Java Programming Tutorial - 44 - Enumeration Video Lecture - Java Programming

sup guys Bucky welcome to your 44th Jeff
tutorial and in this tutorial I'm going
to be going over something called
enumerations or enum we learned about
them before I think we might not have if
we didn't you know no big deal we're
both learning today but the first thing
that we're going to do well let me tell
you what enumerations are they're pretty
much kind of like classes but they
you're going to use them to declare
constants at least in this tutorial you
are so let's go ahead and anytime you
want to do this instead of public class
tuna you put public enum DNA um and now
you can use this in a specific way so
like I said the first thing we're going
to want to do is declare a bunch of
constants of the enum type so let's go
ahead and make some constants or these
are pretty much going to be like
variables that never change so I'm going
to make like three names Bucky and these
are in essence objects so let me give
these a few parameters and then you'll
see why later on Bucky let's give the
first parameter a description word of
the object and I'm going to put nice
since you know I'm doing this story
might as well say something good about
myself and then let's just go ahead and
put a string about like um how old they
are or something I'll make it
interesting for the other two ones now
let's think of a next person let's think
of a will do constants of my first
girlfriends so my first one was Kelsey
and she was she was cutie it was
fifth-grade she's pretty cute and uh
let's see when I went out with her I was
ten years old and now put a comma
because we're not done with our entire
enumeration list and then the next girl
went out with was oh it wasn't really
girlfriend but uh we had thing it was
Julia she was a she was a big mistake
and I was twelve years old when I went
out with her so now we're done we got
three constants let's go ahead
and end the statement with a semicolon
now what we're going to do is since we
just made objects and again each
constant is an object and it's going to
have its own set of variables in this
entire enumeration so let's go ahead and
give it two variables that we're going
to use later drive it final since we
don't want to change string since this
we've just made since we're in quotation
marks and put DSC for description and
we'll copy this entire thing copy paste
and we have description right here and
what's good name for this year or
something year so now we have three
objects which are actually enumerations
or column or constants and they each
have a set of their own variables one
for description one for year so now what
can we do what do we usually want to do
when we create these well the first
thing that we're going to want to do is
create an enumeration constructor so
let's go ahead and do that by of course
typing the name of your class and then
you probably want to play your two
variables and put string description and
make sure since this is um we're going
to use this make sure this is different
than this and you should know why and
then just put string and let's put
birthday or something it isn't their
birthday but I don't want to get
confused at all I can't put yr something
because they'll just confuse me you know
I'm easily confused got something to say
about didn't think so
so now let's put DSC or whatever you
declare it up here just put equal do
description statement and then go ahead
and put birthday year evil birthday and
now what do we got anytime here's what's
going to happen with Bucky is going to
say all right with the object Bucky give
it two variables a description in a year
for the description pass in nice
in this 22 we're going to see his
birthday so set your equal to birthday
so now we can work with DSC in year good
enough but now that we have a
constructor we just pretty much set
these variables equal to where they need
to be we have no way of getting the
variables yet so let's go ahead and
create two methods that we can get the
variables so public string so this is
going to return a string and put get
description or get deaths if you're lazy
which I am so it works out and then in
this one we want to return the des see
that's just going to return a string of
the description easy enough and guess
where we're going to do in this method
public string get output get year seems
like a good name and this one is just
going to return year loan from of this
it's a little too easy so now this is
all we need to do with enumerations
again enumerations are constants that
are also objects pretty much and so we
needed two variables to represent the
two arguments and then once we have
those two variables we can build a
constructor and then this constructor
allows us pretty much to set these
variables equal to each other and return
the information we wanted so let's go
ahead and well let's just go ahead and
use the information right now so what we
want to do pretty much in our main class
right here with our main method is build
and enhance the for loop so let's go do
that right here for and the first
parameter you need is of course the
class name in the variable that you want
to use in your for loop like we use um
like description right here this is just
variable that we just made up this is
going to be the variable that we just
made up right here and that's the first
like it's pretty much what you want to
call your objects when you loop through
them the next argument is you need an
array that you need to loop through and
tell you a little bit about this because
this might be kind of confusing
anytime you make an enumeration like
this Java automatically makes it takes
this constant these constants and makes
a built-in array and the array is called
whatever your enumeration is called
instance on a my toon it's called tuna
and when you write values like that this
is a built-in an array of the constants
right here
so for saying are a um I need an array
BAM you got an array right there and
again you can't change this keyword
values this values is called a static
method in again this is how you get a
built-in RA so this is going to loop
through each of the constants first it's
going to loop through Bucky and Kelsey
then Julia and it's going to assign them
to people well you'll see what does so
now we just need to make a print
statement so let's go ahead and put
system and why do we need to make a
print statement so we can actually see
what's going on
system.out.print out and let's just go
ahead and make our two arguments the
format is going to be percent s and
let's put a tab add some spacing % s @ @
ab % s and a newline so it's going to
write our name our description our age
and then it's going to go to the next
person so now we need our arguments the
first thing we want is people because
that's what the object is pretty much so
in the first one is just going to loop
through our name which is this Bucky
in our next argument what we need is to
take that people object and use the
method get' why would I name that method
people dot get description and what that
is going to do is it's going to return a
arm you find my screen recorder see how
much time I'm at
I got minute 30 what's going to do is
return a string of our description and
this last one people dot get
year and what this is going to do is
first find you to get it messed it up
for me people to get ear and what this
is going to do is return a string of the
year so let's go ahead and make sure I
have a semicolon at the end of that and
once again and make sure I have this and
let's go ahead and run it so run this
okay and look at my results I got the
object the description and the year
object description your object scription
yer so what it did again see if I can
get it was it loop through the entire
array of people and for the first
argument gave us the object name
description name and the year whatever
year I signed will so in the next
tutorial we're going to be going over
this more but thank you for watching
don't forget to subscribe and I will see
you next tutorial