Java Programming Tutorial - 56 - Polymorphic Arguments Video Lecture -

what is going on guys welcome to your
56th job tutorial and in this store I'm
going to be talking about more about
polymorphism in how you can have
polymorphic arguments and also return
types and bunch of boring stuff like
that but I'll try to make it a little
exciting and maybe I'll tell a funny
story maybe I won't I guess you guys are
going to have to wait and see if you've
been following my tutorials the first
thing you probably noticed is I made a
new class called fatty and we're going
to we need to build this class to
demonstrate what fatty can do to food
tuna and pot pie if you haven't guessed
he's going to be eating these classes
because fatties love food tuna and
Popeye trust me I know firsthand I fan I
love them so we made this fatty class
now let's go ahead and make a simple
method in here it's going to do public
void digest which pretty much means eat
then but we can't have eat tuna because
he is already method in here so we're
going to have digest and as a parameter
is going to take a food object so let's
go ahead and type food X and now we can
go ahead and do something with that
object it's tighten that up a bit that's
what she said so now we're going to pass
in a food object and when we pass in the
food object we're going to take that
object which is now named X and we're
going to call the eat method to that and
bam that's all all we're going to do so
here's what we can do right now for
example if we had a food object named
Bucky we can pass in the name Bucky and
then it's going to say alright whenever
we call Bucky II it's going to say this
food is great so when every pass in the
food object is going to call that food
method which is eat right here but what
you didn't know or maybe you did if you
know Java what you didn't know is
anytime you can pass in a food object
you can also pass in objects of a
subclass for example you can pass in
tuna and potpie so since this object or
excuse me this method has the privilege
of accepting a food object is this
argument it can also accept any
subclasses
such as tuna and potpie so Oh would you
say you don't believe me well let me
just go ahead and prove it right here
let's go in our main apples method and
let's go ahead and start making some
objects let's go ahead and make a fatty
object and we'll name it Bucky because
that's me and I am fat
we'll say equals new fatty with no
parameters so what we did here is we
created a fatty object named Bucky and
let's go ahead and now once we can use
this fatty class let's go ahead and give
us a way to use the food objects so
let's go ahead and create food will
create fo for food objects equals new
food and why do we need to create a food
object because first of all put your
semicolons get my wood box so he said
and I correct myself up sometimes and
why did we need to create this object
for food well because this method takes
an argument that's a food object so
that's why so now head now let's go
ahead and call this with our fatty
object which is Bucky because I'm fatty
we put Bucky eat right there and now
let's go ahead and as our argument
remember or excuse me that's digest
isn't it and as our argument for the
digest method in our Bucky object it
takes one food object so we only have
this object right here fo so let's go
ahead and pass that in and see how it
works
okay run that baby and it says this food
is great
wow that food must be great wonder what
it is from a double cheeseburger you fat
piece of oh sorry
and anyways now you pretty much know how
you can pass in objects into methods but
wait Bucky you said that you can pass um
subclasses in as well well I didn't lie
anytime you can pass a food object in as
a method as an argument you can also
pass the subclasses which are in this
case tuna and potpie so for example
we have this fatty digest method that
takes a food object is this argument but
food also has the subclasses of Popeye
and tuna so let's go ahead and make a
food let's limit P Oh equals new food
get out here and BAM just like that so
not only can we pass in this superclass
of food object we can also copy this
because we're lazy and we can also pass
in this object P Oh which would be the
potpie so let's go ahead and run this
and it will be new potpie like that
let's run it and see what we got this
food is great
this potpie is great so what point am i
exactly trying to make well what we did
right here is this we created an object
named Bucky so we can use all the stuff
in this fatty class right here and the
only thing is is this digest method so
you know I don't have a whole lot to
work with here we also created a new
food object because this digests method
it took a food object as its argument
now after that we created a potpie
object
now this potpie object is a subclass of
this food superclass so any time this
digest method can take a food argument
it can also take a tuna or a potpie
argument as well so then I prove that to
you guys because I know I'm a liar and I
had to prove it to you guys
I called that Bucky object with digests
is the food object is my argument and I
also called the Popeye object as my
argument so that is pretty much a way
that you can have polymorphic arguments
and you can also have polymorphic return
types in the same way so we just want
over arguments right here but you guys
can figure out just return any other one
if you want so that's that for this
tutorial hopefully you guys learn if
didn't then you know I don't know what
else to do watch your ass my sorrows I
guess Oh disgusting story I told you
guys that I'll tell you one of my
friends she went to a well I don't want
to say the name of the restaurant but
she went to a fast-food restaurant
before and she got this chicken sandwich
and she bit into it it was like creamy
in the inside and she's like oh cool
like a new cheese on the inside must be
like like a cheese filling or something
like that taste like blue cheese or
something well anyways she ended up
getting food poisoning and they found
out that in the center of the chicken it
wasn't a filling it was actually pus in
the centre of the chicken so when she
bit into it pus burst out and she
thought it was filling and she just ate
it anyways and yeah she got food
poisoning so if you think that's
disgusting leave me a comment and if you
never want to eat a chicken sandwich
again then I don't blame you but it
wasn't from McDonald's or Wendy so you
guys are still good to eat there so in
any way thanking you guys for watching
hopefully you enjoyed my discussing
story in my tutorial so I look forward
to teaching you some more so I will see
you next time oh by the way don't please
subscribe