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  • Documentation tool for .net applications

    - by jovialwhispers
    I have an ASP.NET 2.0 application, developed in the early days of 2.0. There are almost no comment tags in the application. Is there any tool which can grab all the classes from that application generate a report [in chm or html or pdf] with all the classes and belonging methods, hierarchy of the classes and any kind of visual presentation of the over all flow/relationship/architecture? Thanks

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  • JUnit : Is there a way to skip a test belonging to a Test class's parent?

    - by Jon
    I have two classes: public abstract class AbstractFoobar { ... } and public class ConcreteFoobar extends AbstractFoobar { ... } I have corresponding test classes for these two classes: public class AbstractFoobarTest { ... } and public class ConcreteFoobarTest extends AbstractFoobarTest { ... } When I run ConcreteFoobarTest (in JUnit), the annotated @Test methods in AbstractFoobarTest get run along with those declared directly on ConcreteFoobarTest because they are inherited. Is there anyway to skip them?

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  • Reloading Rails Directories on Change for Development, Not in Lib

    - by yar
    I have checked out several questions on this, including all of those you see next to the question. Unfortunately, I'm not working with a plugin, and I don't want to work in lib. I have a directory called File.join(Rails.root, 'classes') and I'd like the classes in this directory to reload automatically in dev. In my environment.rb I have this line config.load_paths << File.join(Rails.root, 'classes') which works fine and blows up if the path isn't there. The reloading line in my development.rb also works fine require_dependency File.join(Rails.root, 'classes', 'blah.rb') which blows up if the file is not there (a good sign). However, the file doesn't reload. This all works if the file is in the root of lib and I use the require_dependency line, but my whole point is to get stuff out of lib as suggested here.

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  • Java how does Key Event Handling Mechanism(KeyListeners notified) work ?

    - by Carbonizer
    How does application/JVM know which classes if implemented key handling interfaces ? Does it use java Reflections or does it check all the classes for methods ? How can a application or executing JVM understanding to deliver the user event or call the specific methods on a class that implemented the keylistener interface. Does it look at all the classes if those methods are implemented or how does it know which classes implmented keylistener interface ? If you dont implement the keylistener Interface for a class but still implmentation all its methods. Do the class still process the user event occurred ?

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  • Call c++ function pointer from c#

    - by Sam
    Is it possible to call a c(++) static function pointer like this typedef int (*MyCppFunc)(void* SomeObject); from c#? void CallFromCSharp(MyCppFunc funcptr, IntPtr param) { funcptr(param); } I need to be able to callback from c# into some old c++ classes. C++ is managed, but the classes are not ref classes (yet). So far I got no idea how to call a c++ function pointer from c#, is it possible?

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  • iOS TableView crash don't know how. Here is the app

    - by jollyr0ger
    Hi! In my app that you can download here: http://ge.tt/2DDqfJa I've started a discussion but is died here iOS TableView crash loading different data The problem is when I back from viewing the YouTube video to the recipes list, the app crash... And when i select a category for the second time, where have to load a tableview with different data source, it crash. This is the crash log Program received signal: “EXC_BAD_ACCESS”. (gdb) bt #0 0x00f0da63 in objc_msgSend () #1 0x04b27ca0 in ?? () #2 0x00002665 in -[RecipesListController viewWillAppear:] (self=0x4b38a00, _cmd=0x6d81a2, animated=1 '\001') at /Users/claudiocanino/Documents/iOS/CottoMangiato/Classes/RecipesListController.m:67 #3 0x00370c9a in -[UINavigationController _startTransition:fromViewController:toViewController:] () #4 0x0036b606 in -[UINavigationController _startDeferredTransitionIfNeeded] () #5 0x0037283e in -[UINavigationController pushViewController:transition:forceImmediate:] () #6 0x04f49549 in -[UINavigationControllerAccessibility(SafeCategory) pushViewController:transition:forceImmediate:] () #7 0x0036b4a0 in -[UINavigationController pushViewController:animated:] () #8 0x00003919 in -[CategoryViewController tableView:didSelectRowAtIndexPath:] (self=0x4b27ca0, _cmd=0x6d19e3, tableView=0x500c200, indexPath=0x4b2d650) at /Users/claudiocanino/Documents/iOS/CottoMangiato/Classes/CategoryViewCotroller.m:104 #9 0x0032a794 in -[UITableView _selectRowAtIndexPath:animated:scrollPosition:notifyDelegate:] () #10 0x00320d50 in -[UITableView _userSelectRowAtPendingSelectionIndexPath:] () #11 0x000337f6 in __NSFireDelayedPerform () #12 0x00d8cfe3 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ () #13 0x00d8e594 in __CFRunLoopDoTimer () #14 0x00ceacc9 in __CFRunLoopRun () #15 0x00cea240 in CFRunLoopRunSpecific () #16 0x00cea161 in CFRunLoopRunInMode () #17 0x016e0268 in GSEventRunModal () #18 0x016e032d in GSEventRun () #19 0x002c342e in UIApplicationMain () #20 0x00001c08 in main (argc=1, argv=0xbfffef58) at /Users/claudiocanino/Documents/iOS/CottoMangiato/main.m:15 Another bt log: (gdb) bt #0 0x00cd76a1 in __CFBasicHashDeallocate () #1 0x00cc2bcb in _CFRelease () #2 0x00002dd6 in -[RecipesListController setRecipesArray:] (self=0x6834d50, _cmd=0x4293, _value=0x4e3bc70) at /Users/claudiocanino/Documents/iOS/CottoMangiato/Classes/RecipesListController.m:16 #3 0x00002665 in -[RecipesListController viewWillAppear:] (self=0x6834d50, _cmd=0x6d81a2, animated=1 '\001') at /Users/claudiocanino/Documents/iOS/CottoMangiato/Classes/RecipesListController.m:67 #4 0x00370c9a in -[UINavigationController _startTransition:fromViewController:toViewController:] () #5 0x0036b606 in -[UINavigationController _startDeferredTransitionIfNeeded] () #6 0x0037283e in -[UINavigationController pushViewController:transition:forceImmediate:] () #7 0x091ac549 in -[UINavigationControllerAccessibility(SafeCategory) pushViewController:transition:forceImmediate:] () #8 0x0036b4a0 in -[UINavigationController pushViewController:animated:] () #9 0x00003919 in -[CategoryViewController tableView:didSelectRowAtIndexPath:] (self=0x4b12970, _cmd=0x6d19e3, tableView=0x5014400, indexPath=0x4b2bd00) at /Users/claudiocanino/Documents/iOS/CottoMangiato/Classes/CategoryViewCotroller.m:104 #10 0x0032a794 in -[UITableView _selectRowAtIndexPath:animated:scrollPosition:notifyDelegate:] () #11 0x00320d50 in -[UITableView _userSelectRowAtPendingSelectionIndexPath:] () #12 0x000337f6 in __NSFireDelayedPerform () #13 0x00d8cfe3 in __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ () #14 0x00d8e594 in __CFRunLoopDoTimer () #15 0x00ceacc9 in __CFRunLoopRun () #16 0x00cea240 in CFRunLoopRunSpecific () #17 0x00cea161 in CFRunLoopRunInMode () #18 0x016e0268 in GSEventRunModal () #19 0x016e032d in GSEventRun () #20 0x002c342e in UIApplicationMain () #21 0x00001c08 in main (argc=1, argv=0xbfffef58) at /Users/claudiocanino/Documents/iOS/CottoMangiato/main.m:15 Thanks

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  • C++ dynamic type construction and detection

    - by KneLL
    There was an interesting problem in C++, but it concerns more likely architecture. There are many (10, 20, 40, etc) classes that describe some characteristics (mix-in classes), for exmaple: struct Base { virtual ~Base() {} }; struct A : virtual public Base { int size; }; struct B : virtual public Base { float x, y; }; struct C : virtual public Base { bool some_bool_state; }; struct D : virtual public Base { string str; } // .... Primary module declares and exports a function (for simplicity just function declarations without classes): // .h file void operate(Base *pBase); // .cpp file void operate(Base *pBase) { // .... } Any other module can has a code like this: #include "mixins.h" #include "primary.h" class obj1_t : public A, public C, public D {}; class obj2_t : public B, public D {}; // ... void Pass() { obj1_t obj1; obj2_t obj2; operate(&obj1); operate(&obj2); } The question is how to know what the real type of given object in operate() without dynamic_cast and any type information in classes (constants, etc)? Function operate() is used with big array of objects in small time periods and dynamic_cast is too slow for it. And I don't want to include constants (enum obj_type { ... }) because this is not OOP-way. // module operate.cpp void some_operate(Base *pBase) { processA(pBase); processB(pBase); } void processA(A *pA) { } void processB(B *pB) { } I cannot directly pass a pBase to these functions. And it's impossible to have all possible combinations of classes, because I can add new classes just by including new .h files. As one of solutions that comed to mind, in editor application I can use a composite container: struct CompositeObject { vector<Base *pBase> parts; }; But editor does not need a time optimization and can use dynamic_cast for parts to determine the exact type. In operate() I cannot use this solution. So, is it possible to not use a dynamic_cast and type information to solve this problem? Or maybe I should use another architecture?

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  • C# InternalsVisibleTo() attribute for VBNET 2.0 while testing?

    - by Will Marcouiller
    I'm building an Active Directory wrapper in VBNET 2.0 (can't use later .NET) in which I have the following: IUtilisateur IGroupe IUniteOrganisation These interfaces are implemented in internal classes (Friend in VBNET), so that I want to implement a façade in order to instiate each of the interfaces with their internal classes. This will allow the architecture a better flexibility, etc. Now, I want to test these classes (Utilisateur, Groupe, UniteOrganisation) in a different project within the same solution. However, these classes are internal. I would like to be able to instantiate them without going through my façade, but only for these tests, nothing more. Here's a piece of code to illustrate it: public static class DirectoryFacade { public static IGroupe CreerGroupe() { return new Groupe(); } } // Then in code, I would write something alike: public partial class MainForm : Form { public MainForm() { IGroupe g = DirectoryFacade.CreerGroupe(); // Doing stuff with instance here... } } // My sample interface: public interface IGroupe { string Domaine { get; set; } IList<IUtilisateur> Membres { get; } } internal class Groupe : IGroupe { private IList<IUtilisateur> _membres; internal Groupe() { _membres = new List<IUtilisateur>(); } public string Domaine { get; set; } public IList<IUtilisateur> Membres { get { return _membres; } } } I heard of InternalsVisibleTo() attribute, recently. I was wondering whether it is available in VBNET 2.0/VS2005 so that I could access the assmebly's internal classes for my tests? Otherwise, how could I achieve this?

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  • Silently binding a variable instance to a class in C++?

    - by gct
    So I've got a plugin-based system I'm writing. Users can create a child class of a Plugin class and then it will be loaded at runtime and integrated with the rest of the system. When a Plugin is run from the system, it's run in the context of a group of plugins, which I call a Session. My problem is that inside the user plugins, two streaming classes called pf_ostream and pf_istream can be used to read/write data to the system. I'd like to bind the plugin instance's session variable to pf_ostream and pf_istream somehow so that when the user instantiates those classes, it's already bound to the session for them (basically I don't want them to see the session internals) I could just do this with a macro, wrapping a call to the constructor like: #define MAKE_OSTREAM = pf_ostream_int(this->session) But I thought there might be a better way. I looked at using a nested class inside Plugin wrapping pf_ostream but it appears nested classes don't get access to the enclosing classes variables in a closure sort of way. Does anyone know of a neat way to do this?

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  • Does Java not support multiple inheritance?

    - by user1720616
    Lets us take instances of two classes public abstract class Shapes { public abstract void draw(Graphics g); } public class Rectangle extends Shapes { public void draw(Graphics g) { //implementation of the method } } here the class Rectangle has extended class Shapes and implicitly it extends class Object.I know no other extension is possible but cant we call inheriting classes Shapes and Object multiple inheritance?(Since inheriting two classes is multiple inheritance from one perspective)

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  • Qt Should I derive from QDataStream?

    - by ShaChris23
    I'm currently using QDataStream to serialize my classes. I have quite a few number of my own classes that I serialize often. Should I derive QDataStream to create my own DataStream class? Or is there a better pattern than this? Note that these custom classes are used by many of our projects, so maybe doing so will make coding easier. Another way to phrase this question is: when a framework provides you with a serialization class, how do you handle serializing your own custom-type classes such that you don't have to remember how to serialize them everytime.

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  • Looking into Entity Framework Code First Migrations

    - by nikolaosk
    In this post I will introduce you to Code First Migrations, an Entity Framework feature introduced in version 4.3 back in February of 2012.I have extensively covered Entity Framework in this blog. Please find my other Entity Framework posts here .   Before the addition of Code First Migrations (4.1,4.2 versions), Code First database initialisation meant that Code First would create the database if it does not exist (the default behaviour - CreateDatabaseIfNotExists). The other pattern we could use is DropCreateDatabaseIfModelChanges which means that Entity Framework, will drop the database if it realises that model has changes since the last time it created the database.The final pattern is DropCreateDatabaseAlways which means that Code First will recreate the database every time one runs the application.That is of course fine for the development database but totally unacceptable and catastrophic when you have a production database. We cannot lose our data because of the work that Code First works.Migrations solve this problem.With migrations we can modify the database without completely dropping it.We can modify the database schema to reflect the changes to the model without losing data.In version EF 5.0 migrations are fully included and supported. I will demonstrate migrations with a hands-on example.Let me say a few words first about Entity Framework first. The .Net framework provides support for Object Relational Mappingthrough EF. So EF is a an ORM tool and it is now the main data access technology that microsoft works on. I use it quite extensively in my projects. Through EF we have many things out of the box provided for us. We have the automatic generation of SQL code.It maps relational data to strongly types objects.All the changes made to the objects in the memory are persisted in a transactional way back to the data store. You can find in this post an example on how to use the Entity Framework to retrieve data from an SQL Server Database using the "Database/Schema First" approach.In this approach we make all the changes at the database level and then we update the model with those changes. In this post you can see an example on how to use the "Model First" approach when working with ASP.Net and the Entity Framework.This model was firstly introduced in EF version 4.0 and we could start with a blank model and then create a database from that model.When we made changes to the model , we could recreate the database from the new model. The Code First approach is the more code-centric than the other two. Basically we write POCO classes and then we persist to a database using something called DBContext.Code First relies on DbContext. We create 2,3 classes (e.g Person,Product) with properties and then these classes interact with the DbContext class we can create a new database based upon our POCOS classes and have tables generated from those classes.We do not have an .edmx file in this approach.By using this approach we can write much easier unit tests.DbContext is a new context class and is smaller,lightweight wrapper for the main context class which is ObjectContext (Schema First and Model First).Let's move on to our hands-on example.I have installed VS 2012 Ultimate edition in my Windows 8 machine. 1)  Create an empty asp.net web application. Give your application a suitable name. Choose C# as the development language2) Add a new web form item in your application. Leave the default name.3) Create a new folder. Name it CodeFirst .4) Add a new item in your application, a class file. Name it Footballer.cs. This is going to be a simple POCO class.Place this class file in the CodeFirst folder.The code follows    public class Footballer     {         public int FootballerID { get; set; }         public string FirstName { get; set; }         public string LastName { get; set; }         public double Weight { get; set; }         public double Height { get; set; }              }5) We will have to add EF 5.0 to our project. Right-click on the project in the Solution Explorer and select Manage NuGet Packages... for it.In the window that will pop up search for Entity Framework and install it.Have a look at the picture below   If you want to find out if indeed EF version is 5.0 version is installed have a look at the References. Have a look at the picture below to see what you will see if you have installed everything correctly.Have a look at the picture below 6) Then we need to create a context class that inherits from DbContext.Add a new class to the CodeFirst folder.Name it FootballerDBContext.Now that we have the entity classes created, we must let the model know.I will have to use the DbSet<T> property.The code for this class follows     public class FootballerDBContext:DbContext     {         public DbSet<Footballer> Footballers { get; set; }             }    Do not forget to add  (using System.Data.Entity;) in the beginning of the class file 7) We must take care of the connection string. It is very easy to create one in the web.config.It does not matter that we do not have a database yet.When we run the DbContext and query against it , it will use a connection string in the web.config and will create the database based on the classes.I will use the name "FootballTraining" for the database.In my case the connection string inside the web.config, looks like this    <connectionStrings>    <add name="CodeFirstDBContext" connectionString="server=.;integrated security=true; database=FootballTraining" providerName="System.Data.SqlClient"/>                       </connectionStrings>8) Now it is time to create Linq to Entities queries to retrieve data from the database . Add a new class to your application in the CodeFirst folder.Name the file DALfootballer.csWe will create a simple public method to retrieve the footballers. The code for the class followspublic class DALfootballer     {         FootballerDBContext ctx = new FootballerDBContext();         public List<Footballer> GetFootballers()         {             var query = from player in ctx.Footballers select player;             return query.ToList();         }     } 9) Place a GridView control on the Default.aspx page and leave the default name.Add an ObjectDataSource control on the Default.aspx page and leave the default name. Set the DatasourceID property of the GridView control to the ID of the ObjectDataSource control.(DataSourceID="ObjectDataSource1" ). Let's configure the ObjectDataSource control. Click on the smart tag item of the ObjectDataSource control and select Configure Data Source. In the Wizzard that pops up select the DALFootballer class and then in the next step choose the GetFootballers() method.Click Finish to complete the steps of the wizzard.Build and Run your application.  10) Obviously you will not see any records coming back from your database, because we have not inserted anything. The database is created, though.Have a look at the picture below.  11) Now let's change the POCO class. Let's add a new property to the Footballer.cs class.        public int Age { get; set; } Build and run your application again. You will receive an error. Have a look at the picture below 12) That was to be expected.EF Code First Migrations is not activated by default. We have to activate them manually and configure them according to your needs. We will open the Package Manager Console from the Tools menu within Visual Studio 2012.Then we will activate the EF Code First Migration Features by writing the command “Enable-Migrations”.  Have a look at the picture below. This adds a new folder Migrations in our project. A new auto-generated class Configuration.cs is created.Another class is also created [CURRENTDATE]_InitialCreate.cs and added to our project.The Configuration.cs  is shown in the picture below. The [CURRENTDATE]_InitialCreate.cs is shown in the picture below  13) ??w we are ready to migrate the changes in the database. We need to run the Add-Migration Age command in Package Manager ConsoleAdd-Migration will scaffold the next migration based on changes you have made to your model since the last migration was created.In the Migrations folder, the file 201211201231066_Age.cs is created.Have a look at the picture below to see the newly generated file and its contents. Now we can run the Update-Database command in Package Manager Console .See the picture above.Code First Migrations will compare the migrations in our Migrations folder with the ones that have been applied to the database. It will see that the Age migration needs to be applied, and run it.The EFMigrations.CodeFirst.FootballeDBContext database is now updated to include the Age column in the Footballers table.Build and run your application.Everything will work fine now.Have a look at the picture below to see the migrations applied to our table. 14) We may want it to automatically upgrade the database (by applying any pending migrations) when the application launches.Let's add another property to our Poco class.          public string TShirtNo { get; set; }We want this change to migrate automatically to the database.We go to the Configuration.cs we enable automatic migrations.     public Configuration()        {            AutomaticMigrationsEnabled = true;        } In the Page_Load event handling routine we have to register the MigrateDatabaseToLatestVersion database initializer. A database initializer simply contains some logic that is used to make sure the database is setup correctly.   protected void Page_Load(object sender, EventArgs e)        {            Database.SetInitializer(new MigrateDatabaseToLatestVersion<FootballerDBContext, Configuration>());        } Build and run your application. It will work fine. Have a look at the picture below to see the migrations applied to our table in the database. Hope it helps!!!  

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  • Code Reuse is (Damn) Hard

    - by James Michael Hare
    Being a development team lead, the task of interviewing new candidates was part of my job.  Like any typical interview, we started with some easy questions to get them warmed up and help calm their nerves before hitting the hard stuff. One of those easier questions was almost always: “Name some benefits of object-oriented development.”  Nearly every time, the candidate would chime in with a plethora of canned answers which typically included: “it helps ease code reuse.”  Of course, this is a gross oversimplification.  Tools only ease reuse, its developers that ultimately can cause code to be reusable or not, regardless of the language or methodology. But it did get me thinking…  we always used to say that as part of our mantra as to why Object-Oriented Programming was so great.  With polymorphism, inheritance, encapsulation, etc. we in essence set up the concepts to help facilitate reuse as much as possible.  And yes, as a developer now of many years, I unquestionably held that belief for ages before it really struck me how my views on reuse have jaded over the years.  In fact, in many ways Agile rightly eschews reuse as taking a backseat to developing what's needed for the here and now.  It used to be I was in complete opposition to that view, but more and more I've come to see the logic in it.  Too many times I've seen developers (myself included) get lost in design paralysis trying to come up with the perfect abstraction that would stand all time.  Nearly without fail, all of these pieces of code become obsolete in a matter of months or years. It’s not that I don’t like reuse – it’s just that reuse is hard.  In fact, reuse is DAMN hard.  Many times it is just a distraction that eats up architect and developer time, and worse yet can be counter-productive and force wrong decisions.  Now don’t get me wrong, I love the idea of reusable code when it makes sense.  These are in the few cases where you are designing something that is inherently reusable.  The problem is, most business-class code is inherently unfit for reuse! Furthermore, the code that is reusable will often fail to be reused if you don’t have the proper framework in place for effective reuse that includes standardized versioning, building, releasing, and documenting the components.  That should always be standard across the board when promoting reusable code.  All of this is hard, and it should only be done when you have code that is truly reusable or you will be exerting a large amount of development effort for very little bang for your buck. But my goal here is not to get into how to reuse (that is a topic unto itself) but what should be reused.  First, let’s look at an extension method.  There’s many times where I want to kick off a thread to handle a task, then when I want to reign that thread in of course I want to do a Join on it.  But what if I only want to wait a limited amount of time and then Abort?  Well, I could of course write that logic out by hand each time, but it seemed like a great extension method: 1: public static class ThreadExtensions 2: { 3: public static bool JoinOrAbort(this Thread thread, TimeSpan timeToWait) 4: { 5: bool isJoined = false; 6:  7: if (thread != null) 8: { 9: isJoined = thread.Join(timeToWait); 10:  11: if (!isJoined) 12: { 13: thread.Abort(); 14: } 15: } 16: return isJoined; 17: } 18: } 19:  When I look at this code, I can immediately see things that jump out at me as reasons why this code is very reusable.  Some of them are standard OO principles, and some are kind-of home grown litmus tests: Single Responsibility Principle (SRP) – The only reason this extension method need change is if the Thread class itself changes (one responsibility). Stable Dependencies Principle (SDP) – This method only depends on classes that are more stable than it is (System.Threading.Thread), and in itself is very stable, hence other classes may safely depend on it. It is also not dependent on any business domain, and thus isn't subject to changes as the business itself changes. Open-Closed Principle (OCP) – This class is inherently closed to change. Small and Stable Problem Domain – This method only cares about System.Threading.Thread. All-or-None Usage – A user of a reusable class should want the functionality of that class, not parts of that functionality.  That’s not to say they most use every method, but they shouldn’t be using a method just to get half of its result. Cost of Reuse vs. Cost to Recreate – since this class is highly stable and minimally complex, we can offer it up for reuse very cheaply by promoting it as “ready-to-go” and already unit tested (important!) and available through a standard release cycle (very important!). Okay, all seems good there, now lets look at an entity and DAO.  I don’t know about you all, but there have been times I’ve been in organizations that get the grand idea that all DAOs and entities should be standardized and shared.  While this may work for small or static organizations, it’s near ludicrous for anything large or volatile. 1: namespace Shared.Entities 2: { 3: public class Account 4: { 5: public int Id { get; set; } 6:  7: public string Name { get; set; } 8:  9: public Address HomeAddress { get; set; } 10:  11: public int Age { get; set;} 12:  13: public DateTime LastUsed { get; set; } 14:  15: // etc, etc, etc... 16: } 17: } 18:  19: ... 20:  21: namespace Shared.DataAccess 22: { 23: public class AccountDao 24: { 25: public Account FindAccount(int id) 26: { 27: // dao logic to query and return account 28: } 29:  30: ... 31:  32: } 33: } Now to be fair, I’m not saying there doesn’t exist an organization where some entites may be extremely static and unchanging.  But at best such entities and DAOs will be problematic cases of reuse.  Let’s examine those same tests: Single Responsibility Principle (SRP) – The reasons to change for these classes will be strongly dependent on what the definition of the account is which can change over time and may have multiple influences depending on the number of systems an account can cover. Stable Dependencies Principle (SDP) – This method depends on the data model beneath itself which also is largely dependent on the business definition of an account which can be very inherently unstable. Open-Closed Principle (OCP) – This class is not really closed for modification.  Every time the account definition may change, you’d need to modify this class. Small and Stable Problem Domain – The definition of an account is inherently unstable and in fact may be very large.  What if you are designing a system that aggregates account information from several sources? All-or-None Usage – What if your view of the account encompasses data from 3 different sources but you only care about one of those sources or one piece of data?  Should you have to take the hit of looking up all the other data?  On the other hand, should you have ten different methods returning portions of data in chunks people tend to ask for?  Neither is really a great solution. Cost of Reuse vs. Cost to Recreate – DAOs are really trivial to rewrite, and unless your definition of an account is EXTREMELY stable, the cost to promote, support, and release a reusable account entity and DAO are usually far higher than the cost to recreate as needed. It’s no accident that my case for reuse was a utility class and my case for non-reuse was an entity/DAO.  In general, the smaller and more stable an abstraction is, the higher its level of reuse.  When I became the lead of the Shared Components Committee at my workplace, one of the original goals we looked at satisfying was to find (or create), version, release, and promote a shared library of common utility classes, frameworks, and data access objects.  Now, of course, many of you will point to nHibernate and Entity for the latter, but we were looking at larger, macro collections of data that span multiple data sources of varying types (databases, web services, etc). As we got deeper and deeper in the details of how to manage and release these items, it quickly became apparent that while the case for reuse was typically a slam dunk for utilities and frameworks, the data access objects just didn’t “smell” right.  We ended up having session after session of design meetings to try and find the right way to share these data access components. When someone asked me why it was taking so long to iron out the shared entities, my response was quite simple, “Reuse is hard...”  And that’s when I realized, that while reuse is an awesome goal and we should strive to make code maintainable, often times you end up creating far more work for yourself than necessary by trying to force code to be reusable that inherently isn’t. Think about classes the times you’ve worked in a company where in the design session people fight over the best way to implement a class to make it maximally reusable, extensible, and any other buzzwordable.  Then think about how quickly that design became obsolete.  Many times I set out to do a project and think, “yes, this is the best design, I can extend it easily!” only to find out the business requirements change COMPLETELY in such a way that the design is rendered invalid.  Code, in general, tends to rust and age over time.  As such, writing reusable code can often be difficult and many times ends up being a futile exercise and worse yet, sometimes makes the code harder to maintain because it obfuscates the design in the name of extensibility or reusability. So what do I think are reusable components? Generic Utility classes – these tend to be small classes that assist in a task and have no business context whatsoever. Implementation Abstraction Frameworks – home-grown frameworks that try to isolate changes to third party products you may be depending on (like writing a messaging abstraction layer for publishing/subscribing that is independent of whether you use JMS, MSMQ, etc). Simplification and Uniformity Frameworks – To some extent this is similar to an abstraction framework, but there may be one chosen provider but a development shop mandate to perform certain complex items in a certain way.  Or, perhaps to simplify and dumb-down a complex task for the average developer (such as implementing a particular development-shop’s method of encryption). And what are less reusable? Application and Business Layers – tend to fluctuate a lot as requirements change and new features are added, so tend to be an unstable dependency.  May be reused across applications but also very volatile. Entities and Data Access Layers – these tend to be tuned to the scope of the application, so reusing them can be hard unless the abstract is very stable. So what’s the big lesson?  Reuse is hard.  In fact it’s damn hard.  And much of the time I’m not convinced we should focus too hard on it. If you’re designing a utility or framework, then by all means design it for reuse.  But you most also really set down a good versioning, release, and documentation process to maximize your chances.  For anything else, design it to be maintainable and extendable, but don’t waste the effort on reusability for something that most likely will be obsolete in a year or two anyway.

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  • What is Inversion of control and why we need it?

    - by Jalpesh P. Vadgama
    Most of programmer need inversion of control pattern in today’s complex real time application world. So I have decided to write a blog post about it. This blog post will explain what is Inversion of control and why we need it. We are going to take a real world example so it would be better to understand. The problem- Why we need inversion of control? Before giving definition of Inversion of control let’s take a simple real word example to see why we need inversion of control. Please have look on the following code. public class class1 { private class2 _class2; public class1() { _class2=new class2(); } } public class class2 { //Some implementation of class2 } I have two classes “Class1” and “Class2”.  If you see the code in that I have created a instance of class2 class in the class1 class constructor. So the “class1” class is dependent on “class2”. I think that is the biggest issue in real world scenario as if we change the “class2” class then we might need to change the “class1” class also. Here there is one type of dependency between this two classes that is called Tight Coupling. Tight coupling will have lots of problem in real world applications as things are tends to be change in future so we have to change all the tight couple classes that are dependent of each other. To avoid this kind of issue we need Inversion of control. What is Inversion of Control? According to the wikipedia following is a definition of Inversion of control. “In software engineering, Inversion of Control (IoC) is an object-oriented programming practice where the object coupling is bound at run time by an assembler object and is typically not known at compile time using static analysis.” So if you read the it carefully it says that we should have object coupling at run time not compile time where it know what object it will create, what method it will call or what feature it will going to use for that. We need to use same classes in such way so that it will not tight couple with each other. There are multiple way to implement Inversion of control. You can refer wikipedia link for knowing multiple ways of implementing Inversion of control. In future posts we are going to see all the different way of implementing Inversion of control.

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  • Working with Legacy code #4 : Remove the hard dependencies

    - by andrewstopford
    During your refactoring cycle you should be seeking out the hard dependencies that the code may have, examples of these can include. File System Database Network (HTTP) Application Server (Crystal) Classes that service these kind (or code that can be abstracted to a class) of these kind of dependencies should be wrapped in an interface for easier mocking. If you team starts refering to the interface version of these classes the hard dependency will over time work it's self free.

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  • Why is Software Engineering not the typical major for future software developers?

    - by FarmBoy
    While most agree that a certain level of Computer Science is essential to being a good programmer, it seems to me that the principles of good software development is even more important, though not as fundamental. Just like mechanical engineers take physics classes, but far more engineering classes, I would expect, now that software is over a half century old, that software development would begin to dominate the undergraduate curriculum. But I don't see much evidence of this. Is there a reason that Software Engineering hasn't taken hold as an academic discipline?

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  • Dependency Injection/IoC container practices when writing frameworks

    - by Dave Hillier
    I've used various IoC containers (Castle.Windsor, Autofac, MEF, etc) for .Net in a number of projects. I have found they tend to encourage a number of bad practices. Are there any established practices for IoC container use, particularly when providing a platform/framework? My aim as a framework writer is to make code as simple and as easy to use as possible. I'd rather write one line of code to construct an object than ten or even just two. For example, a couple of code smells that I've noticed and don't have good suggestions to: Large number of parameters (5) for constructors. Creating services tends to be complex; all of the dependencies are injected via the constructor - despite the fact that the components are rarely optional (except for maybe in testing). Lack of private and internal classes; this one may be a specific limitation of using C# and Silverlight, but I'm interested in how it is solved. It's difficult to tell what a frameworks interface is if all the classes are public; it allows me access to private parts that I probably shouldnt touch. Coupling the object lifecycle to the IoC container. It is often difficult to manually construct the dependencies required to create objects. Object lifecycle is too often managed by the IoC framework. I've seen projects where most classes are registered as Singletons. You get a lack of explicit control and are also forced to manage the internals (it relates to the above point, all classes are public and you have to inject them). For example, .Net framework has many static methods. such as, DateTime.UtcNow. Many times I have seen this wrapped and injected as a construction parameter. Depending on concrete implementation makes my code hard to test. Injecting a dependency makes my code hard to use - particularly if the class has many parameters. How do I provide both a testable interface, as well as one that is easy to use? What are the best practices?

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  • SQL Saturday #157 - San Diego

    Southern California isn't all beach time. SQL Saturday comes to San Diego on Sept 15, 2012. Join fellow SQL Server pros for a day of learning. Learn Agile Database Development Best PracticesAgile database development experts Sebastian Meine and Dennis Lloyd are running day-long classes designed to complement Red Gate’s SQL in the City US tour. Classes will be held in San Francisco, Chicago, Boston and Seattle. Register Now.

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  • Announcement: Employee Info Starter Kit (v6.0–ASP.NET MVC Edition) is Released

    - by Mohammad Ashraful Alam
    Originally posted on: http://geekswithblogs.net/joycsharp/archive/2013/06/16/announcement-employee-info-starter-kit-v6.0asp.net-mvc-edition-is-released.aspxAfter a long wait, the next version of Employee Info Starter Kit is released! This starter kit is basically a project template that contains code samples targeting a specific technology, such as ASP.NET Web Form, ASP.NET MVC etc. Since its first release, this open source project gained a huge popularity in the developer community and had 250K+ combined downloads. This starter kit is honored to be placed at the official ASP.NET site, along with other asp.net starter kits, which all are being considered as the “best” ASP.NET coding standards, recommended by Microsoft. EISK is showcased in Microsoft’s Channel 9’s Weekly Show, as well. The ASP.NET MVC Edition of the new version 6.0 bundles most of the greatest and successful platforms, frameworks and technologies together, to enable web developers to learn and build manageable and high performance web applications with rich user experience effectively and quickly. User End Specifications Creating a new employee record Read existing employee records Update an existing employee record Delete existing employee records Role based security model Key Technology Areas ASP.NET MVC 4 Entity Framework 4.3.1 Sql Server Compact Edition 4 Visual Studio 2012 QuickStart Guide Getting started with EISK 6.0 ASP.NET is pretty easy. Once you've Visual Studio 2012 installed, then just follow the steps as provided below: Download the EISK 6.0 MVC version. Extract the file. From the extracted folder, click the solution file "Eisk.MVC-VS2012.sln". Right click the "Eisk.MVC" project node and select "Select set as StartUp Project". Hit Ctrl+F5 and explore! Architectural Overview Overall architecture is based on Model-View-Controller pattern Support for desktop & mobile browsers. Usage of Domain Model, Repository and Unit of Work pattern from Domain Driven Development approach Usage of Data Annotations in model (entity) classes to centralize basic validation mechanism that facilitates DRY principle Usage of IValidatableObject interface in model (entity) classes that isolates custom business logic from application layer Usage of OOP inheritance and Value Object pattern in model (entity) classes that provides reusability in application architecture Usage of View Model, Editor Model pattern that provides mechanism for testable view rendering logic Several helper classes and extension methods to enable developers build application with reduced code If you want to learn more about it in details, just check the following links: Getting Started - Hands on Coding Walkthrough – Technology Stack - Design & Architecture Enjoy!

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  • Help with "Cannot find ContentTypeReader BB.HeightMapInfoReader, BB, Version=1.0.0.0, Culture=neutral." needed

    - by rFactor
    Hi, I have this irritating problem in XNA that I have spent my Saturday with: Cannot find ContentTypeReader BB.HeightMapInfoReader, BB, Version=1.0.0.0, Culture=neutral. It throws me that when I do (within the game assembly's Renderer.cs class): this.terrain = this.game.Content.Load<Model>("heightmap"); There is a heightmap.bmp and I don't think there's anything wrong with it, because I used it in a previous version which I switched to this new better system. So, I have a GeneratedGeometryPipeline assembly that has these classes: HeightMapInfoContent, HeightMapInfoWriter, TerrainProcessor. The GeneratedGeometryPipeline assembly does not reference any other assemblies under the solution. Then I have the game assembly that neither references any other solution assemblies and has these classes: HeightMapInfo, HeightMapInfoReader. All game assembly classes are under namespace BB and the GeneratedGeometryPipeline classes are under the namespace GeneratedGeometryPipeline. I do not understand why it does not find it. Here's some code from the GeneratedGeometryPipeline.HeightMapInfoWriter: /// <summary> /// A TypeWriter for HeightMapInfo, which tells the content pipeline how to save the /// data in HeightMapInfo. This class should match HeightMapInfoReader: whatever the /// writer writes, the reader should read. /// </summary> [ContentTypeWriter] public class HeightMapInfoWriter : ContentTypeWriter<HeightMapInfoContent> { protected override void Write(ContentWriter output, HeightMapInfoContent value) { output.Write(value.TerrainScale); output.Write(value.Height.GetLength(0)); output.Write(value.Height.GetLength(1)); foreach (float height in value.Height) { output.Write(height); } foreach (Vector3 normal in value.Normals) { output.Write(normal); } } /// <summary> /// Tells the content pipeline what CLR type the /// data will be loaded into at runtime. /// </summary> public override string GetRuntimeType(TargetPlatform targetPlatform) { return "BB.HeightMapInfo, BB, Version=1.0.0.0, Culture=neutral"; } /// <summary> /// Tells the content pipeline what worker type /// will be used to load the data. /// </summary> public override string GetRuntimeReader(TargetPlatform targetPlatform) { return "BB.HeightMapInfoReader, BB, Version=1.0.0.0, Culture=neutral"; } } Can someone help me out?

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  • What is the diffference between "data hiding" and "encapsulation"?

    - by john smith optional
    I'm reading "Java concurrency in practice" and there is said: "Fortunately, the same object-oriented techniques that help you write well-organized, maintainable classes - such as encapsulation and data hiding -can also help you crate thread-safe classes." The problem #1 - I never heard about data hiding and don't know what it is. The problem #2 - I always thought that encapsulation is using private vs public, and is actually the data hiding. Can you please explain what data hiding is and how it differs from encapsulation?

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  • SQL in the City - Austin 2012

    A free day of training in Austin, TX with Grant Fritchey, Steve Jones and a few others. Join us to learn about SQL Server and how you can more efficiently work in your job every day. Learn Agile Database Development Best PracticesAgile database development experts Sebastian Meine and Dennis Lloyd are running day-long classes designed to complement Red Gate’s SQL in the City US tour. Classes will be held in San Francisco, Chicago, Boston and Seattle. Register Now.

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  • Why do we (really) program to interfaces?

    - by Kyle Burns
    One of the earliest lessons I was taught in Enterprise development was "always program against an interface".  This was back in the VB6 days and I quickly learned that no code would be allowed to move to the QA server unless my business objects and data access objects each are defined as an interface and have a matching implementation class.  Why?  "It's more reusable" was one answer.  "It doesn't tie you to a specific implementation" a slightly more knowing answer.  And let's not forget the discussion ending "it's a standard".  The problem with these responses was that senior people didn't really understand the reason we were doing the things we were doing and because of that, we were entirely unable to realize the intent behind the practice - we simply used interfaces and had a bunch of extra code to maintain to show for it. It wasn't until a few years later that I finally heard the term "Inversion of Control".  Simply put, "Inversion of Control" takes the creation of objects that used to be within the control (and therefore a responsibility of) of your component and moves it to some outside force.  For example, consider the following code which follows the old "always program against an interface" rule in the manner of many corporate development shops: 1: ICatalog catalog = new Catalog(); 2: Category[] categories = catalog.GetCategories(); In this example, I met the requirement of the rule by declaring the variable as ICatalog, but I didn't hit "it doesn't tie you to a specific implementation" because I explicitly created an instance of the concrete Catalog object.  If I want to test the functionality of the code I just wrote I have to have an environment in which Catalog can be created along with any of the resources upon which it depends (e.g. configuration files, database connections, etc) in order to test my functionality.  That's a lot of setup work and one of the things that I think ultimately discourages real buy-in of unit testing in many development shops. So how do I test my code without needing Catalog to work?  A very primitive approach I've seen is to change the line the instantiates catalog to read: 1: ICatalog catalog = new FakeCatalog();   once the test is run and passes, the code is switched back to the real thing.  This obviously poses a huge risk for introducing test code into production and in my opinion is worse than just keeping the dependency and its associated setup work.  Another popular approach is to make use of Factory methods which use an object whose "job" is to know how to obtain a valid instance of the object.  Using this approach, the code may look something like this: 1: ICatalog catalog = CatalogFactory.GetCatalog();   The code inside the factory is responsible for deciding "what kind" of catalog is needed.  This is a far better approach than the previous one, but it does make projects grow considerably because now in addition to the interface, the real implementation, and the fake implementation(s) for testing you have added a minimum of one factory (or at least a factory method) for each of your interfaces.  Once again, developers say "that's too complicated and has me writing a bunch of useless code" and quietly slip back into just creating a new Catalog and chalking any test failures up to "it will probably work on the server". This is where software intended specifically to facilitate Inversion of Control comes into play.  There are many libraries that take on the Inversion of Control responsibilities in .Net and most of them have many pros and cons.  From this point forward I'll discuss concepts from the standpoint of the Unity framework produced by Microsoft's Patterns and Practices team.  I'm primarily focusing on this library because it questions about it inspired this posting. At Unity's core and that of most any IoC framework is a catalog or registry of components.  This registry can be configured either through code or using the application's configuration file and in the most simple terms says "interface X maps to concrete implementation Y".  It can get much more complicated, but I want to keep things at the "what does it do" level instead of "how does it do it".  The object that exposes most of the Unity functionality is the UnityContainer.  This object exposes methods to configure the catalog as well as the Resolve<T> method which is used to obtain an instance of the type represented by T.  When using the Resolve<T> method, Unity does not necessarily have to just "new up" the requested object, but also can track dependencies of that object and ensure that the entire dependency chain is satisfied. There are three basic ways that I have seen Unity used within projects.  Those are through classes directly using the Unity container, classes requiring injection of dependencies, and classes making use of the Service Locator pattern. The first usage of Unity is when classes are aware of the Unity container and directly call its Resolve method whenever they need the services advertised by an interface.  The up side of this approach is that IoC is utilized, but the down side is that every class has to be aware that Unity is being used and tied directly to that implementation. Many developers don't like the idea of as close a tie to specific IoC implementation as is represented by using Unity within all of your classes and for the most part I agree that this isn't a good idea.  As an alternative, classes can be designed for Dependency Injection.  Dependency Injection is where a force outside the class itself manipulates the object to provide implementations of the interfaces that the class needs to interact with the outside world.  This is typically done either through constructor injection where the object has a constructor that accepts an instance of each interface it requires or through property setters accepting the service providers.  When using dependency, I lean toward the use of constructor injection because I view the constructor as being a much better way to "discover" what is required for the instance to be ready for use.  During resolution, Unity looks for an injection constructor and will attempt to resolve instances of each interface required by the constructor, throwing an exception of unable to meet the advertised needs of the class.  The up side of this approach is that the needs of the class are very clearly advertised and the class is unaware of which IoC container (if any) is being used.  The down side of this approach is that you're required to maintain the objects passed to the constructor as instance variables throughout the life of your object and that objects which coordinate with many external services require a lot of additional constructor arguments (this gets ugly and may indicate a need for refactoring). The final way that I've seen and used Unity is to make use of the ServiceLocator pattern, of which the Patterns and Practices team has also provided a Unity-compatible implementation.  When using the ServiceLocator, your class calls ServiceLocator.Retrieve in places where it would have called Resolve on the Unity container.  Like using Unity directly, it does tie you directly to the ServiceLocator implementation and makes your code aware that dependency injection is taking place, but it does have the up side of giving you the freedom to swap out the underlying IoC container if necessary.  I'm not hugely concerned with hiding IoC entirely from the class (I view this as a "nice to have"), so the single biggest problem that I see with the ServiceLocator approach is that it provides no way to proactively advertise needs in the way that constructor injection does, allowing more opportunity for difficult to track runtime errors. This blog entry has not been intended in any way to be a definitive work on IoC, but rather as something to spur thought about why we program to interfaces and some ways to reach the intended value of the practice instead of having it just complicate your code.  I hope that it helps somebody begin or continue a journey away from being a "Cargo Cult Programmer".

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