Access Modifiers

[SOUND] Great work so far. 0:00 You've defined your first class with properties and methods, and 0:06 instantiated multiple objects from that single class. 0:09 Currently, all the properties and methods are public 0:13 which means that any object can access those properties and methods directly. 0:17 While this does work, 0:23 it doesn't give us any control over how the data is stored or retrieved. 0:24 Often, we may want to sanitize or format the data before it's stored in the object. 0:29 This is along the same lines as the principle we explored 0:35 when we filtered input and escaped output. 0:38 Take, for example, the title of our recipe. 0:42 We probably want every title to be formatted using title case. 0:44 But if we're setting the title directly, 0:49 we're at the mercy of whatever data is passed to our property. 0:51 This data could contain anything, especially if we're accepting user input. 0:55 So instead of setting the property directly, we create another method called 1:00 a setter, whose job it is to format the incoming data before setting the property. 1:05 Let's take a look at this in work spaces. 1:12 Back in our recipe file, we create a new public method. 1:15 We'll name this setTitle. 1:22 The common practice is to name this with set and then the property name. 1:25 This makes it easy to know what this method is doing. 1:30 We need to be able to accept an argument containing the title. 1:33 So let's name that ($title). 1:37 Then we can use this $title =$title. 1:39 The keyword, this, before the title, gives us access to the object's property. 1:45 And title, without the keyword, this, gives us the passed argument. 1:50 So this line sets the value of the title property 1:55 to the value that was passed as an argument. 1:58 This is exactly the same as if we had accessed the title directly. 2:01 But now we can do something with the title before actually setting the value. 2:04 We're going to use the function, ucwords. 2:09 This stands for uppercase words. 2:12 This is not a comprehensive solution, but 2:16 it does demonstrate how we could use a setter. 2:18 Check the teacher's notes for more robust behaviors. 2:21 So, now we can call the set title and pass in a lower case title. 2:25 Our method should uppercase the first letter of each word. 2:42 Let's give this a try. 2:45 Go to View > Show Console. 2:46 In our Console we're going to type php classes/recipes.php. 2:50 Great, we see My First Recipe by Grandma Holligan. 2:57 However, we could still access the title directly and set it to lowercase. 3:02 We'll see this with my second title. 3:08 Now if we run the script again, 3:16 we see that the second recipe title is all lowercase. 3:19 We don't want to be able to access the property directly, so 3:23 we need to change the access modifier from public to private. 3:26 Now we can run our script again. 3:35 And this time it tells us that it cannot access private property, title. 3:39 Let's change this one to setTitle as well. 3:44 Great, now we can set our title, and it will follow the formatting that we set up. 3:58 However, setting our property to private 4:05 also means that we can't read this title directly, either. 4:07 Right now we're calling the display recipe. 4:11 Let's try echoing out our title. 4:14 We need to set up another method, called a getter. 4:23 Getters and setters work together to access private properties. 4:27 Let's add a new public method. 4:31 We'll name this getTitle. 4:38 Just like with setters, the common practice is to name the method with get, 4:44 and then the property name. 4:47 Also just like setters, I could run any code I want when I call the getter method. 4:50 There isn't any additional formatting that I want to do to this property, so 4:55 I can just return $this->title. 4:59 Now let's call our getTitle instead. 5:06 Great, now we see My First Recipe, My First Recipe, 5:15 because it's calling the title and then displaying the recipe. 5:18 We can use getters and setters to perform any complex formatting or 5:22 calculations before saving or returning a parameter. 5:27 We could update a database or 5:31 alert someone that a new recipe has been created. 5:33 We could even use this to keep someone from changing a property 5:36 after it's been initially set. 5:40 Methods also have access modifiers. 5:42 So you can create private methods that can only be used by other methods within 5:45 the class, but cannot be accessed directly from outside the class. 5:50 In the next video, 5:55 we'll demonstrate a more complicated setter using an associative array. 5:56 Make sure you check the teacher's notes for more information. 6:01