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Let's not create constant exporting classes the classes that exist only for defining constants.

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For example we have Jondrette fill in book and movie classes and it has a range of values in each of

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those domains.

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So instead of defining these values in databases we can also define them in a constant exploding class

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.

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Similarly range of values for gender field in use class cannot be defined using constant exporting class

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and we can do the same for user type feel within the user class.

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These classes will be useful when we have to check if the field has a particular value.

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For example if we want to check if a particular book belongs to a certain genre then the constant exporting

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class corresponding to this feature will be useful.

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We will see this when we later implement east kid friendly eligible method.

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So these classes are useful.

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And let's go ahead and create them.

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Let's first create a new package for constants

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.

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So it's semantics were really are constants.

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Let's create a constant exporting class called user type

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since it's going to expose only the constants.

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So there are no instance variables are there are no methods in this class.

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So it's just going to be static final peak of Feels so that it's compile time constants so we don't

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need to create an instance of this class so we can define a private constructor.

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Now let's define the constants

23

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since it's a compile time constant we need to use all caps.

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That's the convention we know that it's got it as user.

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Now let's simply copy this.

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So let's call the second one as student editor

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and Thirty-One chief editor.

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Okay so that's a user type class.

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Let's create one for gender

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in the private constructor

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and the gender field is here.

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So let's go ahead and create three constants

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.

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Initialize it with zero

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to two on

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transgender.

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Make it two.

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So that's the gender class.

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And we also need to do more for the genre for book genre and movie joinery and I'm just going to create

40

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them off line as darling dear and that's much better.

41

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It will say for some time.

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So let me just create it off line and I'll come back and show it to you.

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OK.

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Here's a book John reckless and these are all the constants that it has.

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And it's in the Constans package.

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And here is a movie class and it has a lot of constants as you can see here the different genres classics

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drama comedy and so on.

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I'm going to upload the book movie genre and book Journey to the resources section so you can just download

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them and that's it.

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So those are the four constant exporting classes that we have created.

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And that's a