- Access Modifiers 6:04
- Access 3 questions
- Associative Arrays 7:36
- Cleaning Up the Class 2:58
- Accessing Arrays 5 objectives
- Adding Getters and Setters 8:32
- Ready Get Set Go 5 questions
- Static Methods 4:52
- Recipe Details 3:16
- Separating Methods 2:43
- Static 4 objectives
- Magic Methods 5:05
- Magic Constants 6:14
- All About the Magic 5 questions
- Populating the Recipes 3:15
- Controlling the Class 3 objectives
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Access Modifiers
6:04While the public access modifier allows a code from outside OR inside the class to access the class’s methods and properties, the private modifier prevents access to a class’s methods or properties from any code that is outside the class. In this video we’ll talk about why that can be useful.
[SOUND] Great work so far.
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You've defined your first class
with properties and methods, and
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instantiated multiple objects
from that single class.
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Currently, all the properties and
methods are public
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which means that any object can access
those properties and methods directly.
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While this does work,
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it doesn't give us any control over
how the data is stored or retrieved.
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Often, we may want to sanitize or format
the data before it's stored in the object.
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This is along the same lines
as the principle we explored
0:35
when we filtered input and escaped output.
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Take, for example,
the title of our recipe.
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We probably want every title to
be formatted using title case.
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But if we're setting the title directly,
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we're at the mercy of whatever
data is passed to our property.
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This data could contain anything,
especially if we're accepting user input.
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So instead of setting the property
directly, we create another method called
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a setter, whose job it is to format the
incoming data before setting the property.
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Let's take a look at this in work spaces.
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Back in our recipe file,
we create a new public method.
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We'll name this setTitle.
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The common practice is to name this
with set and then the property name.
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This makes it easy to know
what this method is doing.
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We need to be able to accept
an argument containing the title.
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So let's name that ($title).
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Then we can use $this->title =$title.
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The keyword, this, before the title,
gives us access to the object's property.
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And title, without the keyword,
this, gives us the passed argument.
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So this line sets the value
of the title property
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to the value that was
passed as an argument.
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This is exactly the same as if we
had accessed the title directly.
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But now we can do something with the title
before actually setting the value.
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We're going to use the function, ucwords.
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This stands for uppercase words.
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This is not a comprehensive solution, but
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it does demonstrate how
we could use a setter.
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Check the teacher's notes for
more robust behaviors.
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So, now we can call the setTitle and
pass in a lower case title.
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Our method should uppercase
the first letter of each word.
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Let's give this a try.
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Go to View > Show Console.
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In our Console we're going to
type php classes/recipes.php.
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Great, we see My First Recipe
by Grandma Holligan.
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However, we could still access the title
directly and set it to lowercase.
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We'll see this with my second title.
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Now if we run the script again,
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we see that the second recipe
title is all lowercase.
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We don't want to be able to
access the property directly, so
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we need to change the access
modifier from public to private.
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Now we can run our script again.
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And this time it tells us that it
cannot access private property, title.
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Let's change this one to setTitle as well.
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Great, now we can set our title, and it
will follow the formatting that we set up.
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However, setting our property to private
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also means that we can't read
this title directly, either.
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Right now we're calling
the display recipe.
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Let's try echoing out our title.
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We need to set up another method,
called a getter.
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Getters and setters work together
to access private properties.
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Let's add a new public method.
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We'll name this getTitle.
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Just like with setters, the common
practice is to name the method with get,
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and then the property name.
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Also just like setters, I could run any
code I want when I call the getter method.
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There isn't any additional formatting
that I want to do to this property, so
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I can just return $this->title.
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Now let's call our getTitle instead.
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Great, now we see My First Recipe,
My First Recipe,
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because it's calling the title and
then displaying the recipe.
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We can use getters and setters to
perform any complex formatting or
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calculations before saving or
returning a parameter.
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We could update a database or
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alert someone that a new
recipe has been created.
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We could even use this to keep
someone from changing a property
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after it's been initially set.
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Methods also have access modifiers.
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So you can create private methods that
can only be used by other methods within
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the class, but cannot be accessed
directly from outside the class.
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In the next video,
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we'll demonstrate a more complicated
setter using an associative array.
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Make sure you check the teacher's
notes for more information.
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