Optionals are misunderstood

[MUSIC] 0:00 Okay, so let's imagine for a second that we got hired to work at a Pot Pots, 0:04 a local mini golf place in our town. 0:09 Now, they have an app that's used to track games. 0:11 So a couple things you need to know is a party is a group of people, right. 0:14 So they're the people who come in and do the mini golf thing. 0:17 And the way things used to work, the analog way was we would give them a sheet. 0:20 And then these tiny little pencils actually and 0:24 the name of the package is tiny pencil, that's what this is based on, right. 0:26 So each of these players has the sheet and they keep their score and 0:29 they turn him in and we used to run them through this big dashboard thing. 0:32 And well, here let me just show you, let me show you the dashboard. 0:35 So they hand on their sheets at the end and we would calculate some stuff for 0:37 them, right. 0:41 So you can see here that there are some optional here. 0:42 This is kind of weird looking that we're kind in the middle of things right now. 0:46 And what's really nice about Pop Pots in my opinion is we 0:50 have the hardest windmill in town. 0:55 So people like to come and they challenge each other at that. 0:57 So we've said that each one of these holes that you go to attempt 1:01 should really only take you six. 1:04 And we don't want to make people feel bad because sometimes it takes like 25 1:05 times to go and get this through. 1:08 So we set things at six, so 1:10 but people like the company like to challenge themselves. 1:11 So they wanna keep track of their actual score and then we also adjust it for them. 1:13 So you'll see here that that's what the scores are, right. 1:18 So Dave, his actual score was 61 but if we adjusted it to 60. 1:20 So that's the sort of thing where he went over a little bit. 1:24 We recently just upgraded to Java 8. 1:26 We were in Java 5. 1:29 So we've got huge leaps, right? 1:31 Now the code base is half the size that it used to be and it's so much more legible. 1:33 Now, this dashboard here. 1:38 It used to just be done at the end of the game, when the party was all over. 1:39 But what we're hoping to do is get this so that it can be on people's phones. 1:44 And so that you'll know as you're going if you're winning or not. 1:47 That's where we're headed. 1:50 Now our original developer, his name's Arnold, he's still here. 1:52 He likes the new code but he is not happy about optionals. 1:55 It's making this transition super hard. 2:00 Actually let's go ahead, 2:02 I just heard him yelling from his cube about why does Welder say optional. 2:03 So let's take a look at what's going on in the dashboard and 2:08 see if we can't get him to calm down a little bit. 2:11 So I'm going to go here and I'm going to navigate to this dashboard code. 2:14 And you can always find Arnold's comments because they're in all uppercases. 2:18 And typically have a bunch of trailing exclamation points, 2:23 saying that he was yelling. 2:27 He's angry and rightfully so, this is kind of these options are kind of a little 2:29 weird to play with at first and people give him a bad rap. 2:33 I think a lot of times they don't understand what can happen. 2:36 So let's let's help him out here. 2:39 And I would help him out for two reasons. 2:41 One, because in order to finish this project, 2:42 we're really going to need to get Arnold on board. 2:44 Not only because we don't want these screaming comments on our code. 2:46 But we just wanted to understand how these optional should be working. 2:50 Because they're a little bit different than the imperative way of thinking. 2:53 So remember in our output, it showed it wrapped in an optional. 2:56 So we know this is returning an optional, so let's go ahead and 3:00 let's take a look at it. 3:02 So let's navigate into this getAdjustedWinner, okay. 3:04 So it's saying getAdjustedWinner but it's returning one of these sheets. 3:08 And these sheets where the score that's there, 3:11 so let's go ahead, let's see first where these are being used. 3:13 This is kind of the trick to understand, 3:17 let's see where does this getAdjustedWinner is being use? 3:19 It's just here, this is the only place that it is. 3:22 So really what we want here is, we want the winners name, 3:23 we don't want to print out the optional even at all. 3:26 So okay, so it is coming in and 3:29 saying if the remaining hole count is less than the par. 3:31 So if they played at all, then you could find the winner, the current winner, 3:33 so that's cool. 3:36 So we really should just be returning the name, right. 3:37 Actually that's interesting. 3:41 What happens if somebody hasn't played? 3:42 Let's take a look back at our app. 3:43 Let's turn this helpers off. 3:45 Let's go ahead and run this. 3:47 And let's see what happens. 3:48 What is said, who? 3:50 The winner is optional empty. 3:51 We don't wanna say that, right. 3:53 So let's go back to our party here and 3:55 we want this to be the name, right. 4:00 So if it exists, we want it to be the name. 4:03 So optionals have a method on them. 4:07 I'm going to chain and remember that this is not optional here. 4:09 This isn't the stream. 4:11 So minimum is going to return an optional and an optional has the ability 4:12 to say map and let's see, what do we want here. 4:19 We really just want to return the name, right? 4:24 So she has a name, the players names. 4:27 So we have get name. 4:29 So we'll do that and then you'll notice that it's saying, wait, you can't do that. 4:31 And it says that this is a little confusing for us, so 4:34 it's bad return type methods cannot convert Java string to you. 4:37 And so what that's talking about is because it's an optional sheet. 4:41 We want this to be a string, but we're still gonna have that problem, right. 4:44 So because the optional needs to do that, but there's a nice function of this. 4:50 So what happens if it didn't find that, right. 4:54 What happens when it's optional empty, that's what we need to tell it. 4:56 So, they have this great feature called orElse. 4:58 Now that seems a little threatening, right? 5:01 It's like give me that value or else! 5:03 So, we'll say what do we want to see? 5:06 We want to see, no winner currently, right? 5:09 When there's nothing and there's nobody there. 5:11 So what's going to happen there is the optional is going to return the name or 5:13 if it's not there, it will return No winner currently. 5:18 Now we've made it return a string and 5:20 we know the only usage of this is in the dashboard. 5:23 So it's right here. 5:26 So I think we just did this. 5:27 We're gonna make Arnold happy. 5:28 Let's do this. 5:30 Let's run that, let's see what we got. 5:32 So no one are currently broke because I have not commented out. 5:33 Let's bring our helpers back and if I start it up, here we go. 5:36 So the winner was Dave, each time this is random. 5:42 Okay so let's come back into our party here and let's see. 5:45 See if there's another option, there is. 5:49 So we got to remember that if we change one of these, right, 5:51 we've got it we kind of got to change them both. 5:54 So again, this will be good practice. 5:56 And just in case, Arnold goes to use this. 5:59 You can see that it's not used yet, it's never used, but 6:01 I'm going to fix this just in case, right. 6:04 Maybe he's planning on using it, so 6:06 I don't want him to fall into the same problem, so we'll say map. 6:08 And again, we want to get the sheet and 6:11 we use the method reference here to get the name of the sheet. 6:14 And again, if it doesn't exist, 6:17 we want to know winner yet there we go, perfect. 6:22 Speaking of angry look at this one, this is a common problem. 6:28 Let's take a look at this in the next video. 6:33