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+1
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+So how do we represent a class in a class
+
+2
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+diagram? Class is represented as a rectangle with three parts. The
+
+3
+00:00:06,140 --> 00:00:09,290
+first part is the class name. Classes should be named using
+
+4
+00:00:09,290 --> 00:00:12,160
+the vocabulary of the domain, so we should pick names that
+
+5
+00:00:12,160 --> 00:00:16,059
+make sense. And the normal naming standard requires that the classes
+
+6
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+are singular nouns starting with a capital letter. The second part
+
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+00:00:19,720 --> 00:00:22,840
+of the class are the attributes of the class, where the
+
+8
+00:00:22,840 --> 00:00:25,310
+set of attribute for the class, we find the state for
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+9
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+the class. And, we can list an attribute simply by
+
+10
+00:00:27,940 --> 00:00:31,060
+name, or we can provide the additional information. For example,
+
+11
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+we might define the title of the attribute, and we
+
+12
+00:00:33,520 --> 00:00:37,450
+might also define the initial. Value for the attribute. Finally, the
+
+13
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+third part of the class consist of the operations of
+
+14
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+the class. And normally, the operations of the class are represented
+
+15
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+by name, with a list of arguments. That the operation
+
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+will take as input, and with a result type. So the
+
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+type of the result produced by the operation. Something
+
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+else you can notice in this representation is the
+
+19
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+fact that there is a minus before these attributes
+
+20
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+and a plus before this operation. This indicates what is
+
+21
+00:01:01,810 --> 00:01:04,739
+called the visibility of these class members. So the
+
+22
+00:01:04,739 --> 00:01:08,950
+minus indicates that the attributes are private to the class.
+
+23
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+So only instances of this class, roughly speaking, can
+
+24
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+access these attributes. And notice that this is what allows
+
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+to enforce the information hiding principle, because clients of
+
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+the class cannot see what's inside this box, what are
+
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+these attributes. The plus conversely indicates that this is a
+
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+public operation. So something that is visible outside the class.
+
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+And, in fact, normally, this is what we use to
+
+30
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+define the interface for my class. So we encapsulate the
+
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+state of the class and we make it accessible to
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+the extent that we want and that is needed through
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+a set of public operations. Last thing I want to
+
+34
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+note is the use of these ellipses that we can
+
+35
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+utilize if we want to indicate that there are more
+
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+attributes for example, or more operations. But we just don't
+
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+want to list them now. Okay now that we know what
+
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+a class is, and how it is represented, let's start
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+our analysis of our course management system. By identifying the
+
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+relevant classes in the system, we need to bring back the
+
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+description of our system. And what we want to
+
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+do, is that we want to go through the description
+
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+and underline the relevant nouns in the description. And here
+
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+I encourage you to stop the video and to do
+
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+the exercise of underlying such nouns yourself before listening to
+
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+my explanation into how I do it. For example in
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+this case I might want to underlined the registration manager which
+
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+is a noun and probably a relevant one. The scheduling
+
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+algorithm, also seems like a relevant concept, so
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+50
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+is the course. The course offerings, again, course offerings
+
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+over here. Definitely, the students seem to be a
+
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+relevant noun and so is probably the registration form
+
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+and the professors. Okay, so, at this point, I
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+identified seven possible classes for my system. So, what
+
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+I'm going to do is simply to create classes for
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+each one of these nouns. So my initial class
+
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+diagram looks exactly like this, with the seven classes where
+
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+for each class, I picked the name that is representative of
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+59
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+the domain. So, in this case, it's pretty straightforward. The
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+60
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+registration form is called registration form, the student is called student
+
+61
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+and so on and so forth. But you can already
+
+62
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+see how this analysis method is starting from a description of
+
+63
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+the real world and it's just identifying objects or classes
+
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+in the real world and transforming them into entities in my
+
+65
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+analysis document.