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  • generating maps

    - by gardian06
    This is a conglomeration question when answering please specify which part you are addressing. I am looking at creating a maze type game that utilizes elevation. I have a few features I would like to have, but am unsure as to some of the implementation. I have done work doing fileIO maze generation (using a key to read the file, and then generate the level based on that file), but I am unsure how to think about this with elevation in the mix. I think height maps might be a good approach, but don't know how to represent them effectively. for a height map which is more beneficial XML(containing h[u,v] data and key definition), CSV (item1 is key reference, item2 is elevation), or another approach that I have not thought of yet? When it comes to placing the elevation values themselves what kind of deltah values are appropriate to have it noticeable at about a 60degree angle while not really effecting gravity driven physics (assuming some effect while moving up/down hill)? I am thinking of maybe going to procedural generation at some point, but am wondering if it is practical to have a procedurally generated grid (wall squares possibly same dimensions as the open space squares), or if designing to a thin wall open spaces is better? this decision will effect the amount of work need on the graphics end for uniform vs. irregular walls. EDIT: game will be a elevation maze shooter. levels/maps will be mazes with elevation the player has to negotiate. elevations will have effects on "combat" vision, and movement

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  • How to plan/manage multi-platform (mobile) products?

    - by PhD
    Say I've to develop an app that runs on iOS, Android and Windows 8 Mobile. Now all three platforms are technically in different program languages. The only 'reuse' that I can see is that of the boxes-and-lines drawings (UML :) charts and nothing else. So how do companies/programmers manage the variation of the same product across different platforms especially since the implementation languages differ? It's 'easier' in the desktop world IMO given the plethora of languages and cross-platform libraries to make your life easier. Not so in the mobile world. More so, product line management principles don't seem to be all that applicable - what is same and variant doesn't really matter - the application is the same (conceptually) and the implementation is variant. Some difficulties that come to mind: Bug Fixing: Applications maybe designed in a similar manner but the bug identification and fixing would be radically different. A bug on iOS may/may-not be existent for that on Android. Or a bug fix approach on one platform may not be the same on another (unless it's a semantic bug like a!=b instead of a==b which would require the same 'approach' to fixing in essence Enhancements: Making a change on one platform would be radically different than on another Code-Design Divergence: They way the code is written/organized, the class structures etc., could be very different given the different implementation environments - leading to further reuse of the (above) UML models. There are of course many others - just keeping the development in sync and making sure all applications are up to the same version with the same set of features etc. Seems the effort is 3x that of a single application. So how exactly does one manage this nightmarish situation? Some thoughts: Split application to client/server to minimize the effect to client side only (not always doable) Use frameworks like Unity-3D that could take care of the cross-platform problem (mostly applicable to games and probably not to other applications etc.) Any other ways of managing a platform line? What are some proven approaches to managing/taming the effects?

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  • Looking for a better Factory pattern (Java)

    - by Sam Goldberg
    After doing a rough sketch of a high level object model, I am doing iterative TDD, and letting the other objects emerge as a refactoring of the code (as it increases in complexity). (That whole approach may be a discussion/argument for another day.) In any case, I am at the point where I am looking to refactor code blocks currently in an if-else blocks into separate objects. This is because there is another another value combination which creates new set of logical sub-branches. To be more specific, this is a trading system feature, where buy orders have different behavior than sell orders. Responses to the orders have a numeric indicator field which describes some event that occurred (e.g. fill, cancel). The combination of this numeric indicator field plus whether it is a buy or sell, require different processing buy the code. Creating a family of objects to separate the code for the unique handling each of the combinations of the 2 fields seems like a good choice at this point. The way I would normally do this, is to create some Factory object which when called with the 2 relevant parameters (indicator, buysell), would return the correct subclass of the object. Some times I do this pattern with a map, which allows to look up a live instance (or constructor to use via reflection), and sometimes I just hard code the cases in the Factory class. So - for some reason this feels like not good design (e.g. one object which knows all the subclasses of an interface or parent object), and a bit clumsy. Is there a better pattern for solving this kind of problem? And if this factory method approach makes sense, can anyone suggest a nicer design?

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  • Advice on designing web application with a 40+ year lifetime

    - by user2708395
    Scenario Currently, I am apart of a health care project whose main requirement is to capture data with unknown attributes using user generated forms by health care providers. The second requirement is that data integrity is key and that the application will be used for 40+ years. We are currently migrating the client's data from the past 40 years from various sources (Paper, Excel, Access, etc...) to the database. Future requirements are: Workflow management of forms Schedule management of forms Security/Role based management Reporting engine Mobile/Tablet support Situation Only 6 months in, the current (contracted) architect/senior programmer has taken the "fast" approach and has designed a poor system. The database is not normalized, the code is coupled, the tiers have no dedicated purpose and data is starting to go missing since he has designed some beans to perform "deletes" on the database. The code base is extremely bloated and there are jobs just to synchronize data since the database is not normalized. His approach has been to rely on backup jobs to restore missing data and doesn't seem to believe in re-factoring. Having presented my findings to the PM, the architect will be removed when his contract ends. I have been given the task to re-architect this application. My team consists of me and one junior programmer. We have no other resources. We have been granted a 6-month requirement freeze in which we can focus on re-building this system. I suggested using a CMS system like Drupal, but for policy reasons at the client's organization, the system must be built from scratch. This is the first time that I will be designing a system with a 40+ lifespan. I have only worked on projects with 3-5 year lifespans, so this situation is very new, yet exciting. Questions What design considerations will make the system more "future proof"? What experiences have you had in designing such systems - both failures and successes? What questions should be asked to the client/PM to make the system more "future proof"?

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  • The balance between client and server functionality

    - by Eugen Martynov
    I want to bring the discussion that started in our teams and get your opinion about it. Assume we have an user account which could have different credentials for authentication and associated email to recover. An user has possibility to do signup with an email or use his social profile to complete signup process. As an Rest API from the backend to client looks like: Create account Authorise Update user data Link social account Register email Verify email In addition our BE is distributed and divided between several services/servers/clusters. So different calls are related to different end points. In case of the social sign up some of steps should be skipped or simplified. For example, with Facebook signup we could already skip email registration and verification step (we ask email permission form user), linking the social account and pre-fill user displayed name. So we proposed to have another end point which will hide/combine different calls on BE and return whole process result to the clients. The pros for this approach: No more duplication of functionality between clients Speed up the networking and user experience The cons for this approach: Additional work for backend Probably most complex scenarios in future updates I would like to get your opinion or experience with this situation. Especially if you already experienced point #2 from against reasons.

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  • Best way to update UI when dealing with data synchronization

    - by developerdoug
    I'm working on a bug at work. The app is written in Objective-C for iOS based device, for the iPad. I'm the new guy there and I've been given a hard task. Sometimes, the UIButton text property does not show the correct state when syncing. Basically, when the app is syncing, my UI control would say "Syncing" and when its not syncing it'll display "Updated @ [specific date]". Right now there is a property on the app delegate called "SyncInProgress". When querying / syncing, occurring on background thread, it updates a counter. The property will return a bool checking expression 'counter 0'. There are three states I need to deal with. Sync has started. Sync is updating tables. Sync finished. These items need to occur in order. My coworker suggested to take a state based approach instead of just responding to events. I'm not sure about how to go about that. Would it be best to have the UI receive a notification to determine what state its in or to pull every so often if state changed? Here are two posts that I put on stackoverflow, in the last few days, that relate to this. http://stackoverflow.com/questions/11025469/ios-syncing-using-a-state-approach-instead-of-just-reacting-to-events http://stackoverflow.com/questions/11037930/viewcontroller-when-viewwillappear-called-does-not-always-correctly-reflect-stat Any ideas that anyone might have to very much appreciated. Thanks, developerDoug

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  • SIMPLEST way to set up password protection for a static site, with basic admin UI?

    - by Joseph Turian
    I have a static site. I would like the simplest approach to password protecting a directory, with a basic admin UI for adding/removing users. I will have so few users that I don't care about performance. I don't care if it's PHP or Django or whatever, I just want a complete software package. Apache basic auth isn't good, because you can't log out. Nor is there a UI for adding users. I tried throwing everything behind Django auth and serving the files through Django. However, Chrome treats all my text/css headers as text/plain, so I don't get any stylesheets showing. I can't use mod_xsendfile on my server because I can't reconfigure Apache to add new modules. I think this approach is overkill anyway. I can try configuring Nginx's X-Accel-Redirect, however that requires implementing all the Django code for auth myself, and I'd prefer an existing solution. However, this is my backup plan. Is there a code package that implements authentication with basic admin for a static site?

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  • What is better for the overall performance and feel of the game: one setInterval performing all the work, or many of them doing individual tasks?

    - by Bane
    This question is, I suppose, not limited to Javascript, but it is the language I use to create my game, so I'll use it as an example. For now, I have structured my HTML5 game like this: var fps = 60; var game = new Game(); setInterval(game.update, 1000/fps); And game.update looks like this: this.update = function() { this.parseInput(); this.logic(); this.physics(); this.draw(); } This seems a bit inefficient, maybe I don't need to do all of those things at once. An obvious alternative would be to have more intervals performing individual tasks, but is it worth it? var fps = 60; var game = new Game(); setInterval(game.draw, 1000/fps); setInterval(game.physics, 1000/a); //where "a" is some constant, performing the same function as "fps" ... With which approach should I go and why? Is there a better alternative? Also, in case the second approach is the best, how frequently should I perform the tasks?

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  • I seem to be missing a few important concepts with PhoneGap

    - by garethdn
    I'm planning on developing an app on multiple platforms and I'm thinking that PhoneGap might be perfect for me. I had been reading that it's one codebase for all platforms but looking at the PhoneGap guide it seems there are separate instructions for each platform. So if i want to develop for iOS, Android, BB and WP7 I need to write 4 different sets of code? I'm sure i'm missing something fundamental here. Aside from that, how do people usually approach a PhoneGap build? You obviously / probably want the finished app to look like a native app - is it more common than not to use jQuery Mobile together with PhoneGap? Is there a preferred IDE? I see, in the guide, for iOS they seem to suggest Xcode. I'm fine using Xcode but it seems a bit overkill for HTML & CSS. Do I need to develop in Xcode and if not how do i approach it? Use a different IDE / Text Editor and then copy paste into Xcode for building and testing? I know this question is long-winded and fundamental but it something which i don't think is properly addressed in the guides. Thanks.

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  • Pure functional programming and game state

    - by Fu86
    Is there a common technique to handle state (in general) in a functional programming language? There are solutions in every (functional) programming language to handle global state, but I want to avoid this as far as I could. All state in a pure functional manner are function parameters. So I need to put the whole game state (a gigantic hashmap with the world, players, positions, score, assets, enemies, ...)) as a parameter to all functions which wants to manipulate the world on a given input or trigger. The function itself picks the relevant information from the gamestate blob, do something with it, manipulate the gamestate and return the gamestate. But this looks like a poor mans solution for the problem. If I put the whole gamestate into all functions, there is no benefit for me in contrast to global variables or the imperative approach. I could put just the relevant information into the functions and return the actions which will be taken for the given input. And one single function apply all the actions to the gamestate. But most functions need a lot of "relevant" information. move() need the object position, the velocity, the map for collision, position of all enemys, current health, ... So this approach does not seem to work either. So my question is how do I handle the massive amount of state in a functional programming language -- especially for game development?

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  • Should I use a separate 'admin' user as my "root sudo" or grant sudo to my 'app' user?

    - by AJB
    I'm still wrapping my brain around the Ubuntu 'nullify root' user management philosophy (and Linux in general) and I'm wondering if I should 'replace' my root user with a user called 'admin' (which basically has all the powers of the root, when using sudo) and create another user called 'app' that will be the primary user for my app. Here's the context: I'll be running a LNMP stack on Ubuntu 12.04 Server LTS. There will be only one app running on the server. The 'app' user needs to have SUPER privileges for MySQL. PHP will need to be able to exec() shell commands. The 'app' user will need to be able to transfer files via SFTP. And I'm thinking this would be the best approach: nullify 'root' user create a user called 'admin' that will be a full sudoer of root, this will be the new "root" user of NGINX, PHP, and MySQL (and all system software) grant SUPER privileges to 'app' in MySQL Grant SFTP privileges to only the 'app' user. As I'm new to this, and the information I've found in researching it tends to be of a more general nature, I'm wondering if this is a solid approach, or if it's unorthodox in a way that would cause issues down the road. Thanks in advance for any help.

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  • Is it appropriate to run a complex enterprise-system configuration and migration project in a similar way to a Scrum development project?

    - by AndyM
    I'm just starting out on the implementation of a large enterprise-wide system, which has complex requirements and many stakeholders. The company has been through high-level evaluation and tender process and determined to purchase a highly configurable "off-the-shelf" product rather than building an entirely bespoke system. The system will replace several existing systems and will require a significant amount of data migration. I'm thinking that the implementation of this system (which is expected to take over 2 years) could be run in a similar way to a Scrum software development project. With the first sprints targeted at building the minimal possible functionality needed (across all functional areas), and then iteratively deepening the level of functionality according the stakeholder feedback. I think this will de-risk the project and help ensure a balance of stakeholder needs within the available time. The user stories are still the same, it's just that to implement them we have work within the constraints of the pre-purchased system. When it comes to 'building stuff', instead of writing custom code the team will be configuring the off-the-shelf package, writing data conversion scripts and the like (and it should be a lot quicker!). Does this sound like a sensible approach? Does the Agile approach makes sense here?

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  • Design in "mixed" languages: object oriented design or functional programming?

    - by dema80
    In the past few years, the languages I like to use are becoming more and more "functional". I now use languages that are a sort of "hybrid": C#, F#, Scala. I like to design my application using classes that correspond to the domain objects, and use functional features where this makes coding easier, more coincise and safer (especially when operating on collections or when passing functions). However the two worlds "clash" when coming to design patterns. The specific example I faced recently is the Observer pattern. I want a producer to notify some other code (the "consumers/observers", say a DB storage, a logger, and so on) when an item is created or changed. I initially did it "functionally" like this: producer.foo(item => { updateItemInDb(item); insertLog(item) }) // calls the function passed as argument as an item is processed But I'm now wondering if I should use a more "OO" approach: interface IItemObserver { onNotify(Item) } class DBObserver : IItemObserver ... class LogObserver: IItemObserver ... producer.addObserver(new DBObserver) producer.addObserver(new LogObserver) producer.foo() //calls observer in a loop Which are the pro and con of the two approach? I once heard a FP guru say that design patterns are there only because of the limitations of the language, and that's why there are so few in functional languages. Maybe this could be an example of it? EDIT: In my particular scenario I don't need it, but.. how would you implement removal and addition of "observers" in the functional way? (I.e. how would you implement all the functionalities in the pattern?) Just passing a new function, for example?

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  • Structuring cascading properties - parent only or parent + entire child graph?

    - by SB2055
    I have a Folder entity that can be Moderated by users. Folders can contain other folders. So I may have a structure like this: Folder 1 Folder 2 Folder 3 Folder 4 I have to decide how to implement Moderation for this entity. I've come up with two options: Option 1 When the user is given moderation privileges to Folder 1, define a moderator relationship between Folder 1 and User 1. No other relationships are added to the db. To determine if the user can moderate Folder 3, I check and see if User 1 is the moderator of any parent folders. This seems to alleviate some of the complexity of handling updates / moved entities / additions under Folder 1 after the relationship has been defined, and reverting the relationship means I only have to deal with one entity. Option 2 When the user is given moderation privileges to Folder 1, define a new relationship between User 1 and Folder 1, and all child entities down to the grandest of grandchildren when the relationship is created, and if it's ever removed, iterate back down the graph to remove the relationship. If I add something under Folder 2 after this relationship has been made, I just copy all Moderators into the new Entity. But when I need to show only the top-level Folders that a user is Moderating, I need to query all folders that have a parent folder that the user does not moderate, as opposed to option 1, where I just query any items that the user is moderating. I think it comes down to determining if users will be querying for all parent items more than they'll be querying child items... if so, then option 1 seems better. But I'm not sure. Is either approach better than the other? Why? Or is there another approach that's better than both? I'm using Entity Framework in case it matters.

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  • Storing editable site content?

    - by hmp
    We have a Django-based website for which we wanted to make some of the content (text, and business logic such as pricing plans) easily editable in-house, and so we decided to store it outside the codebase. Usually the reason is one of the following: It's something that non-technical people want to edit. One example is copywriting for a website - the programmers prepare a template with text that defaults to "Lorem ipsum...", and the real content is inserted later to the database. It's something that we want to be able to change quickly, without the need to deploy new code (which we currently do twice a week). An example would be features currently available to the customers at different tiers of pricing. Instead of hardcoding these, we read them from database. The described solution is flexible but there are some reasons why I don't like it. Because the content has to be read from the database, there is a performance overhead. We mitigate that by using a caching scheme, but this also adds some complexity to the system. Developers who run the code locally see the system in a significantly different state compared to how it runs on production. Automated tests also exercise the system in a different state. Situations like testing new features on a staging server also get trickier - if the staging server doesn't have a recent copy of the database, it can be unexpectedly different from production. We could mitigate that by committing the new state to the repository occasionally (e.g. by adding data migrations), but it seems like a wrong approach. Is it? Any ideas how best to solve these problems? Is there a better approach for handling the content that I'm overlooking?

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  • Is using SVN for development and CM a bad practice?

    - by GatorGuy
    I have a bit of experience with SVN as a pure programmer/developer. Within my company, however, we use SVN as our configuration management tool. I thought using SVN for development at the same time was OK since we could use branches and the trunk for dev, and tags for releases. To me, the tags were the CM part, and the branches/trunk were the dev part. Recently a person, who develops high level code (but outside of the "pure SW" group) mentioned that the existing philosophy (mixing SVN for dev and CM) was wrong... in his opinion. His reasoning is that he thinks the company's CM tool should always link to run-able SW (so branches would break this rule). He also mentioned that a CM tool shouldn't be a backup utility for daily or incremental commits. Finally, he doesn't like the idea of having to jump from revision 143 to 89 in order to get a working copy... and further that CM tools shouldn't allow reversion to a broken state. In general he wants to separate the CM and back-up/dev utilties that SVN offers. Honestly, I am new and the person with this perspective is one of seniority, experience, and success, so I want to field this dilemma with the stackoverflow userbase to see if his approach has merit. My question: Should SVN be purely used for development, and another tool for CM (or vice versa)? Why? If so, what tools would you suggest for this combo? Or do you think that integrating both CM and dev into SVN is the best approach? Why? Thanks.

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  • Is C# development effectively inseparable from the IDE you use?

    - by Ghopper21
    I'm a Python programmer learning C# who is trying to stop worrying and just love C# for what it is, rather than constantly comparing it back to Python. I'm really get caught up on one point: the lack of explicitness about where things are defined, as detailed in this Stack Overflow question. In short: in C#, using foo doesn't tell you what names from foo are being made available, which is analogous to from foo import * in Python -- a form that is discouraged within Python coding culture for being implicit rather than the more explicit approach of from foo import bar. I was rather struck by the Stack Overflow answers to this point from C# programmers, which was that in practice this lack of explicitness doesn't really matter because in your IDE (presumably Visual Studio) you can just hover over a name and be told by the system where the name is coming from. E.g.: Now, in theory I realise this means when you're looking with a text editor, you can't tell where the types come from in C#... but in practice, I don't find that to be a problem. How often are you actually looking at code and can't use Visual Studio? This is revelatory to me. Many Python programmers prefer a text editor approach to coding, using something like Sublime Text 2 or vim, where it's all about the code, plus command line tools and direct access and manipulation of folders and files. The idea of being dependent on an IDE to understand code at such a basic level seems anathema. It seems C# culture is radically different on this point. And I wonder if I just need to accept and embrace that as part of my learning of C#. Which leads me to my question here: is C# development effectively inseparable from the IDE you use?

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  • Unity gizmos vs. referenced game objects

    - by DuckMaestro
    I'm designing a Unity script that I intend to be highly reusable and as easy as possible to setup within the editor. To this end, a number of properties of this script really need some kind of visual representation on screen. It is an unresolved question to me whether the design of the script should require references to placeholder game objects, OR just Vector3's and float's that have associated gizmos drawn for them. Normally a gizmo would be a natural choice, except that Unity gizmos are not directly manipulable (as far as I can tell). Because of this shortcoming I'm having to consider whether depending on references to placeholder game objects is a more designer-friendly approach ultimately, in spite of the extra setup required, and that it might be counter-intuitive when the placeholder game objects disappear at run-time (which my script would do). Is there a community standard or preference here in this case? Can a Unity-experienced game programmer / designer speak to which approach they feel is more intuitive or more convenient to setup, when using a 3rd party script? Or is this just splitting hairs as long as I ship an example prefab with my script?

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  • Differentiating between user script input formats

    - by KChaloux
    I have a .NET project at work that provides a couple of (Iron)Python scripts to the customers, to allow them to customize the output of the program. The application generates code for certain machines, and supports a couple of different formats. Until recently, we only provided a script for one format. We're expanding upon that to include support for the others. If the user is using a script, they select their input script before generating the output code. A script designed for Format1 output is going to cause errors if they're trying to generate Format2 output. I need to deal with this. One option would just be to let the customers use common sense, and if they load the wrong script it will just fail, or worse, produce inaccurate data. I'm inclined to provide a little more protection than that. At the moment I'm considering putting a shebang-style comment line at the top of the script, ala: # OUTPUT - Format1 If the user tries to run a Format2 process with a Format1 script, it will warn them. Alternatively I could create different file extensions for the input scripts that vary by type. The file-type comment approach helps prevent the script from actually loading improperly, at the cost of failing to warn the user until they've already selected it, via a dialog box. Using different file extensions would allow me to cut down on visual clutter when providing a File Dialog, but doesn't actually stop them from loading the wrong script. So I'm really not sure if the right approach is to just leave it alone, or provide some safeguards.

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  • How to define implementation details?

    - by woni
    In our project, an assembly combines logic for the IoC-Container, the project internals and the communication layer. The current version evolved to have only internal classes in addin assemblies. My main problem with this approach is, that the entry point is only available over the IoC-Container. It is not possible to use anything else than reflection to initialize the assembly. Everything behind the IoC-Interface is defined as implementation detail and therefore not intended for usages outside. It is well known that you should not test implementation detail (such as private and internal methods), because they should be tested through the public interface. It is also well known, that your tests should not use the IoC-Container to setup the SUTs, because that would result in too much dependencies. So we are using the InternalsVisibleTo-Attribute to make internals visible to our test assemblies and test the so called implementation details. I recognized that one problem could be the mixup between different concerns in that assembly, changing this would make this discussion useless, because classes have to be defined public. Ignoring my concerns with this, isn't the need to test a class enough reason to make it public, the usages of InternalsVisibleTo seems unintended, and a little bit "hacky". The approach to test only against the publicly available IoC-Container is too costly and would result in integration style tests. The pros of using internals are, that the usages are well known and do not have to be implemented like a public method would have to be (documentation, completeness, versioning,...). Is there a solution, to not test against internals, but keep their advantages over public classes, or do we have to redefine what an implementation detail is.

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  • Static / Shared Helper Functions vs Built-In Methods

    - by Nathan
    This is a simple question but a design consideration that I often run across in my day to day development work. Lets say that you have a class that represents some kinds of collection. Public Class ModifiedCustomerOrders Public Property Orders as List(Of ModifiedOrders) End Class Within this class you do all kinds of important work, such as combining many different information sources and, eventually, build the Modified Customer Orders. Now, you have different processes that consume this class, each of which needs a slightly different slice of the ModifiedCustomerOrders items. To enable this, you want to add filtering functionality. How do you go about this? Do you: Add Filtering calls to the ModifiedCustomerOrders class so that you can say: MyOrdersClass.RemoveCanceledOrders() Create a Static / Shared "tooling" class that allows you to call: OrdersFilters.RemoveCanceledOrders(MyOrders) Create an extension method to accomplish the same feat as #2 but with less typing: MyOrders.RemoveCanceledOrders() Create a "Service" method that handles the getting of Orders as appropriate to the calling function, while using one of the previous approaches "under the hood". OrdersService.GetOrdersForProcessA() Others? I tend to prefer the tooling / extension method approaches as they make testing a little bit simpler. Although I dependency inject all my sourcing data into the ModifiedCustomerOrders, having it as part of the class makes it a little bit more complicated to test. Typically, I choose to use extension methods where I am doing parameterless transformations / filters. As they get more complex, I will move it into a static class instead. Thoughts on this approach? How would you approach it?

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  • MongoDB: Replicate data in documents vs. “join”

    - by JavierCane
    Disclaimer: This is a question derived from this one. What do you think about the following example of use case? I have a table containing orders. These orders has a lot of related information needed by my current queries (think about the products; the buyer information; the region, country and state of the sale point; and so on) In order to think with a de-normalized approach, I don't have to put identifiers of these related items in my main orders collection. Instead, I have to repeat all the information for each order (ie: I will repeat the buyer's name, surname, etc. for each of its orders). Assuming the previous premise, I'm committing to maintain all the data related to an order without a lot of updates (because if I modify the buyer's name, I'll have to iterate through all orders updating the ones made by the same buyer, and as MongoDB blocks at a document level on updates, I would be blocking the entire order at the update moment). I'll have to replicate all the products' related data? (ie: category, maker and optional attributes like color, size…) What if a new feature is requested and I've to make a lot of queries with the products "as the entry point of the query"? (ie: reports showing the products' sales performance grouping by region, country, or whatever) Is it fair enough to apply the $unwind operation to my orders original collection? (What about the performance?) I should have to do another collection with these queries in mind and replicate again all the products' information (and their orders)? Wouldn't be better to store a product_id in the original orders collection in order to be more tolerable to requirements change? (What about emulating JOINs?) The optimal approach would be a mixed solution with a RDBMS system like MySQL in order to retrieve the complete data? I mean: store products, users, and location identifiers in the orders collection and have queries in MySQL like getAllUsersDataByIds in which I would perform a SELECT * FROM users WHERE user_id IN ( :identifiers_retrieved_from_the_mongodb_query )

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  • Call DB Stored Procedure using @NamedStoredProcedureQuery Injection

    - by anwilson
    Oracle Database Stored Procedure can be called from EJB business layer to perform complex DB specific operations. This approach will avoid overhead from frequent network hits which could impact end-user result. DB Stored Procedure can be invoked from EJB Session Bean business logic using org.eclipse.persistence.queries.StoredProcedureCall API. Using this approach requires more coding to handle the Session and Arguments of the Stored Procedure, thereby increasing effort on maintenance. EJB 3.0 introduces @NamedStoredProcedureQuery Injection to call Database Stored Procedure as NamedQueries. This blog will take you through the steps to call Oracle Database Stored Procedure using @NamedStoredProcedureQuery.EMP_SAL_INCREMENT procedure available in HR schema will be used in this sample.Create Entity from EMPLOYEES table.Add @NamedStoredProcedureQuery above @NamedQueries to Employees.java with definition as given below - @NamedStoredProcedureQuery(name="Employees.increaseEmpSal", procedureName = "EMP_SAL_INCREMENT", resultClass=void.class, resultSetMapping = "", returnsResultSet = false, parameters = { @StoredProcedureParameter(name = "EMP_ID", queryParameter = "EMPID"), @StoredProcedureParameter(name = "SAL_INCR", queryParameter = "SALINCR")} ) Observe how Stored Procedure's arguments are handled easily in  @NamedStoredProcedureQuery using @StoredProcedureParameter.Expose Entity Bean by creating a Session Facade.Business method need to be added to Session Bean to access the Stored Procedure exposed as NamedQuery. public void salaryRaise(Long empId, Long salIncrease) throws Exception { try{ Query query = em.createNamedQuery("Employees.increaseEmpSal"); query.setParameter("EMPID", empId); query.setParameter("SALINCR", salIncrease); query.executeUpdate(); } catch(Exception ex){ throw ex; } } Expose business method through Session Bean Remote Interface. void salaryRaise(Long empId, Long salIncrease) throws Exception; Session Bean Client is required to invoke the method exposed through remote interface.Call exposed method in Session Bean Client main method. final Context context = getInitialContext(); SessionEJB sessionEJB = (SessionEJB)context.lookup("Your-JNDI-lookup"); sessionEJB.salaryRaise(new Long(200), new Long(1000)); Deploy Session BeanRun Session Bean Client.Salary of Employee with Id 200 will be increased by 1000.

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  • Search multiple tables

    - by gilden
    I have developed a web application that is used mainly for archiving all sorts of textual material (documents, references to articles, books, magazines etc.). There can be any given number of archive tables in my system, each with its own schema. The schema can be changed by a moderator through the application (imagine something similar to a really dumbed down version of phpMyAdmin). Users can search for anything from all of the tables. By using FULLTEXT indexes together with substring searching (fields which do not support FULLTEXT indexing) the script inserts the results of a search to a single table and by ordering these results by the similarity measure I can fairly easily return the paginated results. However, this approach has a few problems: substring searching can only count exact results the 50% rule applies to all tables separately and thus, mysql may not return important matches or too naively discards common words. is quite expensive in terms of query numbers and execution time (not an issue right now as there's not a lot of data yet in the tables). normalized data is not even searched for (I have different tables for categories, languages and file attatchments). My planned solution Create a single table having columns similar to id, table_id, row_id, data Every time a new row is created/modified/deleted in any of the data tables this central table also gets updated with the data column containing a concatenation of all the fields in a row. I could then create a single index for Sphinx and use it for doing searches instead. Are there any more efficient solutions or best practises how to approach this? Thanks.

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  • What is the standard technique for shifting the frames of a sprite according to user input?

    - by virtual__
    From my own experience, I developed two techniques for changing the sprites of a character that's reacting to user input -- this in the context of a classic 2D platformer. The first one is to store all character's pixmaps in a list, putting the index of the currently used pixmap in an ordinary variable. This way, every time the player presses a key -- say the right arrow for moving the character forward -- the graphics engine sees what's the next pixmap to draw, draws it, and increments the index counter. That's a pretty common approach I believe, the problem is that in this case the animation's quality depends not only on the number of sprites available but also on how often your engine listens to user input. The second technique is to actually play an animation every key press event. For this you can use any sort of animation framework you want. It's only necessary to set the timer, the animation steps and to call the animation's play() method on your key press event handler. The problem with that approach is that is lacks responsiveness, since the character won't react to any input while the current animation is still being played. What I want to know is whether you are using one of these techniques -- or something similar -- in your games, or whether there's a standard method for animating sprites out there that's widely known by everybody but me.

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