1 00:00:00,210 --> 00:00:02,050 Hi everyone it is still Todi. 2 00:00:02,110 --> 00:00:06,160 I want to talk about how to write our code more professionally OK. 3 00:00:06,180 --> 00:00:14,450 In the previous tutorials I talked about objects and methods and how to use objects and methods together. 4 00:00:14,460 --> 00:00:15,060 OK. 5 00:00:15,270 --> 00:00:20,830 But in this tutorial I want to show you how you can write secure codes. 6 00:00:20,850 --> 00:00:21,460 OK. 7 00:00:21,630 --> 00:00:24,240 So first we need to create a Java project. 8 00:00:24,270 --> 00:00:24,840 OK. 9 00:00:25,020 --> 00:00:31,150 So in order to create a Java project you need to click on File New and then click on Java project. 10 00:00:31,170 --> 00:00:31,960 OK. 11 00:00:32,130 --> 00:00:39,100 So for the project name just type in here getters and setters. 12 00:00:39,300 --> 00:00:40,080 OK. 13 00:00:40,470 --> 00:00:42,460 And click and finish. 14 00:00:42,540 --> 00:00:48,300 So as you can see here our project is now created and then we need a main class for our project. 15 00:00:48,300 --> 00:00:48,650 OK. 16 00:00:48,660 --> 00:00:56,160 So just click on this as our RC folder and then click on find new and then click on class. 17 00:00:56,210 --> 00:01:03,360 So for the class name just type in here made and for the package we need a reverse domain here to just 18 00:01:03,360 --> 00:01:14,940 type in here come that your name dot project name OK getters and setters and then make sure that you 19 00:01:14,940 --> 00:01:16,510 check these checkpoints here. 20 00:01:16,980 --> 00:01:19,010 Public static void main method. 21 00:01:19,200 --> 00:01:21,550 And then click on finish. 22 00:01:21,660 --> 00:01:27,990 So as you can see here our class is now created and then let me delete this comment and then let me 23 00:01:28,260 --> 00:01:30,100 make this area right. 24 00:01:30,120 --> 00:01:30,870 OK. 25 00:01:31,380 --> 00:01:34,030 So now we can write our code here. 26 00:01:34,080 --> 00:01:40,920 So now I want to create a blueprint in order to show me how I can't exactly create dog objects. 27 00:01:40,920 --> 00:01:41,330 OK. 28 00:01:41,370 --> 00:01:44,190 So I need to create a class called Talk. 29 00:01:44,190 --> 00:01:44,870 OK. 30 00:01:45,210 --> 00:01:53,160 So in order to create a class I just need to click on this package here and then click on File New and 31 00:01:53,160 --> 00:01:54,860 then click kind of class. 32 00:01:54,870 --> 00:01:55,580 OK. 33 00:01:55,770 --> 00:02:04,470 So the name of our class is Doc OK and it's going to actually put this class inside this package. 34 00:02:04,580 --> 00:02:04,910 OK. 35 00:02:04,910 --> 00:02:10,670 Because we clicked on this package and it's going to put this class inside this package OK. 36 00:02:10,670 --> 00:02:14,740 So for the modifiers use public and then click on finish. 37 00:02:14,870 --> 00:02:18,480 So as you can see here our target class is now created. 38 00:02:18,500 --> 00:02:18,880 OK. 39 00:02:18,890 --> 00:02:27,290 And now that's our blueprint is created we need to put some instructions inside this class in order 40 00:02:27,290 --> 00:02:32,240 to show us the characteristics and behaviors of a dog object. 41 00:02:32,240 --> 00:02:41,000 So for example the characteristics of a dog are create some variables here at speed and I can assign 42 00:02:41,000 --> 00:02:44,610 a value to my variable for example number 70. 43 00:02:45,350 --> 00:02:49,060 And again and power. 44 00:02:50,030 --> 00:02:54,140 And then I can assign a value to my valuable for example number 80. 45 00:02:54,290 --> 00:02:58,570 And as you can see here these are the characteristics of my dog objects. 46 00:02:58,580 --> 00:02:58,990 OK. 47 00:02:59,030 --> 00:03:01,980 And are like objects have behaviors. 48 00:03:02,000 --> 00:03:04,000 So what are the behaviors of a dog. 49 00:03:04,040 --> 00:03:05,990 So for example a dog can run. 50 00:03:05,990 --> 00:03:06,350 OK. 51 00:03:06,350 --> 00:03:19,550 So here I just need to type in voit run ok and insert them and I can write them that out that print. 52 00:03:20,010 --> 00:03:22,930 And then inside the parenthesis I can't just type in here. 53 00:03:22,950 --> 00:03:23,310 Ron 54 00:03:25,950 --> 00:03:26,800 OK. 55 00:03:27,460 --> 00:03:31,390 So as you can see here at the end of my statement I need to put in a semicolon. 56 00:03:31,380 --> 00:03:34,950 Another behavior of a dog is a dog sleeps. 57 00:03:34,990 --> 00:03:44,080 So here I just need to type in Voyt sleep and then I need to open and close my Mfat by using an opening 58 00:03:44,080 --> 00:03:48,760 curly brace followed by our closing curly brace and then inside the left. 59 00:03:48,790 --> 00:03:59,460 I just need to typing system that out that princeling and then inside the apprentice's I can write sleep 60 00:04:03,140 --> 00:04:03,880 OK. 61 00:04:04,310 --> 00:04:07,120 And then at the end of my statement I need to put in a semicolon. 62 00:04:07,130 --> 00:04:11,010 So these are the characteristics and behaviors of my dog objects. 63 00:04:11,030 --> 00:04:11,610 OK. 64 00:04:11,720 --> 00:04:18,000 And now that our blueprint is ready we can create objects from this class. 65 00:04:18,020 --> 00:04:18,570 OK. 66 00:04:18,710 --> 00:04:20,770 So inside the main class. 67 00:04:20,840 --> 00:04:22,810 So as you can see here this is our main class. 68 00:04:22,820 --> 00:04:23,560 OK. 69 00:04:23,960 --> 00:04:26,170 And inside the main method. 70 00:04:26,180 --> 00:04:27,980 So this is our main method. 71 00:04:28,010 --> 00:04:28,620 OK. 72 00:04:28,880 --> 00:04:31,490 We can create objects from this class. 73 00:04:31,490 --> 00:04:32,300 OK. 74 00:04:32,450 --> 00:04:36,370 So first I need to refer to the name of my dog class. 75 00:04:36,670 --> 00:04:37,170 OK. 76 00:04:37,260 --> 00:04:39,780 And then I need to give my object a name. 77 00:04:39,980 --> 00:04:41,760 So for example my dock. 78 00:04:42,220 --> 00:04:42,900 OK. 79 00:04:43,160 --> 00:04:46,000 And then I put an assignment operator here. 80 00:04:46,220 --> 00:04:49,050 And then I put this key vote here Neal. 81 00:04:49,460 --> 00:04:55,940 And then again I refer to the name of my class and then I put a pair of round brackets after my class 82 00:04:55,940 --> 00:04:56,130 name. 83 00:04:56,150 --> 00:05:00,020 OK so this is how we create objects from classes. 84 00:05:00,020 --> 00:05:00,430 OK. 85 00:05:00,500 --> 00:05:07,260 So now I want to actually access the characteristics and behaviors of my dog objects. 86 00:05:07,280 --> 00:05:07,890 OK. 87 00:05:08,090 --> 00:05:14,590 So inside the main class and inside the main method I have to actually to output the value of the speed 88 00:05:14,930 --> 00:05:17,990 instance variable of my dog object. 89 00:05:17,990 --> 00:05:26,750 So here I just need to type in the system that's out that land and then inside the prentices first I 90 00:05:26,750 --> 00:05:29,420 need to refer to the name of my object my dog. 91 00:05:29,480 --> 00:05:30,920 That speed. 92 00:05:31,190 --> 00:05:31,820 OK. 93 00:05:32,060 --> 00:05:37,020 And then I need to put in a semi-colon at the end of my statement aren't here. 94 00:05:37,090 --> 00:05:44,040 Are you want to actually output the value of their power or instance variable to the console. 95 00:05:44,090 --> 00:05:53,510 So I just need to type in system that out that Prince land and then inside the prentices first I need 96 00:05:53,510 --> 00:05:57,440 to refer to the name of my object that power. 97 00:05:57,930 --> 00:05:58,540 OK. 98 00:05:58,850 --> 00:06:05,210 And then I need to put in a semicolon at the end of my statement and I want to actually call the behaviors 99 00:06:05,270 --> 00:06:06,590 of my dog object. 100 00:06:06,620 --> 00:06:09,890 For example I want to tell my dog to run. 101 00:06:10,100 --> 00:06:15,160 So first I need to actually be fair to the name of my object. 102 00:06:15,170 --> 00:06:19,400 My dog got run ok. 103 00:06:19,430 --> 00:06:23,370 Or for example I want to actually tell my dog to sleep. 104 00:06:23,390 --> 00:06:29,510 So inside the main class and inside the main method first I need to refer to the name of my object that 105 00:06:30,070 --> 00:06:31,140 sleep. 106 00:06:31,320 --> 00:06:32,130 OK. 107 00:06:32,450 --> 00:06:39,950 So this is how you can actually access the characteristics or instance variables and the behaviors of 108 00:06:39,950 --> 00:06:40,950 your objects. 109 00:06:41,010 --> 00:06:51,870 OK so now if I on my project as you can see these are the characteristics and behaviors of my dog objects. 110 00:06:51,890 --> 00:06:52,430 OK. 111 00:06:52,580 --> 00:06:56,680 So as you can see here I created a blueprint. 112 00:06:56,690 --> 00:06:57,840 So this is our blueprint. 113 00:06:57,860 --> 00:06:58,580 OK. 114 00:06:58,790 --> 00:07:01,280 So let me now double click on this dog. 115 00:07:01,310 --> 00:07:05,500 The job I have here in order to make this a little area of order. 116 00:07:05,750 --> 00:07:07,910 So as you can see here this is our blueprint. 117 00:07:07,910 --> 00:07:08,710 OK. 118 00:07:09,110 --> 00:07:16,250 And then I created an object from this blueprint from the start class inside the main class and inside 119 00:07:16,250 --> 00:07:16,820 the main method. 120 00:07:16,830 --> 00:07:17,330 OK. 121 00:07:17,330 --> 00:07:22,080 So this is our dog object that we created in line 7. 122 00:07:22,100 --> 00:07:22,610 OK. 123 00:07:22,820 --> 00:07:24,730 But there is a problem here. 124 00:07:24,920 --> 00:07:27,830 My code is not secure enough. 125 00:07:27,830 --> 00:07:28,580 Why. 126 00:07:28,580 --> 00:07:33,670 Because as you can see here I shouldn't allow the main class. 127 00:07:33,710 --> 00:07:35,500 So this is our main class ok. 128 00:07:35,760 --> 00:07:44,450 I shouldn't allow the main class to access the characteristics of my dog object directly. 129 00:07:44,810 --> 00:07:47,490 So inline 8 and inline 9. 130 00:07:47,540 --> 00:07:53,030 I am actually accessing the characteristics of my dog object directly. 131 00:07:53,060 --> 00:07:58,840 First I am referring to the name of my object and then I am actually accessing the instance variable 132 00:07:58,860 --> 00:08:01,120 of this might like object directly. 133 00:08:01,130 --> 00:08:04,710 This is not the proper way to actually write our codes. 134 00:08:04,820 --> 00:08:05,080 OK. 135 00:08:05,090 --> 00:08:06,520 There is something wrong here. 136 00:08:06,590 --> 00:08:09,980 In this way our code is not maintainable. 137 00:08:10,130 --> 00:08:14,050 So what should we do in order to solve this problem. 138 00:08:14,060 --> 00:08:19,470 So in order to solve this problem we should use setters and getters. 139 00:08:19,580 --> 00:08:21,370 For our instance variables. 140 00:08:21,380 --> 00:08:21,880 OK. 141 00:08:22,010 --> 00:08:27,680 So as you can see here inside the class these are the instance variables of our dog objects. 142 00:08:27,710 --> 00:08:28,120 OK. 143 00:08:28,160 --> 00:08:35,240 As I said before we call these characteristics instance about because these characteristics are owned 144 00:08:35,510 --> 00:08:38,960 by the instances or objects of this class. 145 00:08:38,990 --> 00:08:45,240 OK I want to show you how you can create get hearer's and setters for instance variables. 146 00:08:45,260 --> 00:08:45,720 OK. 147 00:08:45,830 --> 00:08:53,600 So what are these getters and setters for example if you want to access the value of this speed instance 148 00:08:53,600 --> 00:08:57,020 variable we should use a method called getter. 149 00:08:57,110 --> 00:09:05,630 OK so if I for example want to access the value of this speed instance variable I should use a method 150 00:09:05,630 --> 00:09:09,560 called Get here in order to actually access that value. 151 00:09:09,560 --> 00:09:10,100 OK. 152 00:09:10,280 --> 00:09:14,980 We shouldn't access the value of this instance variable in this way. 153 00:09:14,990 --> 00:09:21,470 This is not the proper way in order to access the value of this instance variable in this way. 154 00:09:21,500 --> 00:09:28,670 OK but if I want to actually assign another value to my speed instance variable we should use a method 155 00:09:28,670 --> 00:09:30,000 called setter. 156 00:09:30,250 --> 00:09:36,340 OK so here I can actually assign another value to my SPI instance variable. 157 00:09:36,350 --> 00:09:43,010 So first I need to refer to the name of my object my dog that speed and then I put an assignment operator 158 00:09:43,010 --> 00:09:45,590 here and then I assign a value to my variable. 159 00:09:45,590 --> 00:09:47,120 For example number 25. 160 00:09:47,300 --> 00:09:50,680 And then I put a semi-colon at the end of my statement. 161 00:09:50,860 --> 00:09:51,290 OK.