1
00:00:00,530 --> 00:00:01,130
Okay.

2
00:00:01,130 --> 00:00:02,710
Let's talk this through a bit.

3
00:00:02,710 --> 00:00:06,740
You probably noticed that none of
the stories told us about how our app

4
00:00:06,740 --> 00:00:10,780
should be developed or
even on what platform for that matter.

5
00:00:10,780 --> 00:00:14,530
Since so far we've only gone over how
to make console based applications

6
00:00:14,530 --> 00:00:16,420
that seems like the obvious
platform decision.

7
00:00:17,550 --> 00:00:19,170
However if we do this right.

8
00:00:19,170 --> 00:00:22,270
We should be able to reuse
the game code that we write.

9
00:00:22,270 --> 00:00:25,705
Since no matter how we end up playing
the game that logic will stay the same.

10
00:00:25,705 --> 00:00:29,580
We'll need to make sure that
we separate the prompting and

11
00:00:29,580 --> 00:00:33,900
displaying portion of the code
from the game state and behavior.

12
00:00:33,900 --> 00:00:37,680
This approach is called the separation
of concerns and we'll touch on it here

13
00:00:37,680 --> 00:00:41,430
lightly, and it will make a lot of sense
after we get the code up and running.

14
00:00:41,430 --> 00:00:45,000
But, the idea is this, we're building
a console based application and

15
00:00:45,000 --> 00:00:47,635
there is certain code that is needed for
that to work.

16
00:00:47,635 --> 00:00:49,910
But the game logic itself
like the rules and

17
00:00:49,910 --> 00:00:52,720
how you win,
it pretty much stays the same.

18
00:00:52,720 --> 00:00:57,090
By doing the separation, we could in
fact end up using that game logic

19
00:00:57,090 --> 00:01:01,390
code in like a desktop app,
a mobile app, or even a web application.

20
00:01:01,390 --> 00:01:04,650
So with that in mind let's
build our structure out.

21
00:01:04,650 --> 00:01:07,430
Let's build our game and
prompter blueprints.

22
00:01:07,430 --> 00:01:09,750
That separation should be
enough to get us started.

23
00:01:10,970 --> 00:01:13,510
Okay.
So I've created a new workspace for

24
00:01:13,510 --> 00:01:17,910
this part of the course, it has our
starter file Hangman.java in it.

25
00:01:17,910 --> 00:01:21,170
So first thing we should do is
let's build our prompter class,

26
00:01:21,170 --> 00:01:22,670
it should be pretty straightforward.

27
00:01:22,670 --> 00:01:27,500
So I'm gonna make a new file,
I'm gonna call it prompter.java.

28
00:01:27,500 --> 00:01:30,290
Okay, so we wanna have a class.

29
00:01:30,290 --> 00:01:34,000
And it needs to be named the same
as the file that it's in, right.

30
00:01:34,000 --> 00:01:35,830
So we're need to call it Prompter.

31
00:01:37,110 --> 00:01:40,200
And let's open up the code block there.

32
00:01:40,200 --> 00:01:42,070
Remember that's enough.

33
00:01:42,070 --> 00:01:46,880
So we'll use this prompter object to
do all of the IO or input output.

34
00:01:46,880 --> 00:01:51,130
So we also need to separate out
the game logic in it's own file here.

35
00:01:51,130 --> 00:01:54,700
So we'll do new file, game.java.

36
00:01:54,700 --> 00:01:59,260
Okay, and following the similar logic,
we'll make a new class called Game and

37
00:01:59,260 --> 00:02:01,170
I'm gonna open it up, and
I'm gonna close it right away.

38
00:02:02,210 --> 00:02:05,180
Give us some space and now,
one thing that we know for

39
00:02:05,180 --> 00:02:09,510
certain is that this class will need to
know the answer to the puzzle, right?

40
00:02:09,510 --> 00:02:14,346
So, let's say it's gonna be a string and
answer.

41
00:02:14,346 --> 00:02:19,290
Now, it should be private because that's
how we always start things out, right.

42
00:02:19,290 --> 00:02:20,320
We want to be private.

43
00:02:21,650 --> 00:02:25,390
Okay, since a game is not really
any good without an answer,

44
00:02:25,390 --> 00:02:29,130
let's force the creation of
a game to provide an answer.

45
00:02:29,130 --> 00:02:31,420
We should use a constructor to do that.

46
00:02:31,420 --> 00:02:34,630
So let's make a new public, and

47
00:02:34,630 --> 00:02:41,010
a constructor Again has the same
name as the class, so public game.

48
00:02:41,010 --> 00:02:43,790
And we want to have it pass in an answer.

49
00:02:43,790 --> 00:02:45,770
So we'll say string answer.

50
00:02:46,900 --> 00:02:50,480
And then what we'll do is we'll
take what was passed in and

51
00:02:50,480 --> 00:02:53,140
set our private answer variable.

52
00:02:53,140 --> 00:02:59,860
And to avoid naming collisions
we'll say this.answer = answer.

53
00:03:01,350 --> 00:03:04,140
That way, we know for
sure that we're talking about

54
00:03:04,140 --> 00:03:08,880
the instances field versus
the argument that was passed in.

55
00:03:08,880 --> 00:03:12,510
Great, that should be enough to
define at the separation of concern.

56
00:03:12,510 --> 00:03:15,190
So I'm going to save this,
make sure that they're both saved.

57
00:03:15,190 --> 00:03:17,650
I gonna come over to Hangman.

58
00:03:17,650 --> 00:03:23,070
And let's make a brand
new instance of our game.

59
00:03:23,070 --> 00:03:26,088
So we'll say the type is game.

60
00:03:26,088 --> 00:03:29,250
The instance of variable
name is going to be Game and

61
00:03:29,250 --> 00:03:33,170
we're going to say when
you want a new Game.

62
00:03:33,170 --> 00:03:34,870
That's gonna to call
the constructor that we have there.

63
00:03:34,870 --> 00:03:36,280
We're gonna pass in the answer.

64
00:03:36,280 --> 00:03:37,340
Let's pass in tree house.

65
00:03:38,690 --> 00:03:39,800
So let's do that.

66
00:03:39,800 --> 00:03:41,210
I'm just gonna go ahead and compile and

67
00:03:41,210 --> 00:03:43,310
make sure that we got all
of our syntax correct.

68
00:03:43,310 --> 00:03:48,030
And I just need to press to get in there
to hangman.job and what that will do

69
00:03:48,030 --> 00:03:52,089
is because game is in the same folder,
it will try to compile all of this.

70
00:03:53,260 --> 00:03:55,607
Well it'll at least compile Game.

71
00:03:57,839 --> 00:03:59,892
Right.
So I didn't compile Prompter because we

72
00:03:59,892 --> 00:04:01,300
didn't access prompter yet.

73
00:04:01,300 --> 00:04:02,600
But it did compile game.

74
00:04:02,600 --> 00:04:03,380
So we know that's working.

75
00:04:03,380 --> 00:04:04,410
So there's no errors.

76
00:04:04,410 --> 00:04:09,590
And again, since this game class is in
the same folder or package, Hangman

77
00:04:09,590 --> 00:04:14,240
just found the proper class without us
needing to specify where to find it.

78
00:04:14,240 --> 00:04:15,810
Our separation of concerns looks great.

79
00:04:15,810 --> 00:04:19,610
We have the prompter class which
we used to deal with the IO and

80
00:04:19,610 --> 00:04:22,010
the game class which
will maintain the logic.

81
00:04:22,010 --> 00:04:23,820
It's completely separated.

82
00:04:23,820 --> 00:04:28,260
We also have the main executable
file Hangman.Java where we'll use

83
00:04:28,260 --> 00:04:31,480
instances of the prompter and
the game classes.

84
00:04:31,480 --> 00:04:32,250
Awesome.

85
00:04:32,250 --> 00:04:32,800
All right.

86
00:04:32,800 --> 00:04:36,180
Now that we have our main objects defined
let's get to completing those stories.