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• I've made something that might be useful to the community. Now what?

  - by Chris McCall

  If the specifics are important, I made a cruisecontrol.net publisher plugin that notifies a series of phone numbers via voice, announcing the current state of the build. It uses Twilio to do so. I'd like to avoid getting hung up on the specifics of what it is I've made, as I have this question a lot, with a number of little hobby one-offs. What's the state of the art as far as making my hobby output available to the world at large? There seem to be a lot of options for open-source project hosting, community features, and what role to take in all of this. It's a little bewildering. What I'm looking for is to put this out into the wild for free and basically take a hands-off approach from there. Is that realistic? Which project hosting service can I use for free to allow developers to at least download the code, report issues and collaborate with each other to improve the product? What snags have you run into that could make me regret this decision? I'm interested in war stories, advice and guidance on making this little product available to the community where it can be used.

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• Reducing moire when downsampling halftone comic images.

  - by drawnonward

  How can I reduce moire effects when downsampling halftone comic book images during live zoom on an iPhone or iPad? I am writing a comic book viewer. It would be nice to provide higher resolution images and allow the user to zoom in while reading the comic book. However, my client is averse to moire effects and will not allow this feature if there are noticeable moire artifacts while zooming, which of course there are. Modifying the images to be less susceptible to moire would only work if the modifications were not perceptible. Blur was specifically prohibited, as is anything that removes the beloved halftone dots. The images are black and white halftone and line art. The originals are 600 dpi but what we ship with the application will be half that at best, so probably 2500 pixels or less tall. So what are my options? If I write a custom downsampling algorithm would it be fast enough for real time on these devices? Are there other tricks I can do? Would it work to just avoid the size ratios that have the most visual moire effects? As you zoom in an out, there are definitely peaks where the moire effects are worst. Is there a way to calculate what those points are and just zoom to a nearby scale that is not as bad? Any suggestions are welcome. I have very little experience with image and signal processing, but am enjoying the opportunity to learn. I know nothing of wavelets and acutance and other jargon, so please be verbose.

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• Approach for fixing NoClassDefFoundError?

  - by DJC

  I'm seeing this question is getting asked a lot in many different contexts. Perhaps we can set some strategies for locating and fixing it? I'm noobish myself so all I can contribute are horror stories and questions, sorry... It seems this is thrown when a class is visible at compile time but not at run time... how can this happen? In my case I am developing an app that uses the Google APIs, in Eclipse, for the Android platform. I've configured the Project Properties / Java Build Path / Libraries to include the gdata .jars and all is well. When I execute in the emulator I get a force close and the logcat shows a NoClassDefFoundError on a simple new ContactsService("myApp"); I've also tried a new CalendarService("myApp") with the same results. Is it possible or desirable to statically bind at compile time to avoid the problem? How could dynamic binding of an add-on library work in the mobile environment anyway? Either it has to be bound into my .apk or else I need to "install" it? ... hmmm. Advice much appreciated.

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• Check for modification failure in content Integration using visualSvn sever and cruise control.net

  - by harun123

  I am using CruiseControl.net for continous integration. I've created a repository for my project using VisualSvn server (uses Windows Authentication). Both the servers are hosted in the same system (Os-Microsoft Windows Server 2003 sp2). When i force build the project using CruiseControl.net "Failed task(s): Svn: CheckForModifications" is shown as the message. When i checked the build report, it says as follows: BUILD EXCEPTION Error Message: ThoughtWorks.CruiseControl.Core.CruiseControlException: Source control operation failed: svn: OPTIONS of 'https://sp-ci.sbsnetwork.local:8443/svn/IntranetPortal/Source': **Server certificate verification failed: issuer is not trusted** (https://sp-ci.sbsnetwork.local:8443). Process command: C:\Program Files\VisualSVN Server\bin\svn.exe log **sameUrlAbove** -r "{2010-04-29T08:35:26Z}:{2010-04-29T09:04:02Z}" --verbose --xml --username ccnetadmin --password cruise --non-interactive --no-auth-cache at ThoughtWorks.CruiseControl.Core.Sourcecontrol.ProcessSourceControl.Execute(ProcessInfo processInfo) at ThoughtWorks.CruiseControl.Core.Sourcecontrol.Svn.GetModifications (IIntegrationResult from, IIntegrationResult to) at ThoughtWorks.CruiseControl.Core.Sourcecontrol.QuietPeriod.GetModifications(ISourceControl sourceControl, IIntegrationResult lastBuild, IIntegrationResult thisBuild) at ThoughtWorks.CruiseControl.Core.IntegrationRunner.GetModifications(IIntegrationResult from, IIntegrationResult to) at ThoughtWorks.CruiseControl.Core.IntegrationRunner.Integrate(IntegrationRequest request) My SourceControl node in the ccnet.config is as shown below: <sourcecontrol type="svn"> <executable>C:\Program Files\VisualSVN Server\bin\svn.exe</executable> <trunkUrl> check out url </trunkUrl> <workingDirectory> C:\ProjectWorkingDirectories\IntranetPortal\Source </workingDirectory> <username> ccnetadmin </username> <password> cruise </password> </sourcecontrol> Can any one suggest how to avoid this error?

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• Java assignment issues - Is this atomic?

  - by Bob

  Hi, I've got some questions about Java's assigment. Strings I've got a class: public class Test { private String s; public synchronized void setS(String str){ s = s + " - " + str; } public String getS(){ return s; } } I'm using "synchronized" in my setter, and avoiding it in my getter, because in my app, there are a tons of data gettings, and very few settings. Settings must be synchronized to avoid inconsistency. My question is: is getting and setting a variable atomic? I mean, in a multithreaded environment, Thread1 is about to set variable s, while Thread2 is about to get "s". Is there any way the getter method could get something different than the s's old value or the s's new value (suppose we've got only two threads)? In my app it is not a problem to get the new value, and it is not a problem to get the old one. But could I get something else? What about HashMap's getting and putting? considering this: public class Test { private Map<Integer, String> map = Collections.synchronizedMap(new HashMap<Integer, String>()); public synchronized void setMapElement(Integer key, String value){ map.put(key, value); } public String getValue(Integer key){ return map.get(key); } } Is putting and getting atomic? How does HashMap handle putting an element into it? Does it first remove the old value and put the now one? Could I get other than the old value or the new value? Thanks in advance!

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• GWT: Populating a page from datastore using RPC is too slow

  - by Ilya Boyandin

  Is there a way to speed up the population of a page with GWT's UI elements which are generated from data loaded from the datastore? Can I avoid making the unnecessary RPC call when the page is loaded? More details about the problem I am experiencing: There is a page on which I generate a table with names and buttons for a list of entities loaded from the datastore. There is an EntryPoint for the page and in its onModuleLoad() I do something like this: final FlexTable table = new FlexTable(); rpcAsyncService.getAllCandidates(new AsyncCallback<List<Candidate>>() { public void onSuccess(List<Candidate> candidates) { int row = 0; for (Candidate person : candidates) { table.setText(row, 0, person.getName()); table.setWidget(row, 1, new ToggleButton("Yes")); table.setWidget(row, 2, new ToggleButton("No")); row++; } } ... }); This works, but takes more than 30 seconds to load the page with buttons for 300 candidates. This is unacceptable. The app is running on Google App Engine and using the app engine's datastore.

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• Relative Paths in .htaccess, how to attach to a variable?

  - by devians

  I have a very heavy htaccess mod_rewrite file that runs my application. As we sometimes take over legacy websites, I sometimes need to support old urls to old files, where my application processes everything post htaccess. My ultimate goal is to have a 'Demilitarized Zone' for old file structures, and use mod rewrite to check for existence there before pushing to the application. This is pretty easy to do with files, by using: RewriteCond %{IS_SUBREQ} true RewriteRule .* - [L] RewriteCond %{ENV:REDIRECT_STATUS} 200 RewriteRule .* - [L] RewriteCond Public/DMZ/$1 -F [OR] RewriteRule ^(.*)$ Public/DMZ/$1 [QSA,L] This allows pseudo support for relative urls by not hardcoding my base path (I cant assume I will ever be deployed in document root) anywhere and using subrequests to check for file existence. Works fine if you know the file name, ie http://domain.com/path/to/app/legacyfolder/index.html However, my legacy urls are typically http://domain.com/path/to/app/legacyfolder/ Mod_Rewrite will allow me to check for this by using -d, but it needs the complete path to the directory, ie RewriteCond Public/DMZ/$1 -F [OR] RewriteCond /var/www/path/to/app/Public/DMZ/$1 -d RewriteRule ^(.*)$ Public/DMZ/$1 [QSA,L] I want to avoid the hardcoded base path. I can see one possible solutions here, somehow determining my path and attaching it to a variable [E=name:var] and using it in the condition. Any implementation that allows me to existence check a directory is more than welcome.

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• Generic FSM for game in C++ ?

  - by Mr.Gando

  Hello, I was wondering if there's a way I could code some kind of "generic" FSM for a game with C++?. My game has a component oriented design, so I use a FSM Component. my Finite State Machine (FSM) Component, looks more or less this way. class gecFSM : public gecBehaviour { public: //Constructors gecFSM() { state = kEntityState_walk; } gecFSM(kEntityState s) { state = s; } //Interface void setRule(kEntityState initialState, int inputAction, kEntityState resultingState); void performAction(int action); private: kEntityState fsmTable[MAX_STATES][MAX_ACTIONS]; }; I would love to hear your opinions/ideas or suggestions about how to make this FSM component, generic. With generic I mean: 1) Creating the fsmTable from an xml file is really easy, I mean it's just a bunch of integers that can be loaded to create an MAX_STATESxMAX_ACTION matrix. void gecFSM::setRule(kEntityState initialState, int inputAction, kEntityState resultingState) { fsmTable[initialState][inputAction] = resultingState; } 2) But what about the "perform Action" method ? void gecFSM::performAction(int action) { switch( smTable[ ownerEntity->getState() ][ action ] ) { case WALK: /*Walk action*/ break; case STAND: /*Stand action*/ break; case JUMP: /*Jump action*/ break; case RUN: /*Run action*/ break; } } What if I wanted to make the "actions" and the switch generic? This in order to avoid creating a different FSM component class for each GameEntity? (gecFSMZombie, gecFSMDryad, gecFSMBoss etc ?). That would allow me to go "Data Driven" and construct my generic FSM's from files for example. What do you people suggest?

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• Is my method for avoiding dynamic_cast<> faster than dynamic_cast<> itself ?

  - by ereOn

  Hi, I was answering a question a few minutes ago and it raised to me another one: In one of my projects, I do some network message parsing. The messages are in the form of: [1 byte message type][2 bytes payload length][x bytes payload] The format and content of the payload are determined by the message type. I have a class hierarchy, based on a common class Message. To instanciate my messages, i have a static parsing method which gives back a Message* depending on the message type byte. Something like: Message* parse(const char* frame) { // This is sample code, in real life I obviously check that the buffer // is not NULL, and the size, and so on. switch(frame[0]) { case 0x01: return new FooMessage(); case 0x02: return new BarMessage(); } // Throw an exception here because the mesage type is unknown. } I sometimes need to access the methods of the subclasses. Since my network message handling must be fast, I decived to avoid dynamic_cast<> and I added a method to the base Message class that gives back the message type. Depending on this return value, I use a static_cast<> to the right child type instead. I did this mainly because I was told once that dynamic_cast<> was slow. However, I don't know exactly what it really does and how slow it is, thus, my method might be as just as slow (or slower) but far more complicated. What do you guys think of this design ? Is it common ? Is it really faster than using dynamic_cast<> ? Any detailed explanation of what happen under the hood when one use dynamic_cast<> is welcome !

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• Version Control: multiple version hell, file synchronization

  - by SigTerm

  Hello. I would like to know how you normally deal with this situation: I have a set of utility functions. Say..5..10 files. And technically they are static library, cross-platform - SConscript/SConstruct plus Visual Studio project (not solution). Those utility functions are used in multiple small projects (15+, number increases over time). Each project has a copy of a few files or of an entire library, not a link into one central place. Sometimes project uses one file, two files, some use everything. Normally, utility functions are included as a copy of every file and SConscript/SConstruct or Visual Studio Project (depending on the situation). Each project has a separate git repository. Sometimes one project is derived from other, sometimes it isn't. You work on every one of them, in random order. There are no other people (to make things simpler) The problem arises when while working on one project you modify those utility function files. Because each project has a copy of file, this introduces new version, which leads to the mess when you try later (week later, for example) to guess which version has a most complete functionality (i.e. you added a function to a.cpp in one project, and added another function to a.cpp in another project, which created a version fork) How would you handle this situation to avoid "version hell"? One way I can think of is using symbolic links/hard links, but it isn't perfect - if you delete one central storage, it will all go to hell. And hard links won't work on dual-boot system (although symbolic links will). It looks like what I need is something like advanced git repository, where code for the project is stored in one local repository, but is synchronized with multiple external repositories. But I'm not sure how to do it or if it is possible to do this with git. So, what do you think?

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• Code Organization Connundrum: Web Project With Multiple Supporting DLLs?

  - by Code Sherpa

  Hi. I am trying to get a handle on the best practice for code organization within my project. I have looked around on the internet for good examples and, so far, I have seen examples of a web project with one or multiple supporting class libraries that it references or a web project with sub-folders that follow its namespace conventions. Assuming there is no right answer, this is what I currently have for code organization: MyProjectWeb This is my web site. I am referencing my class libraries here. MyProject.DLL As the base namespace, I am using this DLL for files that need to be generally consumable. For example, my class "Enums" that has all the enumerations in my project lives there. As does class MyProjectException for all exception handling. MyProject.IO.DLL This is a grouping of maybe 20 files that handle file upload and download (so far). MyProject.Utilities.DLL ALl my common classes and methods bunched up together in one generally consumable DLL. Each class follows a "XHelper" convention such as "SqlHelper, AuthHelper, SerializationHelper, and so on... MyProject.Web.DLL I am using this DLL as the main client interface. Right now, the majority of class files here are: 1) properties (such as School, Location, Account, Posts) 2) authorization stuff ( such as custom membership, custom role, & custom profile providers) My question is simply - does this seem logical? Also, how do I avoid having to cross reference DLLs from one project library to the next? For example, MyProject.Web.DLL uses code from MyProject.Utilities.DLL and MyProject.Utilities.DLL uses code from MyProject.DLL. Is this solved by clicking on properties and selecting "Dependencies"? I tried that but still don't seem to be accessing the namespaces of the assembly I have selected. Do I have to reference every assembly I need for each class library? Responses appreciated and thanks for your patience.

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• How to use Data aware controls "correctly"?

  - by lyborko

  Hi, I would like to ask experienced users, if you prefer to use data aware controls to add, insert, delete and edit data in DB or you favor to do it manualy. I developed some DB applications, in which for the sake of "user friendly policy" I run into complicated web of table events (afterinsert, afteredit, after... and beforeedit, beforeinsert, before...). After that it was a quite nasty work to debug the application. Aware of this risk (later by another application) I tried to avoid this problem, so I paid increased attention to write code well, readable and comprehensive. It seemed everything all right from the beginning, but as I needed to handle some preprocessing stuff before sending and loading data etc, I run into the same problems again, "slowly and inevitably". Sometime I could not use dataaware controls anyway, and what seemed to be a "cool" feature of DAControl at the beginning it turned to an obstacle on the end. I "had to" write special routine for non-dataaware controls, in order to behave as dataaware. Then I asked myself, why on earth should I use dataaware controls? Is it better to found application architecture on non-dataaware controls? It requires more time to write bug-proof code, of course, but does it worth of it? I do not know... I happened to me several times, like jinxed : paradise on the beginning hell on the end... I do not know, if I use wrong method to write DB program, if there is some standard common practice how to proceed. Or if it is common problem to everybody? Thanx for advices and your experiences

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• How do I design a Wizard-based system with SoC in mind?

  - by Erik Forbes

  I'm building a Windows Forms system (in C# if it matters to anyone) that provides an application automation service. As this application is targeted at users who are not computer savvy, I've decided to break up the functions of the application into various tasks, and provide these tasks via a wizard UI. I'd like to avoid coupling the views and view engine (from which the Wizard will be built) to the automation engine. The problem I'm having is that the automation engine, which runs on a separate thread while it does its thing, needs to report status information back to the user, as well as listen for cancel or pause events from the user. Since I don't want the view engine or the automation engine to rely on each other, I'm having a hard time figuring out how to provide for this information conduit. Any insights into this issue I'm having would be greatly appreciated. I've been wracking my brain for a couple weeks now on this point, and I really don't want to give up and just couple everything together. If anyone needs additional details to help come up with some sort of idea please let me know and I'll be happy to provide them.

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• Project Euler problem 214, How can i make it more efficient?

  - by Once

  I am becoming more and more addicted to the Project Euler problems. However since one week I am stuck with the #214. Here is a short version of the problem: PHI() is Euler's totient function, i.e. for any given integer n, PHI(n)=numbers of k<=n for which gcd(k,n)=1. We can iterate PHI() to create a chain. For example starting from 18: PHI(18)=6 = PHI(6)=2 = PHI(2)=1. So starting from 18 we get a chain of length 4 (18,6,2,1) The problem is to calculate the sum of all primes less than 40e6 which generate a chain of length 25. I built a function that calculates the chain length of any number and I tested it for small values: it works well and fast. sum of all primes<=20 which generate a chain of length 4: 12 sum of all primes<=1000 which generate a chain of length 10: 39383 Unfortunately my algorithm doesn't scale well. When I apply it to the problem, it takes several hours to calculate... so I stop it because the Project Euler problems must be solved in less than one minute. I thought that my prime detection function might be slow so I fed the program with a list of primes <40e6 to avoid the primality test... The code runs now a little bit faster, but there is still no way to get a solution in less than a few hours (and I don't want this). So is there any "magic trick" that I am missing here ? I really don't understand how to be more efficient on this one... I am not asking for the solution, because fighting with optimization is all the fun of Project Euler. However, any small hint that could put me on the right track would be welcome. Thanks !

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• Injecting Dependencies into Domain Model classes with Nhibernate (ASP.NET MVC + IOC)

  - by Sunday Ironfoot

  I'm building an ASP.NET MVC application that uses a DDD (Domain Driven Design) approach with database access handled by NHibernate. I have domain model class (Administrator) that I want to inject a dependency into via an IOC Container such as Castle Windsor, something like this: public class Administrator { public virtual int Id { get; set; } //.. snip ..// public virtual string HashedPassword { get; protected set; } public void SetPassword(string plainTextPassword) { IHashingService hasher = IocContainer.Resolve<IHashingService>(); this.HashedPassword = hasher.Hash(plainTextPassword); } } I basically want to inject IHashingService for the SetPassword method without calling the IOC Container directly (because this is suppose to be an IOC Anti-pattern). But I'm not sure how to go about doing it. My Administrator object either gets instantiated via new Administrator(); or it gets loaded via NHibernate, so how would I inject the IHashingService into the Administrator class? On second thoughts, am I going about this the right way? I was hoping to avoid having my codebase littered with... currentAdmin.Password = HashUtils.Hash(password, Algorithm.Sha512); ...and instead get the domain model itself to take care of hashing and neatly encapsulate it away. I can envisage another developer accidently choosing the wrong algorithm and having some passwords as Sha512, and some as MD5, some with one salt, and some with a different salt etc. etc. Instead if developers are writing... currentAdmin.SetPassword(password); ...then that would hide those details away and take care of those problems listed above would it not?

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• ASP.Net MVC, JS injection and System.ArgumentException - Illegal Characters in path

  - by Mose

  Hi, In my ASP.Net MVC application, I use custom error handling. I want to perform custom actions for each error case I meet in my application. So I override Application_Error, get the Server.GetLastError(); and do my business depending on the exception, the current user, the current URL (the application runs on many domains), the user IP, and many others. Obviousely, the application is often the target of hackers. In almost all the case it's not a problem to detect and manage it, but for some JS URL attacks, my error handling does not perform what I want it to do. Ex (from logs) : http://localhost:1809/Scripts/]||!o.support.htmlSerialize&&[1 When I got such an URL, an exception is raised when accessing the ConnectionStrings section in the web.config, and I can't even redirect to another URL. It leads to a "System.ArgumentException - Illegal Characters in path, etc." The screenshot below shows the problem : http://screencast.com/t/Y2I1YWU4 An obvious solution is to write a HTTP module to filter the urls before they reach my application, but I'd like to avoid it because : I like having the whole security being managed in one place (in the Application_Error() method) In the module I cannot access the whole data I have in the application itself (application specific data I don't want to debate here) Questions : Did you meet this problem ? How did you manage it ? Thanks for you suggestions, Mose

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• C# DynamicMethod prelink

  - by soywiz

  I'm the author of a psp emulator made in C#. I'm generating lots of "DynamicMethod" using ILGenerator. I'm converting assembly code into an AST, and then generating IL code and building that DynamicMethod. I'm doing this in another thread, so I can generate new methods while the program is executing others so it can run smoothly. My problem is that the native code generation is lazy, so the machine code is generated when the function is called, not when the IL is generated. So it generates in the program executing thread, native code generation is prettly slow as it is the asm-ast-il step. I have tried the Marshal.Prelink method that it is suposed to generate the machine code before executing the function. It does work on Mono, but it doesn't work on MS .NET. Marshal.Prelink(MethodInfo); Is there a way of prelinking a DynamicMethod on MS .NET? I thought adding a boolean parameter to the function that if set, exits the function immediately so no code is actually executed. I could "prelink" that way, but I think that's a nasty solution I want to avoid. Any idea?

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• How should i organize authority code?

  - by acidzombie24

  I have users that fall into the following Not logged in Not Verified Verified Moderator Admin All code that only admin and moderators can access (like banning) is in ModeratorUser which inherits from verified which inherits from BaseUser. Some pages are accessible to all users such as public profiles. If a user is logged in he can leave a comment. To check this i use if (IsVerifiedUser). Now here is the problem. To avoid problems if a user is banned he is not recognized as a verified user. However in the rare case i need to know if he is verified i can use usertype & Verified. Should i not be doing this? I have a bunch of code in my VerifiedUser class and find i am moving tons of it to BaseUser. Is this something i help because a not logged in user can access the page? Should i handle the ban user in a different way and allow IsVerifiedUser to be true even if the user is banned?

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• Generating easy-to-remember random identifiers

  - by Carl Seleborg

  Hi all, As all developers do, we constantly deal with some kind of identifiers as part of our daily work. Most of the time, it's about bugs or support tickets. Our software, upon detecting a bug, creates a package that has a name formatted from a timestamp and a version number, which is a cheap way of creating reasonably unique identifiers to avoid mixing packages up. Example: "Bug Report 20101214 174856 6.4b2". My brain just isn't that good at remembering numbers. What I would love to have is a simple way of generating alpha-numeric identifiers that are easy to remember. Examples would be "azil3", "ulmops", "fel2way", etc. I just made these up, but they are much easier to recognize when you see many of them at once. I know of algorithms that perform trigram analysis on text (say you feed them a whole book in German) and that can generate strings that look and feel like German words. This requires lots of data, though, and makes it slightly less suitable for embedding in an application just for this purpose. Do you know of anything else? Thanks! Carl

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• Regular expression to match empty HTML tags that may contain embedded JSTL?

  - by Keith Bentrup

  I'm trying to construct a regular expression to look for empty html tags that may have embedded JSTL. I'm using Perl for my matching. So far I can match any empty html tag that does not contain JSTL with the following? /<\w+\b(?!:)[^<]*?>\s*<\/\w+/si The \b(?!:) will avoid matching an opening JTSL tag but that doesn't address the whether JSTL may be within the HTML tag itself (which is allowable). I only want to know if this HTML tag has no children (only whitespace or empty). So I'm looking for a pattern that would match both the following: <div id="my-id"> </div> <div class="<c:out var="${my.property}" />"></div> Currently the first div matches. The second does not. Is it doable? I tried several variations using lookahead assertions, and I'm starting to think it's not. However, I can't say for certain or articulate why it's not. Edit: I'm not writing something to interpret the code, and I'm not interested in using a parser. I'm writing a script to point out potential issues/oversights. And at this point, I'm curious, too, to see if there is something clever with lookaheads or lookbehinds that I may be missing. If it bothers you that I'm trying to "solve" a problem this way, don't think of it as looking for a solution. To me it's more of a challenge now, and an opportunity to learn more about regular expressions. Also, if it helps, you can assume that the html is xhtml strict.

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• 3 tier application pattern suggestion

  - by Maxim Gershkovich

  I have attempted to make my first 3 tier application. In the process I have run into one problem I am yet to find an optimal solution for. Basically all my objects use an IFillable interface which forces the implementation of a sub as follows Public Sub Fill(ByVal Datareader As Data.IDataReader) Implements IFillable.Fill This sub then expects the Ids from the datareader will be identical to the properties of the object as such. Me.m_StockID = Datareader.GetGuid(Datareader.GetOrdinal("StockID")) In the end I end up with a datalayer that looks something like this. Public Shared Function GetStockByID(ByVal ConnectionString As String, ByVal StockID As Guid) As Stock Dim res As New Stock Using sqlConn As New SqlConnection(ConnectionString) sqlConn.Open() res.Fill(StockDataLayer.GetStockByIDQuery(sqlConn, StockID)) End Using Return res End Function Mostly this pattern seems to make sense. However my problem is, lets say I want to implement a property for Stock called StockBarcodeList. Under the above mentioned pattern any way I implement this property I will need to pass a connectionstring to it which obviously breaks my attempt at layer separation. Does anyone have any suggestions on how I might be able to solve this problem or am I going about this the completely wrong way? Does anyone have any suggestions on how I might improve my implementation? Please note however I am deliberately trying to avoid using the dataset in any form.

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• Opaque tenant identification with SQL Server & NHibernate

  - by Anton Gogolev

  Howdy! We're developing a nowadays-fashionable multi-tenanted SaaS app (shared database, shared schema), and there's one thing I don't like about it: public class Domain : BusinessObject { public virtual long TenantID { get; set; } public virtual string Name { get; set; } } The TenantID is driving me nuts, as it has to be accounted for almost everywhere, and it's a hassle from security standpoint: what happens if a malicious API user changes TenantID to some other value and will mix things up. What I want to do is to get rid of this TenantID in our domain objects altogether, and to have either NHibernate or SQL Server deal with it. From what I've already read on the Internets, this can be done with CONTEXT_INFO (here's a NHibernatebased implementation), NHibernate filters, SQL Views and with combination thereof. Now, my requirements are as follows: Remove any mentions of TenantID from domain objects ...but have SQL Server insert it where appropriate (I guess this is achieved with default constraints) ...and obviously provide support for filtering based on this criteria, so that customers will never see each other's data If possible, avoid SQL Server views. Have a solution which plays nicely with NHibernate, SQL Servers' MARS and general nature of SaaS apps being highly concurrent What are your thoughts on that?

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• Practical rules for premature optimization

  - by DougW

  It seems that the phrase "Premature Optimization" is the buzz-word of the day. For some reason, iphone programmers in particular seem to think of avoiding premature optimization as a pro-active goal, rather than the natural result of simply avoiding distraction. The problem is, the term is beginning to be applied more and more to cases that are completely inappropriate. For example, I've seen a growing number of people say not to worry about the complexity of an algorithm, because that's premature optimization (eg http://stackoverflow.com/questions/2190275/help-sorting-an-nsarray-across-two-properties-with-nssortdescriptor/2191720#2191720). Frankly, I think this is just laziness, and appalling to disciplined computer science. But it has occurred to me that maybe considering the complexity and performance of algorithms is going the way of assembly loop unrolling, and other optimization techniques that are now considered unnecessary. What do you think? Are we at the point now where deciding between an O(n^n) and O(n!) complexity algorithm is irrelevant? What about O(n) vs O(n*n)? What do you consider "premature optimization"? What practical rules do you use to consciously or unconsciously avoid it? This is a bit vague, but I'm curious to hear other peoples' opinions on the topic.

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• How to Elegantly convert switch+enum with polymorphism

  - by Kyle

  I'm trying to replace simple enums with type classes.. that is, one class derived from a base for each type. So for example instead of: enum E_BASE { EB_ALPHA, EB_BRAVO }; E_BASE message = someMessage(); switch (message) { case EB_ALPHA: applyAlpha(); case EB_BRAVO: applyBravo(); } I want to do this: Base* message = someMessage(); message->apply(this); // use polymorphism to determine what function to call. I have seen many ways to do this which all seem less elegant even then the basic switch statement. Using dyanimc_pointer_cast, inheriting from a messageHandler class that needs to be updated every time a new message is added, using a container of function pointers, all seem to defeat the purpose of making code easier to maintain by replacing switches with polymorphism. This is as close as I can get: (I use templates to avoid inheriting from an all-knowing handler interface) class Base { public: template<typename T> virtual void apply(T* sandbox) = 0; }; class Alpha : public Base { public: template<typename T> virtual void apply(T* sandbox) { sandbox->applyAlpha(); } }; class Bravo : public Base { public: template<typename T> virtual void apply(T* sandbox) { sandbox->applyBravo(); } }; class Sandbox { public: void run() { Base* alpha = new Alpha; Base* bravo = new Bravo; alpha->apply(this); bravo->apply(this); delete alpha; delete bravo; } void applyAlpha() { // cout << "Applying alpha\n"; } void applyBravo() { // cout << "Applying bravo\n"; } }; Obviously, this doesn't compile but I'm hoping it gets my problem accross.

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• P/Invoke declarations should not be safe-critical

  - by Bobrovsky

  My code imports following native methods: DeleteObject, GetFontData and SelectObject from gdi32.dll GetDC and ReleaseDC from user32.dll I want to run the code in full trust and medium trust environments (I am fine with exceptions being thrown when these imported methods are indirectly used in medium trust environments). When I run Code Analysis on the code I get warnings like: CA5122 P/Invoke declarations should not be safe-critical. P/Invoke method 'GdiFont.DeleteObject(IntPtr)' is marked safe-critical. Since P/Invokes may only be called by critical code, this declaration should either be marked as security critical, or have its annotation removed entirely to avoid being misleading. Could someone explain me (in layman terms) what does this warning really mean? I tried putting these imports in static SafeNativeMethods class as internal static methods but this doesn't make the warnings go away. I didn't try to put them in NativeMethods because after reading this article I am unsure that it's the right way to go because I don't want my code to be completely unusable in medium trust environments (I think this will be the consequence of moving imports to NativeMethods). Honestly, I am pretty much confused about the real meaning of the warning and consequences of different options to suppressing it. Could someone shed some light on all this? EDIT: My code target .NET 2.0 framework. Assembly is marked with [assembly: AllowPartiallyTrustedCallers] Methods are declared like this: [DllImport("gdi32")] internal static extern int DeleteObject(HANDLE hObject);

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