1 00:00:00,420 --> 00:00:06,000 In this lesson we will be connecting these commands so the drone will move accordingly. 2 00:00:06,000 --> 00:00:11,880 But before we start setting the commands I want to make sure that the drone model won't be invoked multiple 3 00:00:11,880 --> 00:00:14,730 times under the models folder. 4 00:00:14,780 --> 00:00:19,790 We set the drone manager JPY once the drone manager is invoked. 5 00:00:19,800 --> 00:00:25,190 We want all the request to go to the same drone manager object to said this. 6 00:00:25,200 --> 00:00:29,610 We will be using a pattern called Singleton for many of you. 7 00:00:29,610 --> 00:00:32,760 You may not know what Singleton is. 8 00:00:32,760 --> 00:00:40,250 So let's go to Tools and write down what Singleton is right click on tools and choose new. 9 00:00:40,320 --> 00:00:46,040 Click on python file and set the file name to single in this file. 10 00:00:46,050 --> 00:00:50,080 We will be writing some sample codes to create Singleton. 11 00:00:50,400 --> 00:00:54,640 Singleton is a design pattern so you don't have to memorize the entire code. 12 00:00:55,380 --> 00:00:58,860 It's best that you understand how it is written set. 13 00:00:58,890 --> 00:01:00,540 Class singleton. 14 00:01:00,780 --> 00:01:06,510 Usually we would set object between the parentheses but in this case we will be using type. 15 00:01:07,410 --> 00:01:10,680 Let's take a look at what type can do the type. 16 00:01:10,680 --> 00:01:13,790 Class inherits the object in this class. 17 00:01:13,790 --> 00:01:18,250 There is a special method called call by setting type. 18 00:01:18,270 --> 00:01:23,160 We can use this called method to handle the class when it's invoked. 19 00:01:23,170 --> 00:01:25,330 Now let's go back to the code. 20 00:01:25,420 --> 00:01:29,350 Next we set instance which is a class attribute. 21 00:01:29,350 --> 00:01:32,400 Then we use the call method that we just checked earlier. 22 00:01:33,250 --> 00:01:44,230 Change the self to a class start an if statement if the CFS as in class is not in the CLEC instance. 23 00:01:44,340 --> 00:01:47,860 In the beginning there will not be a seamless set. 24 00:01:48,180 --> 00:01:49,110 Let's set to print. 25 00:01:49,110 --> 00:01:53,250 Call so you will see that CLSA is not set in the beginning. 26 00:01:53,250 --> 00:02:02,190 Next we set CFS instance with the CNS as a key and super set to Singleton and CFS followed by the call 27 00:02:02,190 --> 00:02:03,410 method. 28 00:02:03,420 --> 00:02:05,650 Here we set the arcs and K works 29 00:02:08,370 --> 00:02:13,570 the class instance will be set to this instance when the method is invoked. 30 00:02:13,590 --> 00:02:19,310 This class object will be created CFS will be set to the curly braces. 31 00:02:19,470 --> 00:02:22,110 The second time the method is invoked. 32 00:02:22,110 --> 00:02:27,750 The class already exists so that if statement will be a false and will skip printing call. 33 00:02:28,590 --> 00:02:32,160 Lastly we return the CLSA instance. 34 00:02:32,160 --> 00:02:37,170 Even if you didn't understand these codes once we run this code you will get a better understanding 35 00:02:37,980 --> 00:02:39,630 to redefine the class. 36 00:02:39,630 --> 00:02:48,990 We can do so by setting matter class to Singleton defined the init method let's set to print in it by 37 00:02:48,990 --> 00:02:49,870 setting this. 38 00:02:49,950 --> 00:02:52,620 The class t became a singleton. 39 00:02:52,770 --> 00:02:55,510 I'll show an example of what we just created. 40 00:02:55,620 --> 00:03:00,770 Set test to t followed by a parentheses we want to run this code. 41 00:03:00,780 --> 00:03:04,500 So let's go on to the edit configuration button. 42 00:03:04,500 --> 00:03:08,700 Currently the go button is set to the main P Y script. 43 00:03:08,700 --> 00:03:10,500 Let's add a new path. 44 00:03:10,530 --> 00:03:13,800 Click on the plus button and choose python. 45 00:03:13,890 --> 00:03:18,560 I'll set the name to single and set the script path to the one we just made. 46 00:03:18,890 --> 00:03:23,890 Good to be white Tello tools and choose single P Y and click open. 47 00:03:24,000 --> 00:03:31,170 Here you will see that run with python console is set on l object this button so you can see the screen 48 00:03:31,170 --> 00:03:33,480 better if you wish to leave it on. 49 00:03:33,480 --> 00:03:35,230 You could do so as well. 50 00:03:35,340 --> 00:03:42,630 Now hit Okay and let's run this code as we run this code you will see that the text call and in it has 51 00:03:42,630 --> 00:03:44,310 been printed. 52 00:03:44,310 --> 00:03:50,250 If we just do the process once it's hard to understand what is going on so I'll copy and paste the code 53 00:03:50,250 --> 00:03:54,190 for one two three four and five times. 54 00:03:54,240 --> 00:03:56,460 Now let's run the code again. 55 00:03:56,460 --> 00:04:00,360 Again we see the text call and in it has been printed. 56 00:04:00,360 --> 00:04:03,750 Next I will change what we said in the parenthesis from metal. 57 00:04:03,750 --> 00:04:09,420 Class equals Singleton to a regular object as we run this new code. 58 00:04:09,420 --> 00:04:13,100 You will see 5 in its printed. 59 00:04:13,120 --> 00:04:21,040 This means that each test is a different class object but if we use Singleton this text will be call 60 00:04:21,180 --> 00:04:29,700 in a single init printed this means once the class object T is created every time the object is invoked 61 00:04:30,060 --> 00:04:37,440 the process will refer to the same object T created in the beginning so that Singleton. 62 00:04:37,440 --> 00:04:40,220 Now let's quickly go through the script again. 63 00:04:40,500 --> 00:04:47,730 The t gets called and it is set to Singleton type when the call method is invoked and if there is nothing 64 00:04:47,730 --> 00:04:54,510 set in the instance the process will go on to super and create the class which will be set in the instances 65 00:04:56,280 --> 00:04:59,970 for the second time in after the column method is invoked. 66 00:04:59,970 --> 00:05:07,080 CLSA is set in the instances so the first CLSA will be returned no matter how many times the call method 67 00:05:07,080 --> 00:05:12,920 is is invoked the process will return the CFS which was set for the first time. 68 00:05:12,920 --> 00:05:16,190 I hope you understood how the Singleton works it. 69 00:05:16,340 --> 00:05:20,020 Even if you didn't understand each code you don't have to worry. 70 00:05:20,030 --> 00:05:24,860 This is called a design pattern which is also used in other programming languages. 71 00:05:24,860 --> 00:05:30,900 You can always keep this code as a sample and copy paste it when you need it. 72 00:05:30,920 --> 00:05:37,490 Now let's actually copy this code so we can set it in our project go to models folder and right click 73 00:05:38,210 --> 00:05:47,640 choose new and hit python file name the file base and head OK paste the Singleton code you just copied 74 00:05:47,640 --> 00:05:51,890 earlier. 75 00:05:51,930 --> 00:05:54,330 Now go to edit configuration. 76 00:05:54,720 --> 00:06:01,980 We won't be able to use a single button anymore suppress the minus button to delete single hit OK. 77 00:06:02,070 --> 00:06:02,970 And we are done.