Do they contradict?
Decoupling is something great and quite hard to achieve. However in most of the applications we don't really need it, so I can design highly coupled applications and it almost will not change anything other than obvious side effects such as "you can not separate components", "unit testing is pain in the arse" etc.
What do you think? Do you always try to decouple and deal with the overhead?
It seems to me decoupling and YAGNI are very much complementary virtues. (I just noticed Rob's answer, and it seems like we're on the same page here.) The question is how much decoupling you should do, and YAGNI is a good principle to help determine the answer. (For those who speak of unit testing -- if you need to decouple to do your unit test, then YAGNI obviously doesn't apply.)
I really sincerely doubt the people who say they "always" decouple. Maybe they always do every time they think of it. But I have never seen a program where additional layers of abstraction couldn't be added somewhere, and I sincerely doubt there is a non-trivial example of such a program out there. Everyone draws a line somewhere.
From my experience, I've deoupled code and then never taken advantage of the additional flexibility about as often as I've left code coupled and then had to go back and change it later. I'm not sure if that means I'm well-balanced or equally broken in both directions.
YAGNI is a rule of thumb (not a religion). Decoupling is more or less a technique (also not a religion). So they're not really related, nor do they contradict each other.
YAGNI is about pragmatism. Assume you don't need something, until you do.
Usually assuming YAGNI results in decoupling. If you don't apply that knife at all, you end up assuming that you need to have classes that know all about each other's behavior before you have demonstrated that to be true.
"Decouple" (or "loosely couple") is a verb, so it requires work. YAGNI is a presumption, for which you adjust when you find that it's no longer true.
I'd say they don't. Decoupling is about reducing unnecessary dependencies within code and tightening up accesses through clean, well-defined interfaces. "You ain't gonna need it" is a useful principle which generally advises against over-extensibility and overly broad architecture of a solution where there's no obvious and current use case.
The practical upshot of these is that you have a system where it's much easier to refactor and maintain individual components without inadvertently causing a ripple effect across the entire application, and where there are no unnecessarily complicated aspects to the design - it's as simple as is required to meet the current requirements.
I (almost) always decouple. Every time I did this I found it useful, and (almost) every time I didn't I had to do it later. I've also found it a good way to decrease the number of bugs.
Decoupling for the sake of decoupling can be bad.
Building testable components is very important though.
The hard part of the story is to know when and how much decoupling you need.
If "unit testing is a pain in the arse" then I would say that you do need it. Most of the time decoupling can be achieved with virtually zero cost as well, so why wouldn't you want to do it?
Furthermore, one of my biggest bugbears when working on a new codebase is having to decouple the code before I can start writing unit tests when the introduction of an interface somewhere or use of dependency injection could save alot of time
As your tag says, it's highly subjective. It rests entirely upon your own engineering wisdom to decide what you "ain't gonna need". You may need coupling in one case, but you won't in another. Who is to tell? You, of course.
For a decision so subjective, then, there cannot be a guideline to prescribe.
Well, YAGNI is little more than a bogus simplistic phrase people throw around. Decoupling, however, is a fairly well understood concept. YAGNI seems to imply that one is some sort of psychic. It's just programming by cliche, which is never a good idea. To be honest, there is a case to be made that YAGNI is probably not related to decoupling at all. Coupling is typically "quicker" and "who knows if you are you are going to need a decoupled solution; you aren't gonna change X component anyway!"
YAGNI the mess :) ... really, we don't need to have all the code mixed to go "faster".
The unit tests really help on feeling when it is coupled (given one understand well what is an unit test vs. other types of tests). If you instead do it with the "you can not separate components" mindset, you can easily get to add stuff that you ain't gonna need :)
I would say YAGNI comes in when you start twisting and changing logic all around beyond the actual usage scenarios the current implementation calls for. Lets say you have some code that uses a couple external payment providers that both work with redirects to an external site. It is ok to have a design that keeps everything clean, but I don't think it is ok to start thinking of providers that we don't know if will be ever supported that have plenty of different way of handling the integration and the related workflow.
Related
I'm working on developing controllers for hybrid systems in Haskell.
FRP libraries (right now I'm using netwire, but there are several good ones and a lot of interesting research on future ones) provide a great solution for the continuous-time side of the problem. Augmenting them with signal names, dimensions, preferred units, and so forth gets you a system that has modularity, is self-describing, and has a straightforward path to confidence in correctness.
I'm looking for information, folklore, or papers that provide similar properties for the discrete-time side. In some sense the problem is much easier, state machines are well-studied and simple. In other senses it's more difficult, I'll briefly explain how.
Correctness is obviously the most important thing, and thankfully it's also straightforward.
Self-description is more of a problem. You'd like the controller not just to be in the correct state, but to be capable of telling you what state it's in. Also how it got there. And where it might go next. So you can tack names on to everything, and it works, but it conflicts somewhat with modularity. You'd also like to be able to build complex discrete time behaviors from simpler ones. But when you ask the system what state it's in, generally the high-level answer is more interesting (or at least, as interesting) as the low level answer. How do you get this cleanly? I've tried a few naive approaches and have wrapped myself in spaghetti a few different ways, but it seems like there must be elegant solutions?
Another problem I've had with self-description is that I'd like to have a list of self-describing conditions (generally comparisons: has it been 10 seconds? am I within 3 feet of the next waypoint? has the battery power fallen below 15%? etc) that are being monitored which might trigger the next state transition. There are tricky questions of what even are the desirable semantics here, since it seems like some of these events are better handled "from the bottom up" (e.g. expected termination conditions of whatever low level step you are performing) and some "from the top down" (e.g. equipment failure detection, geofencing, ...). This can lead to spaghetti of its own even if you relax the goal of self-description.
In addition to diagnostics, accurate self-description information here could also be very useful for abstract interpretation, projecting the state of the system into the future by guessing which events are likely to occur when. Many of the event conditions lead themselves to fairly simple guesses (e.g. using velocity made good, fuel consumption rate, timers). Others are more complicated but might still be worth the effort to develop projections for some applications (e.g. expected orders from operators, weather forecasts, projected tracks for moving objects of interest). It would be nice to find a design that annotates conditions not only with names, but also with functions for this sort of stuff.
Does anyone have experience with this that they are willing to share?
Okay, so I would say the "real" answer to your question is that some of things that you are asking for are open areas of research --- in particular I think some of the self-describing features you desire may necessitate some degree of "spaghetti" simply because the problem you are trying to solve is inherently complicated.
That being said, your focus on modularity is exactly the right approach. I would say, take a look at Keymaera as I believe it has the features you are looking for despite being in Java. I would also recommend looking at the publications page on the Keymaera website as this should provide you valuable insight to the problem in general.
If you do not like Keymaera's approach you can also look into using Timed Automata which is another direction modeling-wise that should be sufficient for your problem description.
I'm thinking about general modeling (diagramming) standards and tools such as BPMN, UML, data modeling, etc.
Why do we need modeling?
Usually on what phase is modeling essential for you? communication? document and report?
How can you benefit from them in work or daily life?
Thank you!
You coined the most important word already: communication
Not only with others, but also with your future self. If you write an application now, and return to it after a few months pause, it will be hard to find your way around. Certainly, this depends on the size and complexity of the application in question. But having some visual representation will always be helpful.
Also, diagramming the application before actual development is a great way to wrap you head around everything. Normally, you will detect problems in you initial idea that are easy to fix at that stage. And as said, these diagrams will become helpful in the future.
Showing others how the application works internally is equally important. Everybody has a different way to approach problems. So something that is intuitive for you might seem weird in someone else's eyes. This makes it hard to grasp the concepts of an application someone else has written.
Also remember that only few of us (is any) write perfect code, and do a perfect architecture. We are human, we make errors.
Let's say for example that there is this nifty design pattern you heard of called "decorator", and you want to use it. Naturally, the word "decorator" will appear in your code, and people reading it will think: "Hey, I know this pattern. No need to read the gory details. I'll just handle it as a black-box and use it." But what if you misinterpreted the pattern and implemented it incorrectly. Now the person using it as a black-box will run into problems. These may range from small bugs to non-compiling API-calls. If you have a diagram of the whole thing, it will be much easier to pinpoint the cause.
The biggest problem with modelling is to keep the diagrams in-sync with your code. During the project life-time you will make changes. Small ones and big ones. In a perfect world, you would update the diagrams, think about it, let it sink into your brain, and then implement it. But the world's hardly perfect. So you may end up implementing something before diagramming it (if it's actually diagrammed at all). This whole process is cumbersome. Be it because the diagram software you use is crap or just simply because of time constraints.
Personally, I like to create an initial diagram. And once I'm happy with it, I dive into implementation. I won't revisit the diagram for small changes. Yes, after a while the code will deviate from the diagram, but the Big Picture is still there. If I need to make a bigger architectural change, I will revisit the diagram for sure.
What I will do however is keep the in-code documentation up-to-date. Most documentation extraction tools (like javadoc) give you the possibility to use markup which is useful to make the generated docs readable and usable. Especially when using hyperlinks.
So, coming back to one of your points, where you ask what the benefit is during the daily developer life, I think that the larger diagrams don't make that much of a difference there. Simply because once you grasped the concepts of the project, you will not need the diagram anymore as you peruse the codebase on a daily basis. What comes in handy though are proper code docstrings. Primarily because many IDEs display them while coding, or at least make it easy to jump to them. With diagrams, that's not so much the case.
Diagrams however are useful to get started quickly with a project.
One more thought about flow-charts/activity-diagrams: I find these mostly useless. except for complex algorithms, as it helps you visualize the cyclomatic complexity. But quite honestly, I have never needed to write a complex algorithm myself. I always found ready-to-use implementation in either the standard library or in a third-party library.
And one final note: This question should have been posted on https://softwareengineering.stackexchange.com/ ;)
I can only speak for flowcharts and diagrams for state machines, but the answer might apply also here: If you chart something, you are forced to think about your underlying stuctures. Usually bad structures tend to be more hard / ugly to draw as a diagram.
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I had a piece of work thrown out due to a single minor spec change that turned out not to have been spec'ed correctly. If it had been done right at the start of the project then most of that work would have never have been needed in the first place.
What are some good tips/design principles that keep these things from happening?
Or to lessen the amount of re-working to code that is needed in order to implement feature requests or design changes mid implementation?
Modularize. Make small blocks of code that do their job well. However, thats only the beginning. Its usually a large combination of factors that contribute to code so bad it needs a complete rework. Everything from highly unstable requirements, poor design, lack of code ownership, the list goes on and on.
Adding on to what others have brought up: COMMUNICATION.
Communication between you and the customer, you and management, you and the other developers, you and your QA department, communication between everyone is key. Make sure management understands reasonable timeframes and make sure both you and the customer understand exactly what it is that your building.
Take the time to keep communication open with the customer that your building the product for. Make milestones and setup a time to display the project to the customer at each milestone. Even if the customer is completely disappointed with a milestone when you show it, you can scratch what you have and start over from the last milestone. This also requires that your work be built in blocks that work independent of one another as Csunwold stated.
Points...
Keep open communication
Be open and honest with progress of product
Be willing to change daily as to the needs of the customers business and specifications for the product change.
Software requirements change, and there's not much one can do about that except for more frequent interaction with clients.
One can, however, build code that is more robust in face of change. It won't save you from throwing out code that meets a requirement that nobody needs anymore, but it can reduce the impact of such changes.
For example, whenever this applies, use interfaces rather than classes (or the equivalent in your language), and avoid adding operations to the interface unless you are absolutely sure you need them. By building your programs that way you are less likely to rely on knowledge of a specific implementation, and you're less likely to implement things that you would not need.
Another advantage of this approach is that you can easily swap one implementation for another. For example, it sometimes pays off to write the dumbest (in efficiency) but the fastest to write and test implementation for your prototype, and only replace it with something smarter in the end when the prototype is the basis of the product and the performance actually matters. I find that this is a very effective way to avoid premature optimizations, and thus throwing away stuff.
modularity is the answer, as has been said. but it can be a hard answer to use in practice.
i suggest focussing on:
small libraries which do predefined things well
minimal dependencies between modules
writing interfaces first is a good way to achieve both of these (with interfaces used for the dependencies). writing tests next, against the interfaces, before the code is written, often highlights design choices which are un-modular.
i don't know whether your app is UI-intensive; that can make it more difficult to be modular. it's still usually worth the effort, but if not then assume that it will be thrown away before long and follow the iceberg principle, that 90% of the work is not tied to the UI and so easier to keep modular.
finally, i recommend "the pragmatic programmer" by andrew hunt and dave thomas as full of tips. my personal favourite is DRY -- "don't repeat yourself" -- any code which says the same thing twice smells.
iterate small
iterate often
test between iterations
get a simple working product out asap so the client can give input.
Basically assume stuff WILL get thrown out, so code appropriately, and don't get far enough into something that having it be thrown out costs a lot of time.
G'day,
Looking through the other answers here I notice that everyone is mentioning what to do for your next project.
One thing that seems to be missing though is having a washup to find out why the spec. was out of sync. with the actual requirements needed by the customer.
I'm just worried that if you don't do this, no matter what approach you are taking to implementing your next project, if you've still got that mismatch between actual requirements and the spec. for your next project then you'll once again be in the same situation.
It might be something as simple as bad communication or maybe customer requirement creep.
But at least if you know the cause and you can try and help minimise the chances of it happening again.
Not knocking what other answers are saying and there's some great stuff there, but please learn from what happened so that you're not condemned to repeat it.
HTH
cheers,
Sometimes a rewrite is the best solution!
If you are writing software for a camera, you could assume that the next version will also do video, or stereo video or 3d laser scanning and include all hooks for all this functionality, or you could write such a versatile extensible astronaut architecture that it could cope with the next camera including jet engines - but it will cost so much in money, resources and performance that you might have been better off not doing it.
A complete rewrite for new functionality in a new role isn't always a bad idea.
Like csunwold said, modularizing your code is very important. Write it so that if one piece falls prone to errors, it doesn't muck up the rest of the system. This way, you can debug a single buggy section while being able to safely rely on the rest.
Beyond this, documentation is key. If your code is neatly and clearly annotated, reworking it in the future will be infinitely easier for you or whoever happens to be debugging.
Using source control can be helpful too. If you find a piece of code doesn't work properly, there's always the opportunity to revert back to a past robust iteration.
Although it doesn't directly apply to your example, when writing code I try to keep an eye out for ways in which I can see the software evolving in the future.
Basically I try to anticipate where the software will go, but critically, I resist the temptation to implement any of the things I can imagine happening. All I am after is trying to make the APIs and interfaces support possible futures without implementing those features yet, in the hope that these 'possible scenarios' help me come up with a better and more future-proof interface.
Doesn't always work ofcourse.
What are some ways in which I can write code that is easily modified?
The one I have learned from experience is that I almost always need to write one to throw away. That way I have developed a sense of the domain knowledge and program structure required before coding the actual application.
The general guidelines are offcourse
High cohesion, low coupling
Dont repeat yourself
Recognize design patterns and implement them
Dont recognize design patterns where they are not existing or necassary
Use a coding standard, stick to it
Comment everyting that should be commented, when in doubt : comment
Use unit tests
Write comments and tests before implementation, that way you know exactly what you want to do
And when it goes wrong : refactor, refactor, refactor. With good tests you can be sure nothing breaks
And oh yeah:
read this : http://www.pragprog.com/the-pragmatic-programmer
Everything (i think) above and more is in it
I think your emphasis on modifiability is more important than readability. It is not hard to make something easy to read, but the real test of how well it is understood comes when someone else (or you) has to modify it in repsonse to changing requirements.
What I try to do is assume that modifications will be necessary, and if it is not really clear how to do them, leave explicit directions in the code for how to do them.
I assume that I may have to do some educating of the reader of the code to get him or her to know how to modify the code properly. This requires energy on my part, and it requires energy on the part of the person reading the code.
So while I admire the idea of literate programming, that can be easily read and understood, sometimes it is more like math, where the only way to do it is for the reader to buckle down, pay close attention, re-read it a few times, and make sure they understand.
Readability helps a lot: If you do something non-obvious, or you are taking a shortcut, comment. Comments are places where you can go back and refactor if you have time later. Use sensible names for everything, makes it easier to understand what is going on.
Continuous revision will let you move from that first draft to a better one without throwing away (too much) work. Any time you rewrite from scratch you may lose lessons learned. As you code, use refactoring tools to eliminate code representing areas of exploration that are no longer needed, and to make obvious things that were obscure. The first one reduces the amount that you need to maintain; the second reduces the effort per square foot. (Sqft makes about as much sense as lines of code, really.)
Modularize appropriately and enforce encapsulation and separation of logic between your modules. You don't want too many dependencies on any one part of the code or that part becomes inherently harder to understand.
Considering using tried and true methods over cutting edge ones. You give up some functionality for predictability.
Finally, if this is code that people will be using before and after modification, you need(ed) to have an appropriate API insulating your code from theirs. Having a strong API lets you change things behind the scenes without needing to alert all your consumers. I think there's a decent article on Coding Horror about this.
Hang Your Code Out to D.R.Y.
I learned this early when assigned the task of changing the appearance of a web-interface. The code was in C, which I hated, and was compiled to a CGI executable. And, worse, it was built on a library that was abandoned—no updates, no support, and too many man-hours put into its use to change it. On top of the framework was a disorderly web of code, consisting of various form and element builders, custom string implementations, and various other arcane things (for a non-C programmer to commit suicide with).
For each change I made there were several, sometimes many, exceptions to the output HTML. Each one of these exceptions required a small change or improvement in the form builder, thanks to the language there's no inheritance and therefore only functions and structs, and instead of putting the hours in the team instead wrote these exceptions frequently.
In my inexperience I was forced to change the output of each exception, rather than consolidate the changes in an improved form builder. But, trawling through 15,000 lines of code for several hours after ineffective changes would induce code-burn, and a fogginess that took a night's sleep to cure.
Always run your code through the DRY-er.
The easiest way to modify a code is NOT to write code. Write pseudo code not just for algo but how your code should be structured if you are unsure.
Designing while writing code never works...for me :-)
Here is my current experience: I'm working (Java) with a kind of database schema that might often change (fields added/removed, data types modified). My strategy is to parse this schema and to generate the code with apache velocity. The BaseClass generated is never modified by the programmer. Else, a MyClass extends BaseClass is created and the logical components of this class (e.g. toString() ! )are implemented using the 'getters' and the 'setters' of the super class.
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A couple of years ago the media was rife with all sorts of articles on
how the idea of code reuse was a simple way to improve productivity
and code quality.
From the blogs and sites I check on a regular basis it seems as though
the idea of "code reuse" has gone out of fashion. Perhaps the 'code
reuse' advocates have all joined the SOA crowd instead? :-)
Interestingly enough, when you search for 'code reuse' in Google the
second result is titled:
"Internal Code Reuse Considered Dangerous"!
To me the idea of code reuse is just common sense, after all look at
the success of the apache commons project!
What I want to know is:
Do you or your company try and reuse code?
If so how and at what level, i.e. low level api, components or
shared business logic? How do you or your company reuse code?
Does it work?
Discuss?
I am fully aware that there are many open source libs available and that anyone who has used .NET or the Java has reused code in some form. That is common sense!
I was referring more to code reuse within an organizations rather than across a community via a shared lib etc.
I originally asked;
Do you or your company try and reuse code?
If so how and at what level, i.e. low level api, components or shared business logic? How do you or your company reuse code?
From where I sit I see very few example of companies trying to reuse code internally?
If you have a piece of code which could potentially be shared across a medium size organization how would you go about informing other members of the company that this lib/api/etc existed and could be of benefit?
The title of the article you are referring to is misleading, and is actually a very good read. Code reuse is very beneficial, but there are downsides with everything. Basically, if I remember correctly, the gist of the article is that you are sealing the code in a black box and not revisiting it, so as the original developers leave you lose the knowledge. While I see the point, I don't necessarily agree with it - at least not to a "sky is falling" regard.
We actually group code reuse into more than just reusable classes, we look at the entire enterprise. Things that are more like framework enhancement or address cross-cutting concerns are put into a development framework that all of our applications use (think things like pre- and post-validation, logging, etc.). We also have business logic that is applicable to more than one application, so those sort of things get moved to a BAL core that is accessible anywhere.
I think that the important thing is not to promote things for reuse if they are not going to really be reused. They should be well documented, so that new developers can have a resource to help them come up to speed, as well. Chances are, if the knowledge isn't shared, the code will eventually be reinvented somewhere else and will lead to duplication if you are not rigorous in documentation and knowledge sharing.
We reuse code - in fact, our developers specifically write code that can be reused in other projects. This has paid off quite nicely - we're able to start new projects quickly, and we iteratively harden our core libraries.
But one can't just write code and expect it to be re-used; code reuse requires communication among team members and other users so people know what code is available, and how to use it.
The following things are needed for code reuse to work effectively:
The code or library itself
Demand for the code across multiple projects or efforts
Communication of the code's features/capabilities
Instructions on how to use the code
A commitment to maintaining and improving the code over time
Code reuse is essential. I find that it also forces me to generalize as much as possible, also making code more adaptable to varying situations. Ideally, almost every lower level library you write should be able to adapt to a new set of requirements for a different application.
I think code reuse is being done through open source projects for the most part. Anything that can be reused or extended is being done via libraries. Java has an amazing number of open source libraries available for doing a large number of things. Compare that to C++, and how early on everything would have to be implemented from scratch using MFC or the Win32 API.
We reuse code.
On a small scale we try to avoid code duplication as much as posible. And we have a complete library with a lot of frequently used code.
Normally code is developed for one application. And if it is generic enough, it is promoted to the library. This works excelent.
The idea of code reuse is no longer a novel idea...hence the apparent lack of interest. But it is still very much a good idea. The entire .NET framework and the Java API are good examples of code reuse in action.
We have grown accustomed to developing OO libraries of code for our projects and reusing them in other projects. Its a part of the natural life cycle of an idea. It is hotly debated for a while and then everyone accepts and there is no reason for further discussion.
Of course we reuse code.
There are a near infinite amount of packages, libraries and shared objects available for all languages, with whole communities of developers behing them supporting and updating.
I think the lack of "media attention" is due to the fact that everyone is doing it, so it's no longer worth writing about. I don't hear as many people raising awareness of Object-Oriented Programming and Unit Testing as I used to either. Everyone is already aware of these concepts (whether they use them or not).
Level of media attention to an issue has little to do with its importance, whether we're talking software development or politics! It's important to avoid wasting development effort by reinventing (or re-maintaining!) the wheel, but this is so well-known by now that an editor probably isn't going to get excited by another article on the subject.
Rather than looking at the number of current articles and blog posts as a measure of importance (or urgency) look at the concepts and buzz-phrases that have become classics or entered the jargon (another form of reuse!) For example, Google for uses of the DRY acronym for good discussion on the many forms of redundancy that can be eliminated in software and development processes.
There's also a role for mature judgment regarding costs of reuse vs. where the benefits are achieved. Some writers advocate waiting to worry about reuse until a second or third use actually emerges, rather than spending effort to generalize bit of code the first time it is written.
My personal view, based on the practise in my company:
Do you or your company try and reuse code?
Obviously, if we have another piece of code that already fits our needs we will reuse it. We don't go out of our way to use square pegs in round holes though.
If so how and at what level, i.e. low level api, components or shared business logic? How do you or your company reuse code?
At every level. It is written into our coding standards that developers should always assume their code will be reused - even if in reality that is highly unlikely. See below
If your OO model is good, your API probably reflects your business domain, so reusable classes probably equates to reusable business logic without additional effort.
For actual reuse, one key point is knowing what code is already available. We resolve this by having everything documented in a central location. We just need a little discipline to ensure that the documentation is up-to-date and searchable in a meaningful way.
Does it work?
Yes, but not because of the potential or actual reuse! In reality, beyond a few core libraries and UI components, there isn't a large amount of reuse.
In my personal opinion, the real value is in making the code reusable. In doing so, aside from a hopefully cleaner API, the code will (a) be documented sufficiently for another developer to use it without trawling the source code, and (b) it will also be replaceable. These points are a great benefit to on-going software maintenance.
Do you or your company try and reuse code? If so how and at what
level, i.e. low level api, components or shared business logic? How do
you or your company reuse code?
I used to work in a codebase with uber code reuse, but it was difficult to maintain because the reused code was unstable. It was prone to design changes and deprecation in ways that cascaded to everything using it. Before that I worked in a codebase with no code reuse where the seniors actually encouraged copying and pasting as a way to reuse even application-specific code, so I got to see the two extremities and I have to say that one isn't necessarily much better than the other when taken to the extremes.
And I used to be an uber bottom-up kind of programmer. You ask me to build something specific and I end up building generalized tools. Then using those tools, I build more complex generalized tools, then start building DIP abstractions to express the design requirements for the lower-level tools, then I build even more complex tools and repeat, and at some point I start writing code that actually does what you want me to do. And as counter-productive as that sounded, I was pretty fast at it and could ship complex products in ways that really surprised people.
Problem was the maintenance over the months, years! After I built layers and layers of these generalized libraries and reused the hell out of them, each one wanted to serve a much greater purpose than what you asked me to do. Each layer wanted to solve the world's hunger needs. So each one was very ambitious: a math library that wants to be amazing and solve the world's hunger needs. Then something built on top of the math library like a geometry library that wants to be amazing and solve the world's hunger needs. You know something's wrong when you're trying to ship a product but your mind is mulling over how well your uber-generalized geometry library works for rendering and modeling when you're supposed to be working on animation because the animation code you're working on needs a few new geometry functions.
Balancing Everyone's Needs
I found in designing these uber-generalized libraries that I had to become obsessed with the needs of every single team member, and I had to learn how raytracing worked, how fluids dynamics worked, how the mesh engine worked, how inverse kinematics worked, how character animation worked, etc. etc. etc. I had to learn how to do pretty much everyone's job on the team because I was balancing all of their specific needs in the design of these uber generalized libraries I left behind while walking a tightrope balancing act of design compromises from all the code reuse (trying to make things better for Bob working on raytracing who is using one of the libraries but without hurting John too much who is working on physics who is also using it but without complicating the design of the library too much to make them both happy).
It got to a point where I was trying to parametrize bounding boxes with policy classes so that they could be stored either as center and half-size as one person wanted or min/max extents as someone else wanted, and the implementation was getting convoluted really fast trying to frantically keep up with everyone's needs.
Design By Committee
And because each layer was trying to serve such a wide range of needs (much wider than we actually needed), they found many reasons to require design changes, sometimes by committee-requested designs (which are usually kind of gross). And then those design changes would cascade upwards and affect all the higher-level code using it, and maintenance of such code started to become a real PITA.
I think you can potentially share more code in a like-minded team. Ours wasn't like-minded at all. These are not real names but I'd have Bill here who is a high-level GUI programmer and scripter who creates nice user-end designs but questionable code with lots of hacks, but it tends to be okay for that type of code. I got Bob here who is an old timer who has been programming since the punch card era who likes to write 10,000 line functions with gotos in them and still doesn't get the point of object-oriented programming. I got Joe here who is like a mathematical wizard but writes code no one else can understand and always make suggestions which are mathematically aligned but not necessarily so efficient from a computational standpoint. Then I got Mike here who is in outer space who wants us to port the software to iPhones and thinks we should all follow Apple's conventions and engineering standards.
Trying to satisfy everyone's needs here while coming up with a decent design was, probably in retrospect, impossible. And in everyone trying to share each other's code, I think we became counter-productive. Each person was competent in an area but trying to come up with designs and standards which everyone is happy with just lead to all kinds of instability and slowed everyone down.
Trade-Offs
So these days I've found the balance is to avoid code reuse for the lowest-level things. I use a top-down approach from the mid-level, perhaps (something not too far divorced from what you asked me to do), and build some independent library there which I can still do in a short amount of time, but the library doesn't intend to produce mini-libs that try to solve the world's hunger needs. Usually such libraries are a little more narrow in purpose than the lower-level ones (ex: a physics library as opposed to a generalized geometry-intersection library).
YMMV, but if there's anything I've learned over the years in the hardest ways possible, it's that there might be a balancing act and a point where we might want to deliberately avoid code reuse in a team setting at some granular level, abandoning some generality for the lowest-level code in favor of decoupling, having malleable code we can better shape to serve more specific rather than generalized needs, and so forth -- maybe even just letting everyone have a little more freedom to do things their own way. But of course all of this is with the aim of still producing a very reusable, generalized library, but the difference is that the library might not decompose into the teeniest generalized libraries, because I found that crossing a certain threshold and trying to make too many teeny, generalized libraries starts to actually become an extremely counter-productive endeavor in the long term -- not in the short term, but in the long run and broad scheme of things.
If you have a piece of code which could potentially be shared across a
medium size organization how would you go about informing other
members of the company that this lib/api/etc existed and could be of
benefit?
I actually am more reluctant these days and find it more forgivable if colleagues do some redundant work because I would want to make sure that code does something fairly useful and non-trivial and is also really well-tested and designed before I try to share it with people and accumulate a bunch of dependencies to it. The design should have very, very few reasons to require any changes from that point onwards if I share it with the rest of the team.
Otherwise it could cause more grief than it actually saves.
I used to be so intolerant of redundancy (in code or efforts) because it appeared to translate to a product that was very buggy and explosive in memory use. But I zoomed in too much on redundancy as the key problem, when really the real problem was poor quality, hastily-written code, and a lack of solid testing. Well-tested, reliable, efficient code wouldn't suffer that problem to nearly as great of a degree even if some people duplicate, say, some math functions here and there.
One of the common sense things to look at and remember that I didn't at the time is how we don't mind some redundancy when we use a very solid third party library. Chances are that you guys use a third party library or two that has some redundant work with what your team is doing. But we don't mind in those cases because the third party library is great and well-tested. I recommend applying that same mindset to your own internal code. The goal should be to create something awesome and well-tested, not to fuss over a little bit of redundancy here and there as I mistakenly did long ago.
So these days I've shifted my intolerance towards a lack of testing instead. Instead of getting upset over redundant efforts, I find it much more productive to get upset over other people's lack of unit and integration testing! :-D
While I think code reuse is valuable, I can see where this sentiment is rooted. I've worked on a lot of projects where much extra care was taken to create re-usable code that was then never reused. Of course reuse is much preferable to duplicate code, but I have seen a lot of very extenisve object models created with the goal of using the objects across the enterprise in multiple projects (kind of the way the same service in SOA can be used in different apps) but have never seen the objects actually used more than once. Maybe I just haven't been part of organizations taking good advantage of the principle of reuse.
The two software projects I've worked on have both been long term development. One is about 10 years old, the other has been around for over 30 years, rewritten in a couple versions of Fortran along the way. Both make extensive reuse of code, but both rely very little on external tools or code libraries. DRY is a big mantra on the newer project, which is in C++ and lends itself more easily to doing that in practice.
Maybe the better question is when do we NOT reuse code these days? We are either in a state on building using someone elses observed "best practices" or prediscovered "design patterns" or just actually building on legacy code, libraries, or copying.
It seems the degree to which code A is reused to make code B is often based around how much the ideas in code A taken to code B are abstracted into design patterns/idioms/books/fleeting thoughts/actual code/libraries. The hard part is in applying all those good ideas to your actual code.
Non-technical types get overzealous about the reuse thing. They don't understand why everything can't be copy-pasted. They don't understand why the greemelfarm needs a special adapter to communicate the same information that it used to to the old system to the new system, and that, unfortunately we can't change either due to a bazillion other reasons.
I think techies have been reusing from day 1 in the same way musicians have been reusing from day 1. Its an ongoing organic evolution and sythesis that will keep ongoing.
Code reuse is an extremely important issue - where code is not reused, projects take longer and are harder for new team members to get into.
However, writing reusable code takes longer.
Personally, I try to write all my code in a reusable way, this takes longer, but it results in the fact that most of my code has become official infrastructures in my organization and that new projects based on these infrastructures take significantly less time.
The danger in reusing code, is if the reused code is not written as an infrastructure - in a general and encapsulated manner with as few as possible assumptions and as much as possible documentation and unit testing, that the code can end up doing unexpected things.
Also, if bugs are found and fixed, or features added, these changes are rarely returned to the source code, resulting in different versions of the reused code, that no one knows of or understands.
The solution is:
1. To design and write the code with not only one project in mind, but to think of future requirements and try to make the design flexible enough to cover them with minimal code change.
2. To enclose the code within libraries that are to be used as-is and not modified within using projects.
3. To allow users to view and modify the code of of the library withing its solution (not within the using project's solution).
4. To design future projects to be based on the existing infrastructures, making changes to the infrastructures as necessary.
5. To charge maintaining the infrastructure to all projects, thus keeping the infrastructure funded.
Maven has solved code reuse. I'm completely serious.