WEBVTT 00:00.080 --> 00:00.960 Welcome back. 00:01.360 --> 00:09.400 As usual, when finishing the repository and repository implementation, we need to create the module 00:09.560 --> 00:14.800 that provides us with the repository and its implementation. 00:15.000 --> 00:19.840 So here inside dependency injection package, create a new object. 00:19.880 --> 00:22.880 Name it as directions module. 00:22.920 --> 00:31.920 As usual, start with module annotation, then install in Singleton component class. 00:31.960 --> 00:36.040 This object provides us with many instances. 00:36.040 --> 00:40.240 For example, let's start with provides annotation. 00:40.280 --> 00:42.280 Singleton annotation. 00:42.440 --> 00:43.640 Create the function. 00:43.640 --> 00:47.320 Provide directions service. 00:47.400 --> 00:56.800 This function returns directions service return retrofit provider dot create directions service. 00:57.040 --> 01:03.290 And here we need to pass the base URL, so base url equals to. 01:03.490 --> 01:11.610 If you remember, we have the constant part which is maps dot Google maps API. 01:11.930 --> 01:19.250 You can include directions, but I include it in the previous uh calls and endpoints. 01:19.250 --> 01:26.810 So here paste the https maps.google.com api.com slash slash API. 01:26.850 --> 01:34.210 Okay, this function is a dagger hilt module that provides singleton instance of directions. 01:34.210 --> 01:36.890 Service for dependency injection. 01:36.930 --> 01:46.130 Provides marks this function as a dagger provider method telling dagger to use this function when an 01:46.130 --> 01:49.370 instance of direction service is needed. 01:49.570 --> 01:57.330 The singleton annotation ensures that only one instance of directions service is created and shared 01:57.330 --> 02:06.540 across the entire application, important for services that maintain no state or are expensive to create. 02:06.580 --> 02:12.420 The return type is directions service the interface that defines an API. 02:12.580 --> 02:13.380 Endpoints. 02:13.420 --> 02:15.420 Let me go back to here. 02:15.540 --> 02:17.940 As I told you in the previous videos. 02:17.980 --> 02:21.100 This this is the endpoint directions JSON. 02:21.100 --> 02:26.660 This is the base url https to Google API. 02:29.060 --> 02:29.620 API. 02:29.900 --> 02:35.180 So this is for this object directions module. 02:35.460 --> 02:39.900 And this part the directions slash JSON. 02:40.020 --> 02:43.580 This is for the directions service interface. 02:43.740 --> 02:45.260 This is the endpoint. 02:45.500 --> 02:46.060 Okay. 02:46.220 --> 02:49.820 So we define inside this object the base URL. 02:49.980 --> 02:55.940 And we defined inside the interface directions service the endpoint. 02:56.060 --> 03:02.710 This will delegate to Retrofit Provider Redirection Service method. 03:02.710 --> 03:10.830 We saw an error in the previous videos providing the base URL for Google Maps API endpoints. 03:10.830 --> 03:13.470 The base URL is defined in one place. 03:13.470 --> 03:15.830 Easy to change for different environments. 03:15.870 --> 03:21.030 All API path endpoints will be relative to this base URL. 03:21.310 --> 03:27.110 Any class can request directions service through constructor injection. 03:27.150 --> 03:32.150 Easy to mock for testing and single responsibility principle. 03:32.150 --> 03:39.870 The base URL endpoints to Google Maps version, version three endpoint and the complete API call is. 03:39.910 --> 03:44.190 Get it from here and you can check this whole response. 03:44.190 --> 03:51.630 So as I told you and the whole sorry call and the whole request, this is the base URL. 03:51.950 --> 03:58.120 This is the endpoint and this is the Destination variable. 03:58.160 --> 04:01.840 Origin variable and key variable. 04:01.880 --> 04:02.400 Okay. 04:02.520 --> 04:05.400 Let's continue with the directions module. 04:05.440 --> 04:08.200 We need to provide the repository. 04:08.200 --> 04:12.120 So provide and singleton annotation. 04:12.160 --> 04:13.040 Function. 04:13.040 --> 04:16.280 Provide directions repository. 04:16.320 --> 04:20.120 We need two variables to be passed the API key. 04:20.360 --> 04:27.600 It's of type string and the directions service which is of type direction service. 04:27.760 --> 04:31.920 Returning directions repository. 04:31.960 --> 04:38.080 Return directions repository implementation and pass. 04:38.080 --> 04:45.840 The API key equals to API key and the direction service as direction service. 04:45.880 --> 04:51.840 And if you remember in the directions repository implementation we need to inject the API key. 04:52.000 --> 05:00.170 So here instead of manually Inject the API key we can use this way. 05:00.210 --> 05:04.170 So provides named maps API key. 05:04.370 --> 05:06.290 Let's create this function. 05:06.330 --> 05:08.970 Provide maps API key. 05:09.170 --> 05:11.130 And this is the string. 05:11.130 --> 05:13.730 Here we need to put the API key. 05:13.770 --> 05:15.370 Go back to the manifest. 05:15.370 --> 05:18.370 Copy this code and paste it here. 05:18.490 --> 05:24.570 That provides annotation, as we said before marks this as a dependency provider method. 05:24.610 --> 05:31.210 Dagger will use this when a string dependency is requested and named. 05:31.370 --> 05:39.170 Annotation creates a qualifier for this specific string instance needed because you might have multiple 05:39.170 --> 05:46.410 string dependencies in your application, and differentiates this API key from other strings. 05:46.690 --> 05:51.290 Simply returns a hard coded Google Maps API key. 05:51.610 --> 05:56.620 In production, you might get this from a secure source, not hard coded. 05:56.860 --> 05:59.380 So why we use named annotation? 05:59.380 --> 06:08.060 If your app needs a different API keys or configuration strings, you might use them named also for 06:08.060 --> 06:15.140 explicit dependencies, making it easier which string is being injected and where. 06:15.220 --> 06:21.860 Also the type safety preventing accidental injecting the wrong string. 06:22.020 --> 06:31.300 When another class needs this API key, you can inject it using the this this key the maps underscore 06:31.340 --> 06:33.300 API underscore key. 06:33.460 --> 06:39.940 So let me go to here inside this directions repository implementation. 06:40.060 --> 06:51.220 Let me use the named annotation and specify the API key maps underscore API underscore key.