1 00:00:00,240 --> 00:00:06,870 So here I want to for example assign another value to that speed instance variable. 2 00:00:07,040 --> 00:00:07,400 So. 3 00:00:07,430 --> 00:00:10,030 So I need to just refer to the name of my object. 4 00:00:10,050 --> 00:00:15,120 My second thought object that said Speed. 5 00:00:15,380 --> 00:00:16,090 OK. 6 00:00:16,320 --> 00:00:20,100 So here we need to actually pass our value to the Smurfette. 7 00:00:20,100 --> 00:00:22,990 For example number 24 OK. 8 00:00:23,520 --> 00:00:30,080 And here you are actually assigning another value to that speed instance variable. 9 00:00:30,240 --> 00:00:30,700 OK. 10 00:00:30,840 --> 00:00:33,150 But using this settled method. 11 00:00:33,350 --> 00:00:39,050 OK so now let me actually access that value by using q to get here my fifth. 12 00:00:39,060 --> 00:00:41,550 So if we need to actually refer to the name of an object. 13 00:00:41,550 --> 00:00:45,250 My second dog that gets Spizz. 14 00:00:45,780 --> 00:00:46,420 OK. 15 00:00:46,650 --> 00:00:49,980 And at the end of my statement I need to put in a semi-colon. 16 00:00:49,980 --> 00:00:58,350 So because this gets method returns an integer value we can actually directly output that value to the 17 00:00:58,350 --> 00:01:07,830 consulate k so we can just type in here a system that out that print to learn and that inside Apprentice's 18 00:01:08,220 --> 00:01:10,990 I can actually put this statement here. 19 00:01:11,170 --> 00:01:11,650 OK. 20 00:01:11,670 --> 00:01:16,020 My second dog that gets beat and then I can put that here. 21 00:01:16,280 --> 00:01:17,010 OK. 22 00:01:17,490 --> 00:01:22,920 So now I need to put in a semicolon at the end of my statement and if I it on my project. 23 00:01:22,930 --> 00:01:30,250 Now as you can see the value of the speed instance variable of this my second dark object is now 24. 24 00:01:30,280 --> 00:01:35,290 OK because we changed that value to 24 in line 19 OK. 25 00:01:35,340 --> 00:01:42,780 So for example if we want to actually output the value of this instance valuable before assigning this 26 00:01:42,780 --> 00:01:50,210 number 24 to the split instance variable Let's see how we can do that in this line of code. 27 00:01:50,210 --> 00:01:53,870 You are actually assigning another value to our instance variable. 28 00:01:54,030 --> 00:02:00,210 So before this line of code if you want to access the value of this instance variable i just need to 29 00:02:00,210 --> 00:02:03,980 type in system that out that insulin. 30 00:02:04,350 --> 00:02:09,730 And then inside Apprentice's I can just refer to the name of my object. 31 00:02:09,750 --> 00:02:17,320 My second dog don't get speed and then at the end of my statement I need to put in a semi-colon. 32 00:02:17,400 --> 00:02:25,740 So as you can see here R-value is 70 and in line 20 we decided to change that value to number 24 and 33 00:02:25,770 --> 00:02:30,020 in line 22 we decided to output that value to the console. 34 00:02:30,030 --> 00:02:30,480 OK. 35 00:02:30,630 --> 00:02:34,620 So disvalue here is the result of execution of this line of code here. 36 00:02:34,620 --> 00:02:35,340 OK. 37 00:02:35,400 --> 00:02:43,080 Or I can actually access the value of the power instance variable and output that value to the console 38 00:02:43,080 --> 00:02:43,640 OK. 39 00:02:43,830 --> 00:02:51,690 So I just need to type in here system got out that the print line and then inside the apprentice's I 40 00:02:51,690 --> 00:02:58,260 just need to revert to the name of my object and then I put the dot notation here and then I can access 41 00:02:58,500 --> 00:03:04,040 the value of the power instance variables by using this gets power method OK. 42 00:03:04,290 --> 00:03:09,630 And then I need to put in a semicolon at the end of my statements and if I get on my project. 43 00:03:09,660 --> 00:03:14,980 Now as you can see this is the value of the power instance variable of these. 44 00:03:15,000 --> 00:03:16,300 My second dog object. 45 00:03:16,320 --> 00:03:16,980 OK. 46 00:03:17,220 --> 00:03:25,080 Or I can actually set another value to that the power instance variable of the my second dog object. 47 00:03:25,080 --> 00:03:25,530 OK. 48 00:03:25,680 --> 00:03:34,860 So I just need to refer to the name of my object that said power and then I can actually pass another 49 00:03:34,860 --> 00:03:37,190 value to this method. 50 00:03:37,230 --> 00:03:38,800 For example number 40. 51 00:03:39,030 --> 00:03:47,800 And then I can actually again output the value of the power instance variable of this my second dog 52 00:03:47,920 --> 00:03:49,240 object to the console. 53 00:03:49,420 --> 00:03:54,250 So because this gets power my fed returns an integer value. 54 00:03:54,250 --> 00:03:56,910 I can actually assign that value to another right here. 55 00:03:57,220 --> 00:04:07,760 So I can't just type in here ain't returned value OK and that I can assign the value of the power instance 56 00:04:07,760 --> 00:04:09,410 variable to this value. 57 00:04:09,430 --> 00:04:09,810 OK. 58 00:04:09,890 --> 00:04:15,510 So I just need to refer to the name of my object that gets power. 59 00:04:15,780 --> 00:04:16,370 OK. 60 00:04:16,580 --> 00:04:19,450 And then I need to put in a semicolon at the end of my statement. 61 00:04:19,520 --> 00:04:24,530 And now I want to output the value of this variable to the console OK. 62 00:04:24,680 --> 00:04:33,380 So I just need to type in here a system that out that print line and then inside the prentices I can 63 00:04:33,380 --> 00:04:36,900 just refer to the name of my variable return value. 64 00:04:37,310 --> 00:04:40,360 And then I need to put in a semi-colon at the end of my statement. 65 00:04:40,510 --> 00:04:41,150 OK. 66 00:04:41,390 --> 00:04:49,490 And now if I get on my project as you can see this is the value of that power instance variable of this 67 00:04:49,490 --> 00:04:50,760 my second dog object. 68 00:04:50,800 --> 00:04:56,090 OK we changed that value from number 80 to number 40. 69 00:04:56,210 --> 00:04:57,000 OK. 70 00:04:57,320 --> 00:05:04,700 So as you can see here we used these setters and getters in order to access the value of our instance 71 00:05:04,720 --> 00:05:10,520 variables or we actually changed the value of those instance variables to another value. 72 00:05:10,690 --> 00:05:13,810 OK but still there is a big problem here. 73 00:05:13,990 --> 00:05:14,550 OK. 74 00:05:14,640 --> 00:05:22,280 So first of all let me point out that although we have setters and getters for our instance variables 75 00:05:22,340 --> 00:05:23,830 inside that class. 76 00:05:23,840 --> 00:05:24,340 OK. 77 00:05:24,470 --> 00:05:29,790 So this is our class and these are the setters and getters for our instance variables. 78 00:05:29,810 --> 00:05:30,710 OK. 79 00:05:31,160 --> 00:05:39,950 So although we have setters and getters for our instance variables but still I can access these instance 80 00:05:39,950 --> 00:05:42,500 variables from my main class. 81 00:05:42,500 --> 00:05:45,290 OK so now let me show you that. 82 00:05:45,410 --> 00:05:46,660 Inside the main class. 83 00:05:46,820 --> 00:05:50,580 I can easily access these instance variables directly. 84 00:05:50,600 --> 00:05:51,000 OK. 85 00:05:51,050 --> 00:05:55,620 So inside the main class let me actually comment out these lines of code here. 86 00:05:56,120 --> 00:06:01,960 And now I want to show you that still I can actually access those instance variables directly. 87 00:06:02,150 --> 00:06:06,280 So first I want to create another object from the class. 88 00:06:06,430 --> 00:06:09,990 Doug My first dog. 89 00:06:10,270 --> 00:06:10,880 Okay. 90 00:06:11,120 --> 00:06:14,110 And then I put an assignment operator here. 91 00:06:14,330 --> 00:06:16,610 And then I use this keyboard here Neal. 92 00:06:16,760 --> 00:06:23,090 And then again I refer to the name of my class and then I put a pair of round brackets after my class 93 00:06:23,090 --> 00:06:23,300 name. 94 00:06:23,300 --> 00:06:30,020 OK so now as you can see here I want to access the value of the speed instance variable and then output 95 00:06:30,080 --> 00:06:31,400 that value to the console. 96 00:06:31,580 --> 00:06:37,910 So I just need to type in here system that out but princeling and an inside Apprentice's. 97 00:06:37,940 --> 00:06:42,050 I need to refer to the name of my object that speed. 98 00:06:42,110 --> 00:06:49,820 So as you can see here I successfully managed to access this instance variable directory and this is 99 00:06:49,820 --> 00:06:51,030 not right. 100 00:06:51,200 --> 00:06:51,740 OK. 101 00:06:51,860 --> 00:06:53,850 So there is something wrong here. 102 00:06:53,870 --> 00:06:55,230 So what's the problem. 103 00:06:55,460 --> 00:07:03,530 The problem is we don't have any rules in order not to allow any other classes other than this dog class 104 00:07:03,990 --> 00:07:09,950 ok to access those instance variables directly. 105 00:07:09,950 --> 00:07:17,030 We shouldn't allow any other classes to access these instance variables directly. 106 00:07:17,030 --> 00:07:17,530 OK. 107 00:07:17,630 --> 00:07:24,950 We only want to allow any other classes other than this class to use these setters and getters that 108 00:07:25,010 --> 00:07:31,460 I provided for these instance variables in order to manipulate these instance variables. 109 00:07:31,520 --> 00:07:35,410 OK so now the question is what should we do. 110 00:07:35,480 --> 00:07:35,980 OK. 111 00:07:36,080 --> 00:07:44,420 In order not to allow any other classes other than this dog class to access these instance variables 112 00:07:44,420 --> 00:07:45,410 directly. 113 00:07:45,620 --> 00:07:50,530 And the answer is that we have to use the Java access modifiers. 114 00:07:50,720 --> 00:07:59,420 OK so what do you mean by access modifiers access modifiers are keywords in object oriented languages 115 00:07:59,660 --> 00:08:00,690 like Java. 116 00:08:00,890 --> 00:08:07,140 That set the accessibility of classes methods variables or objects. 117 00:08:07,200 --> 00:08:15,390 OK so now I'm going to show you some of those access modifiers that we use a lot in our Java programs. 118 00:08:15,390 --> 00:08:18,180 Their first access modifier is package. 119 00:08:18,210 --> 00:08:27,350 OK we have been using this access modifier in our previous projects and this means that if our variable 120 00:08:27,350 --> 00:08:35,380 for example uses the package access modifier that variable is going to be visible to the whole package. 121 00:08:35,470 --> 00:08:38,640 OK so now let me show you a real example. 122 00:08:38,660 --> 00:08:40,970 Now I want to create a variable here. 123 00:08:40,970 --> 00:08:43,500 For example inside the class. 124 00:08:43,550 --> 00:08:46,040 So int for example A. 125 00:08:46,220 --> 00:08:49,360 And then I can assign a value to a variable for example number of 32. 126 00:08:49,370 --> 00:08:53,510 So this variable uses the package access modifier. 127 00:08:53,650 --> 00:08:55,160 And you may vonder that. 128 00:08:55,180 --> 00:09:01,140 Or how did I actually identify the access modifier of this value. 129 00:09:01,220 --> 00:09:07,810 Because the package access modifier is the default access when the fire for all of our methods or variables. 130 00:09:07,850 --> 00:09:08,330 OK. 131 00:09:08,420 --> 00:09:14,330 And we don't need to actually specify that these are valuable uses the package access modifier. 132 00:09:14,440 --> 00:09:17,040 Ok by default it is package. 133 00:09:17,070 --> 00:09:23,960 OK so now as you can see here I can actually access this variable this instance variable from the main 134 00:09:24,140 --> 00:09:24,540 class. 135 00:09:24,570 --> 00:09:31,940 Ok so I can just refer to the name of my object and then I can actually access that variable and then 136 00:09:31,940 --> 00:09:34,750 I can assign another value to this variable. 137 00:09:34,820 --> 00:09:35,300 OK. 138 00:09:35,360 --> 00:09:38,680 The package means visible to the whole package. 139 00:09:38,870 --> 00:09:39,520 OK. 140 00:09:39,770 --> 00:09:48,020 So for example if I want to actually create another package in this project let's see how we can do 141 00:09:48,020 --> 00:09:48,310 that.