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Extending an Interface5:43 with Alena Holligan
Extending and combining interfaces, guarantees that all methods from all interfaces will be available in an implementing class.
I want to add another requirement to the collection. 0:00 The ability to return a short description. 0:03 Instead of implementing another interface I'm going to combine all of these 0:07 requirements into a single collection interface. 0:11 This will allow us to be certain that any class that implements a collection 0:14 interface will have all the iterator and countable methods, 0:19 as well as the new method we'll define. 0:23 Add a new file to the source interface's folder. 0:26 We'll name this CollectionInterface.php. 0:29 Interface CollectionInterface. 0:42 We'll define our new interface by adding the keyword extends. 0:47 To extend the Iterator and Countable interfaces. 0:54 Note that this is very similar to how classes can extend other classes. 1:04 However, we can extend more than one interface. 1:09 Now we can add our new method, public function shortDescription. 1:12 By extending the iterator and countable interfaces our CollectionInterface 1:22 will now include all of the methods defined in those interfaces. 1:27 This means that anyone implementing our CollectionInterface will also need to 1:32 implement the methods from the Iterator and Countable interfaces as well. 1:37 Back in our Collection class. 1:41 Let's change this to CollectionInterface. 1:44 Now we need to define the short description, 1:49 public function shortDescription. 1:55 We are going to use the current item details. 2:04 First, we're going to check if 2:08 the strlen($this->current()->details) 2:12 Is less than 510, then we're 2:19 going to return the current details. 2:23 But we're going to strip the tags. 2:28 This current- Details. 2:33 If we make it past the early return, 2:42 we're going to return our trimmed down version, 2:46 return, and again we'll start with strip_tags. 2:51 I'm going to add some line spacing to make this easier to read. 2:56 Substring this 3:00 current details. 3:04 We're going to start at our first character, which is 0. 3:10 And then find the string position In this current details. 3:14 And we're going to look for the first space after 500 characters. 3:25 The final touch is to add an ellipses or 3:36 triple dots at the end to identify that there's more to this description. 3:38 We'll just use dot, dot, dot. 3:43 We're finally ready to include our list view with the post which will give us 3:47 a sample of each post. 3:51 Let's add a new view. 3:53 In the views folder, new file list.php. 3:55 The first thing I'm going to do is check if the item status is equal to published. 4:04 Next we'll create an article block with a title. 4:16 We'll add the $item, title, and closer tag. 4:35 Finally we can use our short description. 4:42 Since the collection handles the short description and 4:45 not the item itself, we use content. 4:49 So echo $content->shortDescription. 4:52 Since we've stripped tags, 5:00 let's add a paragraph tag surrounding the short description. 5:01 Now we can add this to our index page. 5:15 In the for each loop, instead of just the title 5:19 we're going to include 'views/list.php. 5:24 Let's take a look at this in the browser. 5:30 It's starting to look like a blog. 5:33 Let's add the ability to read each of these posts in its entirety. 5:35
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