WEBVTT 00:00.470 --> 00:01.010 Hi everyone. 00:01.010 --> 00:02.330 Welcome back to this tutorial. 00:02.330 --> 00:07.190 In this tutorial we will code and explore the partitioning by collector. 00:07.580 --> 00:12.770 The partitioning by collector is also a kind of grouping by collector. 00:14.010 --> 00:20.640 The partitioning by accepts a predicate as an input and the output is going to be a map. 00:22.080 --> 00:27.480 And the key of the return type is always going to be a Boolean. 00:28.550 --> 00:35.270 And then there are two different versions of partitioning by one with a one argument version which accepts 00:35.270 --> 00:38.780 a predicate as an input, and the another one is a predicate. 00:38.780 --> 00:42.760 And the downstream, which is the two parameter version. 00:42.770 --> 00:44.420 Let's go ahead and code this one. 00:46.440 --> 00:47.250 What I'm going to do. 00:47.280 --> 00:50.850 I'm going to create a class called Streams. 00:53.240 --> 00:59.150 Partitioning by sample, and then I'm going to make this class executable. 00:59.180 --> 01:01.400 By adding public static void main. 01:03.440 --> 01:05.030 Understand presentation mode. 01:05.940 --> 01:09.630 And then what I'm going to do, I'm going to create an example. 01:10.570 --> 01:14.110 I'm going to create a method, basically public static void. 01:15.930 --> 01:17.640 Partitioning by. 01:18.650 --> 01:22.400 Want to give it a name as one, because I'm going to quote a couple of examples here. 01:23.830 --> 01:28.750 And let's call the student database class and get all the students. 01:29.780 --> 01:34.640 Call the stream method and then perform the collect method. 01:35.120 --> 01:38.630 So we are going to explore the partitioning by. 01:38.810 --> 01:39.590 Right. 01:40.850 --> 01:41.960 Partitioning. 01:43.570 --> 01:49.720 Thanks to this partitioning by is are going to do a static import of this one from the collectors. 01:49.750 --> 01:52.960 As you see, we have the partitioning by here. 01:54.190 --> 01:55.880 Let's create a predicate here. 01:55.900 --> 01:59.020 The predicate is going to be because we all know partitioning. 01:59.020 --> 02:04.060 If you go and take a look at it, it accepts there are two different versions, but it accepts. 02:05.420 --> 02:05.750 The. 02:07.060 --> 02:08.050 Predicate as an input. 02:08.050 --> 02:09.310 Let's create a predicate. 02:11.210 --> 02:14.870 The predicate is going to be of type student. 02:15.290 --> 02:18.440 I'm going to create a predicate. 02:21.630 --> 02:24.210 This predicate is going to be. 02:27.800 --> 02:29.020 Student dot. 02:30.500 --> 02:35.000 Didn't dot get greater than or equal to 3.8. 02:36.600 --> 02:40.140 So I'm going to parse this predicate here. 02:41.000 --> 02:44.450 The output that it is going to create is going to be a map. 02:44.480 --> 02:48.590 If you go to the partitioning by, it's going to create a map of type boolean. 02:48.620 --> 02:49.870 You cannot override that. 02:49.880 --> 02:50.450 Right. 02:50.450 --> 02:52.730 So it's going to be map. 02:53.780 --> 02:56.620 To import the class which is of type Java.util. 02:58.110 --> 03:05.160 The key is going to be Boolean and the result is going to be a list of prints. 03:06.270 --> 03:06.960 Basically student. 03:10.780 --> 03:14.620 So I'm going to name this one as partitioning map. 03:15.740 --> 03:16.340 Right. 03:16.460 --> 03:19.070 And then let's print this one out. 03:19.790 --> 03:21.530 Partitioning map equal to. 03:22.990 --> 03:24.100 I'm going to call this method. 03:26.010 --> 03:33.960 So the output is going to be whatever that matches this predicate is going to be under the true key. 03:33.990 --> 03:38.190 Whatever the doesn't match, this one is going to be under the false key. 03:38.310 --> 03:41.340 Let's execute this and validate the result. 03:42.250 --> 03:45.280 If you take a look at it, there are two keys. 03:45.280 --> 03:48.730 One is the false key and another one is the true key. 03:48.760 --> 03:55.240 So in the false key, whoever has the GPA less than or equal to 3.8, if you take a look at the GPA 03:55.240 --> 03:56.950 of this one, it is 3.6. 03:56.950 --> 03:59.320 And the GPA of this one is 3.5. 03:59.350 --> 04:06.550 Under the true category, whatever that has the GPA greater than or equal to 3.8, all those things 04:06.550 --> 04:08.530 falls under the true key. 04:10.280 --> 04:13.130 So this is the one argument version. 04:13.130 --> 04:15.740 Let's take a look at the two argument version. 04:16.960 --> 04:19.090 Gonna name this one as partitioning. 04:19.450 --> 04:21.130 Underscore two. 04:22.150 --> 04:24.220 Auditioning underscore two in here. 04:24.220 --> 04:25.210 What we are going to do. 04:25.240 --> 04:27.820 It is going to take in a second argument. 04:27.850 --> 04:31.930 The second argument is a downstream basically, this is again another collector. 04:31.930 --> 04:37.240 So what I'm going to do, I'm going to override this by passing the two set collector. 04:37.570 --> 04:42.040 So what's going to happen instead of this list we are going to have set? 04:43.300 --> 04:43.930 Imported. 04:45.110 --> 04:45.680 There you go. 04:45.890 --> 04:48.380 And then we need to. 04:49.330 --> 04:50.620 What's happening here? 04:50.800 --> 04:53.440 This should not be any issues, actually. 04:53.470 --> 04:55.720 So in here we are passing the two set. 04:55.750 --> 04:57.820 I believe we need to provide one more. 04:59.840 --> 05:01.130 Some issues here. 05:01.990 --> 05:02.960 Is this a comma? 05:03.290 --> 05:03.920 Yep. 05:04.340 --> 05:05.360 You have it. 05:07.010 --> 05:07.520 Okay. 05:08.800 --> 05:10.360 Uh, we should have the comma here. 05:10.360 --> 05:12.130 We should not close that, actually. 05:13.680 --> 05:17.350 Because partitioning by is the one which is going to take two arguments, right? 05:17.370 --> 05:21.540 The first argument is a predicate, and second argument is a downstream. 05:21.540 --> 05:24.210 Basically, there is nothing but a collector, right? 05:24.210 --> 05:26.220 So to set is one of the collector. 05:26.570 --> 05:31.620 Then what I'm going to do, I'm going to call this method, I'm going to comment this one so that it 05:31.620 --> 05:33.060 can avoid the confusion. 05:33.060 --> 05:36.270 The result is going to be the same here In this use case. 05:36.270 --> 05:41.730 It is just that we are overriding the default type of list to to set. 05:41.760 --> 05:43.860 You can pass any kind of collector here. 05:45.020 --> 05:46.790 Gonna run this one. 05:48.180 --> 05:53.510 But on this one, it is going to give me the output as similar to the previous scenario, but it is 05:53.660 --> 05:55.610 of type set instead of a list. 05:56.000 --> 05:58.760 So this is all about the partitioning by. 05:58.790 --> 06:00.950 With this we came to the end of this tutorial. 06:00.980 --> 06:02.120 Thank you for watching.