Description
Introduction
Welcome to your first COMP 2522 assignment. Today you will apply what you have started learning as we
migrate from Python to Java. You will implement the first class for a larger project.
Developing software is often a highly iterative process. Iterative software development involves repeated
cycles of designing, coding, testing, and integrating small sections or increments of a program. We build
a little, show it to our clients, make adjustments, and continue.
By deconstructing a large project into smaller, more manageable tasks, we can abstract away portions of
the application and focus on separate, solvable problems. The knowledge we gain from developing and
testing these smaller modules can be applied to the development of other parts of the project. Ultimately
we generate correct, working, and maintainable software efficiently and quickly.
You have been hired to generate some helpful software for a group of ichthyologists at the Vancouver
Aquarium. A new and invasive species of Poecilia, the live-bearing aquarium fish also known as the guppy,
has been discovered in some of the hot springs, pools, and streams near Skookumchuk. The owners of
the land have asked the scientists to study the prolific little fish and determine, among other things, if its
reproductive rate will be a threat to native aquatic fauna.
Figure 1: Guppies by Per Harald Olsen (Own work) via Wikimedia Commons [GFDL
(http://www.gnu.org/copyleft/fdl.html) or CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)]
The scientists are still studying the problem domain, and they haven’t finalized the scope of the simulations they want to conduct. But that’s okay. Object-oriented analysis, design, and programming are well
suited to developing software systems whose requirements are incomplete and changing.
During the first few analysis meetings with the scientists, you identified some fundamental classes in
the problem domain. For the first iteration of your software project, you will abstract away much of the
potentially complicated logic and design in the application. You will begin by writing one of the classes
that represent the basic building blocks of the simulations the scientists will want to run.
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1 Submission requirements
This assignment must be submitted via GitHub by Sunday January 19th at or before 23:59:59 PM. Tardy
submissions will not be accepted.
Your code must be in the ca.bcit.comp2522.assignments.a1 package of the main COMP 2522 IntelliJ
project you created in Lab 01.
We will mark the code as it appears during the final commit before the due date and time.
2 Grading scheme
Your assignment will be marked out of 10:
1. 5 points for code style (refer to the code style handout)
2. 5 point for code correctness (we will even provide you with some helpful JUnit tests later this week).
3 Implementation requirements
You must implement a class called Guppy.java which contains the following elements:
1. The following nine public symbolic constants. Use these variable names and data types. In Java,
symbolic constants are static and final. Do not use different names or data types, and do not add
any other symbolic constants. Use these constants instead of magic numbers inside your code:
(a) YOUNG_FISH_AGE_IN_WEEKS an integer equal to 10
(b) MATURE_FISH_AGE_IN_WEEKS an integer equal to 30
(c) MAXIMUM_AGE_IN_WEEKS an integer equal to 50
(d) MINIMUM_WATER_VOLUME_ML a double equal to 250.0
(e) DEFAULT_GENUS a String equal to “Poecilia”
(f) DEFAULT_SPECIES a String equal to “reticulata”
(g) DEFAULT_HEALTH_COEFFICIENT a double equal to 0.5
(h) MINIMUM_HEALTH_COEFFICIENT a double equal to 0.0
(i) MAXIMUM_HEALTH_COEFFICIENT a double equal to 1.0
2. The following eight private instance variables. Use these variable names and data types. Do not
use different names or data types, and do not add any other instance variables:
(a) genus (first word of the scientific binomial two-part name) a String
(b) species (second word of the scientific binomial name) a String
(c) ageInWeeks an integer
(d) isFemale a boolean
(e) generationNumber an integer
(f) isAlive a boolean
(g) healthCoefficient a double
(h) identificationNumber an integer
3. numberOfGuppiesBorn, a private static integer that has an initial value of 0. This variable is incremented by 1 each time a new guppy is constructed, and the newly incremented value is assigned
to the new guppy’s identificationNumber instance variable. Further details are provided in the
section about constructors (remember that static variables are shared by all objects of a class).
4. Two (2) constructors:
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(a) A zero-parameter constructor which sets ageInWeeks and generationNumber to zero, and sets:
i. genus to DEFAULT_GENUS
ii. species to DEFAULT_SPECIES
iii. isFemale to true
iv. isAlive to true
v. healthCoefficient to DEFAULT_HEALTH_COEFFICIENT
vi. identificationNumber to the newly incremented value of numberOfGuppiesBorn
(b) A second constructor which accepts the following parameters in the following order:
i. newGenus a String. Format the String passed in newGenus correctly (capital first letter, the
rest lower case) and assign the new String to the genus instance variable.
ii. newSpecies a String. Format the String passed in newSpecies correctly (lower case) and
assign the new String to the species instance variable.
iii. newAgeInWeeks a positive integer. Assign newAgeInWeeks to the ageInWeeks instance variable. If the parameter passed to the method is negative, assign a 0.
iv. newIsFemale a boolean to assign to the isFemale instance variable.
v. newGenerationNumber an integer. If the argument passed as the parameter is less than
zero, set the value to one. Otherwise assign newGenerationNumber to the generationNumber
instance variable.
vi. newHealthCoefficient a double. If the argument passed as the parameter is less than
MINIMUM_HEALTH_COEFFICIENT or greater than MAXIMUM_HEALTH_COEFFICIENT, set the value
to the closest bound. Otherwise assign newHealthCoefficient to the instance variable
called healthCoefficient.
vii. This constructor should not accept a parameter for the isAlive instance variable. Set the
isAlive variable to true. Every new Guppy is alive by default.
(c) Remember that each constructor must also increment the static numberOfGuppiesBorn
variable by 1 and and assign the new value to identificationNumber.
5. A method with the header public void incrementAge() which increases the value in the ageInWeeks
instance variable field by 1. If the new value in ageInWeeks is greater than MAXIMUM_AGE_IN_WEEKS,
set the isAlive instance variable to false.
6. An accessor (getter) for all eight instance variables, and a mutator (setter) for ageInWeeks, isAlive,
and healthCoefficient:
(a) Do not create mutators for genus, species, isFemale, or identificationNumber.
(b) Every accessor method name must follow the pattern getVariableName.
(c) Every mutator method name must follow the pattern setVariableName.
(d) Also create a static accessor for the numberOfGuppiesBorn static variable. It must be called
public static int getNumberOfGuppiesBorn().
(e) The mutator for ageInWeeks must ignore values below 0 and above MAXIMUM_AGE_IN_WEEKS.
(f) The mutator for healthCoefficient must ignore values that would cause the healthCoefficient
variable to exceed its bounds.
7. A method with the header public double getVolumeNeeded() which returns the volume of water
in millilitres that the guppy needs according to the following formula:
(a) If the fish is less than 10 weeks old, return MINIMUM_WATER_VOLUME_ML.
(b) If the fish is 10 to 30 weeks old, return MINIMUM_WATER_VOLUME_ML * ageInWeeks / YOUNG_FISH_WEEKS.
(c) If the fish is 31 to 50 weeks old, return MINIMUM_WATER_VOLUME_ML * 1.5.
(d) If the fish is older than 50 weeks, return 0.0.
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8. a method with the header public void changeHealthCoefficient(double delta) which adds
the value passed in the delta parameter to the healthCoefficient instance variable. The parameter delta may be positive or negative, but if the new value of healthCoefficient would be less than
or equal to MINIMUM_HEALTH_COEFFICIENT, in addition to setting the value of healthCoefficient
to 0.0, set the isAlive instance variable to false. If the new value of healthCoefficient would be
greater than MAXIMUM_HEALTH_COEFFICIENT, set healthCoefficient to MAXIMUM_HEALTH_COEFFICIENT.
9. a method with the header public String toString() which returns a String representation of the
guppy. The version generated by IntelliJ is sufficient.
10. an equals() method. Write this one yourself from scratch.
That’s it! Good luck, and have fun!
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