Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member

Understanding the object-oriented analysis and design processes

From: Foundations of Programming: Object-Oriented Design

Video: Understanding the object-oriented analysis and design processes

So we need those concepts and that vocabulary. But how do we make decisions about polymorphism and inheritance without actually knowing what our classes and objects are? Well, we need to go through a process to identify the classes for our application. Now whether you use a formal software development methodology or not, this is the entire point of object-oriented analysis and design, what classes do you need and what do they do? Now a lot of the formal methodologies have their own unique names for working through their process, but although there are multiple ways to approach this, the ideas are fairly similar, and we'll go through a typical approach using five steps.

Understanding the object-oriented analysis and design processes

So we need those concepts and that vocabulary. But how do we make decisions about polymorphism and inheritance without actually knowing what our classes and objects are? Well, we need to go through a process to identify the classes for our application. Now whether you use a formal software development methodology or not, this is the entire point of object-oriented analysis and design, what classes do you need and what do they do? Now a lot of the formal methodologies have their own unique names for working through their process, but although there are multiple ways to approach this, the ideas are fairly similar, and we'll go through a typical approach using five steps.

One, gather your requirements. Two, describe the application. Three, identify the most important objects. Four, describe the interaction between those objects. And five, create a class diagram. Now we're going to talk about all of these in more detail, and we'll cover techniques you use for each step. But let's take it one level deeper right now. Step one is gathering your requirements. What does the app need to do? What problem are you trying to solve? And you focus here, you get specific, and you write it down, because that's the only way you're going to get past the conflicting and half-formed ideas people have about what this app could do versus what the app is going to do.

Step two is you then describe the application, you build a simple narrative in plain conversational language for how people use the app. You're not trying to write a book, but you are trying to describe in small self-contained pieces, and there are some specific techniques for this, including use cases and user stories, which we'll talk about shortly. Now this is not exhaustive, you're looking for the smallest set of stories that will make this a real application. We're going to make the assumption that what we have here may be inaccurate, it may be incomplete, it may change. That's okay. We still do it.

Now you may or may not at this point also create a mockup or a prototype of the user interface. Sometimes that is essential and sometimes it's just a distraction. We move on to step three, identifying the most important objects. Now this is actually the starting point of identifying your actual classes. So you're trying to use the stories, the descriptions you just wrote to pick out the most important ideas, the most important concepts, the most important things in our application and discard what's around it.

Not everything we pick here will become a class, but a lot of them will. Step four is you then formally describe the interactions between those objects, our customer needs to open a bank account, a spaceship needs to explode when it touches an asteroid. Now this also lets you start to better understand the responsibilities of the different objects, the behaviors they need to have. And when they interact with other objects, what they do and what order they need to do it in. And one way to do this is what's called a sequence diagram.

And step five is Create a Class Diagram. This is a visual representation of the classes you need. And here is where you get to be really specific about object-oriented principles like inheritance and polymorphism. But at no point in any of this do you write code yet. The output is on paper, on index cards, on a whiteboard. It could be done using electronic tools, but it's really better on paper for now. And the main result you expect from the process is the Class Diagram.

That's the most common way you'll write down the classes you need to make, the methods in those classes, and the interaction between the different objects in your application. Now in an iterative approach to developing software, this is not done once, you will continually revisit and refine these steps over weeks and months of development. So we are going to cover these steps in much more detail, including how to create all the diagrams I've already mentioned. But first, we need to get specific about the requirements of our application.

Show transcript

This video is part of

Image for Foundations of Programming: Object-Oriented Design
Foundations of Programming: Object-Oriented Design

47 video lessons · 55942 viewers

Simon Allardice
Author

 
Expand all | Collapse all
  1. 11m 35s
    1. Welcome
      1m 25s
    2. Who this course is for
      1m 15s
    3. What to expect from this course
      3m 6s
    4. Exploring object-oriented analysis, design, and development
      1m 41s
    5. Reviewing software development methodologies
      4m 8s
  2. 26m 14s
    1. Why we use object-orientation
      2m 42s
    2. What is an object?
      5m 22s
    3. What is a class?
      4m 43s
    4. What is abstraction?
      2m 45s
    5. What is encapsulation?
      3m 45s
    6. What is inheritance?
      3m 35s
    7. What is polymorphism?
      3m 22s
  3. 12m 16s
    1. Understanding the object-oriented analysis and design processes
      4m 13s
    2. Defining requirements
      6m 9s
    3. Introduction to the Unified Modeling Language (UML)
      1m 54s
  4. 23m 35s
    1. Understanding use cases
      6m 11s
    2. Identifying the actors
      4m 16s
    3. Identifying the scenarios
      5m 7s
    4. Diagramming use cases
      4m 18s
    5. Employing user stories
      3m 43s
  5. 16m 36s
    1. Creating a conceptual model
      1m 59s
    2. Identifying the classes
      2m 27s
    3. Identifying class relationships
      2m 38s
    4. Identifying class responsibilities
      6m 43s
    5. Using CRC cards
      2m 49s
  6. 22m 25s
    1. Creating class diagrams
      6m 11s
    2. Converting class diagrams to code
      4m 57s
    3. Exploring object lifetime
      5m 55s
    4. Using static or shared members
      5m 22s
  7. 19m 49s
    1. Identifying inheritance situations
      6m 49s
    2. Using inheritance
      2m 43s
    3. Using abstract classes
      2m 2s
    4. Using interfaces
      4m 20s
    5. Using aggregation and composition
      3m 55s
  8. 9m 23s
    1. Creating sequence diagrams
      5m 18s
    2. Working with advanced UML diagrams
      2m 3s
    3. Using UML tools
      2m 2s
  9. 10m 39s
    1. Introduction to design patterns
      2m 40s
    2. Example: the singleton pattern
      4m 53s
    3. Example: the memento pattern
      3m 6s
  10. 21m 47s
    1. Introduction to object-oriented design principles
      2m 50s
    2. Exploring general development principles
      3m 55s
    3. Introduction to SOLID principles
      6m 43s
    4. Introduction to GRASP principles
      8m 19s
  11. 7m 1s
    1. Reviewing feature support across different object-oriented languages
      3m 50s
    2. Additional resources
      2m 27s
    3. Goodbye
      44s

Start learning today

Get unlimited access to all courses for just $25/month.

Become a member
Sometimes @lynda teaches me how to use a program and sometimes Lynda.com changes my life forever. @JosefShutter
@lynda lynda.com is an absolute life saver when it comes to learning todays software. Definitely recommend it! #higherlearning @Michael_Caraway
@lynda The best thing online! Your database of courses is great! To the mark and very helpful. Thanks! @ru22more
Got to create something yesterday I never thought I could do. #thanks @lynda @Ngventurella
I really do love @lynda as a learning platform. Never stop learning and developing, it’s probably our greatest gift as a species! @soundslikedavid
@lynda just subscribed to lynda.com all I can say its brilliant join now trust me @ButchSamurai
@lynda is an awesome resource. The membership is priceless if you take advantage of it. @diabetic_techie
One of the best decision I made this year. Buy a 1yr subscription to @lynda @cybercaptive
guys lynda.com (@lynda) is the best. So far I’ve learned Java, principles of OO programming, and now learning about MS project @lucasmitchell
Signed back up to @lynda dot com. I’ve missed it!! Proper geeking out right now! #timetolearn #geek @JayGodbold
Share a link to this course

What are exercise files?

Exercise files are the same files the author uses in the course. Save time by downloading the author's files instead of setting up your own files, and learn by following along with the instructor.

Can I take this course without the exercise files?

Yes! If you decide you would like the exercise files later, you can upgrade to a premium account any time.

Become a member Download sample files See plans and pricing

Please wait... please wait ...
Upgrade to get access to exercise files.

Exercise files video

How to use exercise files.

Learn by watching, listening, and doing, Exercise files are the same files the author uses in the course, so you can download them and follow along Premium memberships include access to all exercise files in the library.


Exercise files

Exercise files video

How to use exercise files.

For additional information on downloading and using exercise files, watch our instructional video or read the instructions in the FAQ .

This course includes free exercise files, so you can practice while you watch the course. To access all the exercise files in our library, become a Premium Member.

Are you sure you want to mark all the videos in this course as unwatched?

This will not affect your course history, your reports, or your certificates of completion for this course.


Mark all as unwatched Cancel

Congratulations

You have completed Foundations of Programming: Object-Oriented Design.

Return to your organization's learning portal to continue training, or close this page.


OK
Become a member to add this course to a playlist

Join today and get unlimited access to the entire library of video courses—and create as many playlists as you like.

Get started

Already a member ?

Become a member to like this course.

Join today and get unlimited access to the entire library of video courses.

Get started

Already a member?

Exercise files

Learn by watching, listening, and doing! Exercise files are the same files the author uses in the course, so you can download them and follow along. Exercise files are available with all Premium memberships. Learn more

Get started

Already a Premium member?

Exercise files video

How to use exercise files.

Ask a question

Thanks for contacting us.
You’ll hear from our Customer Service team within 24 hours.

Please enter the text shown below:

The classic layout automatically defaults to the latest Flash Player.

To choose a different player, hold the cursor over your name at the top right of any lynda.com page and choose Site preferences from the dropdown menu.

Continue to classic layout Stay on new layout
Exercise files

Access exercise files from a button right under the course name.

Mark videos as unwatched

Remove icons showing you already watched videos if you want to start over.

Control your viewing experience

Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.

Interactive transcripts

Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.

Learn more, save more. Upgrade today!

Get our Annual Premium Membership at our best savings yet.

Upgrade to our Annual Premium Membership today and get even more value from your lynda.com subscription:

“In a way, I feel like you are rooting for me. Like you are really invested in my experience, and want me to get as much out of these courses as possible this is the best place to start on your journey to learning new material.”— Nadine H.

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked
Terms and conditions of use

We've updated our terms and conditions (now called terms of service).Go
Review and accept our updated terms of service.