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You have completed Consumer Functional Interface!
You have completed Consumer Functional Interface!
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Consumers can save the day and help with the execute around method.
The code to this project can be found on GitHub.
Changes are made to the live branch.
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So ideally what would be beautiful
would be if we could get one of these
0:00
connections and this is the code that we
want them to use to express themselves.
0:04
We don't want them to worry
about how to get the connection.
0:09
So we can do a trick called
the execute around method.
0:12
Now this has been around for a while, but
0:17
functional interfaces really
help drive this home.
0:18
Okay so.
0:22
Let's take the dance and
put it someplace else.
0:23
Someplace that can be shared.
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So let's do that.
0:28
So let's go ahead I'm
gonna copy this code.
0:28
And I'm going to go into the legacy
database file and let's just go ahead.
0:32
Let's make a new static method here,
so we'll make a public static.
0:36
It's not gonna return anything.
0:41
And let's say with connection.
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And what we'll do is we will have
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a consumer of type connection.
0:52
And we'll call that action.
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And it is in that package.
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So now basically what we want to do,
I'm just going to paste this here.
1:03
Well, we'll go ahead and import that,
1:07
even though I'm going to
get rid of it really quick.
1:08
I'm gonna take away what it is
that we want them to do here.
1:10
And I want to say action.except, right?
1:13
So that the functional
interface has an accept method.
1:15
And we've said that it can
only accept the connections,
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so we're going to pass
on the connection here.
1:21
So that's it.
1:23
Now believe it or not, so what happens
is we're gonna pass on this action and
1:25
it's gonna be connection.
1:28
Now because it's a functional interface,
we can replace that with a lambda.
1:28
So let's go ahead,
let's use it, what you say?
1:32
So we'll come up here.
1:34
I'm gonna get rid of this stuff here.
1:37
Leave what we had there.
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And we'll say LegacyDatabase and
then we have this .withConnection.
1:41
And it is looking for a lambda, so
we're gonna say a connection and
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then I'm gonna open this up, I'm gonna
grab these guys here, I move this up.
1:52
All right, now we've got a bit of
a problem as you can see there's
1:57
an unhandled exception now.
2:01
This happens quite a bit
when you use lambdas.
2:02
So let's fix this with the way
that IntelliJ suggests for us.
2:05
So we'll surround it with a try and catch.
2:09
[SOUND] That's pretty gross,
but let's go ahead and
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make sure that we are working as expected.
2:15
So I'm gonna run this again.
2:17
Look at that, it's still working.
2:20
It's still doing the new in the called,
but look, it's cleaner, but
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it's kind of gross, right?
2:25
It's kind of gross that
we have this try in here.
2:26
So let's not add new dances, so
2:29
we can actually make our
own functional interface.
2:32
And let's do that right after this.
2:35
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