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  • Can a class Extend or Override himself?

    - by EBAGHAKI
    Suppose we have a class. We create an object from the class and when we do the class Extends himself base on the object initialization value.. For example: $objectType1 = new Types(1); $objectType1->Activate(); // It calls an activation function for type 1 $objectType2 = new Types(2); $objectType2->Activate(); // It calls an activation function for type 2 I don't want to use the standard procedure of class extending: class type1 extends types{}

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  • What is the merit of the "function" type (not "pointer to function")

    - by anatolyg
    Reading the C++ Standard, i see that there are "function" types and "pointer to function" types: typedef int func(int); // function typedef int (*pfunc)(int); // pointer to function typedef func* pfunc; // same as above I have never seen the function types used outside of examples (or maybe i didn't recognize their usage?). Some examples: func increase, decrease; // declares two functions int increase(int), decrease(int); // same as above int increase(int x) {return x + 1;} // cannot use the typedef when defining functions int decrease(int x) {return x - 1;} // cannot use the typedef when defining functions struct mystruct { func add, subtract, multiply; // declares three member functions int member; }; int mystruct::add(int x) {return x + member;} // cannot use the typedef int mystruct::subtract(int x) {return x - member;} int main() { func k; // the syntax is correct but the variable k is useless! mystruct myobject; myobject.member = 4; cout << increase(5) << ' ' << decrease(5) << '\n'; // outputs 6 and 4 cout << myobject.add(5) << ' ' << myobject.subtract(5) << '\n'; // 9 and 1 } Seeing that the function types support syntax that doesn't appear in C (declaring member functions), i guess they are not just a part of C baggage that C++ has to support for backward compatibility. So is there any use for function types, other than demonstrating some funky syntax?

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  • why when I delete a parent on a one to many relationship on grails the beforeInsert event is called

    - by nico
    hello, I have a one to many relationship and when I try to delete a parent that haves more than one child the berforeInsert event gets called on the frst child. I have some code in this event that I mean to call before inserting a child, not when i'm deleting the parent! any ideas on what might be wrong? the entities: class MenuItem { static constraints = { name(blank:false,maxSize:200) category() subCategory(nullable:true, validator:{ val, obj -> if(val == null){ return true }else{ return obj.category.subCategories.contains(val)? true : ['invalid.category.no.subcategory'] } }) price(nullable:true) servedAtSantaMonica() servedAtWestHollywood() highLight() servedAllDay() dateCreated(display:false) lastUpdated(display:false) } static mapping = { extras lazy:false } static belongsTo = [category:MenuCategory,subCategory:MenuSubCategory] static hasMany = [extras:MenuItemExtra] static searchable = { extras component: true } String name BigDecimal price Boolean highLight = false Boolean servedAtSantaMonica = false Boolean servedAtWestHollywood = false Boolean servedAllDay = false Date dateCreated Date lastUpdated int displayPosition void moveUpDisplayPos(){ def oldDisplayPos = MenuItem.get(id).displayPosition if(oldDisplayPos == 0){ return }else{ def previousItem = MenuItem.findByCategoryAndDisplayPosition(category,oldDisplayPos - 1) previousItem.displayPosition += 1 this.displayPosition = oldDisplayPos - 1 this.save(flush:true) previousItem.save(flush:true) } } void moveDownDisplayPos(){ def oldDisplayPos = MenuItem.get(id).displayPosition if(oldDisplayPos == MenuItem.countByCategory(category) - 1){ return }else{ def nextItem = MenuItem.findByCategoryAndDisplayPosition(category,oldDisplayPos + 1) nextItem.displayPosition -= 1 this.displayPosition = oldDisplayPos + 1 this.save(flush:true) nextItem.save(flush:true) } } String toString(){ name } def beforeInsert = { displayPosition = MenuItem.countByCategory(category) } def afterDelete = { def otherItems = MenuItem.findAllByCategoryAndDisplayPositionGreaterThan(category,displayPosition) otherItems.each{ it.displayPosition -= 1 it.save() } } } class MenuItemExtra { static constraints = { extraOption(blank:false, maxSize:200) extraOptionPrice(nullable:true) } static searchable = true static belongsTo = [menuItem:MenuItem] BigDecimal extraOptionPrice String extraOption int displayPosition void moveUpDisplayPos(){ def oldDisplayPos = MenuItemExtra.get(id).displayPosition if(oldDisplayPos == 0){ return }else{ def previousExtra = MenuItemExtra.findByMenuItemAndDisplayPosition(menuItem,oldDisplayPos - 1) previousExtra.displayPosition += 1 this.displayPosition = oldDisplayPos - 1 this.save(flush:true) previousExtra.save(flush:true) } } void moveDownDisplayPos(){ def oldDisplayPos = MenuItemExtra.get(id).displayPosition if(oldDisplayPos == MenuItemExtra.countByMenuItem(menuItem) - 1){ return }else{ def nextExtra = MenuItemExtra.findByMenuItemAndDisplayPosition(menuItem,oldDisplayPos + 1) nextExtra.displayPosition -= 1 this.displayPosition = oldDisplayPos + 1 this.save(flush:true) nextExtra.save(flush:true) } } String toString(){ extraOption } def beforeInsert = { if(menuItem){ displayPosition = MenuItemExtra.countByMenuItem(menuItem) } } def afterDelete = { def otherExtras = MenuItemExtra.findAllByMenuItemAndDisplayPositionGreaterThan(menuItem,displayPosition) otherExtras.each{ it.displayPosition -= 1 it.save() } } }

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  • How to store MySQL query results in another Table?

    - by Taz
    How to store results from following query into another table. Considering there is an appropriate table already created. SELECT labels.label,shortabstracts.ShortAbstract,images.LinkToImage,types.Type FROM ner.images,ner.labels,ner.shortabstracts,ner.types WHERE labels.Resource=images.Resource AND labels.Resource=shortabstracts.Resource AND labels.Resource=types.Resource;

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  • In Emacs, how can I use imenu more sensibly with C#?

    - by Cheeso
    I've used emacs for a long time, but I haven't been keeping up with a bunch of features. One of these is speedbar, which I just briefly investigated now. Another is imenu. Both of these were mentioned in in-emacs-how-can-i-jump-between-functions-in-the-current-file? Using imenu, I can jump to particular methods in the module I'm working in. But there is a parse hierarchy that I have to negotiate before I get the option to choose (with autocomplete) the method name. It goes like this. I type M-x imenu and then I get to choose Using or Types. The Using choice allows me to jump to any of the using statements at the top level of the C# file (something like imports statements in a Java module, for those of you who don't know C#). Not super helpful. I choose Types. Then I have to choose a namespace and a class, even though there is just one of each in the source module. At that point I can choose between variables, types, and methods. If I choose methods I finally get the list of methods to choose from. The hierarchy I traverse looks like this; Using Types Namespace Class Types Variables Methods method names Only after I get to the 5th level do I get to select the thing I really want to jump to: a particular method. Imenu seems intelligent about the source module, but kind of hard to use. Am I doing it wrong?

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  • Managing mandatory fields with triggers

    - by okkesemin
    I would like to set mandatory field backgrounds are red and others are green. So I try to implement below. But I could not set ValueConstraint Nullable property with trigger. Could you help please ? <Window x:Class="TriggerGirilmesigerekenalanlar.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:y="http://infragistics.com/Editors" Title="Window1" Height="300" Width="300"> <Window.Resources> <Style TargetType="{x:Type y:XamTextEditor}"> <Style.Triggers> <Trigger Property="ValueConstraint" Value="{x:Null}"> <Trigger.Setters> <Setter Property="Background" Value="green"></Setter> </Trigger.Setters> </Trigger> <Trigger Property="y:ValueConstraint.Nullable" Value="false"> <Trigger.Setters> <Setter Property="Background" Value="red"></Setter> </Trigger.Setters> </Trigger> </Style.Triggers> </Style> </Window.Resources> <StackPanel> <y:XamTextEditor> <y:XamTextEditor.ValueConstraint> <y:ValueConstraint Nullable="False" ></y:ValueConstraint> </y:XamTextEditor.ValueConstraint> </y:XamTextEditor> <y:XamTextEditor></y:XamTextEditor> </StackPanel> </Window>

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  • Merging .NET assemblies on Windows Store / Phone 8 / Portable Class Library

    - by Gabriel S.
    Is there a way to embed multiple dependent assemblies into a single one for projects written on the following platform types: Windows Store Apps, Windows Phone 8, Portable Class Library? I know that for regular .Net projects there is ILMerge, but on the aforementioned project types it doesn't work. Embedding assemblies as resources and then manually resolving the references using AppDomain.CurrentDomain.AssemblyResolve is not possible either, since AppDomain is not available in these types of project.

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  • Is this a good way to identify the type of a javascript object?

    - by FK82
    Apparently neither instanceof nor typeof deliver in terms of correctly identifying the type of every javascript object. I have come up with this function and I'm looking for some feedback: function getType() { var input = arguments[0] ; var types = ["String","Array","Object","Function","HTML"] ; //!! of the top of my head for(var n=0; n < types.length; n++) { if( input.constructor.toString().indexOf( types[n] ) != -1) { document.write( types[n] ) ; } } } Thanks for reading!

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  • C# - Ensuring an assembly is called via a specified assembly

    - by Adam Driscoll
    Is there any built in functionality to determine if an assembly is being called from a particular assembly? I have assembly A which references assembly B. Assembly A exposes PowerShell cmdlets and outputs types that are found within B. Certain methods and properties with in types of exposed by B are of interest to types in assembly A but not of interest to consumers of PowerShell or anyone attempting to load types in B directly and call methods within it. I have looked into InternalsVisibleToAttribute but it would require extensive rework because of the use of interfaces. I was devising a shared key system that would later be obfuscated but that seemed clunky. Is there any way to ensure B is called only by A?

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  • Money vs. Decimal vs. Float Performance issues (SQL data types for Currency value)?

    - by urz shah
    What data type should be selected in case of Currency value column in SQL server. I have read some where on web Working on customer implementations, we found some interesting performance numbers concerning the money data type. For example, when Analysis Services was set to the currency data type (from double) to match the SQL Server money data type, there was a 13% improvement in processing speed (rows/sec). Is it true??

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  • Foreign keys and NULL in mySQL

    - by Industrial
    Hi everyone, Can I have a column in my values table (value) referenced as a foreign key to knownValues table, and let it be NULL whenever needed, like in the example: Table: values product type value freevalue 0 1 NULL 100 1 2 NULL 25 3 3 1 NULL Table: types id name prefix 0 length cm 1 weight kg 2 fruit NULL Table: knownValues id Type name 0 2 banana Note: The types in the table values & knownValues are of course referenced into the types table. Thanks!

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  • Cast problem with LINQ

    - by yigit
    I'm tring to get my product's types to a list with Linq. var types = (from t in NHibernateSession.Linq<Product>() select t.Type).Distinct().ToList<Type>(); return types; But its giving an Unable to cast object of type error '...Domain.Product' to type '...Domain.Type'. Please tell where am I going wrong.

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  • Why do we need Web-Api? [closed]

    - by user437973
    I was just wondering what the deal is with Asp.net Web-Api. Why did we need a separate type of controller in order to facilitate varying content types for action results? Why wasn't this capability just baked into the ASP.Net MVC base controller? Anyway, I was just wondering if there was a compelling reason to use both types of controllers within the same project, assuming that the project was being freshly created, or if this project structure was due to an inherent technical limitation. Would it be possible to have ApiControllers fulfill the purpose of an MVC Controller in all cases by just serving HTML when that is the specified accept type? It just seems to me like a lot of unnecessary repetition to have to re-implement the same types of actions using both types of controllers if you want those actions to be available to your web application through the API and through the web interface.

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  • Why can't your switch statement data type be long Java?

    - by Fostah
    Here's an excerpt from Sun's Java tutorials: A switch works with the byte, short, char, and int primitive data types. It also works with enumerated types (discussed in Classes and Inheritance) and a few special classes that "wrap" certain primitive types: Character, Byte, Short, and Integer (discussed in Simple Data Objects ). There must be a good reason why the long primitive data type is not allowed. Anyone know what it is?

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  • Not All “Viruses” Are Viruses: 10 Malware Terms Explained

    - by Chris Hoffman
    Most people seem to call every type of malware a “virus”, but that isn’t technically accurate. You’ve probably heard of many more terms beyond virus: malware, worm, Trojan, rootkit, keylogger, spyware, and more. But what do all these terms mean? These terms aren’t just used by geeks. They make their way into even mainstream news stories about the latest web security problems and tech scares. Understanding them will help you understand the dangers your\ hear about. Malware The word “malware” is short for “malicious software.” Many people use the word “virus” to indicate any type of harmful software, but a virus is actually just a specific type of malware. The word “malware” encompasses all harmful software, including all the ones listed below. Virus Let’s start with viruses. A virus is a type of malware that copies itself by infecting other files,  just as viruses in the real world infect biological cells and use those biological cells to reproduce copies of themselves. A virus can do many different things — watch in the background and steal your passwords, display advertisements, or just crash your computer — but the key thing that makes it a virus is how it spreads. When you run a virus, it will infect programs on your computer. When you run the program on another computer, the virus will infect programs on that computer, and so on. For example, a virus might infect program files on a USB stick. When the programs on that USB stick are run on another computer, the virus runs on the other computer and infects more program files. The virus will continue to spread in this way. Worm A worm is similar to a virus, but it spreads a different way. Rather than infecting files and relying on human activity to move those files around and run them on different systems, a worm spreads over computer networks on its own accord. For example, the Blaster and Sasser worms spread very quickly in the days of Windows XP because Windows XP did not come properly secured and exposed system services to the Internet. The worm accessed these system services over the Internet, exploited a vulnerability, and infected the computer. The worm then used the new infected computer to continue replicating itself. Such worms are less common now that Windows is properly firewalled by default, but worms can also spread in other ways — for example, by mass-emailing themselves to every email address in an effected user’s address book. Like a virus, a worm can do any number of other harmful things once it infects a computer. The key thing that makes it a worm is simply how it spreads copies of itself. Trojan (or Trojan Horse) A Trojan horse, or Trojan, is a type of malware that disguises itself as a legitimate file. When you download and run the program, the Trojan horse will run in the background, allowing third-parties to access your computer. Trojans can do this for any number of reasons — to monitor activity on your computer, to join your computer to a botnet. Trojans may also be used to open the floodgates and download many other types of malware onto your computer. The key thing that makes this type of malware a Trojan is how it arrives. It pretends to be a useful program and, when run, it hides in the background and gives malicious people access to your computer. It isn’t obsessed with copying itself into other files or spreading over the network, as viruses and worms are. For example, a piece of pirated software on an unscrupulous website may actually contain a Trojan. Spyware Spyware is a type of malicious software that spies on you without your knowledge. It collects a variety of different types of data, depending on the piece of spyware. Different types of malware can function as spyware — there may be malicious spyware included in Trojans that spies on your keystrokes to steal financial data, for example. More “legitimate” spyware may be bundled along with free software and simply monitor your web browsing habits, uploading this data to advertising servers so the software’s creator can make money from selling their knowledge of your activities. Adware Adware often comes along with spyware. It’s any type of software that displays advertising on your computer. Programs that display advertisements inside the program itself aren’t generally classified as malware. The kind of “adware” that’s particularly malicious is the kind that abuses its access to your system to display ads when it shouldn’t. For example, a piece of harmful adware may cause pop-up advertisements to appear on your computer when you’re not doing anything else. Or, adware may inject additional advertising into other web pages as you browse the web. Adware is often combined with spyware — a piece of malware may monitor your browsing habits and use them to serve you more targeted ads. Adware is more “socially acceptable” than other types of malware on Windows and you may see adware bundled with legitimate programs. For example, some people consider the Ask Toolbar included with Oracle’s Java software adware. Keylogger A keylogger is a type of malware that runs in the background, recording every key stroke you make. These keystrokes can include usernames, passwords, credit card numbers, and other sensitive data. The keylogger then, most likely, uploads these keystrokes to a malicious server, where it can be analyzed and people can pick out the useful passwords and credit card numbers. Other types of malware can act as keyloggers. A virus, worm, or Trojan may function as a keylogger, for example. Keyloggers may also be installed for monitoring purposes by businesses or even jealous spouses. Botnet, Bot A botnet is a large network of computers that are under the botnet creator’s control. Each computer functions as a “bot” because it’s infected with a specific piece of malware. Once the bot software infects the computer, ir will connect to some sort of control server and wait for instructions from the botnet’s creator. For example, a botnet may be used to initiate a DDoS (distributed denial of service) attack. Every computer in the botnet will be told to bombard a specific website or server with requests at once, and such millions or requests can cause a server to become unresponsive or crash. Botnet creators may sell access to their botnets, allowing other malicious individuals to use large botnets to do their dirty work. Rootkit A rootkit is a type of malware designed to burrow deep into your computer, avoiding detection by security programs and users. For example, a rootkit might load before most of Windows, burying itself deep into the system and modifying system functions so that security programs can’t detect it. A rootkit might hide itself completely, preventing itself from showing up in the Windows task manager. The key thing that makes a type of malware a rootkit is that it’s stealthy and focused on hiding itself once it arrives. Ransomware Ransomware is a fairly new type of malware. It holds your computer or files hostage and demands a ransom payment. Some ransomware may simply pop up a box asking for money before you can continue using your computer. Such prompts are easily defeated with antivirus software. More harmful malware like CryptoLocker literally encrypts your files and demands a payment before you can access them. Such types of malware are dangerous, especially if you don’t have backups. Most malware these days is produced for profit, and ransomware is a good example of that. Ransomware doesn’t want to crash your computer and delete your files just to cause you trouble. It wants to take something hostage and get a quick payment from you. So why is it called “antivirus software,” anyway? Well, most people continue to consider the word “virus” synonymous with malware as a whole. Antivirus software doesn’t just protect against viruses, but against all types of malware. It may be more accurately referred to as “antimalware” or “security” software. Image Credit: Marcelo Alves on Flickr, Tama Leaver on Flickr, Szilard Mihaly on Flickr     

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  • Unable to cast transparent proxy to type &lt;type&gt;

    - by Rick Strahl
    This is not the first time I've run into this wonderful error while creating new AppDomains in .NET and then trying to load types and access them across App Domains. In almost all cases the problem I've run into with this error the problem comes from the two AppDomains involved loading different copies of the same type. Unless the types match exactly and come exactly from the same assembly the typecast will fail. The most common scenario is that the types are loaded from different assemblies - as unlikely as that sounds. An Example of Failure To give some context, I'm working on some old code in Html Help Builder that creates a new AppDomain in order to parse assembly information for documentation purposes. I create a new AppDomain in order to load up an assembly process it and then immediately unload it along with the AppDomain. The AppDomain allows for unloading that otherwise wouldn't be possible as well as isolating my code from the assembly that's being loaded. The process to accomplish this is fairly established and I use it for lots of applications that use add-in like functionality - basically anywhere where code needs to be isolated and have the ability to be unloaded. My pattern for this is: Create a new AppDomain Load a Factory Class into the AppDomain Use the Factory Class to load additional types from the remote domain Here's the relevant code from my TypeParserFactory that creates a domain and then loads a specific type - TypeParser - that is accessed cross-AppDomain in the parent domain:public class TypeParserFactory : System.MarshalByRefObject,IDisposable { …/// <summary> /// TypeParser Factory method that loads the TypeParser /// object into a new AppDomain so it can be unloaded. /// Creates AppDomain and creates type. /// </summary> /// <returns></returns> public TypeParser CreateTypeParser() { if (!CreateAppDomain(null)) return null; /// Create the instance inside of the new AppDomain /// Note: remote domain uses local EXE's AppBasePath!!! TypeParser parser = null; try { Assembly assembly = Assembly.GetExecutingAssembly(); string assemblyPath = Assembly.GetExecutingAssembly().Location; parser = (TypeParser) this.LocalAppDomain.CreateInstanceFrom(assemblyPath, typeof(TypeParser).FullName).Unwrap(); } catch (Exception ex) { this.ErrorMessage = ex.GetBaseException().Message; return null; } return parser; } private bool CreateAppDomain(string lcAppDomain) { if (lcAppDomain == null) lcAppDomain = "wwReflection" + Guid.NewGuid().ToString().GetHashCode().ToString("x"); AppDomainSetup setup = new AppDomainSetup(); // *** Point at current directory setup.ApplicationBase = AppDomain.CurrentDomain.BaseDirectory; //setup.PrivateBinPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "bin"); this.LocalAppDomain = AppDomain.CreateDomain(lcAppDomain,null,setup); // Need a custom resolver so we can load assembly from non current path AppDomain.CurrentDomain.AssemblyResolve += new ResolveEventHandler(CurrentDomain_AssemblyResolve); return true; } …} Note that the classes must be either [Serializable] (by value) or inherit from MarshalByRefObject in order to be accessible remotely. Here I need to call methods on the remote object so all classes are MarshalByRefObject. The specific problem code is the loading up a new type which points at an assembly that visible both in the current domain and the remote domain and then instantiates a type from it. This is the code in question:Assembly assembly = Assembly.GetExecutingAssembly(); string assemblyPath = Assembly.GetExecutingAssembly().Location; parser = (TypeParser) this.LocalAppDomain.CreateInstanceFrom(assemblyPath, typeof(TypeParser).FullName).Unwrap(); The last line of code is what blows up with the Unable to cast transparent proxy to type <type> error. Without the cast the code actually returns a TransparentProxy instance, but the cast is what blows up. In other words I AM in fact getting a TypeParser instance back but it can't be cast to the TypeParser type that is loaded in the current AppDomain. Finding the Problem To see what's going on I tried using the .NET 4.0 dynamic type on the result and lo and behold it worked with dynamic - the value returned is actually a TypeParser instance: Assembly assembly = Assembly.GetExecutingAssembly(); string assemblyPath = Assembly.GetExecutingAssembly().Location; object objparser = this.LocalAppDomain.CreateInstanceFrom(assemblyPath, typeof(TypeParser).FullName).Unwrap(); // dynamic works dynamic dynParser = objparser; string info = dynParser.GetVersionInfo(); // method call works // casting fails parser = (TypeParser)objparser; So clearly a TypeParser type is coming back, but nevertheless it's not the right one. Hmmm… mysterious.Another couple of tries reveal the problem however:// works dynamic dynParser = objparser; string info = dynParser.GetVersionInfo(); // method call works // c:\wwapps\wwhelp\wwReflection20.dll (Current Execution Folder) string info3 = typeof(TypeParser).Assembly.CodeBase; // c:\program files\vfp9\wwReflection20.dll (my COM client EXE's folder) string info4 = dynParser.GetType().Assembly.CodeBase; // fails parser = (TypeParser)objparser; As you can see the second value is coming from a totally different assembly. Note that this is even though I EXPLICITLY SPECIFIED an assembly path to load the assembly from! Instead .NET decided to load the assembly from the original ApplicationBase folder. Ouch! How I actually tracked this down was a little more tedious: I added a method like this to both the factory and the instance types and then compared notes:public string GetVersionInfo() { return ".NET Version: " + Environment.Version.ToString() + "\r\n" + "wwReflection Assembly: " + typeof(TypeParserFactory).Assembly.CodeBase.Replace("file:///", "").Replace("/", "\\") + "\r\n" + "Assembly Cur Dir: " + Directory.GetCurrentDirectory() + "\r\n" + "ApplicationBase: " + AppDomain.CurrentDomain.SetupInformation.ApplicationBase + "\r\n" + "App Domain: " + AppDomain.CurrentDomain.FriendlyName + "\r\n"; } For the factory I got: .NET Version: 4.0.30319.239wwReflection Assembly: c:\wwapps\wwhelp\bin\wwreflection20.dllAssembly Cur Dir: c:\wwapps\wwhelpApplicationBase: C:\Programs\vfp9\App Domain: wwReflection534cfa1f For the instance type I got: .NET Version: 4.0.30319.239wwReflection Assembly: C:\\Programs\\vfp9\wwreflection20.dllAssembly Cur Dir: c:\\wwapps\\wwhelpApplicationBase: C:\\Programs\\vfp9\App Domain: wwDotNetBridge_56006605 which clearly shows the problem. You can see that both are loading from different appDomains but the each is loading the assembly from a different location. Probably a better solution yet (for ANY kind of assembly loading problem) is to use the .NET Fusion Log Viewer to trace assembly loads.The Fusion viewer will show a load trace for each assembly loaded and where it's looking to find it. Here's what the viewer looks like: The last trace above that I found for the second wwReflection20 load (the one that is wonky) looks like this:*** Assembly Binder Log Entry (1/13/2012 @ 3:06:49 AM) *** The operation was successful. Bind result: hr = 0x0. The operation completed successfully. Assembly manager loaded from: C:\Windows\Microsoft.NET\Framework\V4.0.30319\clr.dll Running under executable c:\programs\vfp9\vfp9.exe --- A detailed error log follows. === Pre-bind state information === LOG: User = Ras\ricks LOG: DisplayName = wwReflection20, Version=4.61.0.0, Culture=neutral, PublicKeyToken=null (Fully-specified) LOG: Appbase = file:///C:/Programs/vfp9/ LOG: Initial PrivatePath = NULL LOG: Dynamic Base = NULL LOG: Cache Base = NULL LOG: AppName = vfp9.exe Calling assembly : (Unknown). === LOG: This bind starts in default load context. LOG: Using application configuration file: C:\Programs\vfp9\vfp9.exe.Config LOG: Using host configuration file: LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\V4.0.30319\config\machine.config. LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind). LOG: Attempting download of new URL file:///C:/Programs/vfp9/wwReflection20.DLL. LOG: Assembly download was successful. Attempting setup of file: C:\Programs\vfp9\wwReflection20.dll LOG: Entering run-from-source setup phase. LOG: Assembly Name is: wwReflection20, Version=4.61.0.0, Culture=neutral, PublicKeyToken=null LOG: Binding succeeds. Returns assembly from C:\Programs\vfp9\wwReflection20.dll. LOG: Assembly is loaded in default load context. WRN: The same assembly was loaded into multiple contexts of an application domain: WRN: Context: Default | Domain ID: 2 | Assembly Name: wwReflection20, Version=4.61.0.0, Culture=neutral, PublicKeyToken=null WRN: Context: LoadFrom | Domain ID: 2 | Assembly Name: wwReflection20, Version=4.61.0.0, Culture=neutral, PublicKeyToken=null WRN: This might lead to runtime failures. WRN: It is recommended to inspect your application on whether this is intentional or not. WRN: See whitepaper http://go.microsoft.com/fwlink/?LinkId=109270 for more information and common solutions to this issue. Notice that the fusion log clearly shows that the .NET loader makes no attempt to even load the assembly from the path I explicitly specified. Remember your Assembly Locations As mentioned earlier all failures I've seen like this ultimately resulted from different versions of the same type being available in the two AppDomains. At first sight that seems ridiculous - how could the types be different and why would you have multiple assemblies - but there are actually a number of scenarios where it's quite possible to have multiple copies of the same assembly floating around in multiple places. If you're hosting different environments (like hosting the Razor Engine, or ASP.NET Runtime for example) it's common to create a private BIN folder and it's important to make sure that there's no overlap of assemblies. In my case of Html Help Builder the problem started because I'm using COM interop to access the .NET assembly and the above code. COM Interop has very specific requirements on where assemblies can be found and because I was mucking around with the loader code today, I ended up moving assemblies around to a new location for explicit loading. The explicit load works in the main AppDomain, but failed in the remote domain as I showed. The solution here was simple enough: Delete the extraneous assembly which was left around by accident. Not a common problem, but one that when it bites is pretty nasty to figure out because it seems so unlikely that types wouldn't match. I know I've run into this a few times and writing this down hopefully will make me remember in the future rather than poking around again for an hour trying to debug the issue as I did today. Hopefully it'll save some of you some time as well in the future.© Rick Strahl, West Wind Technologies, 2005-2012Posted in .NET  COM   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • How to troubleshoot a PHP script that causes a Segmenation Fault?

    - by johnlai2004
    I posted this on stackoverflow.com as well because I'm not sure if this is a programming problem or a server problem. I'm using ubuntu 9.10, apache2, mysql5 and php5. I've noticed an unusual problem with some of my php programs. Sometimes when visiting a page like profile.edit.php, the browser throws a dialogue box asking to download profile.edit.php page. When I download it, there's nothing in the file. profile.edit.php is supposed to be a web form that edits user information. I've noticed this on some of my other php pages as well. I look in my apache error logs, and I see a segmentation fault message: [Mon Mar 08 15:40:10 2010] [notice] child pid 480 exit signal Segmentation fault (11) And also, the issue may or may not appear depending on which server I deploy my application too. Additonal Details This doesn't happen all the time though. It only happens sometimes. For example, profile.edit.php will load properly. But as soon as I hit the save button (form action="profile.edit.php?save=true"), then the page asks me to download profile.edit.php. Could it be that sometimes my php scripts consume too much resources? Sample code Upon save action, my profile.edit.php includes a data_access_object.php file. I traced the code in data_access_object.php to this line here if($params[$this->primaryKey]) { $q = "UPDATE $this->tableName SET ".implode(', ', $fields)." WHERE ".$this->primaryKey." = ?$this->primaryKey"; $this->bind($this->primaryKey, $params[$this->primaryKey], $this->tblFields[$this->primaryKey]['mysqlitype']); } else { $q = "INSERT $this->tableName SET ".implode(', ', $fields); } // Code executes perfectly up to this point // echo 'print this'; exit; // if i uncomment this line, profile.edit.php will actually show 'print this'. If I leave it commented, the browser will ask me to download profile.edit.php if(!$this->execute($q)){ $this->errorSave = -3; return false;} // When I jumped into the function execute(), every line executed as expected, right up to the return statement. And if it helps, here's the function execute($sql) in data_access_object.php function execute($sql) { // find all list types and explode them // eg. turn ?listId into ?listId0,?listId1,?listId2 $arrListParam = array_bubble_up('arrayName', $this->arrBind); foreach($arrListParam as $listName) if($listName) { $explodeParam = array(); $arrList = $this->arrBind[$listName]['value']; foreach($arrList as $key=>$val) { $newParamName = $listName.$key; $this->bind($newParamName,$val,$this->arrBind[$listName]['type']); $explodeParam[] = '?'.$newParamName; } $sql = str_replace("?$listName", implode(',',$explodeParam), $sql); } // replace all ?varName with ? for syntax compliance $sqlParsed = preg_replace('/\?[\w\d_\.]+/', '?', $sql); $this->stmt->prepare($sqlParsed); // grab all the parameters from the sql to create bind conditions preg_match_all('/\?[\w\d_\.]+/', $sql, $matches); $matches = $matches[0]; // store bind conditions $types = ''; $params = array(); foreach($matches as $paramName) { $types .= $this->arrBind[str_replace('?', '', $paramName)]['type']; $params[] = $this->arrBind[str_replace('?', '', $paramName)]['value']; } $input = array('types'=>$types) + $params; // bind it if(!empty($types)) call_user_func_array(array($this->stmt, 'bind_param'), $input); $stat = $this->stmt->execute(); if($GLOBALS['DEBUG_SQL']) echo '<p style="font-weight:bold;">SQL error after execution:</p> ' . $this->stmt->error.'<p>&nbsp;</p>'; $this->arrBind = array(); return $stat; }

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  • code metrics for .net code

    - by user20358
    While the code metrics tool gives a pretty good analysis of the code being analyzed, I was wondering if there was any such benchmark on acceptable standards for the following as well: Maximum number of types per assembly Maximum number of such types that can be accessible Maximum number of parameters per method Acceptable RFC count Acceptable Afferent coupling count Acceptable Efferent coupling count Any other metrics to judge the quality of .Net code by? Thanks for your time.

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  • Is it possible to predict future using machine learning and/or AI?

    - by Shekhar
    Recently I have started reading about machine learning. From 3000 feet view, machine learning seems really great thing but as if now I have found that machine learning is limited to only 3 types of algorithms namely classification, clustering and recommendations. I would like to know if my assumption about types of machine learning algorithms is correct or not and What is the extreme thing which we can do using machine learning and/or AI? Is it possible to predict future (same way we predict weather) using AI and/or machine learning?

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  • Defining Discovery: Core Concepts

    - by Joe Lamantia
    Discovery tools have had a referencable working definition since at least 2001, when Ben Shneiderman published 'Inventing Discovery Tools: Combining Information Visualization with Data Mining'.  Dr. Shneiderman suggested the combination of the two distinct fields of data mining and information visualization could manifest as new category of tools for discovery, an understanding that remains essentially unaltered over ten years later.  An industry analyst report titled Visual Discovery Tools: Market Segmentation and Product Positioning from March of this year, for example, reads, "Visual discovery tools are designed for visual data exploration, analysis and lightweight data mining." Tools should follow from the activities people undertake (a foundational tenet of activity centered design), however, and Dr. Shneiderman does not in fact describe or define discovery activity or capability. As I read it, discovery is assumed to be the implied sum of the separate fields of visualization and data mining as they were then understood.  As a working definition that catalyzes a field of product prototyping, it's adequate in the short term.  In the long term, it makes the boundaries of discovery both derived and temporary, and leaves a substantial gap in the landscape of core concepts around discovery, making consensus on the nature of most aspects of discovery difficult or impossible to reach.  I think this definitional gap is a major reason that discovery is still an ambiguous product landscape. To help close that gap, I'm suggesting a few definitions of four core aspects of discovery.  These come out of our sustained research into discovery needs and practices, and have the goal of clarifying the relationship between discvoery and other analytical categories.  They are suggested, but should be internally coherent and consistent.   Discovery activity is: "Purposeful sense making activity that intends to arrive at new insights and understanding through exploration and analysis (and for these we have specific defintions as well) of all types and sources of data." Discovery capability is: "The ability of people and organizations to purposefully realize valuable insights that address the full spectrum of business questions and problems by engaging effectively with all types and sources of data." Discovery tools: "Enhance individual and organizational ability to realize novel insights by augmenting and accelerating human sense making to allow engagement with all types of data at all useful scales." Discovery environments: "Enable organizations to undertake effective discovery efforts for all business purposes and perspectives, in an empirical and cooperative fashion." Note: applicability to a world of Big data is assumed - thus the refs to all scales / types / sources - rather than stated explicitly.  I like that Big Data doesn't have to be written into this core set of definitions, b/c I think it's a transitional label - the new version of Web 2.0 - and goes away over time. References and Resources: Inventing Discovery Tools Visual Discovery Tools: Market Segmentation and Product Positioning Logic versus usage: the case for activity-centered design A Taxonomy of Enterprise Search and Discovery

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  • Architecture strategies for a complex competition scoring system

    - by mikewassmer
    Competition description: There are about 10 teams competing against each other over a 6-week period. Each team's total score (out of a 1000 total available points) is based on the total of its scores in about 25,000 different scoring elements. Most scoring elements are worth a small fraction of a point and there will about 10 X 25,000 = 250,000 total raw input data points. The points for some scoring elements are awarded at frequent regular time intervals during the competition. The points for other scoring elements are awarded at either irregular time intervals or at just one moment in time. There are about 20 different types of scoring elements. Each of the 20 types of scoring elements has a different set of inputs, a different algorithm for calculating the earned score from the raw inputs, and a different number of total available points. The simplest algorithms require one input and one simple calculation. The most complex algorithms consist of hundreds or thousands of raw inputs and a more complicated calculation. Some types of raw inputs are automatically generated. Other types of raw inputs are manually entered. All raw inputs are subject to possible manual retroactive adjustments by competition officials. Primary requirements: The scoring system UI for competitors and other competition followers will show current and historical total team scores, team standings, team scores by scoring element, raw input data (at several levels of aggregation, e.g. daily, weekly, etc.), and other metrics. There will be charts, tables, and other widgets for displaying historical raw data inputs and scores. There will be a quasi-real-time dashboard that will show current scores and raw data inputs. Aggregate scores should be updated/refreshed whenever new raw data inputs arrive or existing raw data inputs are adjusted. There will be a "scorekeeper UI" for manually entering new inputs, manually adjusting existing inputs, and manually adjusting calculated scores. Decisions: Should the scoring calculations be performed on the database layer (T-SQL/SQL Server, in my case) or on the application layer (C#/ASP.NET MVC, in my case)? What are some recommended approaches for calculating updated total team scores whenever new raw inputs arrives? Calculating each of the teams' total scores from scratch every time a new input arrives will probably slow the system to a crawl. I've considered some kind of "diff" approach, but that approach may pose problems for ad-hoc queries and some aggegates. I'm trying draw some sports analogies, but it's tough because most games consist of no more than 20 or 30 scoring elements per game (I'm thinking of a high-scoring baseball game; football and soccer have fewer scoring events per game). Perhaps a financial balance sheet analogy makes more sense because financial "bottom line" calcs may be calculated from 250,000 or more transactions. Should I be making heavy use of caching for this application? Are there any obvious approaches or similar case studies that I may be overlooking?

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  • Smart defaults [SSDT]

    - by jamiet
    I’ve just discovered a new, somewhat hidden, feature in SSDT that I didn’t know about and figured it would be worth highlighting here because I’ll bet not many others know it either; the feature is called Smart Defaults. It gets around the problem of adding a NOT NULLable column to an existing table that has got data in it – previous to SSDT you would need to define a DEFAULT constraint however it does feel rather cumbersome to create an object purely for the purpose of pushing through a deployment – that’s the situation that Smart Defaults is meant to alleviate. The Smart Defaults option exists in the advanced section of a Publish Profile file: The description of the setting is “Automatically provides a default value when updating a table that contains data with a column that does not allow null values”, in other words checking that option will cause SSDT to insert an arbitrary default value into your newly created NON NULLable column. In case you’re wondering how it does it, here’s how: SSDT creates a DEFAULT CONSTRAINT at the same time as the column is created and then immediately removes that constraint: ALTER TABLE [dbo].[T1]    ADD [C1] INT NOT NULL,         CONSTRAINT [SD_T1_1df7a5f76cf44bb593506d05ff9a1e2b] DEFAULT 0 FOR [C1];ALTER TABLE [dbo].[T1] DROP CONSTRAINT [SD_T1_1df7a5f76cf44bb593506d05ff9a1e2b]; You can then update the value as appropriate in a Post-Deployment script. Pretty cool! On the downside, you can only specify this option for the whole project, not for an individual table or even an individual column – I’m not sure that I’d want to turn this on for an entire project as it could hide problems that a failed deployment would highlight, in other words smart defaults could be seen to be “papering over the cracks”. If you think that should be improved go and vote (and leave a comment) at [SSDT] Allow us to specify Smart defaults per table or even per column. @Jamiet

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  • Anatomy of a .NET Assembly - CLR metadata 1

    - by Simon Cooper
    Before we look at the bytes comprising the CLR-specific data inside an assembly, we first need to understand the logical format of the metadata (For this post I only be looking at simple pure-IL assemblies; mixed-mode assemblies & other things complicates things quite a bit). Metadata streams Most of the CLR-specific data inside an assembly is inside one of 5 streams, which are analogous to the sections in a PE file. The name of each section in a PE file starts with a ., and the name of each stream in the CLR metadata starts with a #. All but one of the streams are heaps, which store unstructured binary data. The predefined streams are: #~ Also called the metadata stream, this stream stores all the information on the types, methods, fields, properties and events in the assembly. Unlike the other streams, the metadata stream has predefined contents & structure. #Strings This heap is where all the namespace, type & member names are stored. It is referenced extensively from the #~ stream, as we'll be looking at later. #US Also known as the user string heap, this stream stores all the strings used in code directly. All the strings you embed in your source code end up in here. This stream is only referenced from method bodies. #GUID This heap exclusively stores GUIDs used throughout the assembly. #Blob This heap is for storing pure binary data - method signatures, generic instantiations, that sort of thing. Items inside the heaps (#Strings, #US, #GUID and #Blob) are indexed using a simple binary offset from the start of the heap. At that offset is a coded integer giving the length of that item, then the item's bytes immediately follow. The #GUID stream is slightly different, in that GUIDs are all 16 bytes long, so a length isn't required. Metadata tables The #~ stream contains all the assembly metadata. The metadata is organised into 45 tables, which are binary arrays of predefined structures containing information on various aspects of the metadata. Each entry in a table is called a row, and the rows are simply concatentated together in the file on disk. For example, each row in the TypeRef table contains: A reference to where the type is defined (most of the time, a row in the AssemblyRef table). An offset into the #Strings heap with the name of the type An offset into the #Strings heap with the namespace of the type. in that order. The important tables are (with their table number in hex): 0x2: TypeDef 0x4: FieldDef 0x6: MethodDef 0x14: EventDef 0x17: PropertyDef Contains basic information on all the types, fields, methods, events and properties defined in the assembly. 0x1: TypeRef The details of all the referenced types defined in other assemblies. 0xa: MemberRef The details of all the referenced members of types defined in other assemblies. 0x9: InterfaceImpl Links the types defined in the assembly with the interfaces that type implements. 0xc: CustomAttribute Contains information on all the attributes applied to elements in this assembly, from method parameters to the assembly itself. 0x18: MethodSemantics Links properties and events with the methods that comprise the get/set or add/remove methods of the property or method. 0x1b: TypeSpec 0x2b: MethodSpec These tables provide instantiations of generic types and methods for each usage within the assembly. There are several ways to reference a single row within a table. The simplest is to simply specify the 1-based row index (RID). The indexes are 1-based so a value of 0 can represent 'null'. In this case, which table the row index refers to is inferred from the context. If the table can't be determined from the context, then a particular row is specified using a token. This is a 4-byte value with the most significant byte specifying the table, and the other 3 specifying the 1-based RID within that table. This is generally how a metadata table row is referenced from the instruction stream in method bodies. The third way is to use a coded token, which we will look at in the next post. So, back to the bytes Now we've got a rough idea of how the metadata is logically arranged, we can now look at the bytes comprising the start of the CLR data within an assembly: The first 8 bytes of the .text section are used by the CLR loader stub. After that, the CLR-specific data starts with the CLI header. I've highlighted the important bytes in the diagram. In order, they are: The size of the header. As the header is a fixed size, this is always 0x48. The CLR major version. This is always 2, even for .NET 4 assemblies. The CLR minor version. This is always 5, even for .NET 4 assemblies, and seems to be ignored by the runtime. The RVA and size of the metadata header. In the diagram, the RVA 0x20e4 corresponds to the file offset 0x2e4 Various flags specifying if this assembly is pure-IL, whether it is strong name signed, and whether it should be run as 32-bit (this is how the CLR differentiates between x86 and AnyCPU assemblies). A token pointing to the entrypoint of the assembly. In this case, 06 (the last byte) refers to the MethodDef table, and 01 00 00 refers to to the first row in that table. (after a gap) RVA of the strong name signature hash, which comes straight after the CLI header. The RVA 0x2050 corresponds to file offset 0x250. The rest of the CLI header is mainly used in mixed-mode assemblies, and so is zeroed in this pure-IL assembly. After the CLI header comes the strong name hash, which is a SHA-1 hash of the assembly using the strong name key. After that comes the bodies of all the methods in the assembly concatentated together. Each method body starts off with a header, which I'll be looking at later. As you can see, this is a very small assembly with only 2 methods (an instance constructor and a Main method). After that, near the end of the .text section, comes the metadata, containing a metadata header and the 5 streams discussed above. We'll be looking at this in the next post. Conclusion The CLI header data doesn't have much to it, but we've covered some concepts that will be important in later posts - the logical structure of the CLR metadata and the overall layout of CLR data within the .text section. Next, I'll have a look at the contents of the #~ stream, and how the table data is arranged on disk.

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