square units
volume = 4,059.844212 cubic units
surface/volume ratio = 0.322724
Icosahedron “Large” is “white” with 30 edges of length 123.4 units.
surface area = 131,874.537977 square units
volume = 4,099,581.395236 cubic units
surface/volume ratio = 0.032168
Code and Test: As you implement your Icosahedron class, you should compile it and then test it
using interactions. For example, as soon you have implemented and successfully compiled the
constructor, you should create instances of Icosahedron in interactions (e.g., copy/paste the
examples above). Remember that when you have an instance on the workbench, you can unfold
it to see its values. You can also open a viewer canvas window and drag the instance from the
Workbench tab to the canvas window. After you have implemented and compiled one or more
methods, create an Icosahedron object in interactions and invoke each of your methods on the
object to make sure the methods are working as intended. You may find it useful to create a
separate class with a main method that creates an instance of Icosahedron then prints it out. This
would be similar to the IcosahedronApp class you will create below, except that in the
IcosahedronApp class you will read in the values and then create and print the object.
Project: Icosahedron List App Page 4 of 7
Page 4 of 7
• IcosahedronList.java
Requirements: Create an IcosahedronList class that stores the name of the list and an ArrayList
of Icosahedron objects. It also includes methods that return the name of the list, number of
Icosahedron objects in the IcosahedronList, total surface area, total volume, average surface area,
average volume, and average surface to volume ratio for all Icosahedron objects in the
IcosahedronList. The toString method returns a String containing the name of the list followed
by each Icosahedron in the ArrayList, and a summaryInfo method returns summary information
about the list (see below).
Design: The IcosahedronList class has two fields, a constructor, and methods as outlined below.
(1) Fields (or instance variables): (1) a String representing the name of the list and (2) an
ArrayList of Icosahedron objects. These are the only fields (or instance variables) that this
class should have, and both should be private.
(2) Constructor: Your IcosahedronList class must contain a constructor that accepts a parameter
of type String representing the name of the list and a parameter of type ArrayList<
Icosahedron> representing the list of Icosahedron objects. These parameters should be used
to assign the fields described above (i.e., the instance variables).
(3) Methods: The methods for IcosahedronList are described below.
o getName: Returns a String representing the name of the list.
o numberOfIcosahedrons: Returns an int representing the number of Icosahedron
objects in the IcosahedronList. If there are zero Icosahedron objects in the list, zero
should be returned.
o totalSurfaceArea: Returns a double representing the total surface areas for all
Icosahedron objects in the list. If there are zero Icosahedron objects in the list, zero
should be returned.
o totalVolume: Returns a double representing the total volumes for all Icosahedron
objects in the list. If there are zero Icosahedron objects in the list, zero should be
returned.
o averageSurfaceArea: Returns a double representing the average surface area for
all Icosahedron objects in the list. If there are zero Icosahedron objects in the list, zero
should be returned.
o averageVolume: Returns a double representing the average volume for all
Icosahedron objects in the list. If there are zero Icosahedron objects in the list, zero
should be returned.
o averageSurfaceToVolumeRatio: Returns a double representing the average
surface to volume ratio for all Icosahedron objects in the list. If there are zero
Icosahedron objects in the list, zero should be returned.
o toString: Returns a String (does not begin with \n) containing the name of the list
followed by each Icosahedron in the ArrayList. In the process of creating the return
result, this toString() method should include a while loop that calls the toString() method
for each Icosahedron object in the list (adding a \n before and after each). Be sure to
Project: Icosahedron List App Page 5 of 7
Page 5 of 7
include appropriate newline escape sequences. For an example, see lines 2 through 19 in
the output below from IcosahedronListApp for the icosahedron_data_1.txt input file.
[Note that the toString result should not include the summary items in lines 20 through
26 of the example. These lines represent the return value of the summaryInfo method
below.]
o summaryInfo: Returns a String (does not begin with \n) containing the name of the
list (which can change depending of the value read from the file) followed by various
summary items: number of Icosahedrons, total surface area, total volume, average
surface area, average volume, and average surface to volume ratio. Use “#,##0.0##” as
the pattern to format the double values. For an example, see lines 20 through 26 in the
output below from IcosahedronListApp for the icosahedron_data_1.txt input file. The
second example below shows the output from IcosahedronListApp for the
icosahedron_data_0.txt input file which contains a list name but no Icosahedron data.
Code and Test: Remember to import java.util.ArrayList. Each of the methods above requires
that you use a loop (i.e., a while loop) to retrieve each object in the ArrayList. As you implement
your IcosahedronList class, you can compile it and then test it using interactions. Alternatively,
you can create a class with a simple main method that creates an IcosahedronList object and calls
its methods.
• IcosahedronListApp.java
Requirements: Create an IcosahedronListApp class with a main method that reads in the name of
the data file entered by the user and then reads list name and Icosahedron data from the file,
creates Icosahedron objects, stores them in a local ArrayList of Icosahedron objects, creates a
IcosahedronList object with the name of the list and the ArrayList of Icosahedron objects, and
then prints the IcosahedronList object followed summary information about the IcosahedronList
object. All input and output for this project should be done in the main method.
• Design: The main method should prompt the user to enter a file name, and then it should read in
the data file. The first record (or line) in the file contains the name of the list. This is followed by
the data for the Icosahedron objects. After each set of Icosahedron data is read in, a Icosahedron
object should be created and stored in the local ArrayList of Icosahedron objects. After the file
has been read in and the ArrayList has been populated, the main method should create a
IcosahedronList object with the name of the list and the ArrayList of Icosahedron objects as
parameters in the constructor. It should then print the IcosahedronList object, then print the
summary information about the IcosahedronList (i.e., print the value returned by the
summaryInfo method for the IcosahedronList). The output from two runs of the main method in
IcosahedronListApp is shown below. The first is produced after reading in the
icosahedron_data_1.txt file, and the second is produced after reading in the
icosahedron_data_0.txt file. Your program output should be formatted exactly as shown.
Project: Icosahedron List App Page 6 of 7
Page 6 of 7
Line
#
Program output
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
—-jGRASP exec: java IcosahedronListApp
Enter file name: icosahedron_data_1.txt
Icosahedron Test List
Icosahedron “Small” is “blue” with 30 edges of length 0.01 units.
surface area = 0.000866 square units
volume = 0.000002 cubic units
surface/volume ratio = 396.950723
Icosahedron “Medium” is “orange” with 30 edges of length 12.3 units.
surface area = 1,310.209833 square units
volume = 4,059.844212 cubic units
surface/volume ratio = 0.322724
Icosahedron “Large” is “white” with 30 edges of length 123.4 units.
surface area = 131,874.537977 square units
volume = 4,099,581.395236 cubic units
surface/volume ratio = 0.032168
—– Summary for Icosahedron Test List —–
Number of Icosahedrons: 3
Total Surface Area: 133,184.749
Total Volume: 4,103,641.239
Average Surface Area: 44,394.916
Average Volume: 1,367,880.413
Average Surface/Volume Ratio: 132.435
—-jGRASP: operation complete.
Line # Program output
1
2
3
4
5
6
7
8
9
10
11
12
13
—-jGRASP exec: java IcosahedronListApp
Enter file name: icosahedron_data_0.txt
Icosahedron Empty Test List
—– Summary for Icosahedron Empty Test List —–
Number of Icosahedrons: 0
Total Surface Area: 0.0
Total Volume: 0.0
Average Surface Area: 0.0
Average Volume: 0.0
Average Surface/Volume Ratio: 0.0
—-jGRASP: operation complete.
Code: Remember to import java.util.ArrayList, java.util.Scanner, and java.io.File, and
java.io.FileNotFoundException prior to the class declaration. Your main method declaration
should indicate that main throws FileNotFoundException. After your program reads in
the file name from the keyboard, it should read in the data file using a Scanner object that was
created on a file using the file name entered by the user.
… = new Scanner(new File(fileName));
Project: Icosahedron List App Page 7 of 7
Page 7 of 7
You can assume that the first line in the data file is the name of the list, and then each set of three
lines contains the data from which a Icosahedron object can be created. After the name of the list
has been read and assigned to a local variable, a while loop should be used to read in the
Icosahedron data. The boolean expression for the while loop should be
(_________.hasNext()) where the blank is the name of the Scanner you created on the file.
Each iteration through the loop reads three lines. As each of the lines is read from the file, the
respective local variables for the Icosahedron data items (label, color, and edge) should be
assigned, after which the Icosahedron object should be created and added to a local ArrayList of
Icosahedron objects. The next iteration of the loop should then read the next set of three lines
then create the next Icosahedron object and add it to the local ArrayList of Icosahedron objects,
and so on. After the file has been processed (i.e., when the loop terminates after the hasNext
method returns false), name of the list and the ArrayList of Icosahedron objects should be used to
create an IcosahedronList object. The list should be printed by printing a leading \n and the
IcosahedronList object. Finally, the summary information is printed by printing a leading \n and
the value returned by the summaryInfo method invoked on the IcosahedronList object.
Test: You should test your program minimally (1) by reading in the icosahedron_data_1.txt
input file, which should produce the first output above, and (2) by reading in the
icosahedron_data_0.txt input file, which should produce the second output above. Although your
program may not use all of the methods in IcosahedronList and Icosahedron, you should ensure
that all of your methods work according to the specification. You can either user interactions in
jGRASP or you can write another class and main method to exercise the methods. Web-CAT
will test all methods to determine your project grade.
General Notes
1. All input from the keyboard and all output to the screen should done in the main method.
Only one Scanner object on System.in should be created and this should be done in the main
method. All printing (i.e., using the System.out.print and System.out.println methods) should
be in the main method. Hence, none of your methods in the Icosahedron class should do any
input/output (I/O).
2. Be sure to download the test data files (icosahedron_data_1.txt and icosahedron_data_0.txt)
and store them in same folder as your source files. It may be useful examine the contents of
the data files. Find the data files in the jGRASP Browse tab and then open each data file in
jGRASP to see the items that your program will be reading from the file. Be sure to close the
data files without changing them.
