how to get started with Optaplanner - optaplanner

I looked at the user guide http://docs.jboss.org/optaplanner/release/6.1.0.Final/optaplanner-docs/html_single/index.html#d0e2669
I looked at the example code from git, but still feel quite lost about how to model my planning problem (for example some special TSP variant, let's say TSPTW ). the way OptaPlanner user code is structured is that the user code is devided into several packages, and there is not a entire "end-to-end" flow of code, and as a developer I only see these "modules" , sort of. So as a result it's very difficult for me to figure out how to connect the dots, and how these "dots" interact together to accomplish the overall algorithm task.
the section in the link above "Model your planning problem " sort of touches on the above question I have, but still seems out of sync with the example code, so it's difficult to figure out how the current examples work, also it's difficult for me to see how to add my own special logic for the TSP variant .
is there a better "code walk-through" document to show the usage of the framework?
thanks
Yang

Take a look here this guy create a simple optaplanner project to test some concepts and learn how to use it.

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Fastest way to understand business logic in a new project

I would like to know the fastest/best way to learn the business logic in a new project.
Most projects have been running for years, some of them are poorly documented, but you still need to know how to work with them. What is the best way to do this? (Use Case Diagram / support from colleagues / code analysis etc.)
The problem with verbose logging is that you may be overloaded with details that do not help, and even if you have the right details, you may misunderstand the big picture.
Moreover, if projects run for years, and are poorly documented, chances are the little available documentation is already obsolete. And chances are, the team did not invest heavily in logging either.
Reverse engineering the code is another approach, but where to start if there are millions of lines of code in the legacy system? Some things can be easily read in code, but many more complex, emergent behavior comes from the interactions between many classes, and this kind of knowledge is the most difficult to extract.
So here is the way to go:
Talk to colleagues. The best approach to move knowledge from one brain to another is direct conversation. It works much better than any formal diagram or any documentation. Unfortunately this is not always possible (e.g. team left)
If 1 is not possible, understand the business user's point of view. May be there is a user manual? Maybe some colleagues of the user-support? if none of those are possible, the ultimate way is to spend some time in the day of the user's life. You will not understand how the system works, but at least you'll get a quick intro in what the system is supposed to do, what matters to the users, and maybe some business rules.
Check for automated test cases. In fact, such test cases are a hidden and up-to date documentation resource.
Check for non-automated test cases, in particular use acceptance tests, and integration tests. If these are not automated, there are chances that they are already obsolete. But it's better than nothing.
Reverse engineer the code. Identify the main classes and how they interact. And yes, some simplified class diagrams will help you to understand how classes are related (no need to document properties and methods: these can be found back in the code). And some sequence diagram will help you to get a picture of the more complex interactions.
Run server, log verbose everywhere. Follow code flow and dig in.

Does a language describe things beyond itself?

I now have sufficent exposure to the Objective-C that if i'm stuck with anything, I know how to think of the problem in terms of a likely tool I need and go look for it. Simple really. There's A Method For That. So nothings a real problem anymore.
Now I'm looking deeper at the language in broader terms. We write stuff. The compiler hews out all the code to execute it. From a simple flashlight app thats a if/then decision to turn on, to a highly complex accelerometer driven 3D shoot 'em up with blood 'n guts and body parts following all sorts of physics, the compiler prepares the code ready to be executed like a giant railway layout. No matter how random it appears on the screen, everything possible can be generically described and prepared for.
So here's the question:
Are there cases where something completely unexpected to the software designer can still be handled without an execution halt? Maybe I'd better re-frame the question a few different ways: Can a ( objective-C ) program meta-compile within itself in response to an unplanned-for user request? or to re-put my opening remark, are there tools or methods for unlikely descriptions of unlikely problems?
I think #kfb has the right comment about metaprogramming. Check out the Runtime docs in conjunction with metaprogramming tutorials.
Parts of your last question might be in the realm of this doc.
If your looking for ways to reduce the size of your code base for the lesser used features, one idea might be to make the features internet based (assuming connectivity is not a problem).

Coding Test - allow use of web? [closed]

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During hiring a .NET web developer I give the candidate a coding test.
I tend to limit the candidate to MSDN installed on the test server - I think it holds everything the candidate needs to complete the task.
I admit, this is not the normal case as I don't expect the candidate to do his work without use of the web.
On the other hand I don't want the candidate to google for a complete example and copy-paste it, i want to evaluate his skills.
The question is do I need to allow free use of the web during the test?
If you think the whole coding test is wrong - I would like to hear alternatives you may have for me.
As you say, 'I don't expect the candidate to do his work without use of the web' why not allow it too during the test? And what if he does copy and paste? I do that too. Surely the key is to know where to look, be discerning with what you find and apply it intelligently. Do you want to hire someone with a terrific memory or someone who can develop software for you?
When I was at school, calculators were just becoming affordable. As their use was seen as unavoidable, the exams were changed. Simple number-crunching was no longer tested in the way it was before (it was important then). Rather problem-solving techniques were to be tested.
I usually allow candidates to use whatever resources they want. After they're done, I sit down with them and go through their code together, ask questions like why they chose that particular approach etc.
If a couple of minutes of Googling was enough to not just copypaste some code but to learn enough about it to be able to defend the decisions within, then he's intelligent enough!
There are tests, where web access can be given, and there are where it doesn't really make sense.
Case where its fine to allow web access
When its unlikely to find even 60 percent of the code over the net
When you will ask to explain the code after he/she completed the code
A very specific solution using SQL query, which is unlikely to be found on the web
Case where its fine to not allow web access
Some basic programs like, recurssion, fibonacci, factorial, string manipulation, small trick programs, etc. There is no need of computer even in some of these cases
I'm very sceptical about coding tests during interviews. I think that a lot of the test I have seen, represent very specific (artificial, non real-world) problems where you would use the internet to solve them.
I think it's not really important to know how to solve such problems by heart - often time it is much more important that you know how and where to search for answers.
If you want to test the persons during the interview, I think it is better to ask them some conceptual questions instead of a specific programming problem. E.g: questions about object orientation, polymorphism, design of n-tier application, etc. etc.
Or as an example from the ASP.NET world, ask the interviewed person question such as: what is ViewState, what is a postback, what is session-/application-state, etc.
If you want to get an idea of how a candidate will perform in a job, I think it's best to try and make the conditions of the test as close as possible to the actual working conditions.
It should be pretty easy to prevent copy-and-pasters from slipping through the cracks by asking the candidate to explain his/her code.
Well, one thing you want to be aware of is that the developer you hire might not know everything that he will be thrown during the time he is working for you. If you ask him a question that he doesn't know off the top of his head you would want and expect him to research it and come back to you with proof that he understood the concepts that he just learned.
I say let them use the web - but ask them to explain in their own words how their code works. Most of my knowledge comes from online resources. However, I make sure that every line of code I write I understand.
There is a baseline knowledge that developers in a particular field should know; but you also want to figure out how quickly he can learn new things. A good test IMO is to throw a question you know he doesn't know and see how long he can figure it out using the resources he would have if he were an employee of your company.
Is your goal to see what basic knowledge the candidate has and if he can code without copying solutions from the web, then don't allow internet access. If you want to see what strategies he employs to get to a solution, let him use the web if he wants to.
I personally find it more interesting if a candidate can solve problems on a larger scale than just solving a simple programming problem. So I tend to ask him about the methods he uses when programming (Unit testing? Ever worked with it? What do you think of it?). This gives me a better picture than coding in an interview situation.
Sometimes it helps if you ask the candidates beforehand to bring a one-page coding sample to take a look at their coding style. This also saves you time during the interview.
It's important to make sure a candidate is resourceful - you don't want your programmer sitting there when they get stuck, not moving forward; you want them to use whatever resources are at hand - be it MSDN, picking someone else's brains, using the web, etc - to get the job done. Cut-n-paste from the web does seem like cheating, but (a) if you design your task carefully then it will be unique enough for there not to be a standard answer they can copy from the web, and (b) isn't re-using existing code a key part of building software? It's not much different from using 3rd-party libraries, to avoid reinventing the wheel. On the downside, of course, you also want them to show they can develop algorithms, so the unique task needs to include some element that requires that without the solution already being on the web. Trouble is, forums are the achilles heel to all of that since they can simply ask for the solution and someone, somewhere, is going to hand over the answer unwittingly!
Allow the candidate to use the web but tell him beforehand that if he used the web, you will have to evaluate HOW he solved the problem.
If he used the web for something simple such as finding the syntax or parameters which he forgot, don't mark him down. This is normal.
If he used the web for something like look at how a specific function is used, don't mark him down. This is normal.
If he searched for a specific code and then copy-paste it, then ask him about how the code works. If he can explain how the code works, then there's no reason to mark him down. If he can't explain it without looking at the site where he got the code, you have to mark him down.
If he used stackoverflow.com, check his profile for questions, answers and badges. From there, you can check how good a programmer he is.
It all depends what you want out of your successful candidate. I contest the view that knowing how to google makes you a good programmer because the simple fact is that the internet is full of bad examples as well as good ones. You don't really want your codebase to reflect how lucky your googler was on the day he cut and pasted all his code off the web. You want it to demonstrate sound practices, proven methodologies & elegant, efficient solutions that your team understand and are enthusiastic about. Not a jumble of styles that don't resemble each other. There's a wealth of good to be gotten from knowing how to get help from the interweb but real knowledge and ancient wisdom is being lost every day that people who don't really understand what they are doing are given jobs because they appear to solve problems with their ability to "google it".
If you really want to give your candidates access to the web then by all means do, but make the questions hard and scrutinise the results to see if they've picked the first solution they found or if they've picked the best solution to the problem.
As do many other respondents, I'd rather employ a resourceful developer who know how to use the web to the fullest to draw on other's experiences and previous work, than a developer who limits himself and his applications to the MSDN way of doing things.
I copy other peoples code all the time - daily in fact. The knack of it depends on finding the right solution quickly and integrating it into your existing work.
So let your candidate use the web and ask him how he came to his solutions. You might learn more about him from his methods than from how will he can remember previous solutions.
Three things I'd do.
Let applicants send in a coding example along with their cv.
Let applicants produce some real-life code (maybe even pair-program with a developer on your team) this will show you if they can actually use the tools. Internet is a tool too so they should be able to use internet.
Let applicants solve a problem in pseudo code on a blackboard during the interview. In this case you can be their "internet" by helping them.
These three approaches will show you different things. The first is a good early warning mechanism but can easily be faked (they could just download oss code from the web somewhere). The second is good to see if they can actually code but they might score badly if they're unfamiliar with the tools you use. The third will show you if they can solve theoretical problems but won't show you if they actually are good team players or if they write maintainable code.
I recently had a friend start talking to me on IM, he was in a coding test job interview. He had a couple SQL questions. At first i thought, hell you've got to do this yourself. I'm not going to help you cheat during an interview.
Then i thought about it again. I've been answering questions and talking to him about various technical issues for years on IM as part of his work. So when he encounters problems in the real world with the job if he gets hired, he'll do the same thing.
We don't talk about it much, but having a good network of friends to ask questions, and knowing how to search out relevant answers on the net are a big part of being an effective programmer or sysadmin. I've met people who were super smart programmers, but didn't really know how to find information online. They missed a lot, were kind of out of the loop. Knowing how to use resources should be important.
When i do interviews i often ask people what websites they read, what development tools they use, and why. It's a similar thing. Sure it's not about how they write x line of code, but it's about how they work.
No how to get around somebody just copy and pasting "answers". Well first, don't ask questions which have pat answers. Secondly when i'm interviewing i like to give people some code, ask them to refactor it, have them talk through what they are thinking. Then ask them to write some new code which implements a feature. Pair program with them. It's hard to hide inability to code when pair programming. While they are pairing, it totally makes sense to say, "let's go look up the api on the date time library."

Coming up to speed on the programming environment [closed]

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I'm not a full-time software guy. In fact, in the last ten years, 90 % of my work was either on the hardware or doing low-level (embedded) code.
But the other 10% involves writing shell scripts for development tools, making kernel changes to add special features, and writing GUI applications for end-users.
The problem is that I find myself facing significant holes in my knowledge, often because it's been years since I've done "X", and I've either forgotten, or the environment has changed.
Every so often, there are threads on TheDailyWTF.com along the lines of "WTF: the guy spent all day writing tons of code, when he could have called foobar() in library baz". I've been there myself, because I don't remember much beyond the #include <stdio.h> stuff (for example), and my quick search somehow missed the right library.
What methods have you found effective to crash-learn and/or crash-refresh yourself in programming environments that you rarely touch?
Ask developers you know that work in the environment that you are interested in.
Search the web a lot.
Ask specific questions in relevant IRC channels (Freenode is great).
Ask specific questions on StackOverflow and other sites.
There really isn't any substitue for being "in the daily flow" of the programming environment in question. Having a good feel for the current state of the art is something you only get from experience, as I'm sure you can verify in you own areas of expertise.
i try to keep up with general news about languages i'm interested in but aren't necessarily using at the moment. being able to follow the general changes helps a lot for when you have to pick it up again.
beyond that, i personally find it easiest to grab an up to date reference book, and code a few basic things to get me used to the environment again, ie as a web programmer i'd make a simple crud app, or a quick web service/client.
For frameworks/APIs (such as a JavaScript framework or a widget library):
Quickly scan through the entire API documentation; get a glimpse of all that's out there instead of picking the first method that seems to fit your needs.
If available, glance at the source code of the
framework to see how the
API was intended to be used. Seeing what's behind the curtain helps. And also
some of the methods will have been used
internally, showcasing their true intents.
Don't necessarily always trust existing code (Googled, from co-workers, from books) since not everyone does the due diligence to find out the most proper way to use an API. Sometimes even samples in API documentation can be out-of-date.
In newer full-featured environments like Java, .NET, and Python, there are library solutions to almost every common problem. Don't think "how can I program this in plain C", but "which library solves this problem for me?" It's an attitude shift. As far as resources, the library documentation for the three environments I mentioned are all good.
The best solution I think is to get a book on the topic / environment you need to catch up on.
Ask questions from developers who you know who have the experience in that area.
You can also check out news groups (Google Groups makes this easy) and forums. You can ask questions, but even reading 10 minutes of the latest popular questions for a particular topic / environment will keep you a little bit "in the know".
The same thing can go for blogs too if you can find a focussed blog. These are pretty rare though and I personally don't look to blogs to keep me "in the know" on a particular environment. (I personally find blogs most popular and interesting in the "here's something neat" or "here's how I failed and you can avoid it" or "general practice" areas.)
In addition to the answers above, I think what you are asking for will take a significant amount of your time, and you must be willing to spend that time to achieve your goals. My method would be pretty much the same as Owen's answer; get a reference book or tutorial and work through the examples hacking in changes as you go to experiment with how any given thing works. I'd say as a bare minimum, allocate a hour to do this every other day, in a time that you know you won't be interrupted. Any less, and you'll probably continue to struggle.
The best way to crash-learn is simple, simply do it, use google to search for X tutorial, open your favorite browser and start typing away. Once you reached a certain level of feeling with X, do look at other people things, there is lots of open source out there and there must be someboby who has used X before, look at how they solved certain problems and learn from this, this is an easy way to verify that you are 'on the right track' or that you're doing things or thinking in patterns that other people would define as 'common sense'.
Crash-refreshing something is much easier since you have a suspended learning curve already, the way I do this is to keep some of the example you did while writing or keep some projects you did. Then you can easily refresh and use your own examples.
The library issue you mention here well, only improving your search skills will improve that one (although looking on how others solved this will help as well)
Don't try and pick up every environment.
Focus on the one that's useful and/or interesting, and then pick a few quality blogs to regularly read or podcasts to listen to. You'll pick up the current state of the environment fairly quickly.
Concrete example: I've been out of the Java world for a long time, but I've been put on a Java project in the last few months. Since then I've listened to the Java Posse podcast and read a few blogs, and although I'm far from a Java guru I've got back up to speed without too much trouble.
Just a though. While we are working on our code we know that we need to work very hard to optimize the critical path, but on non critical path we usually don't spend to much effort to optimize.
From your description you are working 90% on embedded and 10% on rest, lets assume that in 50% of the rest you are spending more time that needed. So according to my calculation you are optimizing about 5% of your work flow ...
Of course the usual google/SO/forums search is useful before you doing something new, but investing more than just that is waste of time for my opinion, unless you want to waste some time just for fun or general education ... :), but this is another story.
By the way I'm in same position and last time i needed some GUI and used MFC (because i used it sometimes 10 years ago :) ) and i perfectly understand that i probably will get better results with C# and friends, but the learning curve just not justify this especially knowing that i need mix the C code with GUI.

Getting developers to use a wiki [closed]

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I work on a complex application where different teams work on their own modules with a degree of overlap. A while back we got a Mediawiki instance set up, partly at my prompting. I have a hard job getting people to actually use it, let alone contribute.
I can see a lot of benefit in sharing information. It may at least reduce the times we reinvent the wheel.
The wiki is not very structured, but I'm not sure that is a problem as long as you can search for what you need.
Any hints?
Some tips:
Any time someone sends information by email that really should be in a wiki, make a page for that topic and add what they put in the email. Then reply "Thanks for that info, I've put it into the wiki here so that it's easier to find in the future."
Likewise, if you have information you need to share that should be in the wiki, put it there and just send an email with a link to it, rather than email people.
When you ask people for information, phrase it so that putting such documentation in the wiki should be considered the default or standard: "I searched in the wiki but I couldn't find it. Have you put that info up there yet?"
If you are the "wiki champion", make sure other people know how to use it, e.g. "Did I go through how to create a new page with you yet?"
Edit the sidebar to make sure it is relevant to your work.
Use "nav box" style templates on related pages for easier navigation.
Put something like {{Special:NewPages/5}} on the front page, or recent changes, so that people can see the activity.
Take a peek at Recent changes every few days or week, and if you notice someone adding information without being prodded, send them an email or drop by and give them a little compliment.
As I mentioned before, a Wiki is very unorganized.
However, if that is the only argument from your developers, then invest some effort to create a simple index page and keep it updated (either do it yourself or ask people to link their contributions to the index). That way, the Wiki might grow into a very nice and quite comprehensive collection of documentation for all your work.
We've been using a wiki in some form or another for a while now, but it does take a while for people to get on board. You might find that you will be the only one writing articles for some time, but bear with it, other people will come on board eventually.
If someone sends an email around that contains information related to the project then helpfully point them in the direction of the wiki - and keep doing that - they should get the hint.
We have a SharePoint portal and use the wiki from there - we customised it with our own branding so that it "looks the part" - I really feel this has helped to improve the uptake of it.
Make sure that everyone is aware that the wiki is even more informal than email.... because there will be a "fear factor" that people may think anything they add to the wiki will be over-analysed.
I think most of the answers so far are spot on - the more you plug away at it yourself, the larger the body of useful information will become, so slowly but surely people will naturally start to use it.
The other approach you could use is this: Suggest that every time someone asks another team member a question about the project, they should answer the question as normal, but also add the answer to a section of the Wiki. This may take a few minutes extra, but it will mean that the next time someone asks the same question (which they inevitably will), you can save time by pointing them at the Wiki. This, in turn, should help people to start using the Wiki as a first source of information and help overall up-take.
You can't force developers to do something they do not have an incentive of using for; unfortunately wikis, like documentation (well, in fact wikis are documentation) rarely have any "cool" value for developers. Besides, they're already deep into dev work -- could you really bother them with a wiki?
That being said, the people who pushed for the wiki (e.g., you) should be primarily responsible for updating it, and you really would have a lot of work cut out for you if you're serious about it.
You might also try the ff:
It's not very structured you say -- a lot of people get turned off from ill-structured (hard-to-search/browse) wikis. So maybe you can fix that first
Maybe you can ask lead developers/project managers to populate it with things that are issues for them: things like code conventions and API design for your particular project
Lead by example: religiously document your part of the system. Setting a precedent may encourage others to do the same
Sell the idea of using the wiki to the developers. You've identified some benefits, share those with the developers. If they can see that they'll get something of value out of it they'll start using it.
Example advantages from What Is a Wiki
Good for writing down quick ideas or longer ones, giving you more time for formal writing and editing.
Instantly collaborative without emailing documents, keeping the group in sync.
Accessible from anywhere with a web connection (if you don't mind writing in web-browser text forms).
Your archive, because every page revision is kept.
Exciting, immediate, and empowering--everyone has a say.
I have done some selling and even run some training sessions. I think some people are turned off by the lack of WYSIWYG editing and ability to paste formatted text from Word or Outlook. I know there are some tools to work around these, but they are still barriers.
There are some areas where the wiki is being used to log certain areas, but people who update those are not doing anything else with it.
I will use the wiki to document my specialised area regardless as it acts as a convenient brain extension. When starting a new development I use it as a notepad for ideas that I can expand on as it progresses.
It would help if management would give it some vocal support, even if it is not made mandatory.
I have a hard job getting people to actually use it, let alone contribute.
One of the easiest ways to get people to contribute to a wiki, is to actually have them provide contents in a wiki-suitable fashion, i.e. so that whatever they post using their usual channels of communications (newsgroups, mailing lists, forums, issue trackers, chat), is basically suitable for inclusion on the wiki.
So that others (users/volunteers) can simply take such contents and put them on the wiki.
This sounds more complicated than it really is, it's mostly about generalizing questions and answers, so that they are not necessarily part of a conversation, but can be comprehensible, meaningful and useful in a standalone fashion.
For example a question like the following:
how do I get git to clone a remote repository???
Can be answered like this:
Hello,
Just use git clone git://...
But questions can also be answered in a less personal style:
In order to clone a git repository, you will want to use the clone parameter to git:
git clone git://....
What I am trying to say is that most discussions in a project can and should be easily used to become documentation eventually. With this sort of mindset, your documentation can actually grow rather rapidly. You only need to get people to keep in mind that useful information should be ideally provided in a fashion that is suitable for wiki inclusion.
I have witnessed several instances where open source projects started to use this approach to some extent and while some people (largely new users) complained that answers were not very personal, the body of documentation was increasing steadily, because other people simply monitored such discussions and started to copy/paste such responses to the wiki.
Basically, this is one of the easiest ways to get people to contribute to a wiki, without requiring them to actually use it themselves, the only thing that's required of them is a shift in thinking.
If the developers still need to maintain 'real' documentation (s.a. Word documents), I see no way to meaningfully duplicate that on a Wiki.
It does not make sense for people to write twice
Any duplicated data is prone to get out of sync, soon.
What my current customer has done is move all this to Wiki. So I only document once, and I do it on the Wiki.
This is okay. Working with Wiki is more tedious than with Word, but at least the doc is online and others can mix-and-match with it.
Another working solution (imho) would be to store docs alongside the source, on subversion. But then the merging system needs to be able to cope with rich text etc. as well. I don't know, if any solution for that exists (other than using HTML or LaTex, which actually would not be bad picks).
Find "sticky" items (sub-3 pg. docs / diagrams / etc) something that the team seems to be creating again and again & post it on the wiki. Make sure everyone has access to the wiki and knows its there - set up a notification mechanism if possible. With some luck, the next time they have to access, rather than dig it out of version control or their machines - they should hit the wiki.
If they still don't, try to see if the team has enough slack to actually use the wiki - Subtler issues may lie beneath their reluctance.
Take a look at the advice at http://www.ikiw.org/ Grow your Wiki
Just to add to some of the excellent advice being offered here...
As a dev in a small company that does largely gov't contract work in the 6-24 month range, I find that my time is often split between development and writing status reports (right up there with writing documentation, only worse!) Having a wiki to slap down unorganized thoughts and notes as we go along has made report-writing a lot less painful (not pain-LESS, but better all the same).
Further, if you're already in the Mediawiki world, you might want to look at SemanticMediawiki. It allows you to take the organization of your data to another level by semantically tagging it. That doesn't mean a lot on its own, I know, but I can tell you (for example) that it can drastically improve the relevance of the data returned from searches. It is definitely worth a look.
Generally good advice here. I'd like to add:
You really need a champion - someone pushing this to developers and management (without being pushy - that's a challenge!) and providing support & tutorials when possible. This person also needs to be a peer (so a fellow developer, not someone in a remote IT department) and really customer focused i.e. ready to make changes when requested.
Speaking of changes, some people here say wikis are unstructured. I disagree. Our MediaWiki installation is structured using categories, particularly with two extensions:WarnNoCategories (to require users to add a category when saving a page) and CategoryTree to show how all the categories fit together (this can be linked to from the sidebar). I've got more tips on how we keep this low threshold, if you're interested.