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Using Multiple Classes
3:13When using multiple classes, there are several functions in PHP that will allow us to learn about those classes.
In the last video, we saw that we could
easily swap out our new child class,
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where we use the parent.
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Let's take a closer look at the result.
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Open index.php.
We'll start by adding a var_dump of
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the listings within the foreach loop.
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Let's preview this in the browser.
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Lets view the page source,
and increase the font size.
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This shows us that the object itself
is a listing premium object, but
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its variables are taken from
the listing basics class.
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Let's take a look at a couple more
functions that will tell us about
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our class.
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Var_dump get_class,
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This will give us the name
of the object's class.
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We can also check if this
object is of a certain type.
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We'll do a var_dump is_a,
pass the listing,
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And then the class we wish to compare,
ListingBasic.
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Let's preview this again.
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Now we see that it tells us that
our class is a listing premium, but
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our check with the is a function,
returns true.
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That's because listing premium is a child,
and therefore a type of
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ListingBasic, and
can be used wherever ListingBasic is used.
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We could also see in
the status of these listings,
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that some of them are premium,
And some of them are basic.
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Let's go back to our collection class and
use ListingBasic for
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our basic listings, and
ListingPremium for our premium listings.
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In the addListing method,
we need to check the status.
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If isset status,
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And that same status,
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Is equal to premium,
then we're going to use ListingPremium.
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If not, else,
we're going to use listingBasic.
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Let's check this out in
the browser once more.
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Now the listings that have a status of
basic, are of a ListingBasic class.
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And those that have a status of premium,
are of a ListingPremium class.
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We're ready to actually extend our
child class in more than just name
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