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Hi in this video we'll learn how
to implement classes in Scala.

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Like Java, Scala can have multiple
constructors which consist of primary and

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auxiliary constructors.

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Constructors in Scala may be a little
different from what you may be used to.

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Let's get a better idea on these
topics by implementing some examples.

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In Scala the primary constructor is
blended within the class definition

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whereas auxiliary constructors have
to be defined using the this keyword.

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Unlike Java you don't have to prepend
a public key word before defining a class

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as Scala classes have public
visibility by default.

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Let's create a new super hero
class within our project.

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We'll right click on source,
select new Scala class.

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If the parameters passed into
the class definition of vars,

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scala automatically turns them into
public fields with getters and

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setters which I initialize with
a new instance of the class.

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If you need a field with read only
properties, use a val similarly

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to Java if you want to make a field
private prepend the private key word.

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It is quite straightforward to
use these fields in our class,

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let's create a details method within our
class, which prints out the name and

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birthplace of our superhero.

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Great, let's create a new incidence of our
superhero class in our main object and

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check out the results.

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Awesome we created our first Calla Class.

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Let's continue to create additional
constructors for our class.

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We'll implement a constructor that
takes just the name of the super hero,

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and another constructor with name and
birth place.

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We define additional constructors
with the def and this keywords.

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Inside our constructor we make a call
to the primary constructor using this.

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And passing in the values for
the parameters of the primary constructor.

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Remember an auxillary constructor can
either call the primary constructor or

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a previously defined
auxillary constructor.

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Let's go back to our superheroes object,
and

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make calls to our newly created
auxiliary constructors.

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Great as we previously mentioned Scala
provides getters and setters for vars.

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We can rewrite these getters and
setters if we ever wish to.

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Let's take a look at how to do that.

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Within our superhero class we'll
create a new field called hero age.

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Then we'll rewrite the getter and
setter methods for heroAge.

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Our getter, which will return heroAge,
and our setter.

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We'll take a new integer variable which
we can use to update the hero's age.

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Great, we have rewritten the getter and
setter for age respectively.

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We would use these functions
on any superhero instance.

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Let's go back to our main class,
create a new instance of superhero and

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see how we can use our newly created
getters and setters for age.

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Well, first, set the Hulk's age to 30.

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And we'll use the getter of
method to return the Hulk's age.

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Awesome, we're able to get back the value
that we passed in for Hulk's age.

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Scala also has a notion of case classes.

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Case classes are typically
used with pattern matching and

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are very easy to use for matching and
storing the contents of a class.

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Let's create a case class for
power stats of our superheroes.

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Let's see how we can
use our case class for

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pattern matching
the contents of our class.

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Here we build the findHero function
which matches the contents of a class to

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a string of super hero names.

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To use the class, we would simply
call the findHero function,

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passing in the PowerStats for
the hero that we like to match.

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As expected the value
hero should contain thor.

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Awesome.