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  • Python: Calling method A from class A within class B?

    - by Tommo
    There are a number of questions that are similar to this, but none of the answers hits the spot - so please bear with me. I am trying my hardest to learn OOP using Python, but i keep running into errors (like this one) which just make me think this is all pointless and it would be easier to just use methods. Here is my code: class TheGUI(wx.Frame): def __init__(self, title, size): wx.Frame.__init__(self, None, 1, title, size=size) # The GUI is made ... textbox.TextCtrl(panel1, 1, pos=(67,7), size=(150, 20)) button1.Bind(wx.EVT_BUTTON, self.button1Click) self.Show(True) def button1Click(self, event): #It needs to do the LoadThread function! class WebParser: def LoadThread(self, thread_id): #It needs to get the contents of textbox! TheGUI = TheGUI("Text RPG", (500,500)) TheParser = WebParser TheApp.MainLoop() So the problem i am having is that the GUI class needs to use a function that is in the WebParser class, and the WebParser class needs to get text from a textbox that exists in the GUI class. I know i could do this by passing the objects around as parameters, but that seems utterly pointless, there must be a more logical way to do this that doesn't using classes seem so pointless? Thanks in advance!

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  • Virtual functions - base class pointer

    - by user980411
    I understood why a base class pointer is made to point to a derived class object. But, I fail to understand why we need to assign to it, a base class object, when it is a base class object by itself. Can anyone please explain that? #include <iostream> using namespace std; class base { public: virtual void vfunc() { cout << "This is base's vfunc().\n"; } }; class derived1 : public base { public: void vfunc() { cout << "This is derived1's vfunc().\n"; } }; int main() { base *p, b; derived1 d1; // point to base p = &b; p->vfunc(); // access base's vfunc() // point to derived1 p = &d1; p->vfunc(); // access derived1's vfunc() return 0; }

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  • Recommened design pattern to handle multiple compression algorithms for a class hierarchy

    - by sgorozco
    For all you OOD experts. What would be the recommended way to model the following scenario? I have a certain class hierarchy similar to the following one: class Base { ... } class Derived1 : Base { ... } class Derived2 : Base { ... } ... Next, I would like to implement different compression/decompression engines for this hierarchy. (I already have code for several strategies that best handle different cases, like file compression, network stream compression, legacy system compression, etc.) I would like the compression strategy to be pluggable and chosen at runtime, however I'm not sure how to handle the class hierarchy. Currently I have a tighly-coupled design that looks like this: interface ICompressor { byte[] Compress(Base instance); } class Strategy1Compressor : ICompressor { byte[] Compress(Base instance) { // Common compression guts for Base class ... // if( instance is Derived1 ) { // Compression guts for Derived1 class } if( instance is Derived2 ) { // Compression guts for Derived2 class } // Additional compression logic to handle other class derivations ... } } As it is, whenever I add a new derived class inheriting from Base, I would have to modify all compression strategies to take into account this new class. Is there a design pattern that allows me to decouple this, and allow me to easily introduce more classes to the Base hierarchy and/or additional compression strategies?

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  • Help with Abstract Factory Pattern

    - by brazc0re
    I need help with a abstract factory pattern design. This question is a continuation of: Design help with parallel process I am really confused where I should be initializing all of the settings for each type of medium (ex: RS232, TCP/IP, etc). Attached is the drawing on how I am setting up the pattern: As shown, when a medium is created, each medium imposes a ICreateMedium interface. I would assume that the Create() method also create the proper object, such as SerialPort serialPort = new SerialPort("COM1", baud); however, TCPIPMedium would have an issue with the interface because it wouldn't need to initialize a serial port object. I know I am doing something majorly wrong here. I just can't figure it out and have been stuck for a while. What I also get confused on show the interface IMedium will get access to the communication object once it is created so it can write out the appropriate byte[] packet. Any guidance would be greatly appreciated. My main goal is to have the Communicator class spit a packet out without caring which type of medium is active.

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  • How to assign class property as display data member in datagridview

    - by KoolKabin
    hi guys, I am trying to display my data in datagridview. I created a class with different property and used its list as the datasource. it worked fine. but I got confused how to do that in case we have nested class. My Classes are as follows: class Category property UIN as integer property Name as string end class class item property uin as integer property name as string property mycategory as category end class my data list as follows: dim myDataList as list(of Item) = new List(of Item) myDataList.Add(new Item(1,"item1",new category(1,"cat1"))) myDataList.Add(new Item(2,"item2",new category(1,"cat1"))) myDataList.Add(new Item(3,"item3",new category(1,"cat1"))) myDataList.Add(new Item(4,"item4",new category(2,"cat2"))) myDataList.Add(new Item(5,"item5",new category(2,"cat2"))) myDataList.Add(new Item(6,"item6",new category(2,"cat2"))) Now I binded the datagridview control like: DGVMain.AutoGenerateColumns = False DGVMain.ColumnCount = 3 DGVMain.Columns(0).DataPropertyName = "UIN" DGVMain.Columns(0).HeaderText = "ID" DGVMain.Columns(1).DataPropertyName = "Name" DGVMain.Columns(1).HeaderText = "Name" DGVMain.Columns(2).DataPropertyName = "" **'here i want my category name** DGVMain.Columns(2).HeaderText = "category" DGVMain.datasource = myDataList DGVMain.refresh() I have tried using mycategory.name but it didn't worked. What can be done to get expected result? Is there any better idea other than this to accomplish the same task? Edited My question as per comment: I have checked the link given by u. It was nice n very usefull. Since the code was in c# i tried to convert it in vb. Everything went good but failed at a point of case sensitive and next one is that i had my nested class name itemcategory and my property name was category. there it arouse the problem. it didn't searched for category but it searched for itemcategory. so confused on it. My Code as follows: Private Sub DGVMain_CellFormatting(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellFormattingEventArgs) Handles DGVMain.CellFormatting Dim DGVMain As DataGridView = CType(sender, DataGridView) e.Value = EvaluateValue(DGVMain.Rows(e.RowIndex).DataBoundItem, DGVMain.Columns(e.ColumnIndex).DataPropertyName) End Sub Private Function EvaluateValue(ByRef myObj As Object, ByRef myProp As String) As String Dim Ret As String = "" Dim Props As System.Reflection.PropertyInfo() Dim PropA As System.Reflection.PropertyInfo Dim ObjA As Object If myProp.Contains(".") Then myProp = myProp.Substring(0, myProp.IndexOf(".")) Props = myObj.GetType().GetProperties() For Each PropA In Props ObjA = PropA.GetValue(myObj, New Object() {}) If ObjA.GetType().Name = myProp Then Ret = EvaluateValue(ObjA, myProp.Substring(myProp.IndexOf(".") + 1)) Exit For End If Next Else PropA = myObj.GetType().GetProperty(myProp) Ret = PropA.GetValue(myObj, New Object() {}).ToString() End If Return Ret End Function

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  • How to restrict an access to some of the functions at third level in Classes (OOPs)

    - by Shantanu Gupta
    I have created a class say A which has some functions defined as protected. Now Class B inherits A and class C inherits B. Class A has private default constructor and protected parameterized constructor. I want Class B to be able to access all the protected functions defined in Class A but class C can have access on some of the functions only not all the functions and class C is inheriting class B. How can I restrict access to some of the functions of Class A from Class C ? Class A { private A(){} protected A(int ){} } Class B : A {} CLass C:B { }

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  • C# MultiThread Safe Class Design

    - by Robert
    I'm trying to designing a class and I'm having issues with accessing some of the nested fields and I have some concerns with how multithread safe the whole design is. I would like to know if anyone has a better idea of how this should be designed or if any changes that should be made? using System; using System.Collections; namespace SystemClass { public class Program { static void Main(string[] args) { System system = new System(); //Seems like an awkward way to access all the members dynamic deviceInstance = (((DeviceType)((DeviceGroup)system.deviceGroups[0]).deviceTypes[0]).deviceInstances[0]); Boolean checkLocked = deviceInstance.locked; //Seems like this method for accessing fields might have problems with multithreading foreach (DeviceGroup dg in system.deviceGroups) { foreach (DeviceType dt in dg.deviceTypes) { foreach (dynamic di in dt.deviceInstances) { checkLocked = di.locked; } } } } } public class System { public ArrayList deviceGroups = new ArrayList(); public System() { //API called to get names of all the DeviceGroups deviceGroups.Add(new DeviceGroup("Motherboard")); } } public class DeviceGroup { public ArrayList deviceTypes = new ArrayList(); public DeviceGroup() {} public DeviceGroup(string deviceGroupName) { //API called to get names of all the Devicetypes deviceTypes.Add(new DeviceType("Keyboard")); deviceTypes.Add(new DeviceType("Mouse")); } } public class DeviceType { public ArrayList deviceInstances = new ArrayList(); public bool deviceConnected; public DeviceType() {} public DeviceType(string DeviceType) { //API called to get hardwareIDs of all the device instances deviceInstances.Add(new Mouse("0001")); deviceInstances.Add(new Keyboard("0003")); deviceInstances.Add(new Keyboard("0004")); //Start thread CheckConnection that updates deviceConnected periodically } public void CheckConnection() { //API call to check connection and returns true this.deviceConnected = true; } } public class Keyboard { public string hardwareAddress; public bool keypress; public bool deviceConnected; public Keyboard() {} public Keyboard(string hardwareAddress) { this.hardwareAddress = hardwareAddress; //Start thread to update deviceConnected periodically } public void CheckKeyPress() { //if API returns true this.keypress = true; } } public class Mouse { public string hardwareAddress; public bool click; public Mouse() {} public Mouse(string hardwareAddress) { this.hardwareAddress = hardwareAddress; } public void CheckClick() { //if API returns true this.click = true; } } }

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  • how to loop through menu and remove class and then add class to current menu item

    - by Jonathan Lyon
    Hi all I have this menu structure that is used to navigate through content slider panels. <div id="menu"> <ul> <li><a href="#1" class="cross-link highlight">Bliss Fine Foods</a></li> <li><a href="#2" class="cross-link">Menus</a></li> <li><a href="#3" class="cross-link">Wines</a></li> <li><a href="#4" class="cross-link">News</a></li> <li><a href="#5" class="cross-link">Contact Us</a></li> </ul> </div> I would like to loop through these elements and remove the highlight class and then add the highlight class to the current / last clicked menu item. Any ideas? Any help would be greatly appreciated. Thanks Jonathan

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  • DomainContext class is not created in a RIA services class library solution

    - by Konamiman
    I have created a RIA services class library project and things are not going as I expected. The problem is that when I add domain service classes to the server project, the corresponding domain context classes are not generated on the client project. I start by creating a new project of type WCF RIA services class library. The generated solution has two projects: RIAServicesLibrary1 (the Silverlight class library project) and RIAServicesLibrary1.Web (the class library that will hold the services). Then I add a new project item to RIAServicesLibrary1.Web of type DomainServiceClass. I add a sample method so that the resulting class code is: namespace RIAServicesLibrary1.Web { using System; using System.Collections.Generic; using System.ComponentModel; using System.ComponentModel.DataAnnotations; using System.Linq; using System.ServiceModel.DomainServices.Hosting; using System.ServiceModel.DomainServices.Server; // TODO: Create methods containing your application logic. [EnableClientAccess()] public class DomainService1 : DomainService { [Invoke] void DoSomething() { } } } Then I generate the whole solution and... nothing happens on the client project. The Generated_Code folder is empty, and the domain context object for the service is not here. Funny enough, if I add a new item of type Authentication domain service, it works as expected: the file RIAServicesLibrary1.Web.g.cs is created on the client project, containing the AuthenticationDomainService1 class as expected. So what's happening here? Am I doing something wrong? Note: I am using Visual Studio 2010 Ultimate RTM and WCF RIA services 1.0.

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  • Create static instances of a class inside said class in Python

    - by Samir Talwar
    Apologies if I've got the terminology wrong here—I can't think what this particular idiom would be called. I've been trying to create a Python 3 class that statically declares instances of itself inside itself—sort of like an enum would work. Here's a simplified version of the code I wrote: class Test: A = Test("A") B = Test("B") def __init__(self, value): self.value = value def __str__(self): return "Test: " + self.value print(str(Test.A)) print(str(Test.B)) Writing this, I got an exception on line 2 (A = Test("A")). I assume line 3 would also error if it had made it that far. Using __class__ instead of Test gives the same error. File "<stdin>", line 1, in <module> File "<stdin>", line 2, in Test NameError: name 'Test' is not defined Is there any way to refer to the current class in a static context in Python? I could declare these particular variables outside the class or in a separate class, but for clarity's sake, I'd rather not if I can help it. To better demonstrate what I'm trying to do, here's the same example in Java: public class Test { private static final Test A = new Test("A"); private static final Test B = new Test("B"); private final String value; public Test(String value) { this.value = value; } public String toString() { return "Test: " + value; } public static void main(String[] args) { System.out.println(A); System.out.println(B); } } This works as you would expect: it prints: Test: A Test: B How can I do the same thing in Python?

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  • Objective C - creating concrete class instances from base class depending upon type

    - by indiantroy
    Just to give a real world example, say the base class is Vehicle and concrete classes are TwoWheeler and FourWheeler. Now the type of the vehicle - TwoWheeler or FourWheeler, is decided by the base class Vehicle. When I create an instance of TwoWheeler/FourWheeler using alloc-init method, it calls the super implementation like below to set the value of common properties defined in the Vehicle class and out of these properties one of them is type that actually decides if the type is TwoWheeler or FourWheeler. if (self = [super initWithDictionary:dict]){ [self setOtherAttributes:dict]; return self; } Now when I get a collection of vehicles some of them could be TwoWheeler and others will be FourWheeler. Hence I cannot directly create an instance of TwoWheeler or FourWheeler like this Vehicle *v = [[TwoWheeler alloc] initWithDictionary:dict]; Is there any way I can create an instance of base class and once I know the type, create an instance of child class depending upon type and return it. With the current implementation, it would result in infinite loop because I call super implementation from concrete class. What would be the perfect design to handle this scenario when I don't know which concrete class should be instantiated beforehand?

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  • Foreach PHP Error

    - by Logan
    I am receiving the following foreach error on my PHP file and I have no idea how to fix it. Does anyone have any ideas? When I load the page I get this: Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 61 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Warning: Invalid argument supplied for foreach() in /home/mysite/public_html/merge/class/global_functions.php on line 89 Line 61 and 89 of my /class/global_functions.php are as followed: Here is my code from line 61 to line 98: foreach($GLOBALS['userpermbit'] as $v) { if(strstr($v['perm'],'|'.$pageperm_id[0]['id'].'|')) return true; } //if they dont have perms and we're not externally including functions return false if ($GLOBALS['external'] != true) return false; return true; } //FUNCTION: quick perm check using perm info from the onload perm check function stealthPermCheck($req) { #if theyre an admin give them perms if(@in_array($GLOBALS['user'][0]['id'], $GLOBALS['superAdmins'])) return true; if(!is_numeric($req)) { #if the req is numeric we need to match a title, not a permid. So try to do that foreach($GLOBALS['userpermbit'] as $v) { if(stristr($v['title'],$req)) return true; } }else{ #check if they have perms numerically if so return true foreach($GLOBALS['userpermbit'] as $v) { if(strstr($v['perm'],'|'.$req.'|')) return true; } } #if none of this returned true they dont have perms, return false return false; }

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  • How to have Moose return a child class instance instead of its own class, for polymorphism

    - by alex8657
    I want to create a generic class, whose builder would not return an instance of this generic class, but an instance of a dedicated children class. As Moose does automatic object building, i do not get to understand if this something possible, and how to create a Moose class with Moose syntax and having this behaviour Eg: The user asks: $file = Repository-new(uri='sftp://blabla') .... and is returned an Repository::_Sftp instance User would use $file as if it is a Repository instance, without the need to know the real subclass (polymorphism)

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  • Class accessing inner class privates?

    - by aloh
    Class Outer { ... private class Node { private T data; ... private T getData() { return data; } } } What's the purpose of using set and get methods if the outer class can access inner class private members? What's the purpose of making inner classes private? Package access?

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  • CodeIgniter load class into class

    - by user355510
    Hello guys, i have start working with CodeIgniter, but i can't understand one think. How do i load one class into another? $this->load->library("hello_world"); This is not working? my class - load - hello_world class class myclass { function test() { $this->load->library("hello_world"); $this->hello_world->hello(); } } Message: Undefined property: myclass::$load

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  • Get derived class type from a base's class static method

    - by Marco Bettiolo
    Hi, i would like to get the type of the derived class from a static method of its base class. How can this be accomplished? Thanks! class BaseClass { static void Ping () { Type t = this.GetType(); // should be DerivedClass, but it is not possible with a static method } } class DerivedClass : BaseClass {} // somewhere in the code DerivedClass.Ping();

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  • Class Design -- Multiple Calls from One Method or One Call from Multiple Methods?

    - by Andrew
    I've been working on some code recently that interfaces with a CMS we use and it's presented me with a question on class design that I think is applicable in a number of situations. Essentially, what I am doing is extracting information from the CMS and transforming this information into objects that I can use programatically for other purposes. This consists of two steps: Retrieve the data from the CMS (we have a DAL that I use, so this is essentially just specifying what data from the CMS I want--no connection logic or anything like that) Map the parsed data to my own [C#] objects There are basically two ways I can approach this: One call from multiple methods public void MainMethodWhereIDoStuff() { IEnumerable<MyObject> myObjects = GetMyObjects(); // Do other stuff with myObjects } private static IEnumerable<MyObject> GetMyObjects() { IEnumerable<CmsDataItem> cmsDataItems = GetCmsDataItems(); List<MyObject> mappedObjects = new List<MyObject>(); // do stuff to map the CmsDataItems to MyObjects return mappedObjects; } private static IEnumerable<CmsDataItem> GetCmsDataItems() { List<CmsDataItem> cmsDataItems = new List<CmsDataItem>(); // do stuff to get the CmsDataItems I want return cmsDataItems; } Multiple calls from one method public void MainMethodWhereIDoStuff() { IEnumerable<CmsDataItem> cmsDataItems = GetCmsDataItems(); IEnumerable<MyObject> myObjects = GetMyObjects(cmsDataItems); // do stuff with myObjects } private static IEnumerable<MyObject> GetMyObjects(IEnumerable<CmsDataItem> itemsToMap) { // ... } private static IEnumerable<CmsDataItem> GetCmsDataItems() { // ... } I am tempted to say that the latter is better than the former, as GetMyObjects does not depend on GetCmsDataItems, and it is explicit in the calling method the steps that are executed to retrieve the objects (I'm concerned that the first approach is kind of an object-oriented version of spaghetti code). On the other hand, the two helper methods are never going to be used outside of the class, so I'm not sure if it really matters whether one depends on the other. Furthermore, I like the fact that in the first approach the objects can be retrieved from one line-- most likely anyone working with the main method doesn't care how the objects are retrieved, they just need to retrieve the objects, and the "daisy chained" helper methods hide the exact steps needed to retrieve them (in practice, I actually have a few more methods but am still able to retrieve the object collection I want in one line). Is one of these methods right and the other wrong? Or is it simply a matter of preference or context dependent?

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  • How to implement or emulate an "abstract" OCUnit test class?

    - by Quinn Taylor
    I have a number of Objective-C classes organized in an inheritance hierarchy. They all share a common parent which implements all the behaviors shared among the children. Each child class defines a few methods that make it work, and the parent class raises an exception for the methods designed to be implemented/overridden by its children. This effectively makes the parent a pseudo-abstract class (since it's useless on its own) even though Objective-C doesn't explicitly support abstract classes. The crux of this problem is that I'm unit testing this class hierarchy using OCUnit, and the tests are structured similarly: one test class that exercises the common behavior, with a subclass corresponding to each of the child classes under test. However, running the test cases on the (effectively abstract) parent class is problematic, since the unit tests will fail in spectacular fashion without the key methods. (The alternative of repeating the common tests across 5 test classes is not really an acceptable option.) The non-ideal solution I've been using is to check (in each test method) whether the instance is the parent test class, and bail out if it is. This leads to repeated code in every test method, a problem that becomes increasingly annoying if one's unit tests are highly granular. In addition, all such tests are still executed and reported as successes, skewing the number of meaningful tests that were actually run. What I'd prefer is a way to signal to OCUnit "Don't run any tests in this class, only run them in its child classes." To my knowledge, there isn't (yet) a way to do that, something similar to a +(BOOL)isAbstractTest method I can implement/override. Any ideas on a better way to solve this problem with minimal repetition? Does OCUnit have any ability to flag a test class in this way, or is it time to file a Radar? Edit: Here's a link to the test code in question. Notice the frequent repetition of if (...) return; to start a method, including use of the NonConcreteClass() macro for brevity.

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  • Php: Overriding abstract method goes wrong

    - by Lu4
    Hi! I think there is a problem in php's OOP implementation. EDIT: Consider more illustrative example: abstract class Animal { public $name; // public function Communicate(Animal $partner) {} // Works public abstract function Communicate(Animal $partner); // Gives error } class Panda extends Animal { public function Communicate(Panda $partner) { echo "Hi {$partner->name} I'm a Panda"; } } class Human extends Animal { public function Communicate(Human $partner) { echo "Hi {$partner->name} I'm a Human"; } } $john = new Human(); $john->name = 'John'; $mary = new Human(); $mary->name = 'Mary'; $john->Communicate($mary); // should be ok $zuzi = new Panda(); $zuzi->name = 'Zuzi'; $zuzi->Communicate($john); // should give error The problem is that when Animal::Communicate is an abstract method, php tells that the following methods are illegal: "public function Communicate(Panda $partner)" "public function Communicate(Human $partner)" but when Animal::Communicate is non-abstract but has zero-implementation Php thinks that these methods are legal. So in my opinion it's not right because we are doing override in both cases, and these both cases are equal, so it seems like it's a bug... Older part of the post: Please consider the following code: Framework.php namespace A { class Component { ... } abstract class Decorator { public abstract function Decorate(\A\Component $component); } } Implementation.php namespace B { class MyComponent extends \A\Component { ... } } MyDecorator.php namespace A { class MyDecorator extends Decorator { public function Decorate(\B\MyComponent $component) { ... } } } The following code gives error in MyDecorator.php telling Fatal error: Declaration of MyDecorator::Decorate() must be compatible with that of A\Decorator::Decorate() in MyDecorator.php on line ... But when I change the Framework.php::Decorator class to the following implementation: abstract class Decorator { public function Decorate(\A\Component $component) {} } the problem disappears.

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  • PHP extend a class method that is called from another class which extends it and calls the method wi

    - by dan.codes
    I am trying to extend a class and override one of its methods. lets call that class A. My class, class B, is overiding a protected method. Class C extends class A and Class D extends class C. Inside of Class D, the method I am trying to overwrite is also extended here and that calls parent::mymethodimoverriding. That method does not exist in class C so it goes to it in class A. That is the method I am overiding in class B and obviously you can't extend A with B and have those changes show up in D since it does not fall in line with the class hierarchy. I might be wrong, so correct me please. so if my class b is called and ran then class D gets called it runs the method in A and overwrites what I had set. I am thinking there must be a way to get this to work, I am just missing something. here is an example, as you can see in class A there is a call to setTitle and it is set to "Example" In my class I set it to "NewExample". My class is getting called before class D so when class D is called it goes back to the parent and sets the title back to "Example" class A{ protected function _thefunction(){ setTitle("Example"); } } class B extends A{ protected function _thefunction(){ My new code here setTitle("NewExample"); } } class C extends A{ nothing that matters in here for what I am doing } class D extends C{ protected function _thefunction(){ parent::_thefunction(); additional code here } }

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