UML - OOD unified approach

Object-oriented design unified approach

So in the previous video we have discussed object-oriented ysis unified approach

Prior to that we have discussed what is the unified approach and layered architecture

So in this video we are concentrating only on object-oriented design unified approach

So what are the different steps are to be followed in which order that will be explained

explicitly. So let us define the what is the axioms. So an axiom is a fundamental truth

that always is observed to be valid and for which there is no counter example or exception

So action is nothing but a fundamental truth and against which there is no exception

there is no counter example. So Schuze defines axioms can be hypothesized from a large number of

observation by noting the common phenomena shared by all cases. They cannot be proven or derived, but counter examples or exceptions can invalidate them

So this is the actual definition of axioms. So now we are going to discuss what is corollary

So corollary is a proposition that follows from an axioms or from another proposition that has

already been proven again a corollary is shown to be valid if its

referent axioms and deductive steps are valid so here you see these are

the axioms and here we have derived of multiple different corollaries and

here you see we're having multiple different corollaries are there and here we're

having some set of actions so this particular corollary has been derived from this

axiom one along with the axioms too So now we are going to discuss that is our object design step one So here we will be going for business design the business layer classes So apply design axioms to design classes that attributes methods

associations, structures, and the respective protocols. So what are the different attributes

Attribute means those variables which will be defined under this class and can contain some values

So the respective attributes and the methods means what are the different functionalities

can be performed and associations how these classes have got associated that are

multiple different associations are there will be discussing that one in the next

videos and structures and the protocols refine and complete the EML class

diagram by adding details this step consists of refined attributes methods cardinarity visibility association and class hierarchy always we

should go for the required number of attributes don't go on adding redundant attributes to make the class

heavy to understand heavy to deal with so refined attribute means we're going

for those attributes which are essential to represent that very respective class

design methods and protocols by utilizing euml activity diagram to represent the methods and the respective algorithms so using euml activity diagrams

so what is the email activity diagram so here in case of euml activity diagram so here in case of UML activity diagram we can say that how one activity can be initiated

after which activity in which sequence these activities can be initiated we're

having one starting state will be having one final state so all this detailing

we have discussed in our activity diagram chapter refine association between classes if required and refined class hierarchy and design with inheritance if required

so inheritance means we're going for generalization So iterate and refine again and again until the respective business layer classes have got refined Step number two that is the object design step number two design access layer classes create access layer classes for every classes identified

and created in business layer and simple mirror the class that means in case of

access layer classes we are very much close to now to the database so how to access

data from the databases how to have the fruitful and efficient storing and retrieval of the data, these classes will be handling that one

Identify class access layer class relationships. Simplify classes and their relationships by

eliminating redundant classes and classes with single method. So in this way, we are going

for optimization of the classes. Each and every class should not have any redundant attribute

or method, and class numbers, number of classes should be refined accordingly

So we might be having classes like redundant classes. So classes that perform similar requests and activities are called as redundant classes

and selecting one and eliminating other simplifying these classes. If you find there are multiple classes who are behaving as the same

then we shall consider one of them and discarding the rest of them to make the system simple

We're having the method classes. So classes that consists of only one or two method

are called the method classes and they can be eliminated or combined with existing classes if

possible if that is one class which is containing at least so only one method or say two methods

we are having so those classes will be known as the method classes so those classes are to be eliminated

or should be combined with the pre-existing classes where those classes are having higher number

of methods so iterate and refine them again and again until there are, you know

until this access layer classes have got optimized. So that is our object design step number two So now we going for object oriented design step number three so design view layer classes we know that these classes will be accessed by the

client by the user for interacting with the system so design the macro level user interfaces

and identify view layer objects so design the micro level user interface which includes these

following activities. Design the view layer objects by applying the design axioms and corollaries and build

a prototype of the view layer interface. At the beginning of this particular lecture, we have

discussed what are the coloraries and what are the axioms. So do the test for usability and user

satisfaction. So we can go for the feedback taking process or using some testing method

testing tools we can judge that whether this user interaction has been done properly implemented or not

So that's why do the test for usability and user satisfaction. And iterate and refine this view layer classes as far as practical

Now this is our object-oriented design step number four. So iterate and refine the whole design and reapply the design axioms and if needed

repeat the preceding steps if we require then you can go on repeating step number

one to step number four once again so design classes attributes methods

association and the respective structures then go for apply design actions build email class diagrams then design view and access layers and prototypes

and then user satisfaction usability tests based on use cases and this particular

testing will be done on very continuous basis until the object-oriented design has got its final shape

So in this way, we have discussed on this object-oriented design unified approach

Thanks for watching this video