The Surface Is Fine and Powdery

We've finished up our foundation object, but 0:00 rather than move right on to our tableau object, let's see how we can stop 0:02 typing out the entire string every time we want to refer to a suit. 0:06 To do this, we'll create a string property for each suit and 0:10 then use this property in both our deck and game model classes. 0:14 And since the suit is a property of the card, let's declare these new properties, 0:18 and our card class. 0:23 In Java, we would do this by using a static variable. 0:24 But in Collin there's no static anything. 0:28 Instead, Collin has companion objects. 0:31 Check it out. 0:35 Let's first add back in the brackets for our class. 0:36 Then inside the brackets, 0:40 let's declare a companion object by typing, companion object. 0:42 And then, adding brackets. 0:47 Each class can only have one companion object and 0:50 the companion object is basically just a place where we put 0:54 anything that would have been static in Java so, 0:57 inside this companion object is where will be creating the properties for our suits. 1:00 Let's start with the clubs property, 1:05 val clubs = Clubs then we'll do the diamonds property. 1:08 = Diamonds. 1:14 And the hearts property. 1:17 And finally, the spades property. 1:22 Now that we have our properties, 1:27 we can use them to replace the string literals in our game model and our deck. 1:29 Let's head over to our game model class and 1:33 replace these string literals with the properties we just created. 1:35 Card.clubs instead of diamonds. 1:43 It will be Card.diamonds. 1:48 Card.hearts and Card.spades. 1:55 And let's do the same thing for a Deck class. 2:03 So instead of Clubs, We'll use Card.clubs. 2:06 And Card.diamonds. 2:15 Card.hearts. 2:21 And Card.spades. 2:23 Nice. 2:26 It's looking pretty good, right? 2:27 But there is one thing I don't like about it, and 2:29 that's all these little card dot parts. 2:31 This project, and cards in general, are only ever going to have one clubs object. 2:35 Wouldn't it be nice if we could omit the class it belongs to? 2:42 Maybe, but we can't do that to access a property and 2:45 a companion object you need to start with the class it's in. 2:49 So instead let's head over to the card class and 2:53 see one small step we can take to make it better. 2:57 Let's start by cutting out all of our properties from the companion object. 3:00 And then, deleting the companion object. 3:06 Next, I want you to take a deep breath and 3:09 prepare to go where no Java developer has gone before. 3:12 Into a world outside of classes, where functions and 3:17 properties can exist without the shackles of a class. 3:21 Let us boldly go beyond the bounds of our card class, 3:25 as we please back in our problem not the citizens of the current class but 3:30 as citizens of our entire apps package. 3:36 Now, let's jump back to our deck class and 3:40 get rid of those card dots once and for all. 3:42 And let's do the same thing for our game model class. 3:49 And cotland whenever we declare a property or 3:57 a function outside of the class, it gets scoped to the entire package. 4:00 Meaning we can just use it from anywhere within that package. 4:06 It also means that there's nothing special about this card class, 4:09 we could declare these properties in the App class instead. 4:13 And that would be just fine. 4:17 And look, the main function's not part of a class either. 4:19 That said, it does make more sense to store these properties in the Card File. 4:23 But before we add them back, notice the icon next to our card class. 4:28 It's the class icon. 4:33 Now, let's cut, and paste our properties back into our card class. 4:35 And look at that! 4:43 The icon changed to the file icon. 4:44 Since card.kt contains more than just the card class 4:47 IntelliJ decides to show us the file icon, instead of the class icon. 4:53 It's not a big deal, but at least now you know why it's happening. 4:57 Being able to declare properties and 5:01 functions with package level scope is a huge boon to our development. 5:03 It lets us write less code and opens entirely new doors for 5:08 how we can structure our projects. 5:11 It might take a little getting used to but trust me it's well worth it. 5:13 In the next video, we'll pick up where we left off with creating an object 5:18 to represent a tableau pile. 5:21