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[MUSIC]

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If you have a drivers license,
you've probably driven more than one car.

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You don't have to relearn to drive
every time you drive a new car,

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because each car uses the same interface.

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There's the way to accelerate break,
turn and shift gears.

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Each car may handle a little differently,
and

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you'll feel more comfortable with certain
vehicles, and it's the same way with code.

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If you're familiar with one logging system
and switch to another logging system with

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the same interface,
the transition should be fairly easy.

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Although you may feel more comfortable
working with the system that you find most

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familiar.

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Hi, I'm Alina and in this course, we're
going to look at an important concept,

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an object-oriented design
called interfaces.

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An interface is a type of contract

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that assures certain abilities are
available on a particular object class.

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Interfaces have continued
to gain popularity in PHP.

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As the use of package management through
composer has become the standard.

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By having standard interfaces, package
maintainers can more easily build and

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maintain packages for common tasks, such
as logging, caching, and HTTP messages.

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The PHP Framework Interop Group,
or PHP FIG for short,

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has also been a leader in
standardizing common interfaces.

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Check out the notes associated with
this video to learn more about composer,

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standards, and the fig.

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So how do interfaces fit
with class hierarchy?

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Lets talk tomatoes.

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Botanically speaking,
a fruit is a seed baring structure

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that develops from the ovary
of a flowering plant.

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Where as vegetables are all other plant
parts such as, roots, leaves, and stems.

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By those standards, tomatoes are a fruit.

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In culinary terms, however,
it's a different matter.

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When cooking, many foods,

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such as tomatoes,
which botanically speaking are fruits,

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are typically considered vegetables
because they are savory rather than sweet.

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If a tomato were a PHP class, it would
inherit it's properties from the fruit

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class, but it implements the savoryFlavor
interface of a vegetable.

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Allowing us to use these fruits in
recipes that require a savory flavor.

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In this course,
we'll explore interfaces and

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abstract classes by building a website
that displays different types of content.

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Using pages and blog posts, we'll
explore the use of interfaces through

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the creation of these
different types of content.

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We'll also pull that content
from different data sources.

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The project will combine interface
contracts with class hierarchy by creating

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an abstract class and demonstrate
how abstract classes can be used

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to enforce the contract of an interface
while building a class hierarchy.

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This course will explain
the differences between interfaces and

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abstract classes, and give you
the knowledge you need to build, and

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implement both in your own projects.