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  • How to write a cctor and op= for a factory class with ptr to abstract member field?

    - by Kache4
    I'm extracting files from zip and rar archives into raw buffers. I created the following to wrap minizip and unrarlib: Archive.hpp #include "ArchiveBase.hpp" #include "ArchiveDerived.hpp" class Archive { public: Archive(string path) { /* logic here to determine type */ switch(type) { case RAR: archive_ = new ArchiveRar(path); break; case ZIP: archive_ = new ArchiveZip(path); break; case UNKNOWN_ARCHIVE: throw; break; } } Archive(Archive& other) { archive_ = // how do I copy an abstract class? } ~Archive() { delete archive_; } void passThrough(ArchiveBase::Data& data) { archive_->passThrough(data); } Archive& operator = (Archive& other) { if (this == &other) return *this; ArchiveBase* newArchive = // can't instantiate.... delete archive_; archive_ = newArchive; return *this; } private: ArchiveBase* archive_; } ArchiveBase.hpp class ArchiveBase { public: // Is there any way to put this struct in Archive instead, // so that outside classes instantiating one could use // Archive::Data instead of ArchiveBase::Data? struct Data { int field; }; virtual void passThrough(Data& data) = 0; /* more methods */ } ArchiveDerived.hpp "Derived" being "Zip" or "Rar" #include "ArchiveBase.hpp" class ArchiveDerived : public ArchiveBase { public: ArchiveDerived(string path); void passThrough(ArchiveBase::Data& data); private: /* fields needed by minizip/unrarlib */ // example zip: unzFile zipFile_; // example rar: RARHANDLE rarFile_; } ArchiveDerived.cpp #include "ArchiveDerived.hpp" ArchiveDerived::ArchiveDerived(string path) { //implement } ArchiveDerived::passThrough(ArchiveBase::Data& data) { //implement } Somebody had suggested I use this design so that I could do: Archive archiveFile(pathToZipOrRar); archiveFile.passThrough(extractParams); // yay polymorphism! How do I write a cctor for Archive? What about op= for Archive? What can I do about "renaming" ArchiveBase::Data to Archive::Data? (Both minizip and unrarlib use such structs for input and output. Data is generic for Zip & Rar and later is used to create the respective library's struct.)

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  • Converting from One Class to another Class using Xml Serialization in C#

    - by nrk
    Hi, In our project we are consuming WCF webservices exposed at Central location as services with basicHttpBinding. In client desktop application we need consume those webservices. I am able to generate proxy class using WSDL.exe. But, I need to convert data/class given by the webservice into my local class, for that now I am xmlserialzing those class/objects given by webservice and deserializing into my local classes as both classes schema matches exactly same. Is there any better way that I can follow? or Do I need to assign each property from one class to another? thanks nRk.

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  • USE case to Class Diagram - How do I?

    - by 01010011
    Hi, I would like your guidance on how to create classes and their relationships (generalization, association, aggregation and composition) accurately from my USE case diagram (please see below). I am trying to create this class diagram so I can use it to create a simple online PHP application that allows the user to register an account, login and logout, and store, search and retrieve data from a MySQL database. Are my classes correct? Or should I create more classes? And if so, what classes are missing? What relationships should I use when connecting the register, login, logout, search_database and add_to_database to the users? I'm new to design patterns and UML class diagrams but from my understanding, the association relationship relates one object with another object; the aggregation relationship is a special kind of association that allows "a part" to belong to more than one "whole" (e.g. a credit card and its PIN - the PIN class can also be used in a debit card class); and a composition relationship is a special form of aggregation that allows each part to belong to only one whole at a time. I feel like I have left out some classes or something because I just can't seem to find the relationships from my understanding of relationships. Any assistance will be really appreciated. Thanks in advance. USE CASE DIAGRAM CLASS DIAGRAM

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  • How to design shape class

    - by Tomek Tarczynski
    I want to design shape class. I need to distinguish several different shapes: -Point -Line -Triangle -Circle -Polygons The main purpose of this class is to calculate distance between two shapes. I've all methods for calculating those distances, but I want to have a single method that can be used, it should looks like this: float Distance(Shape a, Shape b) Simplest way to do it is to put a lot of if statements and then invoke proper method but this is deffinitely not OOP. How to design such class in OOP style?

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  • Python - help on custom wx.Python (pyDev) class

    - by Wallter
    I have been hitting a dead end with this program. I am trying to build a class that will let me control the BIP's of a button when it is in use. so far this is what i have (see following.) It keeps running this weird error TypeError: 'module' object is not callable - I, coming from C++ and C# (for some reason the #include... is so much easier) , have no idea what that means, Google is of no help so... I know I need some real help with sintax and such - anything woudl be helpful. Note: The base code found here was used to create a skeleton for this 'custom button class' Custom Button import wx from wxPython.wx import * class Custom_Button(wx.PyControl): # The BMP's # AM I DOING THIS RIGHT? - I am trying to get empty 'global' # variables within the class Mouse_over_bmp = None #wxEmptyBitmap(1,1,1) # When the mouse is over Norm_bmp = None #wxEmptyBitmap(1,1,1) # The normal BMP Push_bmp = None #wxEmptyBitmap(1,1,1) # The down BMP Pos_bmp = wx.Point(0,0) # The posisition of the button def __init__(self, parent, NORM_BMP, PUSH_BMP, MOUSE_OVER_BMP, pos, size, text="", id=-1, **kwargs): wx.PyControl.__init__(self,parent, id, **kwargs) # The conversions, hereafter, were to solve another but. I don't know if it is # necessary to do this since the source being given to the class (in this case) # is a BMP - is there a better way to prevent an error that i have not # stumbled accost? # Set the BMP's to the ones given in the constructor self.Mouse_over_bmp = wx.Bitmap(wx.Image(MOUSE_OVER_BMP, wx.BITMAP_TYPE_ANY).ConvertToBitmap()) self.Norm_bmp = wx.Bitmap(wx.Image(NORM_BMP, wx.BITMAP_TYPE_ANY).ConvertToBitmap()) self.Push_bmp = wx.Bitmap(wx.Image(PUSH_BMP, wx.BITMAP_TYPE_ANY).ConvertToBitmap()) self.Pos_bmp = self.pos self.Bind(wx.EVT_LEFT_DOWN, self._onMouseDown) self.Bind(wx.EVT_LEFT_UP, self._onMouseUp) self.Bind(wx.EVT_LEAVE_WINDOW, self._onMouseLeave) self.Bind(wx.EVT_ENTER_WINDOW, self._onMouseEnter) self.Bind(wx.EVT_ERASE_BACKGROUND,self._onEraseBackground) self.Bind(wx.EVT_PAINT,self._onPaint) self._mouseIn = self._mouseDown = False def _onMouseEnter(self, event): self._mouseIn = True def _onMouseLeave(self, event): self._mouseIn = False def _onMouseDown(self, event): self._mouseDown = True def _onMouseUp(self, event): self._mouseDown = False self.sendButtonEvent() def sendButtonEvent(self): event = wx.CommandEvent(wx.wxEVT_COMMAND_BUTTON_CLICKED, self.GetId()) event.SetInt(0) event.SetEventObject(self) self.GetEventHandler().ProcessEvent(event) def _onEraseBackground(self,event): # reduce flicker pass def _onPaint(self, event): dc = wx.BufferedPaintDC(self) dc.SetFont(self.GetFont()) dc.SetBackground(wx.Brush(self.GetBackgroundColour())) dc.Clear() dc.DrawBitmap(self.Norm_bmp) # draw whatever you want to draw # draw glossy bitmaps e.g. dc.DrawBitmap if self._mouseIn: # If the Mouse is over the button dc.DrawBitmap(self, self.Mouse_over_bmp, self.Pos_bmp, useMask=False) if self._mouseDown: # If the Mouse clicks the button dc.DrawBitmap(self, self.Push_bmp, self.Pos_bmp, useMask=False) Main.py import wx import Custom_Button from wxPython.wx import * ID_ABOUT = 101 ID_EXIT = 102 class MyFrame(wx.Frame): def __init__(self, parent, ID, title): wxFrame.__init__(self, parent, ID, title, wxDefaultPosition, wxSize(400, 400)) self.CreateStatusBar() self.SetStatusText("Program testing custom button overlays") menu = wxMenu() menu.Append(ID_ABOUT, "&About", "More information about this program") menu.AppendSeparator() menu.Append(ID_EXIT, "E&xit", "Terminate the program") menuBar = wxMenuBar() menuBar.Append(menu, "&File"); self.SetMenuBar(menuBar) self.Button1 = Custom_Button(self, parent, -1, "D:/Documents/Python/Normal.bmp", "D:/Documents/Python/Clicked.bmp", "D:/Documents/Python/Over.bmp", wx.Point(200,200), wx.Size(300,100)) EVT_MENU(self, ID_ABOUT, self.OnAbout) EVT_MENU(self, ID_EXIT, self.TimeToQuit) def OnAbout(self, event): dlg = wxMessageDialog(self, "Testing the functions of custom " "buttons using pyDev and wxPython", "About", wxOK | wxICON_INFORMATION) dlg.ShowModal() dlg.Destroy() def TimeToQuit(self, event): self.Close(true) class MyApp(wx.App): def OnInit(self): frame = MyFrame(NULL, -1, "wxPython | Buttons") frame.Show(true) self.SetTopWindow(frame) return true app = MyApp(0) app.MainLoop() Errors (and traceback) /home/wallter/python/Custom Button overlay/src/Custom_Button.py:8: DeprecationWarning: The wxPython compatibility package is no longer automatically generated or actively maintained. Please switch to the wx package as soon as possible. I have never been able to get this to go away whenever using wxPython any help? from wxPython.wx import * Traceback (most recent call last): File "/home/wallter/python/Custom Button overlay/src/Main.py", line 57, in <module> app = MyApp(0) File "/usr/lib/python2.6/dist-packages/wx-2.8-gtk2-unicode/wx/_core.py", line 7978, in __init__ self._BootstrapApp() File "/usr/lib/python2.6/dist-packages/wx-2.8-gtk2-unicode/wx/_core.py", line 7552, in _BootstrapApp return _core_.PyApp__BootstrapApp(*args, **kwargs) File "/home/wallter/python/Custom Button overlay/src/Main.py", line 52, in OnInit frame = MyFrame(NULL, -1, "wxPython | Buttons") File "/home/wallter/python/Custom Button overlay/src/Main.py", line 32, in __init__ wx.Point(200,200), wx.Size(300,100)) TypeError: 'module' object is not callable I have tried removing the "wx.Point(200,200), wx.Size(300,100))" just to have the error move up to the line above. Have I declared it right? help?

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  • Class Self-Reference

    - by Free Bullets
    I have the following code. The angle function needs some information from the class it was called from. What's the best way to do this? class MyScannedRobotEvent extends robocode.ScannedRobotEvent { public int angle(robocode.Robot myRobot) { return (int) Math.toRadians((myRobot.getHeading() + getBearing()) % 360); } } public class MyRobot extends robocode.Robot { int a = angle(**WHATDOIPUTHERE?**) }

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  • GAE - Getting TypeError requiring class instance be passed to class's own method...

    - by Spencer Leland
    I'm really new to programming... I set up a class to give supporting information for Google's User API user object. I store this info in the datastore using db.model. When I call the okstatus method of my user_info class using this code: elif user_info.okstatus(user): self.response.out.write("user allowed") I get this error: unbound method okstatus() must be called with user_info instance as first argument (got User instance instead) Here is my user_info class. class user_info: def auth_ctrlr(self, user): if self.status(user) == status_allowed: return ("<a href=\"%s\">Sign Out</a>)" % (users.create_login_url("/"))) else: return ("<a href=\"%s\">Sign In or Get an Account</a>)" % (users.create_logout_url("/"))) def status(self, user): match = sub_user.gql(qu_by_user_id, user.user_id) return match.string_status def group(self, user): match = sub_user.gql(qu_by_user_id, user.user_id) grp = group_names.gql(qu_by_user_id, match.groupID) return grp def okstatus(self, user): match = self.status(user) if match == status_allowed: return True My understanding is that the argument "self" inside the method's calling arguments describes it as a child to the class. I've tried everything I can think of and can't find any related info online. Can someone please tell me what I'm doing wrong? Thanks

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  • compiler warning at C++ template base class

    - by eike
    I get a compiler warning, that I don't understand in that context, when I compile the "Child.cpp" from the following code. (Don't wonder: I stripped off my class declarations to the bare minuum, so the content will not make much sense, but you will see the problem quicker). I get the warning with VS2003 and VS2008 on the highest warning level. The code AbstractClass.h : #include <iostream> template<typename T> class AbstractClass { public: virtual void Cancel(); // { std::cout << "Abstract Cancel" << std::endl; }; virtual void Process() = 0; }; //outside definition. if I comment out this and take the inline //definition like above (currently commented out), I don't get //a compiler warning template<typename T> void AbstractClass<T>::Cancel() { std::cout << "Abstract Cancel" << std::endl; } Child.h : #include "AbstractClass.h" class Child : public AbstractClass<int> { public: virtual void Process(); }; Child.cpp : #include "Child.h" #include <iostream> void Child::Process() { std::cout << "Process" << std::endl; } The warning The class "Child" is derived from "AbstractClass". In "AbstractClass" there's the public method "AbstractClass::Cancel()". If I define the method outside of the class body (like in the code you see), I get the compiler warning... AbstractClass.h(7) : warning C4505: 'AbstractClass::Cancel' : unreferenced local function has been removed with [T=int] ...when I compile "Child.cpp". I do not understand this, because this is a public function and the compiler can't know if I later reference this method or not. And, in the end, I reference this method, because I call it in main.cpp and despite this compiler warning, this method works if I compile and link all files and execute the program: //main.cpp #include <iostream> #include "Child.h" int main() { Child child; child.Cancel(); //works, despite the warning } If I do define the Cancel() function as inline (you see it as out commented code in AbstractClass.h), then I don't get the compiler warning. Of course my program works, but I want to understand this warning or is this just a compiler mistake? Furthermore, if do not implement AbsctractClass as a template class (just for a test purpose in this case) I also don't get the compiler warning...?

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  • Rails class << self

    - by xpepermint
    Hey. I would like to understand what "class << self" stands for in the next example. module Utility class Options #:nodoc: class << self def parse(args) end end end end Thx!

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  • State pattern: Why doesn't the context class implement or inherit the State abstract interface/class

    - by Ricket
    I'm reading about the State pattern. I have only just begun, so of course I begin by reading the entire Wikipedia article on it. I noticed that both of the examples in the article have some base abstract class or Java interface for a generic State's methods/functions. Then there are some states which inherit from the base and implement those methods/functions in different ways. Then there's a Context class which has a private member of type State and which, at any time, can be equal to an instance of one of the implementations. That context class also implements the same methods, and passes them onto the current state instance, and then has an additional method to change the state (or depending on design I understand the change of state could be a reaction to one of the implemented methods). Why doesn't this context class specifically "extend" or "implement" the generic State base class/interface?

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  • Do I correctly understand what a class is?

    - by Matt
    I've had trouble finding a clear, concise laymans definition of a class. Usually, they give general ideas without specifically spelling it out, and I'm wondering if I'm understanding this correctly. As I understand it, a class is the set of code that controls an object. For example, in an app that has a button for 'Yes' and a button for 'No', and a text box for output, the code that tells the computer what to do when the user uses the Yes button is one class, the code for hitting No is another class, and an object is the two buttons and what they do together to influence the output box. Am I right, or am I confusing terms here? Thanks

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  • General question about Ruby singleton class

    - by Dex
    module MyModule def my_method; 'hello'; end end class MyClass class << self include MyModule end end MyClass.my_method # => "hello I'm unsure why "include MyModule" needs to be in the singleton class in order to be called using just MyClass. Why can't I go: X = MyClass.new X.my_method

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  • ruby/datamapper: Refactor class methods to module

    - by DeSchleib
    Hello, i've the following code and tried the whole day to refactor the class methods to a sperate module to share the functionality with all of my model classes. Code (http://pastie.org/974847): class Merchant include DataMapper::Resource property :id, Serial [...] class << self @allowed_properties = [:id,:vendor_id, :identifier] alias_method :old_get, :get def get *args [...] end def first_or_create_or_update attr_hash [...] end end end I'd like to archive something like: class Merchant include DataMapper::Resource include MyClassFunctions [...] end module MyClassFunctions def get [...] def first_or_create_or_update[...] end => Merchant.allowed_properties = [:id] => Merchant.get( :id=> 1 ) But unfortunately, my ruby skills are to bad. I read a lot of stuff (e.g. here) and now i'm even more confused. I stumbled over the following two points: alias_method will fail, because it will dynamically defined in the DataMapper::Resource module. How to get a class method allowed_properties due including a module? What's the ruby way to go? Many thanks in advance.

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  • Compare Database container and class container

    - by Mohit Deshpande
    I am using a SQL Server database in my current project. I was watching the MVC Storefront videos (specifically the repository pattern) and I noticed that Rob (the creator of MVC Storefront) used a class called Category and Product, instead of a database and I have notice that using LINQ-SQL or ADO.NET, that a class is generated. Is there an advantage to using a class over a database to store information? Or is it the other way around? Or are they even comparable?

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  • OOP - Handling Automated Instances of a Class - PHP

    - by dscher
    This is a topic that, as a beginner to PHP and programming, sort of perplexes me. I'm building a stockmarket website and want users to add their own stocks. I can clearly see the benefit of having each stock be a class instance with all the methods of a class. What I am stumped on is the best way to give that instance a name when I instantiate it. If I have: class Stock() { ....doing stuff..... } what is the best way to give my instances of it a name. Obviously I can write: $newStock = new Stock(); $newStock.getPrice(); or whatever, but if a user adds a stock via the app, where can the name of that instance come from? I guess that there is little harm in always creating a new child with $newStock = new Stock() and then storing that to the DB which leads me to my next question! What would be the best way to retrieve 20 user stocks(for example) into instances of class Stock()? Do I need to instantiate 20 new instances of class Stock() every time the user logs in or is there something I'm missing? I hope someone answers this and more important hope a bunch of people answer this and it somehow helps someone else who is having a hard time wrapping their head around what probably leads to a really elegant solution. Thanks guys!

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  • Unable to use 'class' as a key in NSDictionary with Xcode 4.5

    - by Vivin Paliath
    I'm trying to use a class as a key in an NSDictionary. I looked at the answer to this question and what I have is pretty much the same; I'm using setObject: forKey:. However, XCode complains, saying Incompatible pointer types sending 'Class' to parameter of type 'id<NSCopying>'. The call I have is: [_bugTypeToSerializerDictionary setObject: bugToStringSerializer forKey: [bugToStringSerializer serializedObjectType]]; bugToStringSerializer is an instance of BugToStringSerializer whose concrete implementations implement serializedObjectType. An example of a concrete implementation looks like this: - (Class) serializedObjectType { return [InfectableBug class]; } What am I doing wrong here?

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