WEBVTT 00:00.080 --> 00:00.620 Hi everyone. 00:00.620 --> 00:01.190 Welcome back. 00:01.190 --> 00:07.430 In this lecture we are going to learn about how to build a modular application using the Jpms. 00:07.430 --> 00:11.120 So for this specific section we'll be working on the modules project. 00:11.120 --> 00:17.120 So if you open the modules project it will have four different modules module one, module two, module 00:17.120 --> 00:18.470 three and module four. 00:18.470 --> 00:22.430 For this specific lecture we are going to be working on the module one. 00:22.520 --> 00:25.460 Expand this project and then you will have a source directory over here. 00:25.460 --> 00:30.230 And then in here you will have these different packages inside this module one. 00:30.230 --> 00:35.900 And then if you take a look at it this one has a Dtos which is module one DTO which is a very simple 00:35.900 --> 00:37.490 module record type. 00:37.490 --> 00:43.340 In this case the name of this one is module one DTO and it is of type record and it has only one property 00:43.370 --> 00:44.630 named name. 00:44.630 --> 00:49.820 And if you take a look at the HTTP package we have HTTP client class is really empty. 00:49.850 --> 00:52.190 It just have an instance of the client over here. 00:52.190 --> 00:54.230 And if you take a look at the secret package. 00:54.230 --> 00:59.660 So this is has a secret class and it returns a secret using the secret function. 00:59.660 --> 01:03.230 And then we have another package named module one service. 01:03.230 --> 01:06.950 So this one actually has a function named Retrieve Data. 01:06.950 --> 01:10.250 And then this is the one which returns a module one DTO. 01:10.250 --> 01:12.830 So this is all about this particular module. 01:12.830 --> 01:17.360 What we are going to do here is that we are going to make this specific project to be modular. 01:17.360 --> 01:21.650 So we are going to use the Jpms concepts and then make this project to be modular. 01:21.650 --> 01:26.930 So very first thing in order to make this project modular, what we need to do is we need to add a class 01:26.930 --> 01:29.570 named module Hyphen Info dot Java. 01:29.570 --> 01:31.700 So I'm going to right click on the Java folder. 01:31.700 --> 01:33.380 And then I'm going to create a file. 01:33.380 --> 01:36.380 So you need to have the option selected as file over here. 01:36.380 --> 01:42.860 And then we are going to mark this file name as module hyphen info dot Java okay. 01:42.890 --> 01:44.900 So this is the name that you need to provide. 01:44.900 --> 01:47.480 And you can see this is a regular Java file. 01:47.480 --> 01:49.880 And the code will compile without any issues. 01:49.880 --> 01:54.050 And one thing you need to make sure is this needs to be just below the Java directory. 01:54.050 --> 01:57.470 So after this what I'll do is I'll quickly do a refresh over here. 01:57.500 --> 02:02.330 Just to make sure the change that we made is going to be reflected in our workspace. 02:02.360 --> 02:06.710 As you can see, the model refresh is happening over here and it just got completed. 02:06.710 --> 02:11.720 And then what I'm going to do is that I'm going to be introducing you to the modular concepts now. 02:11.720 --> 02:16.610 So the very first thing is in order to define a module you need to create a module like this. 02:16.610 --> 02:19.010 And then you have to give a name for this module. 02:19.010 --> 02:23.300 So I'm going to name this one as module one and then open and close parentheses. 02:23.600 --> 02:28.310 So once this change is done you might be noticing there is a compilation issue right. 02:28.310 --> 02:31.220 So this one is complaining about something. 02:31.220 --> 02:35.750 This was working until now but we started seeing this problem. 02:35.750 --> 02:37.670 Let's go ahead and open this HTTP client. 02:37.670 --> 02:42.320 And then what it says is that if I mouse over on that one package Java dot. 02:42.320 --> 02:47.060 Net dot HTTP is declared in module, but module does not read it. 02:47.060 --> 02:49.820 So this means we need to explicitly add that module. 02:49.820 --> 02:50.300 Let's see. 02:50.300 --> 02:52.670 The IntelliJ is giving the recommendation. 02:52.670 --> 02:55.580 The IntelliJ is giving the recommendation to add this one. 02:55.580 --> 02:56.630 So this is what I said. 02:56.630 --> 03:01.790 Any time you use a code that's not part of the base, the IDE has the ability to tell you what you need 03:01.790 --> 03:03.170 to do in order to make this work. 03:03.200 --> 03:04.640 So in this case, select this one. 03:04.640 --> 03:09.050 And then if you go to the module file you will notice this specific directive added. 03:09.050 --> 03:11.510 So in this case it is requires Java dot. 03:11.660 --> 03:12.680 Net dot HTTP. 03:12.710 --> 03:17.720 This is to make sure the HTTP module is available for our specific project. 03:17.720 --> 03:21.980 So if you want a quick reference on the actual hierarchy if you go here. 03:21.980 --> 03:24.770 So base is what that comes with out of the box. 03:24.770 --> 03:27.710 So we don't have to add any additional module. 03:27.710 --> 03:32.270 As soon as you add that module in for Java the base automatically comes with it. 03:32.270 --> 03:35.990 But HTTP is something which is not going to come out of the box. 03:35.990 --> 03:39.260 So you need to explicitly define hey, I need this specific module. 03:39.260 --> 03:41.570 So make that module available for my project. 03:41.570 --> 03:43.970 So that's exactly what we did over here. 03:43.970 --> 03:49.550 So in order to make that work you need to provide the requires and then provide that base module or 03:49.550 --> 03:51.230 the module that you need actually. 03:51.230 --> 03:55.160 So this is the first thing you need to know about when you are using modular project. 03:55.160 --> 03:59.360 So the next concept that I'm going to introduce you to is that it's going to be exports. 03:59.360 --> 04:02.030 So in this case I have four packages here. 04:02.030 --> 04:02.240 Right. 04:02.240 --> 04:06.170 I have Dtos http secret and service. 04:06.170 --> 04:11.750 So let's say I don't want to be exposing this secret service at all, because by default none of these 04:11.750 --> 04:14.840 packages will get exported unless and until you call it out. 04:14.840 --> 04:20.690 So you need to explicitly call out what this project is going to export or this library is going to 04:20.720 --> 04:21.110 export. 04:21.110 --> 04:25.640 So in this case I want to export comm dot module one dot Dtos. 04:25.670 --> 04:27.770 I want to export this specific package. 04:27.830 --> 04:32.810 When I say export, when you publish this as a library, these package and the classes that's inside 04:32.810 --> 04:35.870 this package is going to be visible to the user of this library. 04:35.870 --> 04:38.660 So the next thing that I'm going to export is a service. 04:38.660 --> 04:43.850 And the next thing that I'm going to export is a HTTP or I don't want HTTP to be exported, so I just 04:43.850 --> 04:46.100 want to export just these two packages. 04:46.100 --> 04:50.060 So this is how you make your code visible to the outside world. 04:50.090 --> 04:56.600 So when you build a Jar file The jar file is just going to have this dto's and the service package and 04:56.600 --> 04:58.190 the classes under those packages. 04:58.190 --> 05:04.430 So this is the first look at how do you build a modular Java application using the modules concept. 05:04.430 --> 05:10.190 So what we learned in this particular lecture is that we learned about how do you add additional modules 05:10.190 --> 05:14.240 other than the Java base by using this requires directive. 05:14.240 --> 05:19.670 And number two is we learned about how do you export packages from this particular project to the outside 05:19.670 --> 05:26.330 world, or any other client library that's going to use module one as a dependency using the exports 05:26.330 --> 05:26.900 directive. 05:26.900 --> 05:29.660 So with this information, I'm going to wrap up this specific lecture. 05:29.660 --> 05:35.270 In the next lecture we will learn about how do you use module one as a dependency to the other module. 05:35.270 --> 05:39.260 So basically we are going to learn about how to work with multiple modules. 05:39.260 --> 05:42.380 When you have a modular project like this is available. 05:42.380 --> 05:44.810 I hope you all were able to successfully implement this. 05:44.840 --> 05:49.460 If you have any questions or clarifications, please don't hesitate to write it in Q&A. 05:49.490 --> 05:50.900 I would be happy to help.