1 00:00:00,610 --> 00:00:06,170 You guys the next pattern we're going to look at is another behavioral pattern like the observer. 2 00:00:06,240 --> 00:00:12,240 It's called the Mediator pattern and the idea is to have a mediator which is basically an interface 3 00:00:12,240 --> 00:00:17,700 for communicating with what are called colleagues which are just mediated objects. 4 00:00:17,820 --> 00:00:21,250 And I think one of the best examples of this is a chat room. 5 00:00:21,270 --> 00:00:26,850 Now this won't be a full project but if you want to implement this you know along with something like 6 00:00:26,850 --> 00:00:33,900 socket I O you could do that but let's go ahead and just create a very basic example that kind of shows 7 00:00:33,900 --> 00:00:36,980 you how the Mediator Pattern is put together. 8 00:00:37,620 --> 00:00:42,460 So we're going to have to construct functions one for the user one for the chat room. 9 00:00:42,450 --> 00:00:52,290 So let's say Konst user set that to a function and each user will have a name. 10 00:00:52,410 --> 00:00:57,000 So we want to set this on name equal to name. 11 00:00:57,150 --> 00:01:03,410 And then we're also going to set this chat room and we're going to initially set that to now. 12 00:01:03,840 --> 00:01:10,560 OK and then we'll also have a constructor function for the chat room. 13 00:01:10,860 --> 00:01:14,390 So we'll set that to function. 14 00:01:15,960 --> 00:01:21,150 And that's not going to take anything in and it's just going to have a property called users which will 15 00:01:21,150 --> 00:01:25,860 be set to just an empty object to start with. 16 00:01:25,860 --> 00:01:29,270 All right so this will be a list of users. 17 00:01:29,340 --> 00:01:33,280 So let's go to the user constructor first. 18 00:01:33,360 --> 00:01:35,660 And actually we're going to create a prototype here. 19 00:01:35,670 --> 00:01:40,010 So it's a user Dortch prototype. 20 00:01:40,170 --> 00:01:43,820 And by the way if you guys want to use ESX classes that's fine. 21 00:01:43,830 --> 00:01:51,540 I think in my opinion you should get used to writing object oriented code like this because this is 22 00:01:51,540 --> 00:02:00,650 what is actually being this is what is actually in the javascript classes are just sugar over this. 23 00:02:00,870 --> 00:02:06,330 Of course you can you know you can you you can write classes but I would suggest when you're practicing 24 00:02:06,390 --> 00:02:09,450 I would suggest doing it this way but it's up to you. 25 00:02:09,450 --> 00:02:12,480 You know you guys can write this as a class if you want. 26 00:02:12,720 --> 00:02:16,710 So and I've done a couple of examples where you can see how to do that. 27 00:02:16,710 --> 00:02:21,780 I mean it's pretty simple you just create your constructor in your class put your properties and then 28 00:02:22,050 --> 00:02:26,980 each of these prototype methods will be an actual class method. 29 00:02:27,000 --> 00:02:29,410 So in here let's do a send. 30 00:02:29,590 --> 00:02:31,470 OK we're going to have a send function 31 00:02:35,640 --> 00:02:41,360 and we're going to have a receive function. 32 00:02:42,180 --> 00:02:49,230 And the idea is to be able to have users that can send messages to another single user or to broadcast 33 00:02:49,230 --> 00:02:51,050 to the entire chat room. 34 00:02:51,050 --> 00:02:51,360 All right. 35 00:02:51,360 --> 00:02:59,570 And again the chat the chat room is the mediator and then the users of the colleagues of the chat room. 36 00:02:59,700 --> 00:03:06,840 So the center function will take in any message and a to sort of be wherever the messages and then the 37 00:03:06,840 --> 00:03:07,790 user. 38 00:03:08,020 --> 00:03:09,280 The to use. 39 00:03:09,600 --> 00:03:14,160 And this will actually call from the chat room. 40 00:03:14,160 --> 00:03:18,050 So say this chat room door send. 41 00:03:18,090 --> 00:03:23,550 Chat Room will also have a send and that will pass in the message. 42 00:03:23,590 --> 00:03:28,030 The two I'm sorry this message is this. 43 00:03:28,050 --> 00:03:34,080 And then two this is pertaining to the user. 44 00:03:34,080 --> 00:03:35,600 All right so let's see. 45 00:03:35,610 --> 00:03:42,280 After that we want to do the receive and the receive is going to take in a message. 46 00:03:42,330 --> 00:03:44,470 It's going to take in a from. 47 00:03:44,790 --> 00:03:45,210 OK. 48 00:03:45,210 --> 00:03:52,090 And then all we want to do when it's received is Konsole dot log and we'll put some back ticks in here 49 00:03:52,090 --> 00:03:54,150 and we're going to put the name. 50 00:03:54,210 --> 00:04:00,450 So we're going to say from DOT name from DOT name to 51 00:04:03,220 --> 00:04:04,230 the current user. 52 00:04:04,230 --> 00:04:06,630 So this Doughton name 53 00:04:09,700 --> 00:04:13,890 and then we want to put the message. 54 00:04:14,950 --> 00:04:15,690 All right. 55 00:04:15,870 --> 00:04:17,270 And that's it for the user. 56 00:04:17,430 --> 00:04:25,750 So now the chat room we're going to go down in and we're going to say return 57 00:04:28,420 --> 00:04:34,240 and here we're going to first have a register because we need users to register with the chat room. 58 00:04:34,360 --> 00:04:37,600 OK the colleagues have to register with the mediator. 59 00:04:37,810 --> 00:04:44,500 So we'll have this as a function that will take in the actual user. 60 00:04:45,370 --> 00:04:45,860 OK. 61 00:04:45,880 --> 00:04:54,550 And then we're going to set users and then as a key We're going to use user dog name. 62 00:04:54,550 --> 00:04:54,930 All right. 63 00:04:54,930 --> 00:05:00,320 So user name and we're going to set that to the user that's being passed in. 64 00:05:01,090 --> 00:05:10,480 And then we just want to set user dot chat room to this day to get to the current chat room and if we 65 00:05:10,480 --> 00:05:16,600 look in the user construct or this chat room it is now by default but now we're setting it to the current 66 00:05:16,600 --> 00:05:18,340 chat room. 67 00:05:18,400 --> 00:05:23,820 Now the chat is also going to have a sense that's what we're doing right here is seeing this chat room 68 00:05:23,820 --> 00:05:24,890 Dotts send. 69 00:05:25,060 --> 00:05:27,560 So we have to add that to the register 70 00:05:34,150 --> 00:05:42,370 and this takes in as you can see here message this which is actually going to be from user and then 71 00:05:42,370 --> 00:05:53,460 to the two years or so here we're going to see a message and from end to. 72 00:05:53,650 --> 00:05:53,990 All right. 73 00:05:54,000 --> 00:05:59,540 Now here's where we need to decide if the message is going to a certain use or if it's going to be broadcasted 74 00:05:59,540 --> 00:06:00,680 to the entire run. 75 00:06:00,680 --> 00:06:05,100 So we're going to check to see if there's a true value. 76 00:06:05,360 --> 00:06:07,130 So we'll say if. 77 00:06:07,550 --> 00:06:20,740 And let's put in place here so if to that is a single user message so will say to dog or see you've 78 00:06:22,180 --> 00:06:31,790 never going to pass the message and then from value else then we're actually going to loop through all 79 00:06:31,790 --> 00:06:33,770 of the users and do the receive. 80 00:06:33,770 --> 00:06:41,460 So let's do a for loop and we'll just say this is a mouse message. 81 00:06:41,540 --> 00:06:42,890 So we'll save for 82 00:06:45,590 --> 00:06:56,610 let's say for key users and then we're going to check in to do an if statement here in me and we're 83 00:06:56,630 --> 00:07:02,990 going to say if users key we want to make sure that it's not the act of the user that's sending it so 84 00:07:03,020 --> 00:07:15,980 if it's not equal to the from user then we want to call users and key and then do our receive. 85 00:07:16,000 --> 00:07:16,480 All right. 86 00:07:16,500 --> 00:07:21,800 And Percival taken message in from just like it did right here. 87 00:07:21,830 --> 00:07:22,220 All right. 88 00:07:22,220 --> 00:07:24,090 So that should do it. 89 00:07:24,110 --> 00:07:27,310 So that gives us our interface Let's go ahead and save it. 90 00:07:27,410 --> 00:07:32,180 Now down here is where we're going to use our pattern here. 91 00:07:32,180 --> 00:07:40,700 So we're going to create a couple of users so let's say conc Brad cools and we'll say new user and that 92 00:07:40,700 --> 00:07:41,660 takes in a name 93 00:07:44,450 --> 00:07:46,710 we'll do a couple. 94 00:07:47,420 --> 00:07:55,940 Let's say Brad will say Jeff and let's say Sarah 95 00:08:01,540 --> 00:08:02,950 so that will create some users. 96 00:08:02,950 --> 00:08:10,420 Now we want to create the chat room the mediator So let's say a chat room equals new 97 00:08:14,200 --> 00:08:17,140 do a chat room like that 98 00:08:20,220 --> 00:08:23,030 and then down here we want to register the users. 99 00:08:23,080 --> 00:08:32,040 So it's a chat room keep it in uppercase our chat room door register know we want to register. 100 00:08:32,040 --> 00:08:32,720 Brad 101 00:08:38,680 --> 00:08:39,990 it's registered. 102 00:08:40,000 --> 00:08:45,250 Jeff and all registers. 103 00:08:45,710 --> 00:08:49,160 OK so now that everyone is registered we should be able to send messages. 104 00:08:49,160 --> 00:08:53,720 So let's say Brad Daunt send. 105 00:08:53,990 --> 00:08:58,150 Let's say hello Jeff. 106 00:08:58,310 --> 00:09:02,750 And then the second parameter is going to be the user I want to send to which is Jeff. 107 00:09:02,750 --> 00:09:05,560 So let's go ahead and save that we get Brad to G.F.. 108 00:09:05,750 --> 00:09:07,320 Hello Jeff. 109 00:09:07,910 --> 00:09:16,740 So let's say that Sarah wants to send a message to Brad. 110 00:09:17,900 --> 00:09:18,830 Hello Brad. 111 00:09:18,830 --> 00:09:27,830 You are the best dev ever. 112 00:09:27,970 --> 00:09:31,290 I can't even spell his own name. 113 00:09:31,910 --> 00:09:33,090 So Sarid a brad. 114 00:09:33,110 --> 00:09:33,770 Hello Brad. 115 00:09:33,770 --> 00:09:35,550 You were the best ever. 116 00:09:35,570 --> 00:09:47,100 Now let's say that Jeff wants to send the message to the whole room so he'll just say hello everyone. 117 00:09:49,250 --> 00:09:51,260 And say when you can see Jeff too Brad. 118 00:09:51,260 --> 00:09:52,820 Hello everyone Jeff to Sarah. 119 00:09:52,820 --> 00:09:53,890 Hello everyone. 120 00:09:53,900 --> 00:10:00,620 He doesn't say it to himself because here we check to see we made sure that it wasn't the from user 121 00:10:00,650 --> 00:10:02,580 that was going to send the message. 122 00:10:02,830 --> 00:10:03,220 All right. 123 00:10:03,230 --> 00:10:05,250 Or received the message I should say. 124 00:10:05,810 --> 00:10:10,290 OK so that I think is a pretty good example of the Mediator pattern. 125 00:10:10,460 --> 00:10:13,970 Hopefully that made sense to you and I will see you in the next video.