This assignment will put into practice the following topics:

ArrayLists $($Chapter $11)$

Collections.sort$($Chapter $11)$

Polymorphism $($Chapter $11)$

Abstract Classes $($Chapter $13)$

Interfaces $($Comparable$)($Chapter $13)$

composition $($Chapter $10)$

For this assignment, we are going to simulate a aquarium that contains fish. One rule about aquariums is that there is a limit to how many fish it can hold due to oxygen consumption. If you add too many, there won't be enough oxygen and the fish will die.$$ So$,$ the careful aquarium owner will keep track of the fish added to the tank so as to maintain a healthy environment for the fish.$$ You'll write a application that helps aquarium owners determine how many fish can be added to a tank.$$ Here's a UML diagram of the classes needed to solve the problem:

$($Image Attached$)$

Fish

Fish will be an abstract class.$$ It's meant to model the common characteristics of all fish.$$ It's a class we will never create an instance of$,$ but it is useful as it defines the attributes and behavior for all subclasses of fish.$$ In this model, we are stating that all fish swim in a zone, and have some amount of oxygen consumption.

$-$ zone is an integer representing the zone of the aquarium where the fish spends most of it's time.$$ The zones are defined as follows:$$ top $=1,$ middle $=2,$ bottom $=3.$

$-$ There is one constructor, that takes an integer representing the zone and saves it in the instance variable named zone.

$-$ There is a getter method for zone variable.

$-$ There is an abstract method $($shown in italics in UML$)$ named getOxygenConsumption$(),$ that returns the oxygen content needed by the fish.

$-$ There is an abstract method $($shown in italics in UML$)$ named swim$()$ that returns a String representing how the fish swims.

The two abstract methods are "instructions" to subclasses.$$ Any subclass that we want to create an instance of will have to define how$/$where they swim, and how much oxygen they require.

Note that the abstract class Fish implements the Comparable interface.$$ This interface is part of the Java API and does not have to be created in this assignment.$$ Since Fish implements Comparable, it means that it must provide a concrete implementation of the compareTo$()$ method.$$ We will use it to sort the fish by zone.$$ The compareTo$()$ method will be analogous to the ComparableRectangle in listing $13\mathrm{.}9,$ except we will order by zone, instead of area.$$

subclasses of Fish

default constructor:$$ for all subclasses are simple and contain just one line of code:$$ a call to the super class constructor, passing a integer representing the zone they swim in$.$ There are no other constructors for subclasses of Fish.

$-$Danio's swim at the top, so it should forward a $1$ to the superclass constructor.

$-$Tetra's swim in the middle, so it should forward a $2$ to the superclass constructor.

$-$Cory's swim at the bottom, so it should forward a $3$ to the superlcass constructor.

getOxygenConsumption$()$:$$ This method just returns an integer representing how much oxygen the fish requires.$$ It could be the result of a calculation, but we'll keep it simple and return an integer as follows:

$-$ Danios:$$ return $12.$

$-$ Tetras:$$ return $10$;

$-$ Corys:$$ return $18$;

swim$()$:$$ This method describes how a particular type of fish swim.$$ For our model, we'll return a string in each sublcass as follows:

$-$ Danios:$$ return "Danio darting".$$

$-$ Tetras:$$ return "Tetra gliding".

$-$ Corys:$$ return Cory just hanging out".

Aquarium

This class contains our fish.$$ To hold our fish, you will use an ArrayList with the concrete type set to Fish $($as shown in UML$).$ ArrayLists allow us to add items to the list without worrying if we are going back the end of the list, as it resizes the list for us$.$ And, it is part of the Collections framework, which allows us to do things like sort the ArrayList $($assuming we implement comparable$).$

You should have a instance variable that represents the oxygen content of the tank.$$ This will be based on the surface area of the tank.

It continues in the image attached because this space only allows $5000$ characters.