Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated: 1 1 00:00:01,407 --> 00:00:02,327 In this video 2 2 00:00:02,327 --> 00:00:05,577 we're gonna cover inversion of control. 3 3 00:00:07,958 --> 00:00:10,752 So, inversion of control's the buzzword that you always hear 4 4 00:00:10,752 --> 00:00:12,717 when you hear of the Spring framework. 5 5 00:00:12,717 --> 00:00:15,521 So, what exactly is inversion of control? 6 6 00:00:15,521 --> 00:00:17,758 Well, it's simply the design process 7 7 00:00:17,758 --> 00:00:21,197 of externalizing, the construction and management 8 8 00:00:21,197 --> 00:00:22,428 of your objects. 9 9 00:00:22,428 --> 00:00:24,743 So, in a nutshell it basically says 10 10 00:00:24,743 --> 00:00:28,106 that your application's gonna outsource the creation 11 11 00:00:28,106 --> 00:00:30,164 and management of the objects, 12 12 00:00:30,164 --> 00:00:33,798 and that outsourcing will be handled by a object factory, 13 13 00:00:33,798 --> 00:00:36,459 and that's the big idea of inversion of control. 14 14 00:00:36,459 --> 00:00:39,083 Now, to kind of help you out with getting a idea 15 15 00:00:39,083 --> 00:00:40,432 of inversion of control, 16 16 00:00:40,432 --> 00:00:43,062 I'll actually walk through some coding examples 17 17 00:00:43,062 --> 00:00:44,491 and I will kind of start from scratch 18 18 00:00:44,491 --> 00:00:46,515 with a very rough prototype 19 19 00:00:46,515 --> 00:00:48,675 and we'll try and refine it 20 20 00:00:48,675 --> 00:00:51,303 and refactor it over time 21 21 00:00:51,303 --> 00:00:53,204 just so you can kinda see the real motivation 22 22 00:00:53,204 --> 00:00:55,016 for inversion of control 23 23 00:00:55,016 --> 00:00:58,933 and you know, why we need the Spring framework. 24 24 00:00:59,866 --> 00:01:01,001 Alright, so let's go ahead and start 25 25 00:01:01,001 --> 00:01:02,371 with this little coding scenario. 26 26 00:01:02,371 --> 00:01:04,052 So, real simple example. 27 27 00:01:04,052 --> 00:01:05,583 We're gonna have our app 28 28 00:01:05,583 --> 00:01:08,744 that will make use of a coach like a baseball coach 29 29 00:01:08,744 --> 00:01:11,412 and so our app will say hey, baseball coach, 30 30 00:01:11,412 --> 00:01:13,256 give me a daily workout, 31 31 00:01:13,256 --> 00:01:15,212 just so you find out what type of workout 32 32 00:01:15,212 --> 00:01:17,401 you need to perform at practice. 33 33 00:01:17,401 --> 00:01:20,433 So, that's the big idea of this application. 34 34 00:01:20,433 --> 00:01:24,109 Now, one thing though is that the management teams says 35 35 00:01:24,109 --> 00:01:25,776 oh yeah, by the way, 36 36 00:01:26,929 --> 00:01:28,957 the app should be configurable, 37 37 00:01:28,957 --> 00:01:32,418 so this app should easily work for a coach 38 38 00:01:32,418 --> 00:01:33,924 in another sport, 39 39 00:01:33,924 --> 00:01:36,040 so you should easily be able to plug in 40 40 00:01:36,040 --> 00:01:40,071 a hockey coach, cricket coach, tennis, gymnastics, so on. 41 41 00:01:40,071 --> 00:01:41,730 So, they want it to be configurable 42 42 00:01:41,730 --> 00:01:44,934 and also work with any type of coach. 43 43 00:01:44,934 --> 00:01:46,606 So, now you're like oh, 44 44 00:01:46,606 --> 00:01:47,622 I thought the project was easy, 45 45 00:01:47,622 --> 00:01:50,161 now it got a little bit difficult but don't worry, 46 46 00:01:50,161 --> 00:01:51,392 we'll kind of walk through this 47 47 00:01:51,392 --> 00:01:53,678 and we'll look at some possible solutions for this 48 48 00:01:53,678 --> 00:01:57,807 and we'll kinda build out a little rough prototype. 49 49 00:01:57,807 --> 00:02:01,057 So, this rough prototype will have four key players. 50 50 00:02:01,057 --> 00:02:03,648 I'll first set off with MyApp.java. 51 51 00:02:03,648 --> 00:02:06,176 It's simply the main program and it has a main method. 52 52 00:02:06,176 --> 00:02:07,770 We'll use BaseballCoach.java. 53 53 00:02:07,770 --> 00:02:09,975 It will be a simple implementation. 54 54 00:02:09,975 --> 00:02:11,790 Then kind of in the version two, 55 55 00:02:11,790 --> 00:02:13,201 once we kind of refactor it, 56 56 00:02:13,201 --> 00:02:16,417 we'll introduce an interface called coach.java, 57 57 00:02:16,417 --> 00:02:19,371 and then we'll also show another implementation 58 58 00:02:19,371 --> 00:02:21,239 called TrackCoach.java. 59 59 00:02:21,239 --> 00:02:22,473 Just the whole idea of switching in 60 60 00:02:22,473 --> 00:02:24,805 a different coach and seeing if our application 61 61 00:02:24,805 --> 00:02:26,260 continues to work. 62 62 00:02:26,260 --> 00:02:27,380 So, those are the main players, 63 63 00:02:27,380 --> 00:02:28,501 that's the big idea. 64 64 00:02:28,501 --> 00:02:30,512 Let's go ahead and move into the next video 65 65 00:02:30,512 --> 00:02:32,381 and let's get our hands dirty 66 66 00:02:32,381 --> 00:02:35,298 and let's start writing some code. 5526