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All right, so we left a little
problem in our PezDispenser class that

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00:00:04,420 --> 00:00:06,390
I want to go in and fix with you.

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00:00:06,390 --> 00:00:09,560
We made a field that exposes
the character's name, and not

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00:00:09,560 --> 00:00:14,030
only can we access the field to get the
current value, but we can also change it.

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00:00:14,030 --> 00:00:17,650
Now in real life, we can't really
change the character of a PezDispenser

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after it's been created, can we?

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00:00:19,420 --> 00:00:20,890
Yet, as we saw,

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you can do exactly that with the newly
created object we just made.

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00:00:24,640 --> 00:00:27,870
We never want people to misuse the object
that we allowed them to create.

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00:00:27,870 --> 00:00:30,570
But it's kind of only us to blame, right?

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00:00:30,570 --> 00:00:32,580
We allowed that to happen.

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00:00:32,580 --> 00:00:36,390
We should make it as clear as
possible to consumers of our class,

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how we intend them to use it.

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00:00:38,870 --> 00:00:40,780
Now when I say consumers,

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I mean the developers who
are going to be using your code.

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00:00:44,290 --> 00:00:46,570
This might seem like a strange concept,
but

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it's one that I think is super
important to grasp early on.

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Are you ready?

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Other people are going to use your code,
they are.

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They need to be able to look at your work
when you aren't there to explain it, and

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they will need to be able to understand
how you were intending it to work.

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00:01:02,860 --> 00:01:05,510
And of course,
sometimes that person is you.

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Sometimes you forget what
you were trying to convey.

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00:01:08,630 --> 00:01:11,010
It always behooves you
to be more explicit, and

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Java is very good at letting
you express yourself.

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It's part of this verbosity that makes
things challenging in the beginning but

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shines bright once you grasp the concepts.

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00:01:20,920 --> 00:01:24,270
So in order to communicate how you
intend people to use your objects,

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you can add some additional
qualifications to your statements.

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In Java these are referred to
as access level modifiers.

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There are keywords that you can
add your field definition to

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00:01:34,740 --> 00:01:38,350
further specify who is intended
to access the information.

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00:01:38,350 --> 00:01:41,510
A table similar to this is
found in the Java SE tutorial,

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I've linked to in the teacher's notes.

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00:01:43,690 --> 00:01:47,070
So our current field isn't using
any of these modifiers, public,

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protected or private.

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So it falls under this row
here that says no modifier.

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00:01:51,500 --> 00:01:55,990
Now we haven't gotten to packages just yet
but you can think of that for now as

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files in the same folder or directory,
which is exactly what we're seeing.

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00:01:59,320 --> 00:02:02,260
In fact, why don't we remove
what we haven't covered yet?

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Now our code in the example file
was able to access the field,

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because it's in the same folder or
package as the PezDispenser class.

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00:02:10,180 --> 00:02:11,310
So let's fix that.

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00:02:11,310 --> 00:02:15,490
In order to ensure that code in the same
folder cannot access our field,

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00:02:15,490 --> 00:02:17,250
which of these should we use?

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00:02:17,250 --> 00:02:19,520
That's right,
we should mark our field as private.

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00:02:19,520 --> 00:02:20,510
Let's do it.

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00:02:20,510 --> 00:02:24,350
Okay, so it's pretty straightforward to
mark a field as private, all you need to

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00:02:24,350 --> 00:02:29,960
do is put the access level modifier
before the type declaration, right?

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00:02:29,960 --> 00:02:34,754
So it's String type declaration here,
so I wanna put private and that's it.

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00:02:34,754 --> 00:02:38,689
Now let's try and rerun our code,
and remember here's our code here.

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So, we're gonna say a clear and

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00:02:43,702 --> 00:02:50,023
javac Example.java and java Example.

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00:02:51,802 --> 00:02:54,880
And bam, our code doesn't even compile.

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Do you see how explicit that is?

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The code doesn't even
work if you misuse it.

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00:02:59,170 --> 00:03:00,730
Now that's pretty powerful, right?

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00:03:00,730 --> 00:03:03,000
So here what this first error is saying,

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00:03:03,000 --> 00:03:08,370
is it's saying it has private access
in the PezDispenser so it can't set it.

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00:03:08,370 --> 00:03:10,460
But, wait a second,
there's a second error here.

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00:03:10,460 --> 00:03:12,860
It's not even accessing the value at all.

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00:03:12,860 --> 00:03:14,395
We can't even get the value.

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00:03:14,395 --> 00:03:16,930
[LAUGH] That's some pretty
good protection, right?

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00:03:16,930 --> 00:03:20,330
So we've completely hidden the part of
our state to anything at all except for

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the class itself over here.

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00:03:21,870 --> 00:03:25,580
This is the only bit
where this is accessible.

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Nobody else knows about this,
not even instances of that class.

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00:03:30,790 --> 00:03:34,800
Now this kind of hiding is used for
very deliberate purposes.

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This is called encapsulation and

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will delve deeper into this
concept as the course progresses.

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00:03:39,540 --> 00:03:42,320
But for now,
how do I get access to that value?

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I'd love to be able to at least
show the current character.

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00:03:45,710 --> 00:03:49,420
Well, the most common way
to expose a value but

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00:03:49,420 --> 00:03:52,750
not let someone set it
is by adding a method.

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00:03:52,750 --> 00:03:54,460
So we best learn how to add methods.

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Let's do that next.