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  • PHP object class variable

    - by mck89
    I have built a class in PHP and I must declare a class variable as an object. Everytime I want to declare an empty object I use: $var=new stdClass; But if I use it to declare a class variable as class foo { var $bar=new stdClass; } a parse error occurs. Is there a way to do this or must I declare the class variable as an object in the constructor function? PS: I'm using PHP 4.

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  • Problem with OOP Class Definitions

    - by oben
    Hi, this is Oben from Turkey. I work for my homework in C++ and i have some problems with multiply definitions. My graph class ; class Graph{ private: string name; //Graph name fstream* graphFile; //Graph's file protected: string opBuf; //Operations buffer int containsNode(string); //Query if a node is present Node* nodes; //Nodes in the graph int nofNodes; //Number of nodes in the graph public: static int nOfGraphs; //Number of graphs produced Graph(); //Constructors and destructor Graph(int); Graph(string); Graph(const Graph &); ~Graph(); string getGraphName(); //Get graph name bool addNode(string); //add a node to the graph bool deleteNode(string); //delete a node from the graph bool addEdge(string,string); //add an edge to the graph bool deleteEdge(string,string); //delete an edge from the graph void intersect(const Graph&); //intersect the graph with the <par> void unite(const Graph&); //intersect the graph with the <par> string toString(); //get string representation of the graph void acceptTraverse(BreadthFirst*); void acceptTraverse(DepthFirst *); }; and my traversal class; class Traversal { public: string *visitedNodes; virtual string traverse (const Graph & ); }; class BreadthFirst : public Traversal { public : BreadthFirst(); string traverse(); }; class DepthFirst : public Traversal { public : DepthFirst(); string traverse(); }; My problem is in traversal class , i need to declare Graph class at the same time , in graph class i need traversal class to declare. I have big problems with declerations :) Could you please help me ?

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  • Difference between abstract class and interface

    - by nectar
    A class implementing an interface has to implement all the methods of the interface, but if that class is implementing an abctract class is it necessary to implement all abstract methods? If not, can we create the object of that class which is implementing the Abstract class???

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  • Using java abstract class

    - by user969131
    In my UI project, I have few screens that share the same header style only the text is specific to the screens. What will be a good way to implement this? Have the super class create all the header component and open the components to the sub class, the sub class will access to component's setText method to update the text? or Have abstract method in super class to create the components, sub class will implement these methods to create the component. Hope it make sense..

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  • Create a new instance in a static function of an abstract class

    - by arno
    abstract class db_table { static function get_all_rows() { ... while(...) { $rows[] = new self(); ... } return $rows; } } class user extends db_table { } $rows = user::get_all_rows(); I want to create instances of a class from a static method defined in the abstract parent class but PHP tells me "Fatal error: Cannot instantiate abstract class ..." How should I implement it correctly?

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  • How to determine which inheriting class is using an abstract class' methods.

    - by Kin
    In my console application have an abstract Factory class "Listener" which contains code for listening and accepting connections, and spawning client classes. This class is inherited by two more classes (WorldListener, and MasterListener) that contain more protocol specific overrides and functions. I also have a helper class (ConsoleWrapper) which encapsulates and extends System.Console, containing methods for writing to console info on what is happening to instances of the WorldListener and MasterListener. I need a way to determine in the abstract ListenerClass which Inheriting class is calling its methods. Any help with this problem would be greatly appreciated! I am stumped :X Simplified example of what I am trying to do. abstract class Listener { public void DoSomething() { if(inheriting class == WorldListener) ConsoleWrapper.WorldWrite("Did something!"); if(inheriting class == MasterListener) ConsoleWrapper.MasterWrite("Did something!"); } } public static ConsoleWrapper { public void WorldWrite(string input) { System.Console.WriteLine("[World] {0}", input); } } public class WorldListener : Listener { public void DoSomethingSpecific() { ConsoleWrapper.WorldWrite("I did something specific!"); } } public void Main() { new WorldListener(); new MasterListener(); } Expected output [World] Did something! [World] I did something specific! [Master] Did something! [World] I did something specific!

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  • Cannot access Class methods from previous windows form - C#

    - by George
    I am writing an app, still, where I need to test some devices every minute for 30 minutes. It made sense to use a timer set to kick off every 60 secs and do whats required in the event handler. However, I need the app to wait for the 30 mins until I have finished with the timer since the following code alters the state of the devices I am trying to monitor. I obviously don't want to use any form of loop to do this. I thought of using another windows form, since I also display the progress, which will simply kick off the timer and wait until its complete. The problem I am having with this is that I use a device Class and cant seem to get access to the methods in the device class from the 2nd (3rd actually - see below) windows form. I have an initial windows form where I get input from the user, then call the 2nd windows form where it work out which tests need to be done and which device classes need to be used, and then I want to call the 3rd windows form to handle the timer. I will have up to 6-7 device classes and so wanted to only instantiate them when actually requiring them, from the 2nd form. Should I have put this logic into the 1st windows form (program class ??) ? Would I not still have the problem of not being able to access device class methods from there too ? Anyway, perhaps someone knows of a better way to do the checks every minute without the rest of the code executing (and changing the status of the devices) or how I should be accessing the methods in the app ?? Well that's the problem, I cant get that part of it to work correctly. Here is the definition for the calling form including the device class - namespace NdtStart { public partial class fclsNDTCalib : Form { NDTClass NDT = new NDTClass(); public fclsNDTCalib() (new fclsNDTTicker(NDT)).ShowDialog(); Here is the class def for the called form - namespace NdtStart { public partial class fclsNDTTicker : Form { public fclsNDTTicker() I tried lots but couldn't get the arguments to work.

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  • How to determine which inheriting class is using an abstract class's methods.

    - by Kin
    In my console application have an abstract Factory class "Listener" which contains code for listening and accepting connections, and spawning client classes. This class is inherited by two more classes (WorldListener, and MasterListener) that contain more protocol specific overrides and functions. I also have a helper class (ConsoleWrapper) which encapsulates and extends System.Console, containing methods for writing to console info on what is happening to instances of the WorldListener and MasterListener. I need a way to determine in the abstract ListenerClass which Inheriting class is calling its methods. Any help with this problem would be greatly appreciated! I am stumped :X Simplified example of what I am trying to do. abstract class Listener { public void DoSomething() { if(inheriting class == WorldListener) ConsoleWrapper.WorldWrite("Did something!"); if(inheriting class == MasterListener) ConsoleWrapper.MasterWrite("Did something!"); } } public static ConsoleWrapper { public void WorldWrite(string input) { System.Console.WriteLine("[World] {0}", input); } } public class WorldListener : Listener { public void DoSomethingSpecific() { ConsoleWrapper.WorldWrite("I did something specific!"); } } public void Main() { new WorldListener(); new MasterListener(); } Expected output [World] Did something! [World] I did something specific! [Master] Did something! [World] I did something specific!

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  • Jquery adding and removing class dynamically

    - by user244394
    I am trying to add the class"selected" when a link is clicked and when the user click on the next link , I want to remove the previously "selected" class and add "selected" to the link clicked.. -Thanks in advance $(document).ready(function() { $('.news a').click(function(){ $(this).addClass("selected"); }); }); <div class="news-w"> <div class="news" id="getnews-1"> <a href="#" >topic</a> </div> <div class="news" id="getnews-2"> <a href="#">topic</a> </div> <div class="news" id="getnews-3"> <a href="#" >topic</a> </div> <div class="news" id="getnews-4"> <a href="#">topic</a> </div> <div class="news" id="getnews-5"> <a href="#">topic</a> </div> </div>

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  • How to access 'private functions' in a singleton from another object inside it.

    - by Cedric Dugas
    I am currently trying to create a test suite for my javascript apps. My problem is that, it seems I cannot get access to init() from my utils object, as you can see below: I have my app that follow a singleton pattern: var appModal = function () { var utils = Object.create(moduleUtils); function init(caller, options ) { } }(); My test suite is in moduleUtils, this is a object literal converted to a prototype moduleUtils.debug = { addSlideTest : function(){ /* this function cannot fire init() from appModal */ }}

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  • How does this Singleton Web Class persists session data, even though session is not updated in the p

    - by Micah Burnett
    Ok, I've got this singleton-like web class which uses session to maintain state. I initially thought I was going to have to manipulate the session variables on each "set" so that the new values were updated in the session. However I tried using it as-is, and somehow, it remembers state. For example, if run this code on one page: UserContext.Current.User.FirstName = "Micah"; And run this code in a different browser tab, FirstName is displayed correctly: Response.Write(UserContext.Current.User.FirstName); Can someone tell me (prove) how this data is getting persisted in the session? Here is the class: using System; using System.Collections.Generic; using System.Linq; using System.Web; public class UserContext { private UserContext() { } public static UserContext Current { get { if (System.Web.HttpContext.Current.Session["UserContext"] == null) { UserContext uc = new UserContext(); uc.User = new User(); System.Web.HttpContext.Current.Session["UserContext"] = uc; } return (UserContext)System.Web.HttpContext.Current.Session["UserContext"]; } } private string HospitalField; public string Hospital { get { return HospitalField; } set { HospitalField = value; ContractField = null; ModelType = null; } } private string ContractField; public string Contract { get { return ContractField; } set { ContractField = value; ModelType = string.Empty; } } private string ModelTypeField; public string ModelType { get { return ModelTypeField; } set { ModelTypeField = value; } } private User UserField; public User User { get { return UserField; } set { UserField = value; } } public void DoSomething() { } } public class User { public int UserId { get; set; } public string FirstName { get; set; } }

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  • Remove second class from an element and add another class

    - by rahul
    Hi, $(document).ready ( function () { $(".MenuItem").mouseover ( function () { // Remove second class and add another class [ Maintain MenuItem class ] // Eg: For div1 remove Sprite1 and then add Sprite1Dis and for div2 // remove Sprite2 and add Spprite2Dis }); $(".MenuItem").mouseout ( function () { // Reverse of mouseover. ie Remove Sprite1Dis and add Sprite1 }); }); <div id="div1" class="MenuItem Sprite1"> &nbsp; </div> <div id="div2" class="MenuItem Sprite2"> &nbsp; </div> <div id="div3" class="MenuItem Sprite3"> &nbsp; </div> <div id="div4" class="MenuItem Sprite4"> &nbsp; </div> <div id="div5" class="MenuItem Sprite5"> &nbsp; </div> <div id="div6" class="MenuItem Sprite6"> &nbsp; </div> My problem is listed as comment inside the code section. What will be the easiest way to achieve this? Thanks in advance

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  • Which is better: many class definitions in the same file or every class definition in a separate file?

    - by Javed Akram
    Which is better: many class definitions in same file or every class definition in separate file? Examples: 1) Many classes in same file. Say, myManyClasses.cs: namespace myPack { class myClass1() { } class myClass2() { } class myClass3() { } . . . } 2) Every class in separate file: myClass1.cs namespace myPack { class myClass1() { } } myClass2.cs namespace myPack { class myClass2() { } } . . .

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  • Using Lazy<T> and abstract wrapper class to lazy-load complex system parameters

    - by DigiMortal
    .NET Framework 4.0 introduced new class called Lazy<T> and I wrote blog post about it: .Net Framework 4.0: Using System.Lazy<T>. One thing is annoying for me – we have to keep lazy loaded value and its value loader as separate things. In this posting I will introduce you my Lazy<T> wrapper for complex to get system parameters that uses template method to keep lazy value loader in parameter class. Problem with original implementation Here’s the sample code that shows you how Lazy<T> is usually used. This is just sample code, don’t focus on the fact that this is dummy console application. class Program {     static void Main(string[] args)     {         var temperature = new Lazy<int>(LoadMinimalTemperature);           Console.WriteLine("Minimal room temperature: " + temperature.Value);         Console.ReadLine();     }       protected static int LoadMinimalTemperature()     {         var returnValue = 0;           // Do complex stuff here           return true;     } } The problem is that our class with many lazy loaded properties will grow messy if it has all value loading code inside it. This code may be complex for more than one parameter and in this case it is better to use separate class for this parameter. Defining base class for parameters As a first step I will define base class for all lazy-loaded parameters. This class is wrapper around Lazy<T> and it also offers one template method that parameter classes have to override to provide loaded data. public abstract class LazyParameter<T> {     private Lazy<T> _lazyParam;       public LazyParameter()     {         _lazyParam = new Lazy<T>(Load);     }       protected abstract T Load();       public T Value     {         get { return _lazyParam.Value; }     } } It is also possible to extend Lazy<T> but I don’t prefer to do it as Lazy<T> has six constructors we have to take care of. Also I don’t like to expose Lazy<T> public interface to users of my parameter classes. Creating parameter class Now it’s time to create our first parameter class. Notice how few stuff we have in this class besides overridden Load() method. public class MinimalRoomTemperature : LazyParameter<int> {     protected override int Load()     {         var returnValue = 0;           // Do complex stuff here           return returnValue;     } } Using parameter class is simple. Here’s my test code. class Program {     static void Main(string[] args)     {         var parameter = new MinimalRoomTemperature();         Console.WriteLine("Minimal room temperature: " + parameter.Value);         Console.ReadLine();     } } Conclusion Lazy<T> is useful class that you usually don’t want to use outside from API-s. I like this class but I don’t like when people are using this class directly in application code. In this posting I showed you how to use Lazy<T> with wrapper class to get complex parameter loading code out from classes that use this parameter. We ended up with generic base class for parameters that you can also use as base for other similar classes (you have to find better name to base class in this case).

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  • abstract class NumberFormat - very confuse about getInstance()

    - by Alex
    Hi, I'm new to Java and I have a beginner question: NumberFormat is an abstract class and so I assume I can't make an instance of it. But there is a public static (factory?) method getInstance() that allow me to do NumberFormat nf = NumberFormat.getInstance(); I'm quite confuse. I'll be glad if someone could give me hints on: 1) If there is a public method to get an instance of this abstract class, why don't we have also a constructor? 2) This is an abstract class ; how can we have this static method giving us an instance of the class? 3) Why choosing such a design? If I assume it's possible to have an instance of an abstract class (???), I don't get why this class should be abstract at all. Thank you.

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  • abstract class NumberFormat - very confused about getInstance()

    - by Alex
    Hi, I'm new to Java and I have a beginner question: NumberFormat is an abstract class and so I assume I can't make an instance of it. But there is a public static (factory?) method getInstance() that allow me to do NumberFormat nf = NumberFormat.getInstance(); I'm quite confuse. I'll be glad if someone could give me hints on: 1) If there is a public method to get an instance of this abstract class, why don't we have also a constructor? 2) This is an abstract class ; how can we have this static method giving us an instance of the class? 3) Why choosing such a design? If I assume it's possible to have an instance of an abstract class (???), I don't get why this class should be abstract at all. Thank you.

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  • NetBeans 6.8/6.7 UML Class Diagrams

    - by ikurtz
    i have tried to generate Class Diagrams in NetBeans 6.7 and 6.8 but all i get is: i figured out installing UML for 6.8 here: NetBeans 6.8 UML i have followed the instructions here: UML Class diagrams i so far i failed to generate anything meaningful. i have followed the tips: Open your project, then create a new UML project (choose "Reverse Engineered Java-Platform model"). After that all your classes will be available in the UML project under "Model". You can now create a new class diagram and drag your classes from "Model" onto the diagram. but nothing meaningful happens when i drag my classes to the Class Diagrams. it always represents the classes as "datatype" on the diagram and class info is not displayed. any helpful tips regarding how can i fix this? or another way of generating Java class diagrams? thank you for your time.

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  • change the class loading order google app engine java

    - by Shekhar
    I am trying to create an application on google app engine using struts2. Struts2 internally uses freemarker .One of the Freemarker framework classes suppose X internally uses a class javax.swing.Treenode which is not in google app engine jre white list. Now in order to run my application i created a new class X in the same package structure as it was in freemarker framework and copied the class to WEB-INF classes.Then When i run my application it run fine. The problem is that i want to take out the class X from my application sourcecode and move it to newly created jar and place it in WEB-INF/lib folder. So that i can reuse the code in multiple project and my code remains clean of the freemarker code. But when i run the application it picks the old class X from the original freemarker framework.As a result i get ClassNotFoundException. Can anyone provide any help such that i can change the ClassLoading order such that my jar containing X class loads first.

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  • ZipArchive php Class - Does it support all servers?

    - by SoLoGHoST
    Ok, just wondering on the versions of PHP that this class is built into. And if they are built into all platforms (OS's). I'm wanting an approach to search through a zip file and place files using file_put_contents in different filepaths within the webroot. In any case, I'm familiar with how to do this with the ZipArchive class, but I'm wondering if using this class would be a good solution and support MOST, if not ALL servers?? I mean, I'd rather not use a method that requires the Server to have it installed. I'm looking for a solution to this that will support at least MOST servers without having to install the class... Thanks :) Also, I'd like to support opening tar.gz and/or .tgz files if possible, but I don't think the ZipArchive class supports this, but perhaps a different built-in php class does??

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  • Singleton class design in C#, are these two classes equivalent?

    - by Oskar
    I was reading up on singleton class design in C# on this great resource and decided to go with alternative 4: public sealed class Singleton1 { static readonly Singleton1 _instance = new Singleton1(); static Singleton1() { } Singleton1() { } public static Singleton1 Instance { get { return _instance; } } } Now I wonder if this can be rewritten using auto properties like this? public sealed class Singleton2 { static Singleton2() { Instance = new Singleton2(); } Singleton2() { } public static Singleton2 Instance { get; private set; } } If its only a matter of readability I definitely prefer the second version, but I want to get it right.

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  • Visual Studio: Design a UserControl class that derives from an abstract base class

    - by Marcel
    Hi All, I want to have an abstract base class for some of my custom UserControl's. The reason is obvious: they share some common properties and methods (a basic implementation of some elements of an interface actually), and I want to implement them only once. I have done this by defining my abstract base class: public abstract class ViewBase : UserControl, ISomeInterface Then I went to implement one of my views, as usual, with the designer: public partial class SpecialView : UserControl //all OK Up to here all is fine. Now I replace the derivation of my SpecialView class with the abstract base class: public partial class SpecialView : ViewBase //disrupts the designer Now, the designer in Visual Studio 2008 won't work anymore, stating: The designer must create an instance of type 'ViewBase' but it cannot because the type is declared as abstract. How can I circumvent this? I just do not want to have the same code copied for all those views. Info: there is a question question with virtual methods, instead of abstract classes, but there is no suitable solution for me.

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  • Class Methods Inheritence

    - by Roman A. Taycher
    I was told that static methods in java didn't have Inheritance but when I try the following test package test1; public class Main { /** * @param args the command line arguments */ public static void main(String[] args) { TB.ttt(); TB.ttt2(); } } package test1; public class TA { static public Boolean ttt() { System.out.println("TestInheritenceA"); return true; } static public String test ="ClassA"; } package test1; public class TB extends TA{ static public void ttt2(){ System.out.println(test); } } it printed : TestInheritenceA ClassA so do java static methods (and fields have) inheritance (if you try to call a class method does it go down the inheritance chai looking for class methods). Was this ever not the case,are there any inheritance OO languages that are messed up like that for class methods?

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  • C++ Class Inheritance architecture - preventing casting

    - by Some One
    I have a structure of base class and a couple of inherited classed. Base class should be pure virtual class, it should prevent instantiation. Inherited classes can be instantiated. Code example below: class BaseClass { public: BaseClass(void); virtual ~BaseClass(void) = 0; }; class InheritedClass : public BaseClass { public: InheritedClass1(void); ~InheritedClass1(void); }; class DifferentInheritedClass : public BaseClass { public: DifferentInheritedClass(void); ~DifferentInheritedClass(void); }; I want to prevent the following operations to happen: InheritedClass *inherited1 = new InheritedClass(); DifferentInheritedClass *inherited2 = new DifferentInheritedClass (); BaseClass *base_1 = inherited1; BaseClass *base_2 = inherited2; *base_1 = *base_2;

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  • method __getattr__ is not inherited from parent class

    - by ??????
    Trying to subclass mechanize.Browser class: from mechanize import Browser class LLManager(Browser, object): IS_AUTHORIZED = False def __init__(self, login = "", passw = "", *args, **kwargs): super(LLManager, self).__init__(*args, **kwargs) self.set_handle_robots(False) But when I make something like this: lm["Widget[LinksList]_link_1_title"] = anc then I get an error: Traceback (most recent call last): File "<pyshell#8>", line 1, in <module> lm["Widget[LinksList]_link_1_title"] = anc TypeError: 'LLManager' object does not support item assignment Browser class have overridden method __getattr__ as shown: def __getattr__(self, name): # pass through _form.HTMLForm methods and attributes form = self.__dict__.get("form") if form is None: raise AttributeError( "%s instance has no attribute %s (perhaps you forgot to " ".select_form()?)" % (self.__class__, name)) return getattr(form, name) Why my class or instance don't get this method as in parent class?

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