Classes

Creating Our Own Classes

• declaring instance variables
• methods in classes
• local variables
• toString method

Dog.java
DogHarness.java
Bunny.java
BunnyHarness.java
Cat.java

Deitel chapter 3

Classwork

☑  Create a class modeling some type of creature, (do not use previous example types such as Bunny, Cat, etc).  Remember to name your class for the type of creature, in the singular. (Your creature does not have to be real or zoologically accurate, but your design in the choices you make below should make some sense)

☑ For your new creature class

• include a name
• include an instance variable of type double or boolean for some characteristic appropriate to your creature
• add a method for some behavior appropriate to your creature. This method only need print a description of the action, using the name. (remember you can copy and make changes to example code)
• add an appropriate toString method

☑ In a separate harness class, in a main,

• create two instances of your class,
• set their  names and other instance var to different values
• test the behavior,
• print them

(This may look a lot like BunnyHarness.)

☑ Create a second new creature class. You will test it in the same test harness.  This class represents a creature that keeps the first type as a pet.  

☑ For your new creature class

• include a name
• include a variable pet of the other creature type (NOT just its name, the whole other creature; think about dogs who know about cats )
• include a method, play, for this creature to  play with its pet, which prints a message using the  other creature's name.  This might print something like "I'm playing with Harvey, my pet Godzilla." (you may want to look at how Dogs chase Cats)
• Include another method, eat, that prints a message using the pet's other instance variable, and then changes the pet's name to "Dinner."  For example it might print "Since it is false that my pet Godzilla can fly, I've decided to eat it"  or "Despite all my love and care my pet butterfly only weighs 3.7 tons, so I'm going to have to eat it."  (no matter what the value, the pet is getting eaten)
• include the name and the pet in the toString

☑ In your harness, test out this creature, including its interactions with the creature from part A.   Your methods in the second class will blow up if you don't give your second creature a pet before  calling play or eat, so make sure you give this creature a pet!!

[EC]  Give your second class a myBestFriend, who is of the same type, and a method swapPets, which prints that they are swapping pets with their bestFriend, after which they should have their myBestFriend's old pet, and their myBestFriend should have their old pet.  This DOES NOT MEAN just to swap the names and other vars for the pets, swap the ACTUAL pets!!!  (hint: if you had a glass of milk and a glass of wine, could you swap their contents using just those two glasses...?)  Test this in main (it will only work if you give them a myBestFriend in main before you call the method, and the myBestFriend should have a pet too).