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Search found 50247 results on 2010 pages for 'base class'.

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  • abstract class extends abstract class in php?

    - by user151841
    I am working on a simple abstract database class. In my usage of this class, I'll want to have some instance be a singleton. I was thinking of having a abstract class that is not a singleton, and then extend it into another abstract class that is a singleton. Is this possible? Recommended?

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  • Deriving a class from an abstract class (C++)

    - by cemregoksu
    I have an abstract class with a pure virtual function f() and i want to create a class inherited from that class, and also override function f(). I seperated the header file and the cpp file. I declared the function f(int) in the header file and the definition is in the cpp file. However, the compiler says the derived class is still abstract. How can i fix it?

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  • C# vector class - Interpolation design decision

    - by Benjamin
    Currently I'm working on a vector class in C# and now I'm coming to the point, where I've to figure out, how i want to implement the functions for interpolation between two vectors. At first I came up with implementing the functions directly into the vector class... public class Vector3D { public static Vector3D LinearInterpolate(Vector3D vector1, Vector3D vector2, double factor) { ... } public Vector3D LinearInterpolate(Vector3D other, double factor { ... } } (I always offer both: a static method with two vectors as parameters and one non-static, with only one vector as parameter) ...but then I got the idea to use extension methods (defined in a seperate class called "Interpolation" for example), since interpolation isn't really a thing only available for vectors. So this could be another solution: public class Vector3D { ... } public static class Interpolation { public static Vector3D LinearInterpolate(this Vector3D vector, Vector3D other, double factor) { ... } } So here an example how you'd use the different possibilities: { var vec1 = new Vector3D(5, 3, 1); var vec2 = new Vector3D(4, 2, 0); Vector3D vec3; vec3 = vec1.LinearInterpolate(vec2, 0.5); //1 vec3 = Vector3D.LinearInterpolate(vec1, vec2, 0.5); //2 //or with extension-methods vec3 = vec1.LinearInterpolate(vec2, 0.5); //3 (same as 1) vec3 = Interpolation.LinearInterpolation(vec1, vec2, 0.5); //4 } So I really don't know which design is better. Also I don't know if there's an ultimate rule for things like this or if it's just about what someone personally prefers. But I really would like to hear your opinions, what's better (and if possible why ).

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  • Cannot create class diagram for simple dll class in Visual Studio 2010

    - by xenn_33
    Hi, It seems that there is a really annoying issue in Class Diagram designer in VS (my version is 2010 Ultimate, but the issue is also observed in VS 2008). When I'm trying to create a class diagram for particular simple class from DLL I'm getting the following error: "Some of the selected type(s) cannot be added to the class diagram. Check the code for errors and ensure that all required assemblies ... blah-blah-blah" My code doesn't contain any error. I have multiple class and interface definitions in one separate .cs file, but these classes are really simple - even no calls to unmanaged/interop. Any solution for this?

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  • adhoc struct/class in C#?

    - by acidzombie24
    Currently i am using reflection with sql. I find if i want to make a specialize query it is easiest to get the results by creating a new class inheriting from another and adding the 2 members/columns for my specialized query. Then due to reflections in the lib in my c# code i can write foreach(var v in list) { v.AnyMember and v.MyExtraMember) Now instead of having the class scattered around or modifying my main DB.cs file can i define a class inside a function? I know i can create an anonymous object by writing new {name=val, name2=...}; but i need a to pass this class in a generic function func(query, args);

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  • Returning new base class when the parent class shared pointer is the return type

    - by Ben Dol
    Can you have a parent class shared pointer return type of a function and then return a new child class without it being a shared pointer? I'm not sure how shared pointers work in these situations, do they act like a regular pointer? Here is my example: BaseEventPtr Actions::getEvent(const std::string& nodeName) { if(asLowerCaseString(nodeName) == "action") return new ActionEvent(&m_interface); return nullptr; } ActionEvent is the subclass of BaseEvent in this situation. Cheers!

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  • Reference inherited class's <T>ype in a derived class

    - by DRapp
    I don't know if its possible or not, but here's what I need. I'm toying around with something and want to know if its possible since you can't create your own data type based on a sealed type such as int, Int32, Int64, etc. I want to create a top-level class that is defined of a given type with some common stuff. Then, derive this into two subclasses, but in this case, each class is based on either and int or Int64 type. From THAT instance, create an instance of either one and know its yped basis for parameter referenc / return settings. So when I need to create an instance of the "ThisClass", I don't have to know its type basis of either int or Int64, yet IT will know the type and be able to allow methods/functions to be called with the typed... This way, If I want to change my ThisClass definition from SubLevel1 to SubLevel2, I don't have to dance around all different data type definitions. Hope this makes sense.. public class TopLevel<T> { ... } pubic class SubLevel1 : TopLevel<int> { ... } public class SubLevel2 : TopLevel<Int64> { ... } public class ThisClass : SubLevel1 { ... public <based on the Int data type from SubLevel1> SomeFunc() { return <the Int value computed>; } }

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  • jquery: set variable based on one class from an element that has more than one class

    - by John
    Hi I'm trying to make a table who's columns and rows highlight on hover (I realise there are jquery plugins out there that will do this, but I'm trying to learn, so thought I'd have a stab at doing it for myself.) Here's what I've got so far: $('th:not(.features), td:not(.features)').hover(highlight); function highlight(){ $('th.highlightCol, td.highlightCol').removeClass('highlightCol'); var col = $(this).attr('class'); $('.' + col).addClass('highlightCol'); }; $('tr').hover(highlightRowOn, highlightRowOff); function highlightRowOn(){ $(this).children('td:not(.highlightCol)').addClass('highlightRow'); }; function highlightRowOff(){ $(this).children('td:not(.highlightCol)').removeClass('highlightRow'); }; This works fine apart from one problem: Each 'td' has a class specific to it's column (package1, package2, package3, package4). It is this that gets passed to the variable (col) to add the class 'highlightCol' to a column when one of its 'td's are hovered on. However, If you move the cursor to a new column along a highlighted row, the 'td' you land on has two classes (highlightedRow and package* ). These both get passed to the variable and as a result the new column does not receive the correct class to highlight. Is there a way for me to target just the 'package* ' class and pass that to the variable while ignoring the 'highlightedRow' class? I hope that's not too jumbled for someone to make sense of and many thanks for any help offered.

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  • Accessing a Class Member from a First-Class Function

    - by dbyrne
    I have a case class which takes a list of functions: case class A(q:Double, r:Double, s:Double, l:List[(Double)=>Double]) I have over 20 functions defined. Some of these functions have their own parameters, and some of them also use the q, r, and s values from the case class. Two examples are: def f1(w:Double) = (d:Double) => math.sin(d) * w def f2(w:Double, q:Double) = (d:Double) => d * q * w The problem is that I then need to reference q, r, and s twice when instantiating the case class: A(0.5, 1.0, 2.0, List(f1(3.0), f2(4.0, 0.5))) //0.5 is referenced twice I would like to be able to instantiate the class like this: A(0.5, 1.0, 2.0, List(f1(3.0), f2(4.0))) //f2 already knows about q! What is the best technique to accomplish this? Can I define my functions in a trait that the case class extends? EDIT: The real world application has 7 members, not 3. Only a small number of the functions need access to the members. Most of the functions don't care about them.

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  • DBIx::Class base result class

    - by Rob
    Hi there, I am trying to create a model for Catalyst by using DBIx::Class::Schema::Loader. I want the result classes to have a base class I can add methods to. So MyTable.pm inherits from Base.pm which inherits from DBIx::Class::core (default). Somehow I cannot figure out how to do this. my create script is below, can anyone tell me what I am doing wrong? The script creates my model ok, but all resultset classes just directly inherit from DBIx::Class::core without my Base class in between. #!/usr/bin/perl use DBIx::Class::Schema::Loader qw/ make_schema_at /; #specifically for the entities many-2-many relation $ENV{DBIC_OVERWRITE_HELPER_METHODS_OK} = 1; make_schema_at( 'MyApp::Schema', { dump_directory => '/tmp', debug => 1, overwrite_modifications => 1, components => ['EncodedColumn'], #encoded password column use_namespaces => 1, default_resultset_class => 'Base' }, [ 'DBI:mysql:database=mydb;host=localhost;port=3306','rob', '******' ], );

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  • Instantiating a class within a class

    - by Ink-Jet
    Hello. I'm trying to instantiate a class within a class, so that the outer class contains the inner class. This is my code: #include <iostream> #include <string> class Inner { private: std::string message; public: Inner(std::string m); void print() const; }; Inner::Inner(std::string m) { message = m; } void Inner::print() const { std::cout << message << std::endl; std::cout << message << std::endl; } class Outer { private: std::string message; Inner in; public: Outer(std::string m); void print() const; }; Outer::Outer(std::string m) { message = m; } void Outer::print() const { std::cout << message << std::endl; } int main() { Outer out("Hello world."); out.print(); return 0; } "Inner in", is my attempt at containing the inner within the outer, however, when I compile, i get an error that there is no matching function for call to Inner::Inner(). What have I done wrong? Thanks.

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  • polymorphism, inheritance in c# - base class calling overridden method?

    - by Andrew Johns
    This code doesn't work, but hopefully you'll get what I'm trying to achieve here. I've got a Money class, which I've taken from http://www.noticeablydifferent.com/CodeSamples/Money.aspx, and extended it a little to include currency conversion. The implementation for the actual conversion rate could be different in each project, so I decided to move the actual method for retrieving a conversion rate (GetCurrencyConversionRate) into a derived class, but the ConvertTo method contains code that would work for any implementation assuming the derived class has overriden GetCurrencyConversionRate so it made sense to me to keep it in the parent class? So what I'm trying to do is get an instance of SubMoney, and be able to call the .ConvertTo() method, which would in turn use the overriden GetCurrencyConversionRate, and return a new instance of SubMoney. The problem is, I'm not really understanding some concepts of polymorphism and inheritance yet, so not quite sure what I'm trying to do is even possible in the way I think it is, as what is currently happening is that I end up with an Exception where it has used the base GetCurrencyConversionRate method instead of the derived one. Something tells me I need to move the ConvertTo method down to the derived class, but this seems like I'll be duplicating code in multiple implementations, so surely there's a better way? public class Money { public CurrencyConversionRate { get { return GetCurrencyConversionRate(_regionInfo.ISOCurrencySymbol); } } public static decimal GetCurrencyConversionRate(string isoCurrencySymbol) { throw new Exception("Must override this method if you wish to use it."); } public Money ConvertTo(string cultureName) { // convert to base USD first by dividing current amount by it's exchange rate. Money someMoney = this; decimal conversionRate = this.CurrencyConversionRate; decimal convertedUSDAmount = Money.Divide(someMoney, conversionRate).Amount; // now convert to new currency CultureInfo cultureInfo = new CultureInfo(cultureName); RegionInfo regionInfo = new RegionInfo(cultureInfo.LCID); conversionRate = GetCurrencyConversionRate(regionInfo.ISOCurrencySymbol); decimal convertedAmount = convertedUSDAmount * conversionRate; Money convertedMoney = new Money(convertedAmount, cultureName); return convertedMoney; } } public class SubMoney { public SubMoney(decimal amount, string cultureName) : base(amount, cultureName) {} public static new decimal GetCurrencyConversionRate(string isoCurrencySymbol) { // This would get the conversion rate from some web or database source decimal result = new Decimal(2); return result; } }

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  • Java: reusable encapsulation with interface, abstract class or inner classes?

    - by HH
    I try to encapsulate. Exeption from interface, static inner class working, non-static inner class not working, cannot understand terminology: nested classes, inner classes, nested interfaces, interface-abstract-class -- sounds too Repetitive! Exception 'illegal type' from interface apparently because values being constants(?!) static interface userInfo { File startingFile=new File("."); String startingPath="dummy"; try{ startingPath=startingFile.getCanonicalPath(); }catch(Exception e){e.printStackTrace();} } Working code but no succes with non-static inner class import java.io.*; import java.util.*; public class listTest{ public interface hello{String word="hello word from Interface!";} public static class hej{ hej(){} private String hejo="hello hallo from Static class with image"; public void printHallooo(){System.out.println(hejo);} } public class nonStatic{ nonStatic(){} //HOW TO USE IT? public void printNonStatic(){System.out.println("Inside static class with an image!");} } public static void main(String[] args){ //INTERFACE TEST System.out.println(hello.word); //INNNER CLASS STATIC TEST hej h=new hej(); h.printHallooo(); //INNER CLASS NON-STATIC TEST nonStatic ns=new nonStatic(); ns.printNonStatic(); //IS there a way to it without STATIC? } } Output The above code works but how non-staticly? Output: hello word from Interface! hello hallo from Static class with image! StaticPrint without an image of the class! Related Nesting classes inner classes? interfacses

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  • How to remove CRUD operations from Entity Class

    - by GlutVonSmark
    Trying to get my head around removing dataStore access from my entity classes. Lets say I have an AccountsGroup entity class. I put the all DBAccess into AccountsGroupRepository class. Now should I have a DeleteFromDB method in the AccountsGroup class, that will call the repository? Public Sub DeleteFromDB dim repository as new AccountsGroupRepository(me) repository.DelteFromDB End Sub Or should I just always use repositry whenever I need to delete an entity, and not have the CRUD methods in the entity class? What happens when there is some business logic validation that needs to be done before the delete can proceed. For example if AccountsGroup still has some Accounts in it the delete method should throw an exception. Where do I put that?

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  • Unable to access A class variables in B Class - Unity-Monodevelop

    - by Syed
    I have made a class including variables in Monodevelop which is: public class GridInfo : MonoBehaviour { public float initPosX; public float initPosY; public bool inUse; public int f; public int g; public int h; public GridInfo parent; public int y,x; } Now I am using its class variable in another class, Map.cs which is: public class Map : MonoBehaviour { public static GridInfo[,] Tile = new GridInfo[17, 23]; void Start() { Tile[0,0].initPosX = initPosX; //Line 49 } } Iam not getting any error on runtime, but when I play in unity it is giving me error NullReferenceException: Object reference not set to an instance of an object Map.Start () (at Assets/Scripts/Map.cs:49) I am not inserting this script in any gameobject, as Map.cs will make a GridInfo type array, I have also tried using variables using GetComponent, where is the problem ?

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  • Making Class Diagram for MVC Pattern Project

    - by iMohammad
    I have a question about making a class diagram for an MVC based college senior project. If we have 2 actors of users in my system, lets say Undergrad and Graduate students are the children of abstract class called User. (Generalisation) Each actor has his own features. My question, in such case, do we need to have these two actors in separate classes which inherits from the abstract class User? even though, I'm going to implement them as roles using one Model called User Model ? I think you can see my confusion here. I code using MVC pattern, but I've never made a class diagram for this pattern. Thank you in advance!

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  • Using "public" vars or attributes in class calls, functional approach

    - by marw
    I was always wondering about two things I tend to do in my little projects. Sometimes I will have this design: class FooClass ... self.foo = "it's a bar" self._do_some_stuff(self) def _do_some_stuff(self): print(self.foo) And sometimes this one: class FooClass2 ... self.do_some_stuff(foo="it's a bar") def do_some_stuff(self, foo): print(foo) Although I roughly understand the differences between functional and class approaches, I struggle with the design. For example, in FooClass the self.foo is always accessible as an attribute. If there are numerous calls to it, is that faster than making foo a local variable that is passed from method to method (like in FooClass2)? What happens in memory in both cases? If FooClass2 is preferred (ie. I don't need to access foo) and other attributes inside do not change their states (the class is executed once only and returns the result), should the code then be written as a series of functions in a module?

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  • Nested class or not nested class?

    - by eriks
    I have class A and list of A objects. A has a function f that should be executed every X seconds (for the first instance every 1 second, for the seconds instance every 5 seconds, etc.). I have a scheduler class that is responsible to execute the functions at the correct time. What i thought to do is to create a new class, ATime, that will hold ptr to A instance and the time A::f should be executed. The scheduler will hold a min priority queue of Atime. Do you think it is the correct implementation? Should ATime be a nested class of the scheduler?

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  • C++ threaded class design from non-threaded class

    - by macs
    I'm working on a library doing audio encoding/decoding. The encoder shall be able to use multiple cores (i.e. multiple threads, using boost library), if available. What i have right now is a class that performs all encoding-relevant operations. The next step i want to take is to make that class threaded. So i'm wondering how to do this. I thought about writing a thread-class, creating n threads for n cores and then calling the encoder with the appropriate arguments. But maybe this is an overkill and there is no need for another class, so i'm going to make use of the "user interface" for thread-creation. I hope there are any suggestions.

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  • Include a Class in another model / class / lib

    - by jaycode
    I need to use function "image_path" in my lib class. I tried this (and couple of other variations): class CustomHelpers::Base include ActionView::Helpers::AssetTagHelper def self.image_url(source) abs_path = image_path(source) unless abs_path =~ /^http/ abs_path = "#{request.protocol}#{request.host_with_port}#{abs_path}" end abs_path end end But it didn't work. Am I doing it right? Another question is, how do I find the right class to include? For example if I look at this module: http://api.rubyonrails.org/classes/ActionView/Helpers/AssetTagHelper.html is there a rule of thumb how to include that module in a model / library / class / anything else ?

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  • How to call a method from another class that's been instantiated within the current class

    - by Pavan
    my screen has a few views like such __________________ | _____ | | | | | //viewX is a video screen | | | | | viewX | vY | | //viewY is a custom uiview i created. | |____| | //it contains a method which i would like to call that toggles |_________________| //the hidden property of this view. and when it hides, a little | | //button is replaced no the top right corner on top of viewX | viewZ | //the video layer | | |_________________| //viewZ is a view containing many square views - thumbnails. my question is, i dont know how to register for touch events so that it recognises any touch event on no matter which view the user touches the screen.. atm im handling the touch events for each view inside it. so all works well... however what im trying to do is that when the user taps anywhere else on the screen but on viewY, viewY should dissapear by calling that method in the viewY class. this viewY class is instantiated and has no xib file attached to it. the uiview is created progammatically in the viewY class. this whole class for viewY behviour is instantiated in viewX - the video view. my boss says add delegates.. although i have now clue how to do that... any help? is there anyway i can just make it really simple and be able to say REMOVE VIEW no matter which class im calling from? Also ive seen other people achieve this by using these funky arrows - ... <- etc.. although im not sure if thats what i need or how to implement such a thing. ah i think ive made my question quite complicated but i really mean it to be a simple one, and know it can be done in an easy way!

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  • Use nested static class as ActionListener for the Outer class

    - by Digvijay Yadav
    I want to use an nested static class as an actionListener for the enclosing class's GUI elements. I did something like this: public class OuterClass { public static void myImplementation() { OuterClass.StartupHandler startupHandler = new OuterClass.StartupHandler(); exitMenuItem.addActionListener(startupHandler); // error Line } public static class StartupHandler implements ActionListener { @Override public void actionPerformed(ActionEvent e) { //throw new UnsupportedOperationException("Not supported yet."); if (e.getSource() == exitMenuItem) { System.exit(1); } else if (e.getSource() == helpMenuItem) { // show help menu } } } } But when I invoke this code I get the NullPointerException at the //error Line. Is this the right method to do do this or there is something I did am missing?

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  • Thread class closing from other Class (Activity) with protected void onStop() Android

    - by user1761337
    I have a Problem with Closing the Thread. I will Closing the Thread with onStop,onPause and onDestroy. This is my Source in the Activity Class: @Override protected void onStop(){ super.onStop(); finish(); } @Override protected void onPause() { super.onPause(); finish(); } @Override public void onDestroy() { this.mWakeLock.release(); super.onDestroy(); } And the Thread Class: public class GameThread extends Thread { private SurfaceHolder mSurfaceHolder; private Handler mHandler; private Context mContext; private Paint mLinePaint; private Paint blackPaint; //for consistent rendering private long sleepTime; //amount of time to sleep for (in milliseconds) private long delay=1000/30; //state of game (Running or Paused). int state = 1; public final static int RUNNING = 1; public final static int PAUSED = 2; public final static int STOPED = 3; GameSurface gEngine; public GameThread(SurfaceHolder surfaceHolder, Context context, Handler handler,GameSurface gEngineS){ //data about the screen mSurfaceHolder = surfaceHolder; mHandler = handler; mContext = context; gEngine=gEngineS; } //This is the most important part of the code. It is invoked when the call to start() is //made from the SurfaceView class. It loops continuously until the game is finished or //the application is suspended. private long beforeTime; @Override public void run() { //UPDATE while (state==RUNNING) { Log.d("State","Thread is runnig"); //time before update beforeTime = System.nanoTime(); //This is where we update the game engine gEngine.Update(); //DRAW Canvas c = null; try { //lock canvas so nothing else can use it c = mSurfaceHolder.lockCanvas(null); synchronized (mSurfaceHolder) { //clear the screen with the black painter. //reset the canvas c.drawColor(Color.BLACK); //This is where we draw the game engine. gEngine.doDraw(c); } } finally { // do this in a finally so that if an exception is thrown // during the above, we don't leave the Surface in an // inconsistent state if (c != null) { mSurfaceHolder.unlockCanvasAndPost(c); } } this.sleepTime = delay-((System.nanoTime()-beforeTime)/1000000L); try { //actual sleep code if(sleepTime>0){ this.sleep(sleepTime); } } catch (InterruptedException ex) { Logger.getLogger(GameThread.class.getName()).log(Level.SEVERE, null, ex); } while (state==PAUSED){ Log.d("State","Thread is pausing"); try { this.sleep(1000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } }} How i can close the Thread from Activity Class??

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  • this pointer to base class constructor?

    - by Rolle
    I want to implement a derived class that should also implement an interface, that have a function that the base class can call. The following gives a warning as it is not safe to pass a this pointer to the base class constructor: struct IInterface { void FuncToCall() = 0; }; struct Base { Base(IInterface* inter) { m_inter = inter; } void SomeFunc() { inter->FuncToCall(); } IInterface* m_inter; }; struct Derived : Base, IInterface { Derived() : Base(this) {} FuncToCall() {} }; What is the best way around this? I need to supply the interface as an argument to the base constructor, as it is not always the dervied class that is the interface; sometimes it may be a totally different class. I could add a function to the base class, SetInterface(IInterface* inter), but I would like to avoid that.

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