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diff --git a/usth/ICT2.7/P2L2 OO Software Engineering and UML Subtitles/26 - Use Case Diagram: Actors - lang_en_vs5.srt b/usth/ICT2.7/P2L2 OO Software Engineering and UML Subtitles/26 - Use Case Diagram: Actors - lang_en_vs5.srt deleted file mode 100644 index 4d80c61..0000000 --- a/usth/ICT2.7/P2L2 OO Software Engineering and UML Subtitles/26 - Use Case Diagram: Actors - lang_en_vs5.srt +++ /dev/null @@ -1,167 +0,0 @@ -1 -00:00:00,110 --> 00:00:02,320 -Now, let's look at use cases in a little more detail. - -2 -00:00:02,320 --> 00:00:05,480 -And start by defining exactly what an actor is. An actor - -3 -00:00:05,480 --> 00:00:08,710 -represents an entity, which can be a human or a device, - -4 -00:00:08,710 --> 00:00:12,750 -that plays a role within my system, so that interacts with my - -5 -00:00:12,750 --> 00:00:15,660 -system. It's some entity from the outside world, with respect to - -6 -00:00:15,660 --> 00:00:18,510 -my system, that interacts with my system. It is important to - -7 -00:00:18,510 --> 00:00:21,750 -clarify that an entity can play more than one role. For - -8 -00:00:21,750 --> 00:00:25,240 -example, you might have somebody working in a bank that can be - -9 -00:00:25,240 --> 00:00:28,400 -both an employee of the bank, or a customer of - -10 -00:00:28,400 --> 00:00:31,280 -the bank, depending on how it interacts with the banking - -11 -00:00:31,280 --> 00:00:34,360 -system. And, obviously, more than one entity can play the - -12 -00:00:34,360 --> 00:00:37,570 -same role. Using the same example, we can have both an - -13 -00:00:37,570 --> 00:00:40,350 -employee of the bank and just a regular customer, playing - -14 -00:00:40,350 --> 00:00:43,280 -the role of the customer. So again, it all depends on - -15 -00:00:43,280 --> 00:00:46,120 -what the entity does, how the entity interacts with the - -16 -00:00:46,120 --> 00:00:50,150 -system, what kind of functionality of the system the entity uses. - -17 -00:00:50,150 --> 00:00:53,270 -And finally, actors may appear in more than one use case. - -18 -00:00:53,270 --> 00:00:55,930 -So it's fairly normal for the same actor to interact with - -19 -00:00:55,930 --> 00:00:58,540 -the system in different ways. And therefore, to appear in more - -20 -00:00:58,540 --> 00:01:00,710 -than one use case. Just think about the use cases in - -21 -00:01:00,710 --> 00:01:04,230 -scenarios of usage. If the same actor can interact with the - -22 -00:01:04,230 --> 00:01:07,440 -system in different ways, that actor will appear in multiple use - -23 -00:01:07,440 --> 00:01:11,210 -cases. Now let's go back to the description of our course - -24 -00:01:11,210 --> 00:01:15,140 -management system, and see how we can identify actors in the system. - -25 -00:01:15,140 --> 00:01:17,500 -And as we did for the class diagram before, I encourage - -26 -00:01:17,500 --> 00:01:20,160 -you to stop the video and try to identify the actors - -27 -00:01:20,160 --> 00:01:22,301 -in the system yourself, before I do it. - -28 -00:01:23,475 --> 00:01:27,250 -If we look at the description, we can see that, for example, the Registration - -29 -00:01:27,250 --> 00:01:30,890 -Manager is clearly an actor for the system. Students are actors - -30 -00:01:30,890 --> 00:01:34,400 -for the system. Professors are actors for the system. And notice - -31 -00:01:34,400 --> 00:01:36,060 -that we're not doing the same thing that we were doing - -32 -00:01:36,060 --> 00:01:38,360 -when identifying classes. Here we're identifying - -33 -00:01:38,360 --> 00:01:40,460 -entities that are from the outside - -34 -00:01:40,460 --> 00:01:43,090 -world, and have an active role in interacting with my - -35 -00:01:43,090 --> 00:01:46,830 -system. Again, Registration Manager, that we will just call registrar for - -36 -00:01:46,830 --> 00:01:50,660 -simplicity, students, and professors. So once we have identified the - -37 -00:01:50,660 --> 00:01:53,760 -actors for our example, we can simply draw them, using the - -38 -00:01:53,760 --> 00:01:56,550 -notation that we just introduced. So we have the registrar, - -39 -00:01:56,550 --> 00:01:59,830 -and notice how for every actor we clarify the role that - -40 -00:01:59,830 --> 00:02:02,450 -the actor plays. We have the professor, and we have - -41 -00:02:02,450 --> 00:02:05,480 -the student. So here, these are the three actors that we - -42 -00:02:05,480 --> 00:02:07,000 -identified for our system. |