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• How to "translate" interdependent object states in code?

  - by Earl Grey

  I have the following problem. My UI interace contains several buttons, labels, and other visual information. I am able to describe every possible workflow scenario that should be be allowed on that UI. That means I can describe it like this - when button A is pressed, the following should follow - In the case of that A button, there are three independent factors that influence the possible result when pushing the A button. The state of the session (blank, single, multi, multi special), the actual work that is being done by the system at the moment of pressing the A button (nothing was happening, work was being done, work was paused) and a separate UI element that has two states (on , off)..This gives me a 3 dimensional cube with 24 possible outcomes. I could write code for this using if cycles, switch cycles etc....but the problem is, I have another 7 buttons on that ui, I can enter this UI from different states..some buttons change the state, some change parameters... To sum up, the combinations are mindbogling and I am not able come up with a methodology that scales and is systematically reliable. I am able to describe EVERY workflow with words, I am sure my description is complete and without logical errors. But I am not able to translate that into code. I was trying to draw flowcharts but it soon became visually too complicated due to too many if "emafors". Can you advice how to proceeed?

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• Is true multithreading really necessary?

  - by Jonathan Graef

  So yeah, I'm creating a programming language. And the language allows multiple threads. But, all threads are synchronized with a global interpreter lock, which means only one thread is allowed to execute at a time. The only way to get the threads to switch off is to explicitly tell the current thread to wait, which allows another thread to execute. Parallel processing is of course possible by spawning multiple processes, but the variables and objects in one process cannot be accessed from another. However the language does have a fairly efficient IPC interface for communicating between processes. My question is: Would there ever be a reason to have multiple, unsynchronized threads within a single process (thus circumventing the GIL)? Why not just put thread.wait() statements in key positions in the program logic (presuming thread.wait() isn't a CPU hog, of course)? I understand that certain other languages that use a GIL have processor scheduling issues (cough Python), but they have all been resolved.

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• Starting point for a simple game written in action script [closed]

  - by Hossein

  Possible Duplicate: AS3/Flash Game Dev: Looking for good & current step by step. Hi, I want to develop a simple game like: http://www.albinoblacksheep.com/games/falldown2 And then making it a bit more fancy. But I don't know where to start. I have already started AS3 so I know about the syntax and stuff, but I am kinda lost. Does anyone knows of a nice starting point or a tutorial that can help me with this? Thanks

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• Algorithm for tracking progress of controller method running in background

  - by SilentAssassin

  I am using Codeigniter framework for PHP on Windows platform. My problem is I am trying to track progress of a controller method running in background. The controller extracts data from the database(MySQL) then does some processing and then stores the results again in the database. The complete aforesaid process can be considered as a single task. A new task can be assigned while another task is running. The newly assigned task will be added in a queue. So if I can track progress of the controller, I can show status for each of these tasks. Like I can show "Pending" status for tasks in the queue, "In Progress" for tasks running and "Done" for tasks that are completed. Main Issue: Now first thing I need to find is an algorithm to track the progress of how much amount of execution the controller method has completed and that means tracking how much amount of method has completed execution. For instance, this PHP script tracks progress of array being counted. Here the current state and state after total execution are known so it is possible to track its progress. But I am not able to devise anything analogous to it in my case. Maybe what I am trying to achieve is programmtically not possible. If its not possible then suggest me a workaround or a completely new approach. If some details are pending you can mention them. Sorry for my ignorance this is my first post here. I welcome you to point out my mistakes. EDIT: Database outline: The URL(s) and keyword(s) are first entered by user which are stored in a database table called link_master and keyword_master respectively. Then keywords are extracted from all the links present in this table and compared with keywords entered by user and their frequency is calculated which is the final result. And the results are stored in another table called link_result. Now sub-links are extracted from the domain links and stored in a table called sub_link_master. Now again the keywords are extracted from these sub-links and the corresponding results are stored in a table called sub_link_result. The number of records cannot be defined beforehand as the number of links on any web page can be different. Only the cardinality of *link_result* table can be known which will be equal to multiplication of number of keyword(s) and URL(s) . I insert multiple records at a time using this resource. Controller outline: The controller extracts keywords from a web page and also extracts keywords from all the links present on that page. There is a method called crawlLink. I used Rolling Curl to extract keywords and web page content. It has callback function which I used for extracting keywords alongwith generating results and extracting valid sub-links. There is a insertResult method which stores results for links and sub-links in the respective tables. Yes, the processing depends on the number of records. The more the number of records, the more time it takes to execute: Consider this scenario: Number of Domain Links = 1 Number of Keywords = 3 Number of Domain Links Result generated = 3 (3 x 1 as described in the question) Number of Sub Links generated = 41 Number of Sub Links Result = 117 (41 x 3 = 123 but some links are not valid or searchable) Approximate time taken for above process to complete = 55 seconds. The above result is for a single link. I want to track the progress of the above results getting stored in database. When all results are stored, the task is complete. If results are getting stored, the task is In Progress. I am not clear how can I track this progress.

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• Publish/Subscribe/Request for exchange of big, complex, and confidential data?

  - by Morten

  I am working on a project where a website needs to exchange complex and confidential (and thus encrypted) data with other systems. The data includes personal information, technical drawings, public documents etc. We would prefer to avoid the Request-Reply pattern to the dependent systems (and there are a LOT of them), as that would create an awful lot of empty traffic. On the other hand, I am not sure that a pure Publisher/Subscriber pattern would be apropriate -- mainly because of the complex and bulky nature of the data to be exchanged. For that reason we have discussed the possibility of a "publish/subscribe/request" solution. The Publish/Subscribe part would be to publish a message to the dependent systems, that something is ready for pickup. The actual content is then picked up by old-school Request-Reply action. How does this sound to you?? Regards, Morten

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• Preffered lambda syntax?

  - by Roger Alsing

  I'm playing around a bit with my own C like DSL grammar and would like some oppinions. I've reserved the use of "(...)" for invocations. eg: foo(1,2); My grammar supports "trailing closures" , pretty much like Ruby's blocks that can be passed as the last argument of an invocation. Currently my grammar support trailing closures like this: foo(1,2) { //parameterless closure passed as the last argument to foo } or foo(1,2) [x] { //closure with one argument (x) passed as the last argument to foo print (x); } The reason why I use [args] instead of (args) is that (args) is ambigious: foo(1,2) (x) { } There is no way in this case to tell if foo expects 3 arguments (int,int,closure(x)) or if foo expects 2 arguments and returns a closure with one argument(int,int) - closure(x) So thats pretty much the reason why I use [] as for now. I could change this to something like: foo(1,2) : (x) { } or foo(1,2) (x) -> { } So the actual question is, what do you think looks best? [...] is somewhat wrist unfriendly. let x = [a,b] { } Ideas?

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• Avoiding the Anaemic Domain - How to decide what single responsibility a class has

  - by thecapsaicinkid

  Even after reading a bunch I'm still falling into the same trap. I have a class, usually an enity. I need to implement more than one, similar operations on this type. It feels wrong to (seemingly arbitrarily) choose one of these operations to belong inside the entity and push the others out to a separate class; I end up pushing all operations to service classes and am left with an anaemic domain. As a crude example, imagine the typical Employee class with numeric properties to hold how many paid days the employee is entitled to for both sickness and holiday and a collection of days taken for each. public class Employee { public int PaidHolidayAllowance { get; set; } public int PaidSicknessAllowance { get; set; } public IEnumerable<Holiday> Holidays { get; set; } public IEnumerable<SickDays> SickDays { get; set; } } I want two operations, one to calculate remaining holiday, another for remaining paid sick days. It seems strange to include say, CalculateRemaingHoliday() in the Employee class and bump CalculateRemainingPaidSick() to some PaidSicknessCalculator class. I would end up with a PaidSicknessCalculator and a RemainingHolidayCalculator and the anaemic Employee entity as seen above. The other alternative would be to put both operations in the Employee class and kick Single Responsibility to the curb. That doesn't make for particularly maintainable code. I suppose the Employee class should have some initialisation/validation logic (not accepting negative alowances etc.) So maybe I just stick to basic initialisation and validation in the entities themselves and be happy with my separate calculator classes. Or maybe I should be asking myself if Anaemic Domain is actually causing me some tangible problems with my code.

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• Server-side Architecture for Online Game

  - by Draiken

  Hi, basically I have a game client that has communicate with a server for almost every action it takes, the game is in Java (using LWJGL) and right now I will start making the server. The base of the game is normally one client communicating with the server alone, but I will require later on for several clients to work together for some functionalities. I've already read how authentication server should be sepparated and I intend on doing it. The problem is I am completely inexperienced in this kind of server-side programming, all I've ever programmed were JSF web applications. I imagine I'll do socket connections for pretty much every game communication since HTML is very slow, but I still don't really know where to start on my server. I would appreciate reading material or guidelines on where to start, what architecture should the game server have and maybe some suggestions on frameworks that could help me getting the client-server communication. I've looked into JNAG but I have no experience with this kind of thing, so I can't really tell if it is a solid and good messaging layer. Any help is appreciated... Thanks !

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• Good free CSS Sprite for icons

  - by Saif Bechan

  I am working on a small project where I need some of the basic icons: edit, favorite, delete. You know them. Now i can download them all seperate, and put them together in a sprite, but I was wondering if there are ready to download sprites which I can use. Now I am working on an accounting app, so it would be nice if the icons were not too childish. A little but of fancy business type icons. Thanks

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• Building a distributed system on Amazon Web Services

  - by Songo

  Would simply using AWS to build an application make this application a distributed system? For example if someone uses RDS for the database server, EC2 for the application itself and S3 for hosting user uploaded media, does that make it a distributed system? If not, then what should it be called and what is this application lacking for it to be distributed? Update Here is my take on the application to clarify my approach to building the system: The application I'm building is a social game for Facebook. I developed the application locally on a LAMP stack using Symfony2. For production I used an a single EC2 Micro instance for hosting the app itself, RDS for hosting my database, S3 for the user uploaded files and CloudFront for hosting static content. I know this may sound like a naive approach, so don't be shy to express your ideas.

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• Why not expose a primary key

  - by Angelo Neuschitzer

  In my education I have been told that it is a flawed idea to expose actual primary keys (not only DB keys, but all primary accessors) to the user. I always thought it to be a security problem (because an attacker could attempt to read stuff not their own). Now I have to check if the user is allowed to access anyway, so is there a different reason behind it? Also, as my users have to access the data anyway I will need to have a public key for the outside world somewhere in between. Now that public key has the same problems as the primary key, doesn't it?

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• The next next C++ [closed]

  - by Roger Pate

  It's entirely too early for speculation on what C++ will be like after C++0x, but idle hands make for wild predictions. What features would you find useful and why? Is there anything in another language that would fit nicely into the state of C++ after 0x? What should be considered for the next TC and TR? (Mostly TR, as the TC would depend more on what actually becomes the next standard.) Export was removed, rather than merely deprecated, in 0x. (It remains a keyword.) What other features carry so much baggage to also be more harmful than helpful? ISO Standards' process I'm not involved in the C++ committee, but it's also a mystery, unfortunately, to most programmers using C++. A few things worth keeping in mind: There will be 10 years between standards, barring extremely exceptional circumstances. The standard can get "bug fixes" in the form of a Technical Corrigendum. This happened to C++98 with TC1, named C++03. It fixed "simple" issues such as making the explicit guarantee that std::vector stores items contiguously, which was always intended. The committee can issue reports which can add to the language. This happened to C++98/03 with TR1 in 2005, which introduced the std::tr1 namespace.

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• Is extensive documentation a code smell?

  - by Griffin

  Every library, open-source project, and SDK/API I've ever come across has come packaged with a (usually large) documentation file, and this seems contradictory to the wide-spread belief that good code needs little to no comments. What separates documentation from this programming methodology? a one to two page overview of a package seems reasonable, but elegant code combined with standard intelisense should have theoretically deprecated the practice of documentation by now IMO. I feel like companies only create detailed documentation and tutorials because its what they've always done. Why should developers have to constantly be searching through online documentation in order to learn how to do things when such information should be intrinsic to the classes, methods and namespaces?

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• Requiring multithreading/concurrency for implementation of scripting language

  - by Ricky Stewart

  Here's the deal: I'm looking at designing my own scripting/interpreted language for fun. I'm only in the planning stages right now; I want to make sure I have a very strong hold on exactly how I will implement everything before I start coding. What I'm currently struggling with is concurrency. It seems to me like an easy way to avoid the unpredictable performance that comes with garbage collection would be to put the garbage collector in its own thread, and have it run concurrently with the interpreter itself. (To be clear, I don't plan to allow the scripts to be multithreaded themselves; I would simply put a garbage collector to work in a different thread than the interpreter.) This doesn't seem to be a common strategy for many popular scripting languages, probably for portability reasons; I would probably write the interpreter in the UNIX/POSIX threading framework initially and then port it to other platforms (Windows, etc.) if need be. Does anyone have any thoughts in this issue? Would whatever gains I receive by exploiting concurrency be nullified by the portability issues that will inevitably arise? (On that note, am I really correct in my assumption that I would experience great performance gains with a concurrent garbage collector?) Should I move forward with this strategy or step away from it?

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• Are there specific legal issues for web developers working on sex dating sites?

  - by YumYumYum

  Say I have created many ordinary websites which are not related to any dating/sexual content. Are the rules and regulations for a developer the same when making a sex-related dating site? I'm talking about a site where people meet together and get to know each other, with the intent of having a sexual relationship (you know what I mean), also featuring webcam sex, but not explicitly a porno site. Do such sites have any special legal issues for developers compared with non-sexual/dating sites?

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• How to approach big developer companies if I have a killer game idea? (for mobile devices)

  - by Balázs Dávid

  I have an idea for a game that has a potential, but I'm not a programmer. How to tell this to development companies without being my idea stolen? All I want from the company is first to watch a 3-minute long video presentation about my idea and if they see fantasy in it then we can talk about the details. I have already sent an e-mail to several big companies that have the expertise needed to code the game, they haven't answer me. Actually the idea is nothing fancy, no 3D, but fun and unique.

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• Use adapter pattern for coupled classes

  - by kaiseroskilo

  I need (for unit testing purposes) to create adapters for external library classes.ExchangeService and ContactsFolder are Microsoft's implementations in its' EWS library. So I created my adapters that implement my interfaces, but it seems that contactsFolder has a dependency for ExchangeService in its' constructor. The problem is that I cannot instantiate ContactsFolderAdapter without somehow accessing the actual ExchangeService instance (I see only ExchangeServiceAdapter in scope). Is there a better pattern for this that retains the adapter classes? Or should I "infect" ExchangeServiceAdapter with some kind of GetActualObject method?

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• What to include in metadata?

  - by shyam

  I'm wondering if there are any general guidelines or best practices regarding when to split data into a metadata format, as oppose to directly embedding it within the data. (Specific example below). My understanding of metadata is that it describes data (without the need to actually look at the data), allowing for data to be quickly search/filtered for easy access. Let's take for example a simple 3D model format. The actual data file itself is a binary file containing vertices and colors. Things like creation date, modified data and author name would be things that describe the binary data, so I would say these belong as metadata (outside of the binary file). But what if the application had no need to search or filter by these fields? Would it be acceptable to embed these fields directly into the binary data itself? Could they be duplicated in both the binary data and the meta data, or would this be considered bad practice? What about more ambiguous fields such as the model name, which could be considered part of the data itself, but also as data describing the binary data?... How do you decide which data to embed in the actual binary file, as opposed to separating into a more flexible metadata format? Thanks!

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• When to use abstract classes instead of interfaces and extension methods in C#?

  - by Gulshan

  "Abstract class" and "interface" are similar type of ideas, while interface being more abstract. One need of abstract classes was to provide method implementations for the derived classes. But in C#, that need has also been reduced by lately introduced extension methods. So, in C#, when should we use abstract classes instead of using interfaces and extension methods associated with the interface? And now, we can use 'Properties' in interfaces also. A notable example of interface+ extension methods is the Heavily used IEnumerable and it's helper methods. You use Linq and it's all by this extension methods!

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• More Tables or More Databases?

  - by BuckWoody

  I got an e-mail from someone that has an interesting situation. He has 15,000 customers, and he asks if he should have a database for their data per customer. Without a LOT more data it’s impossible to say, of course, but there are some general concepts to keep in mind. Whenever you’re segmenting data, it’s all about boundary choices. You have not only boundaries around how big the data will get, but things like how many objects (tables, stored procedures and so on) that will be involved, if there are any cross-sections of data (do they share location or product information) and – very important – what are the security requirements? From the answer to these types of questions, you now have the choice of making multiple tables in a single database, or using multiple databases. A database carries some overhead – it needs a certain amount of memory for locking and so on. But it has a very clean boundary – everything from objects to security can be kept apart. Having multiple users in the same database is possible as well, using things like a Schema. But keeping 15,000 schemas can be challenging as well. My recommendation in complex situations like this is similar to a post on decisions that I did earlier – I lay out the choices on a spreadsheet in rows, and then my requirements at the top in the columns. I  give each choice a number based on how well it meets each requirement. At the end, the highest number wins. And many times it’s a mix – perhaps this person could segment customers into larger regions or districts or products, in a database. Within that database might be multiple schemas for the customers. Of course, he needs to query across all customers, that becomes another requirement. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• Moving camera, or camera with discrete "screens"?

  - by Jacob Millward

  I'm making a game with a friend, but having trouble deciding on a camera style. The basic idea for the game, is having a randomly generated 2-dimensional world, with settlements in it. These settlements would have access to different resources, and it would be the job of the player to create bridges and ladders and links between these villages so they can trade. The player would advance personally by getting better gear, fighting monsters and looking for materials in the world, in order to craft and trade them at the settlements. My friend wants to use an old-style camera, where the world is split into a discrete number of screens that the player moves between. Similar to early Zelda dungeons, or Knytt Stories. This is opposite to me, as I want a standard camera that follows the player around as I feel the split-screen style camera limits the game. Can anyone argue the case either way? We've hit a massive roadblock here and can't seem to get past it.

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• Microkernel architectural pattern and applicability for business applications

  - by Pangea

  We are in the business of building customizable web applications. We have the core team that provides what we call as the core platform (provides services like security, billing etc.) on top of which core products are built. These core products are industry specific solutions like telecom, utility etc. These core products are later used by other teams to build customer specific solutions in a particular industry. Until now we have a loose separation between platform and core product. The customer specific solutions are build by customizing 20-40% of the core offering and re-packaging. The core-platform and core products are released together as monolithic apps (ear). I am looking to improvise the current situation so that there is a cleaner separation on these 3. This allows us to have evolve each of these 3 separately etc. I've read through the Mircokernel architecture and kind of felt that I can take apply the principles in my context. But most of my reading about this pattern is always in the context of operating systems or application servers etc. I am wondering if there are any examples on how that pattern was used for architecting business applications. Or you could provide some insight on how to apply that pattern to my problem.

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• Variable declaration versus assignment syntax

  - by rwallace

  Working on a statically typed language with type inference and streamlined syntax, and need to make final decision about syntax for variable declaration versus assignment. Specifically I'm trying to choose between: // Option 1. Create new local variable with :=, assign with = foo := 1 foo = 2 // Option 2. Create new local variable with =, assign with := foo = 1 foo := 2 Creating functions will use = regardless: // Indentation delimits blocks square x = x * x And assignment to compound objects will do likewise: sky.color = blue a[i] = 0 Which of options 1 or 2 would people find most convenient/least surprising/otherwise best?

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• How to expose game data in the game without a singelton?

  - by zardon

  I'm quite new to cocos2d and games programming, and am currently I am writing a game that is currently in Prototype stage. Everything is going okay, but I've realized a potentially big problem and I am not sure how to solve it. I am using a singelton to store a bunch of arrays for everything, a global list of planets, a global list of troops, a global list of products, etc. And only now I'm realizing that all of this will be in memory and this is the wrong way to do it. I am not storing files or anything on the disk just yet, with exception to a save/load state, which is a capture of everything. My game makes use of a map which allows you to select a planet, then it will give you a breakdown of that planets troops and resources, Lets use this scenario: My game has 20 planets. On which you can have 20 troops. Straight away that's an array of 400! This does not add the NPC, which is another 10. So, 20x10 = 200 So, now we have 600 all in arrays inside a Singelton. This is obviously very bad, and very wrong. Especially as the game scales in the amount of data. But I need to expose pretty much everything, especially on the map page, and I am not sure how else to do it. I've been told that I can use a controller for the map page which has the information I need for each planet, and other controllers for other items I require global display for. I've also thought about storing each planet's data in a save file, using initWithCoder however there could be a boatload of files on the user's device? I really don't want to use a database, mainly because I would need to translate NSObjects and non-NSObjects like CGRects and CGPoints and Colors into/from SQL. I am open to other ideas on how to store and read game data to prevent using a singelton to store everything, everywhere. Thanks for your time.

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• Code and Slides: Techniques, Strategies, and Patterns for Structuring JavaScript Code

  - by dwahlin

  This presentation was given at the spring 2012 DevConnections conference in Las Vegas and is based on my Structuring JavaScript Code course from Pluralsight. The goal of the presentation is to show how closures combined with code patterns can be used to provide structure to JavaScript code and make it more re-useable, maintainable, and less susceptible to naming conflicts.  Topics covered include: Closures Using Object literals Namespaces The Prototype Pattern The Revealing Module Pattern The Revealing Prototype Pattern View more of my presentations here. Sample code from the presentation can be found here. Check out the full-length course on the topic at Pluralsight.com.

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