WEBVTT 00:00.110 --> 00:00.680 Hi everyone. 00:00.680 --> 00:02.000 Welcome back to this tutorial. 00:02.000 --> 00:06.170 In this tutorial we will discuss about the terminal operations. 00:07.040 --> 00:12.110 Terminal operations are the ones that collects the data for you in the Streams API. 00:12.800 --> 00:16.910 Terminal operations starts the whole stream pipeline. 00:17.030 --> 00:24.200 Some of the terminal operations are for each min max reduce, collect and et-cetera. 00:25.580 --> 00:32.720 In this section, the main focus is going to be on the collect terminal operation and we'll be focusing 00:32.720 --> 00:38.360 on what are the different approaches of collecting the data using the collect method. 00:38.390 --> 00:42.200 The collect method takes in an input of type collector. 00:43.160 --> 00:48.500 It produces a result as per the input passed to the collect method. 00:48.530 --> 00:54.260 Basically, the collect method is going to be like an accumulator, which is going to accumulate the 00:54.260 --> 00:57.830 result until the streams are exhausted. 00:59.550 --> 01:03.510 The first terminal operation that we are going to talk about is joining. 01:04.450 --> 01:11.300 Joining is used to perform the string concatenation on the elements in the stream. 01:11.370 --> 01:14.800 So joining will be an input to the collect method. 01:15.370 --> 01:18.640 Joining has three different overloaded versions. 01:18.670 --> 01:22.270 Let's go ahead and explore all of those in this tutorial. 01:22.300 --> 01:23.410 Back to the IntelliJ. 01:25.170 --> 01:28.740 And in here what I'm going to do, I'm going to create a package called. 01:29.880 --> 01:30.780 Dreams. 01:32.010 --> 01:34.110 Underscore terminal. 01:36.370 --> 01:41.590 And then what I'm going to do, I'm going to create an example called dreams. 01:43.170 --> 01:45.180 Joining example. 01:45.630 --> 01:49.080 Let's make this class executable by adding public static void main. 01:49.560 --> 01:50.370 Here we go. 01:54.420 --> 01:59.370 The use case that we are going to code here is that we want to concatenate all the names that are part 01:59.370 --> 02:03.150 of the student database and return that as a result. 02:03.670 --> 02:06.630 So I'm going to create a method called public static. 02:07.020 --> 02:10.620 We all know joining is going to return you a string. 02:10.920 --> 02:15.720 I'm going to have the return type A string for this method, and then I'm going to name this one as 02:15.720 --> 02:21.540 joining underscore one, because there is going to be three different overloaded versions of joining. 02:21.690 --> 02:24.540 That's the reason why I'm naming it as one for now. 02:25.020 --> 02:31.300 First up is let's call the student database dot, get all students dot stream. 02:31.320 --> 02:38.790 The first call to that method is stream is going to give us a stream of students followed by that we 02:38.790 --> 02:40.250 want just the name, right? 02:40.260 --> 02:49.170 So I'm going to use the map method and then call the get name method, which is going to give me the 02:49.170 --> 02:49.930 names. 02:49.950 --> 02:55.140 Basically, this is going to return a stream of string. 02:56.290 --> 02:57.130 As an output. 02:57.130 --> 03:00.790 And then what we are going to do, we are going to call the collect method. 03:00.970 --> 03:04.210 The collect method is going to accept a collector. 03:05.880 --> 03:08.610 Collectors basically dot joining. 03:10.400 --> 03:10.790 Right. 03:10.790 --> 03:12.410 And then I'm going to return this year. 03:15.880 --> 03:18.130 Let's run this and then check the result. 03:18.450 --> 03:21.370 Going to have dining one here. 03:23.780 --> 03:24.950 Then call this method. 03:26.710 --> 03:29.270 Let's run this example and then check what is the result. 03:29.300 --> 03:34.840 So here we are calling the joining method and then we are printing the value using this result. 03:37.700 --> 03:41.860 So here it printed the name in concatenation. 03:41.870 --> 03:45.890 Here it printed the concatenated name of all the students. 03:45.890 --> 03:48.710 But if you take a look at it, it is not readable. 03:48.710 --> 03:49.190 Right? 03:49.230 --> 03:51.740 So there is an overloaded version of this one. 03:51.890 --> 03:56.240 What I'm going to do, I'm going to add joining underscore to. 03:56.460 --> 03:58.940 So in this, you can pass the delimiter also. 03:59.270 --> 04:08.870 If I pass this, basically this is going to create a delimited string values in here finding to going 04:08.870 --> 04:17.330 to be renamed as joining to run this it is going to print all the values by injecting the delimiter 04:17.330 --> 04:19.730 between each and every variable. 04:19.760 --> 04:22.670 Now, this is in a readable format. 04:22.700 --> 04:26.170 There is an another version of joining that is available here. 04:26.210 --> 04:27.620 Let's go ahead and take a look at it. 04:28.940 --> 04:29.900 You take a look at it. 04:31.600 --> 04:36.520 This is going to be joining three and it accepts a prefix and suffix. 04:36.910 --> 04:42.730 So you can give this is a prefix and then this is a suffix. 04:42.760 --> 04:49.000 Basically, this whole name string is going to have this as a prefix and this as a suffix. 04:49.120 --> 04:51.340 Let's go ahead and run this and check this one. 04:53.120 --> 04:54.440 Going to be joining three. 04:55.690 --> 04:57.400 And this is going to be joining three. 04:57.730 --> 04:59.200 Let's go ahead and run this one. 05:00.870 --> 05:03.120 This result is going to be. 05:03.630 --> 05:04.170 Take a look at it. 05:04.170 --> 05:06.660 It has the brackets, meaning it has the braces. 05:07.780 --> 05:09.160 Here and it has the. 05:10.170 --> 05:10.910 Races here. 05:10.920 --> 05:16.920 Basically, this is a prefix, the value that you passed here and this is a suffix, the value that 05:16.920 --> 05:17.460 we passed. 05:18.930 --> 05:24.270 Before we wind up this tutorial, I would like to show you another approach of using joining here. 05:24.270 --> 05:27.690 If you notice this, we are using collectors dot joining, right? 05:27.690 --> 05:31.140 But actually you don't have to use the collectors all the time. 05:31.140 --> 05:33.360 You can do a static import of joining. 05:33.360 --> 05:39.630 I'm pressing the alt and enter and Mac in the case of windows you have the alt plus enter. 05:39.630 --> 05:44.760 Basically we have added the static import of collectors with this. 05:44.760 --> 05:50.790 It is going to perform the same operation as you perform using the collectors dot joining. 05:50.940 --> 05:54.150 So this is all about the joining collector. 05:54.180 --> 06:00.360 Let's talk about some more collectors in the future tutorials with this we came to the end of this tutorial. 06:00.390 --> 06:01.560 Thank you for watching.