OOP - pass one object to several others? - oop

I am not quite sure if this question belongs here or to another community on stackexchange, if the latter, I could not find the right one and would be glad about a hint.
I am at the moment programming a little game (roundbased -no threading) in Java and I am wondering:
Is it bad practice if one object is known to several others?
In my case I wonder if I should create an Object o and then pass it as a constructor argument to several other, later created objects.
It does work, but I wonder if this should in general rather not be done?
Does someone have an answer?

Yes of course. It is normal case in the world of oop. One of simple examples of such usage is dependency injection. For more information see https://en.m.wikipedia.org/wiki/Dependency_injection
Besides, many design patterns use such approach : strategy, observer etc.

Related

What's the correct object-oriented way to define something in multiple ways?

I'd like to clarify in advance that this is NOT a techincal, but an ideological question. I can think of billions of workarounds, but I'd like to learn a way that would satisfy the OOP paradigm the most. Now, the question itself:
Say, for instance, that I have two methods in a class, where each one may be defined on its own or utilising the other one (and, let us assume, that a recursive case would go infinite). Defining both on their own would mean having duplicate code. I could, of course, choose one as the basic one and reference it in the other one, but if such relation isn't explicitly derived from the specifications, this could lead to issues upon further development and expansion, etc.
The best solution I can think of is somehow separating the common part into a different method, but I can't tell if that would cause further problems or not.
In general, if we leave aside the specific example, Object-Orientedness, as I understand it, allows me to define abstractions through other abstractions, but only in a strict tree-like hierarchy (+multiple inheritance, but that still doesn't cover everything). In some cases, however, an abstraction can be defined in several different ways through different sets of other abstractions, and I'd like to learn how to implement that in practice.
For code examples, if you wish to give those, I'd prefer you to use python (as it features the widest support for object-orientedness among languages known to me), but in the end, anything is fine, as long as it's not something like haskell (a.k.a. not object-oriented at all), or javascipt (where the language itself doesn't respect standards and uniformity).
Thank you in advance, and sorry for any possible English-related mistakes

Object oriented design pattern query

i went through different questions on SO and was trying to find out what is the best way to design an application .I found that somewhere it was written that we should make the object of the class if it has a state this.
i found on the same page that utilities should be avoided so my question is how to implement the functionality. we can not create object because functionality can have and can not have state. and we can also not use static methods also. then how.
P.S---- my question can be layman bcoz i am newbie trying to learn/implement design patterns so whould be happy if somebody can provide me reading material,links with examples.
i know a bit of design patterns theoretically.
You're reading guidelines and treating them like mandates, which puts you in the impossible position of coding with rules that are too strict.
Guidelines are guidelines, and no more than that. If it's a good idea not to use utility classes, then don't use them a lot. Use them sparingly, where it makes sense.
If it's a bad idea (and it is) to use some global variables, then don't do it a lot. But if you need a static helper classes with a variable or two available to the app, then do it in that case.
Don't treat guidelines as law. Treat them as guidelines, and go against them when it makes sense. You will only gain this knowledge by programming. So start doing it, make mistakes, learn from it, and improve your code as you go. You won't get it done perfectly right from the start.

First step in OOD?

What is the frst step in OOD?
There are no steps, it's not a process.
The answer is..
(source: headfirstlabs.com)
http://headfirstlabs.com/books/hfooad/
http://www.amazon.com/dp/0596008678/?tag=forelangstud-20
Practice, read broadly and more practice.
Especially with others to review and comment on approaches.
Reading should cover not just OOD, but also patterns to see how others have approached common problems.
It's a lot of practice. The first thing is to get your mind around the way objects work--especially if you are a procedural programmer.
Practice making many small objects--I've literally never seen a system with too many objects; it's possible but I've never seen it. It should be really obvious when you need to put many objects into one, but it's not as obvious when an object should be broken up.
Ask an object to do something, don't ask for it's data. Try to avoid getters and setters and concentrate on methods where you ask it to do something with it's data. If you EVER see code like o.a=o.b+o.c or o.setA(o.getB()+o.getC() you are doing it wrong.
Constantly try to refactor out duplication. Rewrite your code repeatedly until there is none (or as little as possible). This will probably do more for your OO design skills than any other practice. As you get more knowledgeable, try refactoring things you didn't think you could refactor before. Anything that even looks like a pattern can probably be refactored. For instance here's a very basic example--if you had lines of code that looked like this:
a = b + c * d;
g = h + i * d;
Chances are there are HUGE refactorings missing in your code even though it doesn't look like it off the bat. You probably are missing an object that would hold a,b,c and a second instance would hold g,h,i, after creating these objects a bunch of stuff would factor into your new object. Learning to recognize new opportunities like this is critical.
I've been programming for over 20 years now, over half of it has been OO at this point and it seems like every few years I think I know it all--a year later I look back and realize how ignorant I was.
the first step is object oriented analysis - its aim is to identify the objects that make up a system and how they interact; given this knowledge you can then specify the behavior of the object (the interface methods) and then the internals (what are the required data members of an object)
The design process produces a number of diagrams - these are tools that are supposed to help with working out the details of the system :
first come a set of 'use cases' - a use case is a verbal description of a scenario that is implemented by the system (one is supposed to pick the most substantial ones); these are then used to identify the main actors and concepts which are supposed to map to the classes of a system. This understanding is then refined by working out 'object interaction diagrams' 'class diagrams' and 'sequence diagrams' sometimes state charts are used to visual state machines - these diagrams are tools to gain an even better understanding of the system, as a result you have a sufficient understanding of the system to write the class header files/class definitions. There are no fixed rules which one of these diagrams come first, these are used as appropriate.
i found the following book very useful :
OBJECT-ORIENTED ANALYSIS AND DESIGN With applications (second edition) by Grady Booch
the book goes through the process of designing several example systems step by step (i think it is enough to read the design process for these example systems); One minor problem is that the notation used in this book is a bit dated : modern practice is to use the UML notation for diagrams, however the book still uses the older Booch notation. The strong point of the book is that it is always explaining each concept by working through concrete examples.
There are some preliminary steps:
Understand OOD (in general)
Understand the problem/application domain (the functional specification)
Have a high-level/architectural design: know what O/S, libraries, frameworks etc. you can use
I then use a mixture of top-down and bottom-up development:
Top-down: decide what components and what APIs (object interfaces) I would like to have in order to implement the application (and then, develope those API)
Bottom-up: decide how to add new functionality to existing APIs (object interfaces), by adding new methods and new types of object (and sometimes splitting a large object into several smaller objects).
The first step of OOD are the OOD principles. Check out The Principles of OOD.

How can I practice better object-oriented programming? [closed]

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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.

Anyone else find naming classes and methods one of the most difficult parts in programming? [closed]

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.
So I'm working on this class that's supposed to request help documentation from a vendor through a web service. I try to name it DocumentRetriever, VendorDocRequester, DocGetter, but they just don't sound right. I ended up browsing through dictionary.com for half an hour trying to come up with an adequate word.
Start programming with bad names is like having a very bad hair day in the morning, the rest of the day goes downhill from there. Feel me?
What you are doing now is fine, and I highly recommend you stick with your current syntax, being:
context + verb + how
I use this method to name functions/methods, SQL stored procs, etc. By keeping with this syntax, it will keep your Intellisense/Code Panes much more neat. So you want EmployeeGetByID() EmployeeAdd(), EmployeeDeleteByID(). When you use a more grammatically correct syntax such as GetEmployee(), AddEmployee() you'll see that this gets really messy if you have multiple Gets in the same class as unrelated things will be grouped together.
I akin this to naming files with dates, you want to say 2009-01-07.log not 1-7-2009.log because after you have a bunch of them, the order becomes totally useless.
One lesson I have learned, is that if you can't find a name for a class, there is almost always something wrong with that class:
you don't need it
it does too much
A good naming convention should minimize the number of possible names you can use for any given variable, class, method, or function. If there is only one possible name, you'll never have trouble remembering it.
For functions and for singleton classes, I scrutinize the function to see if its basic function is to transform one kind of thing into another kind of thing. I'm using that term very loosely, but you'll discover that a HUGE number of functions that you write essentially take something in one form and produce something in another form.
In your case it sounds like your class transforms a Url into a Document. It's a little bit weird to think of it that way, but perfectly correct, and when you start looking for this pattern, you'll see it everywhere.
When I find this pattern, I always name the function xFromy.
Since your function transforms a Url into a Document, I would name it
DocumentFromUrl
This pattern is remarkably common. For example:
atoi -> IntFromString
GetWindowWidth -> WidthInPixelsFromHwnd // or DxFromWnd if you like Hungarian
CreateProcess -> ProcessFromCommandLine
You could also use UrlToDocument if you're more comfortable with that order. Whether you say xFromy or yTox is probably a matter of taste, but I prefer the From order because that way the beginning of the function name already tells you what type it returns.
Pick one convention and stick to it. If you are careful to use the same names as your class names in your xFromy functions, it'll be a lot easier to remember what names you used. Of course, this pattern doesn't work for everything, but it does work where you're writing code that can be thought of as "functional."
Sometimes there isn't a good name for a class or method, it happens to us all. Often times, however, the inability to come up with a name may be a hint to something wrong with your design. Does your method have too many responsibilities? Does your class encapsulate a coherent idea?
Thread 1:
function programming_job(){
while (i make classes){
Give each class a name quickly; always fairly long and descriptive.
Implement and test each class to see what they really are.
while (not satisfied){
Re-visit each class and make small adjustments
}
}
}
Thread 2:
while(true){
if (any code smells bad){
rework, rename until at least somewhat better
}
}
There's no Thread.sleep(...) anywhere here.
I do spend a lot of time as well worrying about the names of anything that can be given a name when I am programming. I'd say it pays off very well though. Sometimes when I am stuck I leave it for a while and during a coffee break I ask around a bit if someone has a good suggestion.
For your class I'd suggest VendorHelpDocRequester.
The book Code Complete by Steve Mcconnell has a nice chapter on naming variables/classes/functions/...
I think this is a side effect.
It's not the actual naming that's hard. What's hard is that the process of naming makes you face the horrible fact that you have no idea what the hell you're doing.
I actually just heard this quote yesterday, through the Signal vs. Noise blog at 37Signals, and I certainly agree with it:
"There are only two hard things in Computer Science: cache invalidation and naming things."
— Phil Karlton
It's good that it's difficult. It's forcing you to think about the problem, and what the class is actually supposed to do. Good names can help lead to good design.
Agreed. I like to keep my type names and variables as descriptive as possible without being too horrendously long, but sometimes there's just a certain concept that you can't find a good word for.
In that case, it always helps me to ask a coworker for input - even if they don't ultimately help, it usually helps me to at least explain it out loud and get my wheels turning.
I was just writing on naming conventions last month: http://caseysoftware.com/blog/useful-naming-conventions
The gist of it:
verbAdjectiveNounStructure - with Structure and Adjective as optional parts
For verbs, I stick to action verbs: save, delete, notify, update, or generate. Once in a while, I use "process" but only to specifically refer to queues or work backlogs.
For nouns, I use the class or object being interacted with. In web2project, this is often Tasks or Projects. If it's Javascript interacting with the page, it might be body or table. The point is that the code clearly describes the object it's interacting with.
The structure is optional because it's unique to the situation. A listing screen might request a List or an Array. One of the core functions used in the Project List for web2project is simply getProjectList. It doesn't modify the underlying data, just the representation of the data.
The adjectives are something else entirely. They are used as modifiers to the noun. Something as simple as getOpenProjects might be easily implemented with a getProjects and a switch parameter, but this tends to generate methods which require quite a bit of understanding of the underlying data and/or structure of the object... not necessarily something you want to encourage. By having more explicit and specific functions, you can completely wrap and hide the implementation from the code using it. Isn't that one of the points of OO?
More so than just naming a class, creating an appropriate package structure can be a difficult but rewarding challenge. You need to consider separating the concerns of your modules and how they relate to the vision of the application.
Consider the layout of your app now:
App
VendorDocRequester (read from web service and provide data)
VendorDocViewer (use requester to provide vendor docs)
I would venture to guess that there's a lot going on inside a few classes. If you were to refactor this into a more MVC-ified approach, and allow small classes to handle individual duties, you might end up with something like:
App
VendorDocs
Model
Document (plain object that holds data)
WebServiceConsumer (deal with nitty gritty in web service)
Controller
DatabaseAdapter (handle persistance using ORM or other method)
WebServiceAdapter (utilize Consumer to grab a Document and stick it in database)
View
HelpViewer (use DBAdapter to spit out the documention)
Then your class names rely on the namespace to provide full context. The classes themselves can be inherently related to application without needing to explicitly say so. Class names are simpler and easier to define as a result!
One other very important suggestion: please do yourself a favor and pick up a copy of Head First Design Patterns. It's a fantastic, easy-reading book that will help you organize your application and write better code. Appreciating design patterns will help you to understanding that many of the problems you encounter have already been solved, and you'll be able to incorporate the solutions into your code.
Leo Brodie, in his book "Thinking Forth", wrote that the most difficult task for a programmer was naming things well, and he stated that the most important programming tool is a thesaurus.
Try using the thesaurus at http://thesaurus.reference.com/.
Beyond that, don't use Hungarian Notation EVER, avoid abbreviations, and be consistent.
Best wishes.
In short:
I agree that good names are important, but I don't think you have to find them before implementing at all costs.
Of course its better to have a good name right from the start. But if you can't come up with one in 2 minutes, renaming later will cost less time and is the right choice from a productivity point of view.
Long:
Generally it's often not worth to think too long about a name before implementing. If you implement your class, naming it "Foo" or "Dsnfdkgx", while implementing you see what you should have named it.
Especially with Java+Eclipse, renaming things is no pain at all, as it carefully handles all references in all classes, warns you of name collisions, etc. And as long as the class is not yet in the version control repository, I don't think there's anything wrong with renaming it 5 times.
Basically, it's a question of how you think about refactoring. Personally, I like it, though it annoys my team mates sometimes, as they believe in never touch a running system. And from everything you can refactor, changing names is one of the most harmless things you can do.
Why not HelpDocumentServiceClient kind of a mouthful, or HelpDocumentClient...it doesn't matter it's a vendor the point is it's a client to a webservice that deals with Help documents.
And yes naming is hard.
There is only one sensible name for that class:
HelpRequest
Don't let the implementation details distract you from the meaning.
Invest in a good refactoring tool!
I stick to basics: VerbNoun(arguments). Examples: GetDoc(docID).
There's no need to get fancy. It will be easy to understand a year from now, whether it's you or someone else.
For me I don't care how long a method or class name is as long as its descriptive and in the correct library. Long gone are the days where you should remember where each part of the API resides.
Intelisense exists for all major languages. Therefore when using a 3rd party API I like to use its intelisense for the documentation as opposed to using the 'actual' documentation.
With that in mind I am fine to create a method name such as
StevesPostOnMethodNamesBeingLongOrShort
Long - but so what. Who doesnt use 24inch screens these days!
I have to agree that naming is an art. It gets a little easier if your class is following a certain "desigh pattern" (factory etc).
This is one of the reasons to have a coding standard. Having a standard tends to assist coming up with names when required. It helps free up your mind to use for other more interesting things! (-:
I'd recommend reading the relevant chapter of Steve McConnell's Code Complete (Amazon link) which goes into several rules to assist readability and even maintainability.
HTH
cheers,
Rob
Nope, debugging is the most difficult thing thing for me! :-)
DocumentFetcher? It's hard to say without context.
It can help to act like a mathematician and borrow/invent a lexicon for your domain as you go: settle on short plain words that suggest the concept without spelling it out every time. Too often I see long latinate phrases that get turned into acronyms, making you need a dictionary for the acronyms anyway.
The language you use to describe the problem, is the language you should use for the variables, methods, objects, classes, etc. Loosely, nouns match objects and verbs match methods. If you're missing words to describe the problem, you're also missing a full understanding (specification) of the problem.
If it's just choosing between a set of names, then it should be driven by the conventions you are using to build the system. If you've come to a new spot, uncovered by previous conventions, then it's always worth spending some effort on trying extend them (properly, consistently) to cover this new case.
If in doubt, sleep on it, and pick the first most obvious name, the next morning :-)
If you wake up one day and realize you were wrong, then change it right away.
Paul.
BTW: Document.fetch() is pretty obvious.
I find I have the most trouble in local variables. For example, I want to create an object of type DocGetter. So I know it's a DocGetter. Why do I need to give it another name? I usually end up giving it a name like dg (for DocGetter) or temp or something equally nondescriptive.
Don't forget design patterns (not just the GoF ones) are a good way of providing a common vocabulary and their names should be used whenever one fits the situation. That will even help newcomers that are familiar with the nomenclature to quickly understand the architecture. Is this class you're working on supposed to act like a Proxy, or even a Façade ?
Shouldn't the vendor documentation be the object? I mean, that one is tangible, and not just as some anthropomorphization of a part of your program. So, you might have a VendorDocumentation class with a constructor that fetches the information. I think that if a class name contains a verb, often something has gone wrong.
I definitely feel you. And I feel your pain. Every name I think of just seems rubbish to me. It all seems so generic and I want to eventually learn how to inject a bit of flair and creativity into my names, making them really reflect what they describe.
One suggestion I have is to consult a Thesaurus. Word has a good one, as does Mac OS X. That can really help me get my head out of the clouds and gives me a good starting place as well as some inspiration.
If the name would explain itself to a lay programmer then there's probably no need to change it.