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So design patterns seem pretty great,
right?

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Well, I got some bad news for you.

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Design patterns are not a magic bullet.

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They aren't going to solve
all of your coding issues.

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In fact, you shouldn't ever really start
with a pattern you should reach for

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them only when you need them
never before you start coding.

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Most languages these days have some sort
of package manager that allows you to use

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packaged up code.

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Now whether those packages are called
modules, libraries, pods, Gems, JARs,

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NuGet whatever.

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They represent code that is available for
you to use so

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that you don't need to recreate the wheel
Design patterns are a lot like this.

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Except instead of viewing
them as code reuse

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you should view them more
like experience reuse.

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People have been there and
they've done that, so

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you should lean on their experience.

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Again, for clarity's sake,

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don't go grabbing from the experience
repository right out of the gate.

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Always go for
the simplest solution first and

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introduce the pattern only
when the need arises.

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The great acronym that we should all
live by goes well with this, K-I-S-S.

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Kiss, Keep It Simple Smarty pants,
or something more rude than that.

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So then you ask, should I even bother
learning about them if I can't use them?

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And that's a great question,
and I'm glad you asked.

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The simple answer is this,
you need to be familiar with them.

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There are two major reasons I want you
to get familiar with design patterns.

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Well, look at both of
them in more depth here.

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So the most amazing benefit of design
patterns is that they create a shared

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vocabulary.

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Since these patterns are named
they can be used to communicate

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a very specific solution
in just a few words.

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Now there's a huge difference
between these two examples.

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You should just kind of make
the first class behave like

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the other one by making the methods
in here the same as the other one, so

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that the caller thinks that it's
actually doing its thing but

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really is calling specific
methods on the original object.

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And you should use the adapter pattern.

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That first statement is pretty much
exactly what the adapter pattern does.

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The adapter pattern is a lot like
one of these power adapters here,

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that you would use when
you're traveling the world.

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There are many different
types of electrical outlets.

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And this hair dryer that you brought for

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home, might not plug into
the outlet in the other country.

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A power adapter lets you connect
your hair dryer to the outlet.

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You plug the hair dryer into
one side of the adapter and

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the other side of the adapter
fits into the outlet.

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This is your adapter.

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The port in the wall is what
you're trying to adhere to,

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and this is your original class.

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By applying the adapter,
they work together.

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Now, this is the level of
familiarity that i suggest

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that you need when
understanding design patterns.

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You don't need to know how exactly to code
up the adapter in your specific language

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because you've got your catalog of
patterns to draw that experience from.

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Now take a quick second with me here and
try to feel the difference

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between these two approaches and the power
that the shared vocabulary word brings.

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Okay, so I have this device and it has
this plug that doesn't fit into the other

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outlet right, so the side has like
a three standard prongs right and

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the other one has like a two broad
thing sort of scene going on right?

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So, what I need is like a thing-a-ma-jig
kind of one like, one side has it works

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with that and then When I go on the other
side needs a thing like that two thing.

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I think that's all right?

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Something else?

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Okay, thanks bye.

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And I need a power adapter.

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It's a different world right?

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That direct kind of communication
is what your team wants and

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it's definitely something that hiring
managers look for when building a team.

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This is why questions about
design patterns are often part

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of the interview process.

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It's not because interviewers
are trying to stump you.

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They're trying to make sure that you can
understand the shared vocabulary, and

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communicate with your
new potential teammates.

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Check the teacher's notes for
more on this.

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Now the second, equally important, reason
that you should get familiar with design

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patterns is because you
are already surrounded by them and

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you probably don't even realize it.

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You can hardly refresh your
browser these days without

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landing on a new web framework.

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Most of these frameworks organize their
code using something known as MVC, or

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model view controller.

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MVC is called a complex pattern because
it combines several design patterns.

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The controller follows
the mediator pattern.

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The view usually performs
the composite pattern.

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And the model employs the observer pattern
to control communications with the view.

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Like I said,
you're surrounded by these patterns.

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The reason why frameworks
are heavy users of patterns

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is because their authors want you to
integrate your code by extending theirs.

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Writing extensible code like that
makes the architecting of a framework

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quite the difficult task and patterns
are definitely used to lighten the load.

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Patterns allow framework authors
to structure their code in a way

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that is predictable and

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understandable by developers looking
to integrate their framework.

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Without requiring their users, and

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that's us,
to edit the source code of the framework.

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In fact, most software libraries use
design patterns for the same reasons.

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The author's intent you to extend
their code and use the library for

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your specific application while not
needing to modify their library directly.

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So most likely just about any one
of those gyms jars new gets or

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pods that you use include one or
more design patterns.

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And that makes sense, right?

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It's a known solution to make
the code more extensible.

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Why reinvent the wheel?

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Recognizing the patterns at play
will help you better grok or

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understand what the code is attempting
to do from a bird's eye view.

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If you're going to contribute
to open source software,

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which I highly recommend that you do
You'll be able to jump right in and

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start coding if you're able to
recognize the patterns being used.

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Here's a tip to help you recognize
design patterns in other people's code.

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The patterns name is usually added
to the name of the class method or

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function that uses the pattern.

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For instance, string builder,
event facade, and message mediator.

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Now you can bet that the result of
the conversation that I just had with my

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imaginary team members result in
a class that had adapter in its name.

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Okay, so now that you know why you should
familiarize yourself with these patterns,

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why don't we take a look at one
pattern in a little more detail.

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At the same time you'll learn
the general make up of a pattern.