JavaFX Java GUI Tutorial - 3 - Anonymous Inner Classes and Lambda Expressions Video Lecture | JavaFX Java GUI: Learn to build Powerful Applications - Front-End Programming

all righty hostage so in this video I'm
going to show you guys some alternative
ways of handling user events so the
first thing I actually want to do is
delete all the code that we wrote in the
last video which was this implements and
remember we got this handle from the
interface so we can delete that too
don't need it anymore and also this so
remember the code that we write in here
which was this is saying whenever an
event occurs on this fun look in this
class to handle the code so essentially
any code that's in here is the code to
handle this button click now instead of
just implementing it in writing some
method down here we can actually stick
all that right in these parameters and
this is called an anonymous inner class
and if we write new event handler
remember anytime a button click occurred
what we needed to do was we needed to
call this handle method and it was
inside the event handler interface so
this is just a little more compact
version of what we did in the last video
on pretty much everything is just right
here instead of spread out all over and
just to demonstrate this real quick it's
just thumb out print line I'll say it
like I am and Heddy spell anonymous oh
and a y ml US is that it all right so
I'm an anonymous inner class there you
go and if I run this in click hey baby
you can see that it pretty much does the
exact same thing now another reason that
I like this aside from just being a
little bit cleaner and not having your
code spread out all over the place
is whenever you use anonymous inner
classes you don't have to check the
event source remember I said in the last
tutorial if we had multiple buttons we
would need to add an if condition if
button if button two of fun three what
code or excuse me what object is
responsible for calling this hand
well now the functionality is tied
directly to that object so it takes care
of that problem however check this out
every time we want to print a simple
line of code whenever they cook a button
we need to call this interface and this
method and if we make another bun look
how clunky it'll look it's like twelve
different lines of code for just two
buttons kind of pain in the butt now the
fine ladies and gentlemen Oracle they
realize that this was a problem as well
so beginning with Java 8 what they did
is they introduced the syntax called
lambda expressions and I want to show
you guys how easy this is so get rid of
all this crap and instead of
implementing anything or using an
anonymous inner class type this syntax E
- greater then and then just have some
kind of called like system.out.print
line and this will print out some text
like hey now brown cow
now the reason that this is underlined
is because remember I said that this new
syntax to make everything more compact
called lambda expressions was introduced
in Java 8 now if I go to file and
where's that I believe it's in project
structure all right so the project
language Lula tongue twister project
language level is set to 6 right now I
want to go ahead and set that to 8 and
you can actually see lambdas type
annotations all that good stuff but if I
hit apply it goes away so that's pretty
much saying what version of Java are
using I want to use Java 8 there you go
all right so now let's break this up and
see what happened well let's first of
all let me show you guys that it works
so I'm going to click hey baby and it's
going to print out hey now brown cow
that is stinking awesome it's a lot
easier than writing any code here using
an
you know implementing anything and
writing that handle stuff all your
functionality is in one little line of
code now there's actually a lot to cover
regarding lambdas and this isn't a
lambda tutorial this is a Java FX
tutorial but essentially what's
happening is this since the event
handler interface only has one method
inside it remember that handle method we
can use this lambda because Java
automatically knows by the context of
our code and how it's written to treat
this as your event handler so e
represents the event this little thing
again is called the arrow operator so is
your parameter on the left hand side and
any code that you're running right in
your method body goes on the right hand
side now since we only have one line of
code we don't need those curly braces
just like a if statement if we had
multiple lines of code we can actually
here let me copy this we can actually
use curly braces and then write like a
now brown cow arm
I am a meatball these were the first few
things that popped in my head for some
reason so again one line of code can
just go on the same line if you have
multiple lines of code they can go on
multiple lines but look how clean this
is lambdas are freaking awesome so let
me run this and check it out hey baby
prints out your code that is amazing so
again a lot cleaner and I want to
reiterate one more time that there is a
lot to cover regarding lambda
expressions I'm probably going to make
an advance Java tutorial we're covering
lambda expressions and also these things
called streams which are another awesome
feature in Java 8 but for right now I
just want to show you guys this new
syntax because this is a syntax that I'm
likely going to be using from here on
out so again all the source code is on
github I think as we're watching don't
forget subscribe yeah oh yeah de tomates
model I'll see you next time