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You have completed Java Objects!
You have completed Java Objects!
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We will build out the starts of our objects, thinking heavily on Separation of Concerns. We will focus on separating the display and prompting from the game logic.
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Okay.
0:00
Let's talk this through a bit.
0:01
You probably noticed that none of
the stories told us about how our app
0:02
should be developed or
even on what platform for that matter.
0:06
Since so far we've only gone over how
to make console based applications
0:10
that seems like the obvious
platform decision.
0:14
However if we do this right.
0:17
We should be able to reuse
the game code that we write.
0:19
Since no matter how we end up playing
the game that logic will stay the same.
0:22
We'll need to make sure that
we separate the prompting and
0:25
displaying portion of the code
from the game state and behavior.
0:29
This approach is called the separation
of concerns and we'll touch on it here
0:33
lightly, and it will make a lot of sense
after we get the code up and running.
0:37
But, the idea is this, we're building
a console based application and
0:41
there is certain code that is needed for
that to work.
0:45
But the game logic itself
like the rules and
0:47
how you win,
it pretty much stays the same.
0:49
By doing the separation, we could in
fact end up using that game logic
0:52
code in like a desktop app,
a mobile app, or even a web application.
0:57
So with that in mind let's
build our structure out.
1:01
Let's build our game and
prompter blueprints.
1:04
That separation should be
enough to get us started.
1:07
Okay.
So I've created a new workspace for
1:10
this part of the course, it has our
starter file Hangman.java in it.
1:13
So first thing we should do is
let's build our prompter class,
1:17
it should be pretty straightforward.
1:21
So I'm gonna make a new file,
I'm gonna call it prompter.java.
1:22
Okay, so we wanna have a class.
1:27
And it needs to be named the same
as the file that it's in, right.
1:30
So we're need to call it Prompter.
1:34
And let's open up the code block there.
1:37
Remember that's enough.
1:40
So we'll use this prompter object to
do all of the IO or input output.
1:42
So we also need to separate out
the game logic in it's own file here.
1:46
So we'll do new file, game.java.
1:51
Okay, and following the similar logic,
we'll make a new class called Game and
1:54
I'm gonna open it up, and
I'm gonna close it right away.
1:59
Give us some space and now,
one thing that we know for
2:02
certain is that this class will need to
know the answer to the puzzle, right?
2:05
So, let's say it's gonna be a string and
answer.
2:09
Now, it should be private because that's
how we always start things out, right.
2:14
We want to be private.
2:19
Okay, since a game is not really
any good without an answer,
2:21
let's force the creation of
a game to provide an answer.
2:25
We should use a constructor to do that.
2:29
So let's make a new public, and
2:31
a constructor Again has the same
name as the class, so public game.
2:34
And we want to have it pass in an answer.
2:41
So we'll say string answer.
2:43
And then what we'll do is we'll
take what was passed in and
2:46
set our private answer variable.
2:50
And to avoid naming collisions
we'll say this.answer = answer.
2:53
That way, we know for
sure that we're talking about
3:01
the instances field versus
the argument that was passed in.
3:04
Great, that should be enough to
define at the separation of concern.
3:08
So I'm going to save this,
make sure that they're both saved.
3:12
I gonna come over to Hangman.
3:15
And let's make a brand
new instance of our game.
3:17
So we'll say the type is game.
3:23
The instance of variable
name is going to be Game and
3:26
we're going to say when
you want a new Game.
3:29
That's gonna to call
the constructor that we have there.
3:33
We're gonna pass in the answer.
3:34
Let's pass in tree house.
3:36
So let's do that.
3:38
I'm just gonna go ahead and compile and
3:39
make sure that we got all
of our syntax correct.
3:41
And I just need to press to get in there
to hangman.job and what that will do
3:43
is because game is in the same folder,
it will try to compile all of this.
3:48
Well it'll at least compile Game.
3:53
Right.
So I didn't compile Prompter because we
3:57
didn't access prompter yet.
3:59
But it did compile game.
4:01
So we know that's working.
4:02
So there's no errors.
4:03
And again, since this game class is in
the same folder or package, Hangman
4:04
just found the proper class without us
needing to specify where to find it.
4:09
Our separation of concerns looks great.
4:14
We have the prompter class which
we used to deal with the IO and
4:15
the game class which
will maintain the logic.
4:19
It's completely separated.
4:22
We also have the main executable
file Hangman.Java where we'll use
4:23
instances of the prompter and
the game classes.
4:28
Awesome.
4:31
All right.
4:32
Now that we have our main objects defined
let's get to completing those stories.
4:32
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