Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
We don’t allow questions seeking recommendations for books, tools, software libraries, and more. You can edit the question so it can be answered with facts and citations.
Closed 4 years ago.
Improve this question
I find that whenever I begin writing an app in Java/C#, things start off good, but over time, as the app becomes more complex, it just gets more and more complicated. I've become aware of the fact that I'm not very good at design and high level architecture. All my classes become fairly strongly coupled and the design isn't "elegant" at all. I'm fairly competent at "low level" programming. That is, I can get just about anything done within a function or a class, but my high level design is weak and I'd really like to improve it. Does anyone have pointers to techniques, books, etc. that would be helpful in making me a better software engineer?
I disagree about starting with a book on design patterns or refactoring.
In my opinion, for a solid OO design, you should first be familiar with the main OO design principles, then understand how your problem can be represented in those basic principles. Then you can start discovering opportunities for applying design patterns and refactoring techniques in order to achieve those fundamental principles.
I would start with this book:
Agile Software Development, Principles, Patterns, and Practices by Robert C. Martin
In this book, Robert Martin describes the fundamental principles that make a good OO design, all of them related to encapsulation, coupling and modularity:
The Open/Closed Principle
Liskov Substitution
Dependency Inversion
Granularity
Common Closure
Reuse
No Cyclic Dependency
Stability Of Dependency
Abstraction And Stability
After all, almost every Design Pattern and Refactoring technique I have seen documented in GoF and Fowler is aimed at achieving one of several of these basic principles, depending on their relative priority for a given scenario.
Books:
Code Complete, by Steve McConnel
Design Patterns, by Gamma, et. al.
I would start by sketching my design. That sketch could be a box and arrow diagram to show relationships between classes or it could be a variation on UML (or perhaps even standard UML). But I find that sketches help me see that a design is good/bad and maybe even how to fix it.
I would also look at a book on design patterns.
Write a large project and let it spread as big as you can. Then study what you can do to improve your code.
Perhaps single large routines can be clean and understandable too, if they are well-structured.
There's no single good answer on good design. It's actually one of those valuable things a programmer can learn.
You can refactor mercilessly to improve the design of existing code.
The main idea is, at some point the code did make sense, when new features are bring into the code then probably some features or responsibilities must be moved around to another classes, that's fine. Then you stop developing new features and start refacoring your code.
I would recommend you to read:
Refactoring by Martin Fowler
use Object Oriented Design Principles (http://www.surfscranton.com/Architecture/ObjectOrientedDesignPrinciples.htm). also consider some oo design heursitics (http://www.cs.colorado.edu/~kena/classes/6448/s02/lectures/lecture27.pdf)
Try making program outlines and diagrams before you start, and have someone else review and critique it. Then as the program grows, continually update the outlines and diagrams to include the new functionality. Get it reviewed and critiqued by someone else. Eventually, assuming you are learning from the critiques, you will become better at designing programs.
Books and tutorials can only get you so far. While you do need to learn the tools and methods available, knowledge on its own won't help you here. Practice is what will make you better at design, along with having a mentor coach you from time to time to show you how you can better apply some of the knowledge you've gained from the books.
Read the books by all means, but don't feel bad if you write code that ends up having stupidities in it. Everybody does. The question is, can you refactor what you have to fix it? To be able to do that effectively and often, you need to use TDD and write lots of unit tests.
I would highly recommend you try Test Driven Development (TDD). You will find that to make your code testable, and not need to constantly perform rework of your tests, you will need to have a solid design. What you will find is that when you add \ change \ remove functionality, your better designs will require a very small set of changes to a specific set of tests. A poor design will wipe out a huge set of tests - because you have tight coupling, objects responsible for multiple concerns, etc, etc, etc ...
I have found that the better I get at TDD, the better my architecture is, and the better the end result is.
Be advised, TDD takes real mental discipline. You should not expect that you use it for 1-2 days and see immediate results. You will need to really want to do it, and really make the effort - otherwise you won't benefit and likely just end up hating it.
HTH ...
There are a couple of things that you can do
Use tools for high-level and
low level design before you
actually start programming. E.g.
Creating Class UML Diagrams will
help your mind visualize the
solution in a Diagramtic form rather
than Code form.
Familiarize yourself with Java
Design Patterns. E.g. Using
Inheritance Polymorphically to begin
with will warm you up to start using
the standard Java and J2EE design
patterns.
There are a tonne of books and websites pertaining to both the subjects I just pointed out here.
Browse through good API code. For instance Spring framework code.
Read some good books such as Design Patterns (like everyone else mentioned here) and some other books on good practices. For example in Java, Head First Design, Effective Java series, etc.
C++ - Effective C++ series
I would start with : Head first object-oriented analysis and design. and once you mastered it : Head first design patterns.
Obviously, reading some of the recommmended books will help. I think Head First Design Patterns is definitely less abstract than GoF book.
The primary question I ask is "Is this code doing something very specific that could be re-used anywhwere else?" If so, put in in a class in an assembly that allows for re-use.
If you truly are just starting then one thing I used to do was to consider each database table an 'object'. So each database table represents a class. The purists will tell you this is a disaster, but I found it a good way to get myself started thinking in object terms.
Read Head First Design Patterns.
Related
Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 4 years ago.
Improve this question
Being a core developer for couple of years, coding applications seeing the class diagrams, sequence diagrams, I decided to improve my self, taking the next step of designing.
As I'm an OO developer, I'm interested in improving my design skills.
For Example, I had a hard time designing a currency converter.
My questions to the SO:
Is it by experience the design skills
can be acquired?
Will learning books/blog/material
over internet etc help?
Is it that one needs the domain
knowledge of the application being
developed?
Knowing Design patterns, principles?
Studying 'Code Complete' book ?
Need to have Problem-solving skills?
In short, given a problem, I just want to solve it in Object-oriented way??
You have to do bad OO design before you can do good OO design.
A fantastic project would be take your currency converter and slowly move the code to use OO concepts. OO is a creative process: there are no wrong answers, but worse and better do exist. Basically, when your code retains functionality and gets shorter/easier-to-read, it's better. When it gains flexibility without adding more code, that's better too. But it's a creative process. Use a version control system like GIT to be able to "undo" easily, try stuff out, and MAKE MISTAKES. OO design is a process.
Is it by experience the design skills
can be acquired?
Yes.
Will learning
books/blog/material over internet etc
help?
Yes.
Is it that one needs the domain
knowledge of the application being
developed?
Yes, but I think that knowing the domain too well can screw up good design. When working with Airline programmers, I noticed that the known, unquestioned abstractions ("ticket," "reservation") inhibited good OO design. Your OO model is not the real world model. It's a model for your program.
Knowing Design patterns,
principles?
Yes, more is better, always.
Studying 'Code Complete'
book ?
Lots of people say it's a great book. But, have you read Italo Calvino? Or Jorge Luis Borges? All kinds of books may help.
Need to have Problem-solving
skills?
No. You get problem-solving skills by applying OO (or any other paradigm).
It is pretty obvious that if you want to learn something, you have to practice. If you want to learn how to be a better programmer, practice programming will help. And if you want to learn how to be a better OO programmer, practicing OOP will obviously help you most. Problem solving skills and knowledge of the domain are things every good programmer needs to have, not only for OOP. And there are a lot of good books out there, they will help you probably, if you are not the "to-less-focused-to-get-something-out-of-a-book" type of person.
Here is a list of programming books. From this list, "Design Patterns" and "Refactoring" seem to be very focused on OOP (I did not read "Head first design patterns", perhaps it is, too). And the book I learned most from (OOP, functional and other concepts), I think, is "Structure and interpretation of computer programs".
I think you're going about this somewhat wrong, because some problems simply have no need of an object-orientated solution. The solution should match the problem, not the other way around.
However, there's no silver bullet to being a better object-orientated designer. The best way, in my opinion, would be to write a complex program, then maintain it solidly for a few years.
The biggest challenge in object-oriented design is not learning the implementation techniques, which come naturally with time and experience. The biggest challenge is understanding the problem domain sufficiently well that you can clearly abstract it with an object model. This is one of the points you hit upon in your question and I think it's certainly one of the most critical. If the problem is not well understood, then you run the risk of implementing a solution for the wrong problem. Further, it's easy to get caught up in the beauty of abstraction and architecture for its own sake, losing sight of the original task.
Is it by experience the design skills can be acquired?
Experience and innate ability - some people just cannot do it.
Will learning books/blog/material over internet etc help?
Of course. But they won't turn you into an OO god.
Is it that one needs the domain knowledge of the application being developed?
Either you need to have it, or you need access to someone who does.
Knowing Design patterns, principles?
Knowing what design patterns are would be a good start - they are just common ways of doing things - nothing magic.
Studying 'Code Complete' book ?
I flicked through it in bookshop once.
Need to have Problem-solving skills?
Obviously yes, I would have thought.
I suggest you to learn Smalltalk. YES..I know it's a bit outdated but I think this is the only environment to experiment, appreciate and 'have fun' with Object Orientation.
In Smalltalk everything from the IDE is an object. You can think about objects without wasting time with details such as header/source files, compilation and so on.
Download a copy of Squeak Smalltalk (http://www.squeak.org/) and start practicing
Try to learn and truly grasp the meaning of "abstraction". I mean abstraction as a general concept, at least as it applies to computer science and software engineering.
From abstraction follows object-orientation. Since, abstraction is about separating the concepts in a system from the implementation, for instance any logical representation of a system or application is an abstraction. Any modeling of an application/system is an abstraction. So, among many ways of modeling an application/system/problem, one is called the object-oriented way. So, abstraction first. Once you get the point of abstraction, then you will see that among many ways of modeling things, object-oriented modeling is superior, in most cases. That is how you get the point of OO.
Then, from abstraction follows fundamental principles of object-orientation: abstract data types, information hiding etc, and mechanisms of achieving them like encapsulation, inheritance etc.
To number your points - I think 2 - 6 are great and I think anyone writing code should read code complete, even if its not OO. But unfortunately it seems that point 1 is the most important!!!
I think that's a problem in our profession. We learn on the job as opposed to studying great code. So essentially everybody is re-inventing the wheel in terms of learning.
Additionally you can use the unit testing, as tool to improve the class design.
As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.
Closed 10 years ago.
I have been programming in object-oriented languages for years now but secretly I look at some of the things my colleagues do with envy. A lot of them seem to have some inner OO instinct that I don't have - no matter how hard I try. I've read all the good books on OO but still can't seem to crack it. I feel like the guy who gave 110% to be a professional footballer but just didn't have the natural talent to make it. I'm at a loss and thinking of switching careers - what should do I?
I would say focus less on the OO programming and focus more on the OO design. Grab a paper and a pencil (or maybe a UML modelling tool), and get away from the screen.
By practicing how to design a system, you'll start to get a natural feel for object relationships. Code is just a by-product of design. Draw diagrams and model your application in a purely non-code form. What are the relationships? How do your models interact? Don't even think about the code.
Once you've spent time designing... then translate it to code. You'll be surprised at just how quickly the code can be written from a good OO design.
After a lot of design practice, you'll start seeing common areas that can be modularized or abstracted out, and you'll see an improvement in both your designs and your code.
The easiest way is to learn concepts such as SOLID, DRY, FIT, DDD, TDD, MVC, etc. As you look up these acronyms it will lead you down many other rabbit holes and once you are done with your reading you should have a good understanding of what better object-oriented programming is!
SOLID podcasts: http://www.hanselminutes.com/default.aspx?showID=168, http://www.hanselminutes.com/default.aspx?showID=163
SOLID breakdown: http://butunclebob.com/ArticleS.UncleBob.PrinciplesOfOod
DRY: http://en.wikipedia.org/wiki/Don%27t_repeat_yourself
FIT: http://www.netwellness.org/question.cfm/38221.htm
DDD: http://dddcommunity.org/
DDD required reading: http://www.infoq.com/minibooks/domain-driven-design-quickly
TDD: http://en.wikipedia.org/wiki/Test-driven_development
MVC: http://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller
And yes, rolling up your sleeves and coding is always a good idea. Make a small project to the best of your current abilities. Then read an article from above. Then refactor your code to meet the needs of what you just read. Repeat until you have refactored the hell out of your code. At the end you should not only know what OO is all about but you should be able to explain why it is important and how to get their the first time. Learning how to refactor is a key to good code too. What is right now is not right tomorrow.
Too many people think of coding first, objects, last.
You can read all the books you want but that's not going to teach you how to think in an object-oriented fashion--that takes practice and a certain methodology.
Here are a few methods that have
helped me: When you're away from
work and open-minded you can
practice by looking at everything as an object. Don't look at these
objects and wonder how you're going
to program them, look at them as
properties and functions only and
how they relate or inherit from each
other. For example, when you see a
person, they are an object and
therefore would represent a class.
They have properties like hair
color, skin tone, height, etc. They
do certain functions as well. They
walk, talk, sleep, etc. Some of the
functions these people do returns
results. For example, their working
function returns a dollar amount.
You can do this with everything you
see because everything is an object.
Bicycle, car, star, etc.
Before coding a project, design it by
using post-it notes and a dry-erase
board. This will make good practice
until you get the hang of this.
Think of your specific
object/function/property. Each of
those items will have its own
post-it note. Place them as a
hierarchy on the dry-erase board. In
this regard, function/properties
will be placed under the object. If
you have another object, do the same
for that one. Then ask yourself, do
any of these post it notes
(objects/functions/properties)
relate to each other. If two objects
use the same function, create a
parent object (post-it note) and put
it above the others with the
reusable function under the new
note. Draw a line using the
dry-erase marker from the two child
objects to the parent.
When all this is done, then worry
about the internals of how the class
works.
My suggestion would be to learn something different.
Learn functional programming, and apply what you learn from that to OOP. If you know C++, play around with generic programming.
Learn non-object-oriented languages.
Not just because you should use all these things as well (you should), or because they should completely replace OOP (they probably shouldn't), but because you can apply lessons from these to OOP as well.
The secret to OOP is that it doesn't always make sense to use it. Not everything is a class. Not every relationship or piece of behavior should be modeled as a class.
Blindly trying to apply OOP, or striving to write the best OOP code possible tends to lead to huge overengineered messes with far too many levels of abstraction and indirection and very little flexibility.
Don't try to write good OOP code. Try to write good code. And use OOP when it contributes to that goal.
In many fields there's a "eureka" moment where everything kind of comes together.
I remember feeling frustrated in high school geometry. I didn't know which theorem to apply on each step of the proof. But I kept at it. I learned each theorem in detail, and studied how they were applied in different example proofs. As I understood not only the definition of each theorem, but how to use it, I built up a "toolbox" of familiar techniques that I could pull out as needed.
I think it's the same in programming. That's why algorithms, data structures, and design patterns are studied and analyzed. It's not enough to read a book and get the abstract definition of a technique. You have to see it in action too.
So try reading more code, in addition to practicing writing it yourself. That's one beauty of open source, you can download lots of code to study. Not all of that code is good, but studying bad code can be just as educational as studying good code.
Learn a different language! Most developers using only Java (just as an example) have only a limited understanding of OO because they cannot separate language features and concepts. If you don't know it yet, have a look at python. If you know python, learn Ruby. Or choose one of the functional languages.
The aswer is in your question ;)
Practice, practice, practice.
Review your own code and learn from the mistakes.
TDD has helped me most in improving my overall skillset including OOP.
The more code you write, the more you will notice the pitfalls of certain programming practices. After enough time, and enough code, you will be able to identify the warning signs of these pitfalls and be able to avoid them. Sometimes when I write code, I will get this itch in the back of my mind telling me that there may be a better way to do this, even though it does what I need it to. One of my greatest programming weaknesses is "over-analyzing" things so much that it starts to dramatically slow down development time. I am trying to prevent these "itches" by spending a little more time on design, which usually results in a lot less time writing code.
...secretly I look at some of the things my colleagues do with envy. A lot of them seem to have some inner OO instinct that I don't have - no matter how hard I try...
I think you have answered your own question here. Reading good code is a good start, and understanding good code is even better, but understanding the steps to get to that good code is the best. When you see some code that you are envious of, perhaps you could ask the author how he/she arrived at that solution. This is entirely dependent on your work environment as well as the relationships with your colleagues. In any event, if anyone asks me the thought process behind any code I write, I don't hesitate to tell them because I know I would want them to do the same for me.
Language designers have interpreted "Object Oriented Programming" in different ways. For instance, see how Alan Kay, the man who first used the term OOP, defined it:
OOP to me means only messaging, local
retention and protection and hiding of
state-process, and extreme
late-binding of all things. It can be
done in Smalltalk and in LISP. There
are possibly other systems in which
this is possible, but I'm not aware of
them.
(Quoted from http://userpage.fu-berlin.de/~ram/pub/pub_jf47ht81Ht/doc_kay_oop_en).
It might seem strange that he don't consider Java and C++ OOP languages! But as the designer of one of the first and best OOP languages (Smalltalk) he has his own valid reasons for that. Why did Alan Kay consider Lisp an Object Oriented language but not Java? That question demands serious consideration by anyone who claims to understand OOP.
Erlang has an altogether different implemntation of OOP, Scheme has another.
It is worth considering all these alternative views. If possible learn all these languages! That will give you a broader outlook, put some new and powerful tools in your hand and make you a better programmer.
I have summarized my experiments with implementing an OOP language, based on ideas borrowed from Smalltalk, Scheme and Erlang in this article.
public void MasteryOfOOP()
{
while(true)
/* My suggestion is: */
DO: find a lot of well-written object oriented code and read it. Then
try to use the insights from it on your own coding. Then do it again. Then
have a colleague who is a good OOP look at it and comment. Maybe post a chunk
of your code on SO and ask for how it could be improved.
Then read some more of those books. Maybe they make a little more
sense now...?
Now go back to the top of this post, and do it again.
Repeat Forever.
}
}
If you're lost as to how to design object-oriented systems, start with the data. Figure out what stuff you need to keep track of and what information naturally goes together (for example, all of the specs of a model of car group together nicely).
Each of these kinds of thing you decide to track becomes a class.
Then when you need to be able to execute particular actions (for example, marking a model of car as decommissioned) or ask particular questions (for example, asking how many of a given model of car were sold in a given year), you load that functionality onto the class it interacts with most heavily.
In general, there should always be a pretty natural place for a given bit of code to live in your class structure. If there isn't, that signals that there's a place where the structure needs to be built out.
There's too much information about objects. The most important thing is to master the basics and everything falls into place more easily.
Here's a way to think about objects. Think about data structures in procedural languages. They are a group of fields without behaviour. Think about functions that receive pointers to those data structures and manipulate the latter. Now, instead of having them separate, define the functions inside the definition of the the structures and assume the functions usually receive a pointer to the data structure to manipulate. That pointer is called this. In sum, think about objects as the combination of status (data) and behaviour (methods - the fancy name for functions in OOP).
This is the absolute basic. There are three more concepts you must absolutely master:
Inheritance - This is all about code reuse.
Encapsulation - This is all about hiding the implementation from the interface. Simply put, everything ought to be private until proven otherwise.
Polymorphism - It doesn't matter the type of the reference variable, but the type of the actual instance to know which behaviour (method) is called. Java doesn't make it easy to have this concept very visible because by definition everything is polymorphic. .Net makes it easier to understand as you decide what is polymorphic and what is not, hence noticing the difference in behaviour. This is achieved by the combination of virtual and override.
If these concepts are very well understood, you'll be fine.
One last final tip: You mention the best books. Have you read "Thinking in Java" by Bruce Eckel? I recommend this book even to people who are beginning in .Net, as the OOP concepts are clearly laid out.
Become more agile, learn junit testing and study about Domain Driven Design. I suggest the book Domain-Driven Design: Tackling Complexity in the Heart of Software although it's a bit tough at some points.
OOP skills comes over time. Reading 1, 2 ...10 books doesn't cut it. Practice writing some code. If you are working in a programming enviornment...that can be helpful. If not try getting into one. Offer to develop some application(s) for free. You have to get your hands dirty. Remember...no application is perfect from the ground up.That's why there is re-factoring.
Also...don't get carried away with the OOP too much...it somes over time. Worry about developing fully functional applications.
Try some programming in Self, one of the most pure OO languages around. So pure, in fact, that it doesn't even have classes, only objects. It also doesn't have variables, fields, statics, attributes, only methods. Also interesting is the fact that every object in the system is also an object on the screen and vice-versa.
Some of the interesting papers on Self are Prototype-Based Application Construction Using SELF 4.0 (the Self tutorial), Self: The Power of Simplicity and Organizing Programs Without Classes. Also, Self: The Video (Randall B. Smith; Dave Ungar) is terrific, having two of the language's designers explain Self's ideas.
This works for pretty much any concept, actually, at least for me: find the language which most purely embodies the concept you want to learn about and just use it.
OO finally clicked for me after I tried to program a bank-like program that handled transactions, calculated interest, and kept track of it all. I did it while I was learning Java. I would suggest just trying it, completing it, and then when you're done go look at a GOOD solution and see what you could've done better.
I also think OOP skills strenghten mostly with practice. Consider changing your company, if you've been there for more than 3 years. Certainly, this is not valid for all jobs, but often a man gets used to the projects and practices at a company and stops advancing as time passes.
Roll up your sleeves and code!
You said the answer yourself: practice. Best solution for this is to develop a game. Use the concepts you learnt in the books there.
Have you read the chapter on OO from the first edition of Scott Meyers "Effective C++" book? It didn't make it to later editions, but it was a great explanation. The title was basically "say what you mean, mean what you say" about suitable conventions.
Actually, you might like to see my answer to a similar question over here.
HTH
cheers,
OOP is not a thing you can master by reading thousands of books. Rather you have to feel the inner concepts. Read anything but try to feel what you read. Build a concept in the back of your mind and try to match those concepts when you face a new scenario. Verify and Update your concepts as you explore new things.
Good luck!
Plan things out. Ask yourself how you want your objects to relate to eachother and seek out how things can be changed and modularized.
Code things in such a way that if you wanted to change 1 piece of the code, you only have to change that 1 piece of code and not 50 instances of it.
beer helps. seriously. lie out on a couch with an A3 sized scribble pad, a pen and a beer. Lock the dog, cat and wife outside. And think about the problem while relaxed. Don't even dare draw an API on it!
Flowcharts, Responsibity cards (CRC) and beer (but not too much) go a long way.
Easiest way to refactor code is to not have to in the first place.
http://misko.hevery.com/code-reviewers-guide/
Those small simple rules will make you a better OO programmer. Follow the rules religiously as you code and you will find your code is better than it would otherwise be.
You'll also want to learn the Solid Principles: http://butunclebob.com/ArticleS.UncleBob.PrinciplesOfOod
As much as these principles and ways of programming cause debate, they are the only way to truly write excellent code.
You may already write code this way and not know it-- if so, great. But if you need a goal to strive towards, these are the gold standard.
Give up! Why do you need that that OOP? Just write some usable app. Doesnt metter using OOP, procedual or functional approach.
Whataver approach you choose Python language should be sutable to practice it.
You're my target audience. Look at Building Skills in OO Design
Perhaps this can help.
Closed. This question is opinion-based. It is not currently accepting answers.
Want to improve this question? Update the question so it can be answered with facts and citations by editing this post.
Closed 8 years ago.
Improve this question
The question seems pretty simple, and so is the answer. I am a developer who recently started working. So far I had taken few bachelor and master level courses on OOP. And yet I am not comfirtable and confident with OOP concepts. Recently, I was searching for employment opportunities and I found that many employers were keen to know how much confident I am on OOP concepts.
I have a very strong theorotical knowledge on OOP concepts. Although this theorotical knowledge is helping me in clearing the interviews and getting a job but when it comes to implementation I am getting dumb. If you ask me what is reflection then you will get a perfect answer from me, but if someone asks me why and where do we use it, then I get fumbled.
Now I really want to know what I should do when I am not getting an opportunity to implement all or most of the OO concepts in my projects.
Also I really feel with all the latest development tools and programming environments, many of the programmers are getting pampered to use already built components, frameworks and libraries and this is might create a vacuum of good architects.
I want to become a successful architect and for that I think I must be very strong in this area.
Then I thought of learning NHibernate where you will be dealing with objects entirely.
Now what I need is few valuable tips that would help me in grasping all or most of the OOP concepts.
It sound like you're missing real programming experience. Nothing will substitute that.
Go working, exercise, read, learn from your more experienced colleagues. Eventually you'll get it.
As for very advanced tools, you are correct. They produce code monkeys in ever increasing amounts. If you see it right now you are on a good start. Just keep to the path. Good architects will always be needed and valued.
You want to start looking at design patterns. Knowing the when, how and why of using OOP is more valuable than knowing OOP itself.
Frameworks are great and I don't fault people for using them. But, there is still a lot of room for great architects in this space. Exploit the gap of programmers knowing how to use them, but not why or when. Frameworks quickly become a hammer looking for a nail for many developers. Open source is your friend here - dive into the source code and learn them from the inside out so you really understand what's being done and why.
In my experience, you learn the "conceptual" side of development from school and the "applications" side from real experience. There is no substitute for working on the job; no matter how much schooling I've had it never equates to what I've learned doing the real work. This is why it's also a good idea to get an internship in college if you're able.
As for the value of OOP itself, I find that it's most useful in large projects and in team projects. The whole point is to break down the solution into workable "conceptual" elements which makes intercommunication between team members easier as well as visualizing the solution. Visualization is the other big pro to OOP.
One thing to note about OOP IMHO is that entry level developers tend to overuse a lot of the OOP concepts. Not everything requires inheritance. Design patterns are extremely useful but also shouldn't be over applied. Look at your problem and first try to think of a solution on your own then compare it to known patterns and see if they provide a better answer. Simplicity can't be overrated.
Also, playing with tools like UML editors and Mind Mappers (such as XMind) are helpful in getting into the right frame of mind.
Check and see if there are any programming groups around you too; I find it's a good way to meet people that you can talk programming with and another advantage of OOP is its much easier to communicate programming ideas with.
Your next stop should be to look into design patterns (Applied OO). For an introductory text, check out Headfirst Design Patterns.
Interesting question. To some extent I've grown up with Object programming, I've evolved as the various frameworks have evolved, I'd never before considered how it would feel to come to a landscape where so many sophisticated frameworks already exist. Their very presence tends to inhibit that degree of fumbling and stumbling and generallly getting it wrong that leads to deeper understanding.
My perception though is that serious development is still a matter of good design, it's not all just fill-in-the-gaps, hey IOC framwork tell me what to do, programming.
You can enhance your theoretic knowlege by studying the "how" of the framworks you use. But I guess what you need is practical experience, can't comment upon what's open to you in your place of work, but if you can't get it there you may need to do some "hobbyist" or open source development.
One thing I would recommend is trying to get involved in design discussions, try to get your designs reviewed by experienced developers. With any luck they may even say: "hey why didn't you use reflection there ..."
It is the 'thinking' that is important, in OOP one needs to change thinking
while going about programming/developing in oop environment or using OOP
paradigm.
I have faced many a times this question myself: why use OOPL or
Object Oriented Programming Language when I can develop software in Procedural
Programming Language? Why use OOP methodology at all? What benefit does it have
what other non-oop doesn't?
I read from many sources (numerous books and articles on the subject to name!)
to trace the real reason, to hit the fundamental underlying idea or principle
for its being there as a paradigm of software engineering. I think what I found
is simple and that's why I suggest to bring a change in thinking.
If we look around we see things that surround us and the things we interact
with, directly or indirectly. We recognize them with names, we gave them.
Whatever the things are, either they exist in real plane or conceptual plane
and we 'know' them 'recognize' them and interact with them. And importantly we
'name' them. This naming is important because to interact with the 'things' and
for that knowledge of that interaction we need 'Names'.
What have you eaten today? Chocolate and coffee. So you have 'interacted' with
chocolate and coffee. Now Chocolate and coffee are edibles we have (humans)
have given names and with those names we recognize them. And also, we, in our
knowledge of our interaction with them - lets say keeping record of our
interaction with chocolate and coffee, know them with names as having
interacted with.
Interaction is a general term I am using here. Actually in our case, in the
example, you have performed an 'action' - eating. Through 'eating' action you
have interacted with chocolate and coffee. Now think this way, you, chocolate,
coffee are entities in the real world through an action came in interaction.
You may say a 'Process'.
What course Alice has enrolled for? Computer Science.
Computer Science does not have a real existence in the world in the sense a man
exists or a tree or a house, or coffee cup or other 'tangible things' exist. It
is a subject, 'conceptual thing'. The study of computer science has some
'topics' to be studied (or to have interaction with through our mental
faculty/processes)e.g discrete mathematics, design and analysis of algorithms,
Data Structure etc. Together they are named, as a subject of study, 'Computer
Science'. Now Alice 'study' (interaction) Computer Science.What is happening
here? OK, if We now think this way and say that Alice is a thing, an object.
Computer Science is a thing, an object.
Coffee is an object. Chocolate is an object. You, again, are an object. We find
that objects interacting with objects. Fantastic! One may exclaim! That's the
real world scenario! Actually it is a generalization reached through
Abstraction.
It is nothing but -at the surface level at least- naming with
meaning. Or you can say 'meaningful naming'. It is a process. It is so natural
and obvious to us that we simply overlook it.
In OOP we simply have to bring ourselves to this form of thinking process,
knowing and reminding ourselves that "Objects interact with Objects". Oh!
There are more than thinking only this. You have to remember that an object
may interact with itself! Think of you, what are you doing when you are
thinking? Yeah! And there is another very important thing I shall come to
in due time. Though I think it is obvious. But in due time. OK. What we
really do with computers? Actually we solve problems. Particularly those
problems which we try to do or solve in our minds. In broad sense we are
simulating mental processes in a machine, so designed by us. Remember AI is
still a far off thing in reality and there are debates both scientific and
philosophical, on whether a computer can become Intelligent at all. Another
way of putting it whether a computer can really simulate a real mental
process. But that's not for us to take here. Leave it!
If we want to solve problems in real life through a computing device we
would like to go as closely in representing the real life as possible.There
comes the term in OOP 'real life modelling'. It can be seen that in solving
real life problems, be it launching a space shuttle, or keeping the customer
and product sale information for processing we do abstraction and do
calculation, which is another form of abstract process, in turn we deal with
objects mentally, in our mind. So we represent real life objects (conceptual
objects such as numbers) in abstraction and deal with them with abstract
processes, as in mathematics. In computer too we would like to represent
objects and also like to represent processes in the form of objects. So here
comes the Object Orientation so to speak to software engineering. Now comes
that 'due time' to deal with another aspect of OO.
To go back to our example, What did you eat? Eating is an action, a form of
interaction. Which can be thought of as process which again can be thought of
as an Object, like a processes is thought of and represented as 'function' or
'routine' or 'procedure' in Non-OOPL. In OOP we can represent (abstract away)
eating as a process embodied as an object. Similarly studying is an object. In
the same line of thinking 'thing' and 'process' both be thought of as objects
and be represented in virtual plane which is computer memory. Therefore
Alice-an Object-Studies-an object-Computer Science-an Object is valid in OOP
parlance as far as our argument goes.
Can we write a piece of code here? Lets try.
class Alice {
private String name;
private String address;
private String stdID;
private Course courseOfStudy;
... other codes...
public void studies(Course sub) {
courseOfStudy=sub;
}
...
public Course getStudyCourse() {
return courseOfStudy;
}
}
class Course {
codes....
}
This way in OOP (here Java code) one can go about writing codes. I have just
given a simplistic coding. One can come up with better coding and design
approach depending on the software in mind to be written. In OOP design is very
important. So in thinking which I mentioned at the beginning the change should
be brought in. That's important! I prefer to go this way when it comes to OOPL
or OOAD, "everything is object".
Well that's what I wanted to say. You may or may not like it but comment and
say your mind.
Closed. This question is opinion-based. It is not currently accepting answers.
Want to improve this question? Update the question so it can be answered with facts and citations by editing this post.
Closed 9 years ago.
Improve this question
I recently read an interesting comment on an OOP related question in which one user objected to creating a "Manager" class:
Please remove the word manager
from your vocabulary when talking
about class names. The name of the
class should be descriptive of its'
purpose. Manager is just another word
for dumping ground. Any
functionality will fit there. The word
has been the cause of many extremely
bad designs
This comment embodies my struggle to become a good object-oriented developer. I have been doing procedural code for a long time at an organization with only procedural coders. It seems like the main strategy behind the relatively little OO code we produce is to break the problem down into classes that are easily identifiable as discrete units and then put the left over/generalized bits in a "Manager" class.
How can I break my procedural habits (like the Manager class)? Most OO articles/books, etc. use examples of problems that are inherently easy to transform into object groups (e.g., Vehicle -> Car) and thus do not provide much guidance for breaking down more complex systems.
First of all, I'd stop acting like procedural code is wrong. It's the right tool for some jobs. OO is also the right tool for some jobs. So is functional. Each paradigm is just a different point of view of computation, and exists because it's convenient for certain problems, not because it's the only right way to program. In principle, all three paradigms are mathematically equivalent, so use whichever one best maps to the problem domain. IMHO, if using a multiparadigm language it's even ok to blend paradigms within a module if different subproblems are best modeled by different worldviews.
Secondly, I'd read up on design patterns. It's hard to understand OO without some examples of the real-world problems it's good for solving. Head First Design Patterns is a good read, as it answers a lot of the "why" of OO.
Becoming good at OO takes years of practice and study of good OO code, ideally with a mentor. Remember that OO is just one means to an end. That being said, here are some general guidelines that work for me:
Favor composition over inheritance. Read and re-read the first chapter of the GoF book.
Obey the Law of Demeter ("tell, don't ask")
Try to use inheritance only to achieve polymorphism. When you extend one class from another, do so with the idea that you'll be invoking the behavior of that class through a reference to the base class. ALL the public methods of the base class should make sense for the subclass.
Don't get hung up on modeling. Build a working prototype to inform your design.
Embrace refactoring. Read the first few chapters of Fowler's book.
The single responsibility principle helps me break objects into manageable classes that make sense.
Each object should do one thing, and do it well without exposing how it works internally to other objects that need to use it.
A 'manager' class will often:
Interogate something's state
Make a decision based on that state
As an antidote or contrast to that, Object-Oriented design would encourage you to design class APIs where you "tell don't ask" the class itself to do things itself (and to encapsulate its own state): for more about "tell don't ask" see e.g. here and here (and maybe someone else has a better explanation of "tell don't ask" but these are first two articles that Google found for me).
It seems like the main strategy the little OO code we produce is to break the problem down into classes that are easily identifiable as discrete units and then put the left over/generalized bits in a "Manager" class.
That may well be true even at the best of times. Coplien talked about this towards the end of his Advanced C++: Programming Styles and Idioms book: he said that in a system, you tend to have:
Self-contained objects
And, "transactions", which act on other objects
Take, for example, an airplane (and I'm sorry for giving you another vehicular example; I'm paraphrasing him):
The 'objects' might include the ailerons, the rudder, and the thrust
The 'manager' or autpilot would implement various commands or transactions
For example, the "turn right" transaction includes:
flaps.right.up()
flaps.left.down()
rudder.right()
thrust.increase()
So I think it's true that you have transactions, which cut across or use the various relatively-passive 'objects'; in an application, for example, the "whatever" user-command will end up being implemented by (and therefore, invoking) various objects from every layer (e.g. the UI, the middle layer, and the DB layer).
So I think it's true that to a certain extent you will have 'bits left over'; it's a matter of degree though: perhaps you ought to want as much of the code as possible to be self-contained, and encapsulating, and everything ... and the bits left over, which use (or depend on) everything else, should be given/using an API which hides as much as possible and which does as much as possible, and which therefore takes as much responsibility (implementation details) as possible away from the so-called manager.
Unfortunately I've only read of this concept in that one book (Advanced C++) and can't link you to something online for a clearer explanation than this paraphrase of mine.
Reading and then practicing OO principles is what works for me. Head First Object-Oriented Analysis & Design works you through examples to make a solution that is OO and then ways to make the solution better.
You can learn good object-oriented design principles by studying design patterns. Code Complete 2 is a good book to read on the topic. Naturally, the best way to ingrain good programming principles into your mind is to practice them constantly by applying them to your own coding projects.
How can I break my procedural habits (like the Manager class)?
Make a class for what the manager is managing (for example, if you have a ConnectionManager class, make a class for a Connection). Move everything into that class.
The reason "manager" is a poor name in OOP is that one of the core ideas in OOP is that objects should manage themselves.
Don't be afraid to make small classes. Coming from a procedural background, you may think it isn't worth the effort to make a class unless it's a thousand lines of code and is some core concept in your domain. Think smaller. A ten line class is totally valid. Make little classes where you see they make sense (a Date, a MailingAddress) and then work your way up by composing classes out of those.
As you start to partition little pieces of your codebase into classes, the remaining procedural code soup will shrink. In that shrinking pool, you'll start to see other things that can be classes. Continue until the pool is empty.
How many OOP programmers does it take to change a light bulb?
None, the light bulb changes itself.
;)
You can play around with an OO language that has very bad procedural support like Smalltalk. The message sending paradigm will force you into OO thinking.
i think you should start it with a good plan.
planning using CLASS Diagrams would be a good start.
you should identify the ENTITIES needed in the applicaiton,
then define each entitie's ATTRIBUTES, and METHODS.
if there are repeated ones, you could now re-define your entities
in a way that inheritance could be done, to avoid redundancy.
:D.
I have a three step process, this is one that I have gone through successfully myself. Later I met an ex-teacher turned programmer (now very experienced) who explained to me exactly why this method worked so well, there's some psychology involved but it's essentially all about maintaining control and confidence as you learn. Here it is:
Learn what test driven development (TDD) is. You can comfortably do this with procedural code so you don't need to start working with objects yet if you don't want to. The second step depends on this.
Pick up a copy of Refactoring: Improving the Design of Existing Code by Martin Fowler. It's essentially a catalogue of little changes that you can make to existing code. You can't refactor properly without tests though. What this allows you to do is to mess with the code without worrying that everything will break. Tests and refactoring take away the paranoia and sense that you don't know what will happen, which is incredibly liberating. You left to basically play around. As you get more confident with that start exploring mocks for testing the interactions between objects.
Now comes the big that most people, mistakenly start with, it's good stuff but it should really come third. At this point you can should reading about design patterns, code smells (that's a good one to Google) and object oriented design principles. Also learn about user stories or use cases as these give you good initial candidate classes when writing new applications, which is a good solution to the "where do I start?" problem when writing apps.
And that's it! Proven goodness! Let me know how it goes.
My eureka moment for understanding object-oriented design was when I read Eric Evans' book "Domain-Driven Design: Tackling Complexity in the Heart of Software". Or the "Domain Driven Design Quickly" mini-book (which is available online as a free PDF) if you are cheap or impatient. :)
Any time you have a "Manager" class or any static singleton instances, you are probably building a procedural design.
Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking us to recommend or find a tool, library or favorite off-site resource are off-topic for Stack Overflow as they tend to attract opinionated answers and spam. Instead, describe the problem and what has been done so far to solve it.
Closed 9 years ago.
Improve this question
What is a good challenge to improve your skills in object oriented programming?
The idea behind this poll is to provide an idea of which exercises are useful for learning OOP.
The challenge should be as language agnostic as possible, requiring either little or no use of specific libraries, or only the most common of libraries. Try to include only one challenge per answer, so that a vote will correspond to the merits of that challenge alone. Would also be nice if a level of skill required was indicated, and also the rationale behind why it is a useful exercise.
Solutions to the challenges could then be posted as answers to a "How to..." question and linked to from here.
For example:
Challenge - implement a last-in-first-out stack
Skill level - beginner
Rationale - gives experience of how to reference objects
Building Skills in Object-Oriented Design is a free book that might be of use.
The description is as follows:
"The intent of this book is to help the beginning designer by giving them a sequence of interesting and moderately complex exercises in OO design. This book can also help managers develop a level of comfort with the process of OO software development. The applications we will build are a step above trivial, and will require some careful thought and design. Further, because the applications are largely recreational in nature, they are interesting and engaging. This book allows the reader to explore the processes and artifacts of OO design before project deadlines make good design seem impossible."
Write a challenging program from scratch. Try to get some people (around five, that should be doable) to use it. Respond to their change requests.
Adapt your program's design. Start small, then watch it grow. Manage this growth. This is hard. You will also have to fix bugs and maintain the thing over time, which for me was a very valuable lesson.
Challenge: Write a wrapper for your web site/service API of choice in your language of choice, that doesn't already exist (ex. a ZenDesk API wrapper written in C#). Release the wrapper as open source for others to use.
Skill Level: Beginner to Intermediate
Rationale: To learn how to extrapolate a 3rd party web service API into a meaningful set of objects/classes, making the reuse of that API easier in your chosen language.
After you have learned the basics, study the "Gang of four" design patterns book.
http://www.amazon.com/Design-Patterns-Object-Oriented-Addison-Wesley-Professional/dp/0201633612/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1221488916&sr=8-1
This is a classic, and a must read for any coder who wants to understand how to use OO to design elegant solutions to common coding problems.
Take a procedural-style written piece of code and try to transform it into OOP based solution. During the process, consult a book on refactoring and design patterns. A friend of mine was able to make a huge step forward in understanding object oriented concepts exactly this way. As with anything, this might not work for everyone.
I have found CRC cards to be quite effective in learning, teaching and building good OO design.
Certainly a good challenge, although less accessible than a "start from scratch" assignment, is to refactor some existing code that either doesn't use inheritance or doesn't use very much of it to make greater use of inheritance. The process of refactoring will expose a lot of the benefits and gotchas of oop, as it certainly has for me on my most recent project. It also pushed me to understand the concepts better than past projects have where I've created my own object oriented designs.
A given task has very little to do with being "OOP", it's more in how you grade it.
I would look at the Refactoring book, chapter 3, and make sure none of the bad code smells exist in the solution. Or, more importantly, go over ones that do apply.
Most importantly, watch for the existence of setters and getters (indicating that you are operating on values from a class and not asking the class to operate on it's own values)--or using "extends" without applying the Liskov Substitution Principle, stuff like that.