1 00:00:00,180 --> 00:00:08,810 So that was an important point that I wanted to actually let you know about running your Java projects. 2 00:00:08,810 --> 00:00:15,870 Another important point that I want to talk about is about get here and setters setter's So inside the 3 00:00:16,170 --> 00:00:23,220 class as you can see here we've got our Get help my friend and our settlement Fred for our sweet instance 4 00:00:23,220 --> 00:00:23,770 variable. 5 00:00:23,770 --> 00:00:24,150 OK. 6 00:00:24,180 --> 00:00:31,950 And we've got our little faith and on Saturday I'm afraid for our power instance variable and remember 7 00:00:31,950 --> 00:00:39,810 that I told you that we shouldn't allow any other classes other than this class to access our instance 8 00:00:39,810 --> 00:00:40,920 variables directly. 9 00:00:40,920 --> 00:00:41,660 OK. 10 00:00:41,790 --> 00:00:45,950 So always declare your instance variables private. 11 00:00:45,960 --> 00:00:46,390 OK. 12 00:00:46,440 --> 00:00:52,050 So always use the private access modifier for your instance variables. 13 00:00:52,050 --> 00:00:52,590 OK. 14 00:00:52,650 --> 00:01:00,210 At the start of the value creation I just need to type in here private and as you can see here now our 15 00:01:00,210 --> 00:01:03,970 power instance variable is private only to this class. 16 00:01:03,990 --> 00:01:04,540 OK. 17 00:01:04,830 --> 00:01:10,410 Is private and only diskless can use this power instance variable. 18 00:01:10,440 --> 00:01:14,460 No other classes can even refer to this variable. 19 00:01:14,520 --> 00:01:14,940 OK. 20 00:01:14,990 --> 00:01:22,020 If any other classes want to actually access the value of the power instance variable they can just 21 00:01:22,560 --> 00:01:24,230 use these getter I'm afraid. 22 00:01:24,300 --> 00:01:25,860 All these settled my fate. 23 00:01:25,860 --> 00:01:26,330 OK. 24 00:01:26,420 --> 00:01:31,030 So always declare your getters and setters public. 25 00:01:31,050 --> 00:01:31,530 OK. 26 00:01:31,650 --> 00:01:36,240 Use this public access modifier for your getters and setters. 27 00:01:36,420 --> 00:01:42,980 If you want to if you want to actually let any other classes in your project to use these two methods. 28 00:01:42,990 --> 00:01:43,720 OK. 29 00:01:43,800 --> 00:01:50,040 Or if you want to actually only allow the classes inside the package that this class is within it you 30 00:01:50,040 --> 00:01:54,460 can use the package access modifier which is the default access modifier OK. 31 00:01:54,570 --> 00:02:01,350 So for the instance variables always use these private access modifier and for the getters and setters 32 00:02:01,830 --> 00:02:04,470 always use the public access modifier. 33 00:02:04,470 --> 00:02:05,120 OK. 34 00:02:05,250 --> 00:02:12,600 In order to allow any other classes in your projects to access these getters and setters OK and if you 35 00:02:12,600 --> 00:02:20,700 want to actually allow only the classes inside the package to use these getters and setters just use 36 00:02:20,760 --> 00:02:26,400 the package access modifier OK which is the default access modifier and you don't need to actually put 37 00:02:26,490 --> 00:02:29,660 any keyboard at the start of your Meffert creation. 38 00:02:29,670 --> 00:02:30,070 OK. 39 00:02:30,090 --> 00:02:33,880 And here for example consider this search term effect. 40 00:02:33,910 --> 00:02:40,030 OK so now as you can see I chose a name for my argument. 41 00:02:40,140 --> 00:02:40,550 OK. 42 00:02:40,560 --> 00:02:43,010 As you can see the name of my argument is value. 43 00:02:43,010 --> 00:02:50,370 OK so now I want to actually show you another type of setter method with an argument that has the same 44 00:02:50,370 --> 00:02:53,800 name as this instance variable. 45 00:02:53,820 --> 00:02:57,300 So now let me actually comment out this set in my foot here. 46 00:02:57,300 --> 00:03:02,050 So I want to actually create a set in my faith for my speed instance variable. 47 00:03:02,250 --> 00:03:06,140 So the access modifier of my method is public. 48 00:03:06,690 --> 00:03:07,450 OK. 49 00:03:07,740 --> 00:03:12,100 And the return type of My method is void. 50 00:03:12,420 --> 00:03:16,010 The name of my method is set speed. 51 00:03:16,560 --> 00:03:17,210 OK. 52 00:03:17,640 --> 00:03:22,790 And then inside the apprentice's I can specify the arguments of my method. 53 00:03:22,920 --> 00:03:30,900 So the data type of my argument is int and the name of my argument this time is speed. 54 00:03:31,380 --> 00:03:32,150 OK. 55 00:03:32,430 --> 00:03:37,020 And then I need to open and close my method by using these curly braces. 56 00:03:37,020 --> 00:03:37,520 OK. 57 00:03:37,650 --> 00:03:38,750 As you can see here. 58 00:03:38,760 --> 00:03:44,770 So inside a method or even to actually refer to this speed instance variable. 59 00:03:44,850 --> 00:03:51,450 Ok so I cannot just type in here speed and then put an assignment operator here and then revert to the 60 00:03:51,450 --> 00:03:53,580 name of this argument here speed. 61 00:03:53,960 --> 00:03:55,770 Ok this is not right. 62 00:03:56,150 --> 00:03:56,720 OK. 63 00:03:56,730 --> 00:03:58,080 There is a problem here. 64 00:03:58,320 --> 00:04:04,670 Here in this line of code we are actually referring to this speed local variable two times. 65 00:04:04,740 --> 00:04:05,290 OK. 66 00:04:05,310 --> 00:04:10,640 In this line of code we are not actually referring to this instance variable at all. 67 00:04:10,800 --> 00:04:17,700 OK because we've got an local variable with the same name as our speed instance variable. 68 00:04:17,700 --> 00:04:18,250 OK. 69 00:04:18,540 --> 00:04:25,650 And here inside the Mefford we are actually referring only to this speed local variable not this instance 70 00:04:25,650 --> 00:04:26,690 variable. 71 00:04:26,730 --> 00:04:32,430 So in order to solve this problem we need to actually put the key word this here. 72 00:04:32,430 --> 00:04:38,630 So this dot speed assignment operator speed. 73 00:04:38,910 --> 00:04:43,880 So here as you can see I am referring to this speed instance variable. 74 00:04:43,910 --> 00:04:44,830 Ok so here. 75 00:04:44,850 --> 00:04:49,120 This means this keyword here means this class. 76 00:04:49,140 --> 00:04:49,880 OK. 77 00:04:50,190 --> 00:04:51,880 That's speed. 78 00:04:51,990 --> 00:04:57,620 And by using the dot notation we can actually access the instance variables of this class. 79 00:04:57,640 --> 00:05:02,490 Ok I could successfully is this split into this variable. 80 00:05:02,680 --> 00:05:05,150 And then I put an assignment operator here. 81 00:05:05,190 --> 00:05:08,320 Here actually referred to this argument. 82 00:05:08,340 --> 00:05:10,050 Ok to the name of this argument. 83 00:05:10,210 --> 00:05:10,670 OK. 84 00:05:10,750 --> 00:05:15,090 So this is another way for actually writing in your system if it's OK. 85 00:05:15,100 --> 00:05:21,460 You can actually specify a name like value for your arguments and then inside the method you can easily 86 00:05:21,460 --> 00:05:24,490 refer to the name of your instance variable. 87 00:05:24,490 --> 00:05:28,940 And then you can assign that argument to your instance variable. 88 00:05:29,200 --> 00:05:36,460 But if you want to actually use the same name as your instance variable for your argument name you need 89 00:05:36,460 --> 00:05:40,840 to actually put this key vote here and then use the documentation. 90 00:05:41,080 --> 00:05:44,290 And then you can access this instance variable. 91 00:05:44,290 --> 00:05:50,770 And after that we can actually assign this argument to your instance variable. 92 00:05:50,770 --> 00:05:55,630 Ok so this is another way for actually creating your set her Moffats. 93 00:05:55,640 --> 00:05:58,410 OK for our power instance variable. 94 00:05:58,540 --> 00:06:05,920 So here I can I try to comment out this certain method and then I can actually create a set method for 95 00:06:05,920 --> 00:06:08,230 my power instance variable. 96 00:06:08,410 --> 00:06:16,040 So the access modifier of my method is public and the return type of My method is void. 97 00:06:16,120 --> 00:06:19,460 The name of my method is said Power. 98 00:06:19,960 --> 00:06:25,720 And then inside the parenthesis I need to specify the arguments of my method. 99 00:06:25,960 --> 00:06:33,850 So if it is going to actually accept one argument so the data type of my argument is int and the name 100 00:06:33,850 --> 00:06:42,880 of my argument this time is power and then I need to open and close my method by using these curly braces. 101 00:06:42,880 --> 00:06:43,520 OK. 102 00:06:43,720 --> 00:06:48,920 So here first of all I want to actually refer to the power instance variable. 103 00:06:49,120 --> 00:06:52,530 So I need to actually put this key word here. 104 00:06:52,660 --> 00:06:55,910 These dots power. 105 00:06:56,110 --> 00:06:59,240 So here this refers to this dog class. 106 00:06:59,260 --> 00:07:00,320 OK. 107 00:07:00,490 --> 00:07:06,520 And then we use the starting rotation and then if we refer to our power instance variable as you can 108 00:07:06,520 --> 00:07:14,010 see here and then we put an assignment operator here and then we referred to the name of our argument. 109 00:07:14,020 --> 00:07:14,560 OK. 110 00:07:14,680 --> 00:07:21,060 Now I want to show you how you can create these getters and setters in another way. 111 00:07:21,280 --> 00:07:21,860 OK. 112 00:07:22,300 --> 00:07:33,810 So for example let me actually comment out this get on my feet here and let me comment out this setter 113 00:07:33,820 --> 00:07:34,700 here. 114 00:07:37,490 --> 00:07:43,120 So now I want to actually create our get here and our set here for my speed. 115 00:07:43,130 --> 00:07:44,410 Instance variable. 116 00:07:44,570 --> 00:07:45,210 Ok. 117 00:07:45,590 --> 00:07:46,490 So here. 118 00:07:46,940 --> 00:07:51,590 First of all I want to create a get out of my faith for my speed instance variable. 119 00:07:51,680 --> 00:07:54,870 So the access modifier public. 120 00:07:55,390 --> 00:07:56,080 OK. 121 00:07:56,330 --> 00:08:04,130 And the return type of my Manford is in and the name of my method is good speed 122 00:08:06,930 --> 00:08:07,890 Okay. 123 00:08:08,440 --> 00:08:12,110 And then I need to put in a pair of round brackets after my name. 124 00:08:12,310 --> 00:08:16,510 And then I need to open and close my method by using these curly braces. 125 00:08:16,510 --> 00:08:16,900 OK. 126 00:08:16,930 --> 00:08:24,040 So inside this method I want to actually get the value of this instance variable and then do some operations 127 00:08:24,250 --> 00:08:27,260 on the value of this spit instance instance value. 128 00:08:27,310 --> 00:08:30,200 And after that I want to return that value. 129 00:08:30,310 --> 00:08:32,050 So let me show you how we can do that. 130 00:08:32,140 --> 00:08:41,180 So first of all I referred to the name of my speed instance variable speed OK and then I put an assignment 131 00:08:41,210 --> 00:08:48,950 operator here and then again I refer to the name of my spit instance variable and then here I want to 132 00:08:48,950 --> 00:08:57,230 multiply the value of this instance variable by 2 and then I want to assign that value to my speed instance 133 00:08:57,230 --> 00:08:57,990 variable here. 134 00:08:58,020 --> 00:09:04,560 OK so now I want to return that value speed. 135 00:09:04,760 --> 00:09:12,680 So as you can see here this time I didn't actually return the value of this instance variable directly. 136 00:09:12,680 --> 00:09:16,050 First I did some changes to this value. 137 00:09:16,220 --> 00:09:23,840 And then I assigned that value to this instance variable and in line 11 and I returned the value of 138 00:09:23,840 --> 00:09:25,450 the speed instance variable. 139 00:09:25,580 --> 00:09:32,510 So now inside the main class here let me actually create another object from the class. 140 00:09:32,510 --> 00:09:36,410 First of all I need to refer to the name of my dog class 141 00:09:39,370 --> 00:09:40,130 OK. 142 00:09:40,560 --> 00:09:43,290 And then I need to get my object on name. 143 00:09:43,440 --> 00:09:48,950 So for example the name of my object is my fourth dog. 144 00:09:49,470 --> 00:09:50,320 OK. 145 00:09:50,730 --> 00:09:53,360 And then I put an assignment operator here. 146 00:09:53,700 --> 00:09:56,740 And then I use this keyboard here new. 147 00:09:57,060 --> 00:09:59,890 And then again I'll refer to the name of my class. 148 00:09:59,910 --> 00:10:00,490 OK. 149 00:10:00,690 --> 00:10:04,620 And then I put a pair of round brackets after my class name.