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  • Javascript static method intheritance

    - by Matteo Pagliazzi
    I want to create a javascript class/object that allow me to have various method: Model class Model.all() » static method Model.find() » static method Model delete() » instance method Model save() » instance method Model.create() » static that returns a new Model instance For static method I can define them using: Model.staticMethod(){ method } while for instance method is better to use: function Model(){ this.instanceMethod = function(){} } and then create a new instance or using prototype? var m = function Model(){ } m.prototype.method() = function(){ } Now let's say that I want to create a new class based on Model, how to inherit not only its prototypes but also its static methods?

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  • Using injected EntityManager in class hierarchies

    - by Emre Sahin
    The following code works: @Stateless @LocalBean public class MyClass { @PersistenceContext(name = "MyPU") EntityManager em; public void myBusinessMethod(MyEntity e) { em.persist(e); } } But the following hierarchy gives a TransactionRequiredException in Glassfish 3.0 (and standard JPA annotations with EclipseLink.) at the line of persist. @Stateless @LocalBean public class MyClass extends MyBaseClass { public void myBusinessMethod(MyEntity e) { super.update(e); } } public abstract class MyBaseClass { @PersistenceContext(name = "MyPU") EntityManager em; public void update(Object e) { em.persist(e); } } For my EJB's I collected common code in an abstract class for cleaner code. (update also saves who did the operation and when, all my entities implement an interface.) This problem is not fatal, I can simply copy update and sister methods to subclasses but I would like to keep all of them together in a single place. I didn't try but this may be because my base class is abstract, but I would like to learn a proper method for such a (IMHO common) use case.

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  • Call Ruby class over java with jruby

    - by r2
    Hi all If I implement a class in ruby and compile it with jrubyc than it is not possible to call it from a java class directly if I start it with java. If I see this right I have to use org.jruby.embed... to implement a wrapper wich takes a class name and a metod to call my ruby class. Do I have to do this also if I start the application with jruby? In my current project I start java workflow engine completely with jruby. The workflow has to call a method in a ruby class which he cant find. Maybe easier to understand: [ruby_class] <-----has to call----. | jruby [ruby_start_script] --starts--> [java wfe]

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  • Adding Class instance as a new Row in DataGridView (c#)

    - by Amit Shah
    Hi All, I have a class say [Serializable] public class Answer { [DisplayName("ID")] public string ID { get; set; } [DisplayName("Value")] public string Value { get; set; } } and I have a datagridview with bounded columns to the above class. instances of this class Answer are created dynamically as and when required. How do I update datagridview when each and every instance of class is created. is it possible to do something of this sort. dataGridView.Rows.Add(classInstance); Thanks in Advance, Amit

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  • Limited options for accessing events in derived classes?

    - by maxp
    Im refactoring a class, and moving sections into a base class. I have a few events similar to public event EventHandler GridBinding; Which are now in the base class, but i am finding i cannot now check to see if the event is null in my derived class. Doing so gives me the error: The event 'xyz.GridBinding' can only appear on the left hand side of += or -= (except when used from within the type 'xyz._MyBaseClass'). Is this correct, am i missing anything, or is there any way to get around this or is writing an accessor the only way to do this? I am using c#/.net 4.0

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  • CentOS5 python wrong ELF class: ELFCLASS32

    - by user788171
    Has anybody ever encountered this wrong ELF class error? The failure is provided in more detail below: [root@nocloud ~]# system-config-users Traceback (most recent call last): File "/usr/share/system-config-users/system-config-users.py", line 25, in ? import libuser ImportError: /usr/lib/python2.4/site-packages/libusermodule.so: wrong ELF class: ELFCLASS32 Can anybody tell me how I might possibly be able to fix this? It looks like python broke on my server.

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  • Class inheritance in PHP 5.2: Overriding static variable in extension class?

    - by Christoffer
    Hi, I need to bea be able to use a static variable set in a class that extends a base class... from the base class. Consider this: class Animal { public static $color = 'black'; public static function get_color() { return self::$color; } } class Dog { public static $color = 'brown'; } echo Animal::get_color(); // prints 'black' echo Dog::get_color(); // also prints 'black' This works wonderfully in PHP 5.3.x (Dog::get_color() prints 'brown') since it has late static binding. But my production server runs PHP 5.2.11 and so I need to adapt my script. Is there a somewhat pretty workaround to solve this issue? Cheers! Christoffer

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  • Help required in adding new methods, properties into existing classes dynamically

    - by Bepenfriends
    Hi All, I am not sure whether it is possible to achieve this kind of implementation in Dot Net. Below are the information Currently we are on an application which is done in COM+, ASP, XSL, XML technologies. It is a multi tier architecture application in which COM+ acts as the BAL. The execution steps for any CRUD operation will be defined using a seperate UI which uses XML to store the information. BAL reads the XML and understands the execution steps which are defined and executes corresponding methods in DLL. Much like EDM we have our custom model (using XML) which determines which property of object is searchable, retrievable etc. Based on this information BAL constructs queries and calls procedures to get the data. In the current application both BAL and DAL are heavily customizable without doing any code change. the results will be transmitted to presentation layer in XML format which constructs the UI based on the data recieved. Now I am creating a migration project which deals with employee information. It is also going to follow the N Tier architecture in which the presentation layer communicates with BAL which connects to DAL to return the Data. Here is the problem, In our existing version we are handling every information as XML in its native form (no converstion of object etc), but in the migration project, Team is really interested in utilizing the OOP model of development where every information which is sent from BAL need to be converted to objects of its respective types (example employeeCollection, Address Collection etc). If we have the static number of data returned from BAL we can have a class which contains those nodes as properties and we can access the same. But in our case the data returned from our BAL need to be customized. How can we handle the customization in presentation layer which is converting the result to an Object. Below is an example of the XML returned <employees> <employee> <firstName>Employee 1 First Name</firstName> <lastName>Employee 1 Last Name</lastName> <addresses> <address> <addressType>1</addressType> <StreetName>Street name1</StreetName> <RegionName>Region name</RegionName> <address> <address> <addressType>2</addressType> <StreetName>Street name2</StreetName> <RegionName>Region name</RegionName> <address> <address> <addressType>3</addressType> <StreetName>Street name3</StreetName> <RegionName>Region name</RegionName> <address> <addresses> </employee> <employee> <firstName>Employee 2 First Name</firstName> <lastName>Employee 2 Last Name</lastName> <addresses> <address> <addressType>1</addressType> <StreetName>Street name1</StreetName> <RegionName>Region name</RegionName> <address> <address> <addressType>2</addressType> <StreetName>Street name2</StreetName> <RegionName>Region name</RegionName> <address> <addresses> </employee> </employees> If these are the only columns then i can write a class which is like public class Address{ public int AddressType {get;set;}; public string StreetName {get;set;}; public string RegionName {get;set;}; } public class Employee{ public string FirstName {get; set;} public string LastName {get; set;} public string AddressCollection {get; set;} } public class EmployeeCollection : List<Employee>{ public bool Add (Employee Data){ .... } } public class AddressCollection : List<Address>{ public bool Add (Address Data){ .... } } This class will be provided to customers and consultants as DLLs. We will not provide the source code for the same. Now when the consultants or customers does customization(example adding country to address and adding passport information object with employee object) they must be able to access those properties in these classes, but without source code they will not be able to do those modifications.which makes the application useless. Is there is any way to acomplish this in DotNet. I thought of using Anonymous classes but, the problem with Anonymous classes are we can not have methods in it. I am not sure how can i fit the collection objects (which will be inturn an anonymous class) Not sure about datagrid / user control binding etc. I also thought of using CODEDom to create classes runtime but not sure about the meory, performance issues. also the classes must be created only once and must use the same till there is another change. Kindly help me out in this problem. Any kind of help meterial/ cryptic code/ links will be helpful.

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  • Can I pass a child class to a reference of a parent class?

    - by michael
    Hi, I have a class A which takes a reference of B in its constructor. class A { public: A(B& b); } And I have a class SubB which is a child class of B: class SubB : public B { //omitted... } In my code, I create a SubB and pass it to A: SubB subB; A a(subB); But I get this compile Error: error: ‘B’ is an inaccessible base of ‘SubB’ Can I pass a reference of SubB as B? Thank you.

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  • Ruby get inheriting class

    - by Brian D.
    I'm working on creating my first plugin for rails. I'm still pretty new to ruby and I was wondering if its possible to get the inheriting class? For example, I'm trying to create a plugin that will allow unit testing and functional testing when you are not using migrations. What I'm trying to do is initialize a class variable named controller to be initialized to the type of controller that is being tested. If I have a base class ControllerTest: class ControllerTest < Test::Unit::TestCase attr_accessor :controller def initialize super @controller = "call function that will find the inheriting classes name and create an instance of that controller type." end end So what I'm currently stuck on is getting the name of the inheriting class. Is this possible? And if not, does anyone know another way on how I could go about implementing this? Thanks in advance.

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  • jQuery add class is not working

    - by user1269625
    Hey ya'll I have this code here and it suppose to add the class name "cboxElement" $(".wpcart_gallery a:first").addClass("cboxElement"); but it does not work. I have the proper Jquery file in my header, I have surrounded this in jQuery('document').ready(function($){......}); and it works for all my other Jquery but the add class call. here is what I am trying to add the class to... <div class="wpcart_gallery" style="text-align:center; padding-top:5px;"> <a class="thickbox" href="DSC_0037.jpg" rev="DSC_0037.jpg"></a> </div> Anybody know why this isnt working? I am new to jquery this is also in wordpress hence the jQuery('document')

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  • abstract class MouseAdapter vs. interface

    - by Stefano Borini
    I noted this (it's a java.awt.event class). public abstract class MouseAdapter implements MouseListener, MouseWheelListener, MouseMotionListener { .... } Then you are clearly forced to extend from this adapter public class MouseAdapterImpl extends MouseAdapter {} the class is abstract and implements no methods. Is this a strategy to combine different interfaces into a single "basically interface" ? I assume in java it's not possible to combine different interfaces into a single one without using this approach. In other words, it's not possible to do something like this in java public interface MouseAdapterIface extends MouseListener, MouseWheelListener, MouseMotionListener { } and then eventually public class MouseAdapterImpl implements MouseAdapterIface {} Is my understanding of the point correct ? what about C# ?

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  • abstract method signature, inheritance, and "Do" naming convention

    - by T. Webster
    I'm learning about design patterns and in examples of code I've seen a convention where the abstract class declares a method, for example: public abstract class ServiceBase { ... public virtual object GetSomething(); and then protected abstract object DoGetSomething(); My question is on why these two methods exist, since they appear to serve the same purpose. Is this so that the base class GetSomething() method logic cannot be overridden by inherited classes? But then again, the method is marked virtual, so it can be overridden anyway. What is the usefulness here in requiring derived class implementers to implement the abstract method when the virtual method can be called anyway?

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  • C#: Abstract classes need to implement interfaces?

    - by bguiz
    My test code in C#: namespace DSnA { public abstract class Test : IComparable { } } Results in the following compiler error: error CS0535: 'DSnA.Test' does not implement interface member 'System.IComparable.CompareTo(object)' Since the class Test is an abstract class, why does the compiler require it to implement the interface? Shouldn't this requirement only be compulsory for concrete classes?

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  • accessing base class's method with derived class's object which has a method of same name.

    - by ashish yadav
    when accessing foo() of "base" using derived class's object. include class base { public: void foo() { std::cout<<"\nHello from foo\n"; } }; class derived : public base { public: void foo(int k) { std::cout<<"\nHello from foo with value = "< } how to access base class method having a method of same name in derived class. the error generated has been shown. i apologize if i am not clear but i feel i have made myself clear as water. thanks in advance.

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  • How can I process a form's events in another class / module automatically in VB.NET

    - by CowKingDeluxe
    Here's my code: Public Class Form1 End Class Public Class Form1Handler Inherits Form1 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click MsgBox("I") End Sub End Class I'm trying to get Form1Handler to process Form1's events automatically. How can I do this? Should I use a module instead? I'm doing this in VB 2010. I don't want to have to make an event handler in Form1 and then pipe it to the other class / module, is there some way to automatically "pipe" the events from form1 to form1handler?

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  • Class Not found exception in JApplet.

    - by Nitesh Panchal
    Hello, I created a simple Applet using JApplet and everything seems to work fine but as soon i create an object of my userdefined class named ChatUser in my applet, i get this error :- SEVERE: java.lang.ClassNotFoundException: applet.ChatUser at com.sun.enterprise.loader.ASURLClassLoader.findClassData(ASURLClassLoader.java:713) at com.sun.enterprise.loader.ASURLClassLoader.findClass(ASURLClassLoader.java:626) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at java.lang.ClassLoader.loadClass(ClassLoader.java:252) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:247) at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:604) at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1575) at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1496) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1732) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351) at misc.ChatClient.run(ChatClient.java:43) Any idea what can be wrong? It only happens when i create an object of any user defined class. Do i need to set some security settings or something? Please help :(

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  • Properly design a code editor application

    - by Hemaulo
    I'm working on personal project which is basically a code editor. Imagine standard File menu with menu items New, Open, Save, Save As, Save All, Close, Close All. I'm stuck with proper design. Currently I have: A Document class which represents a document - code editing control, respective tab in tab bar and various properties such as Caption, Filename, IsModified etc. A Documents class which represents all open documents. Contains methods like New, Open(FileName), ... The problem is that I can't figure out which class / menu command is responsible for which tasks. For example, with File-New menu command is simple - call Documents.New and that's it. But what for File-Open? The Documents.Open method expects filename as a parameter. So before calling this method I need to open an file selection dialog, let user select files and for each file call Documents.Open(FileName). Where is best place for this supporting code, in menu command, rewrite Documents.Open and put it there? The same with Save actions. Which is responsible for saving? Is it Documents class which uses Document.Editor.SaveToFile(FileName) or better create Save method in Document class? Somewhere in the middle also need to ask user if he wants to save current document... I'm stuck. Any ideas? Edited: The programming language is Delphi.

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  • Wicket app in embedded Jetty causes UnsupportedClassVersionError

    - by Ondra Žižka
    I've tried to run a Wicket app in an embedded Jetty, using this code: public static void main( String[] args ){ Server server = new Server(8080); Context root = new Context( server, "/", Context.SESSIONS ); FilterHolder filterHolder = new FilterHolder( new WicketFilter() ); filterHolder.getInitParameters().put("applicationClassName", cz.dw.test.WicketApplication.class.getName() ); root.addFilter( filterHolder, "/*" , Handler.ALL ); try { server.start(); } catch (Exception ex) { ex.printStackTrace(); } } But I got java.lang.UnsupportedClassVersionError: Bad version number in .class file. Switching the target class version for my app (1.6 - 1.5) did not help. I use Sun JDK 1.6.0_17, Wicket 1.4.8, Jetty 6.1.24. I tried to debug, but the JRE classes have no debug data. The stacktrace is of no use as it happens when loading the classes into JVM. Any ideas what could be wrong? How can I find which class is causing this? Thanks, Ondra

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  • Ruby: Calling class method from instance

    - by Peter
    In Ruby, how do you call a class method from one of that class's instances? Say I have class Truck def self.default_make # Class method. "mac" end def initialize # Instance method. Truck.default_make # gets the default via the class's method. # But: I wish to avoid mentioning Truck. Seems I'm repeating myself. end end the line Truck.default_make retrieves the default. But is there a way of saying this without mentioning Truck? It seems like there should be.

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  • In PHP, is it possible to create an instance of an class without calling class's constructor ?

    - by Rachel
    By any means, is it possible to create an instance of an php class without calling its constructor ? I have Class A and while creating an instance of it am passing file and in constructor of Class A am opening the file. Now in Class A, there is function which I need to call but am not required to pass file and so there is not need to use constructor functionality of opening file as am not passing file. So my question is, Is it possible by any means to create an instance of an PHP class without calling its constructor ?

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  • Get class of caller's method (via inspect) in Python (alt: super() emulator)

    - by Slava Vishnyakov
    Is it possible to get reference to class B in this example? class A(object): pass class B(A): def test(self): test2() class C(B): pass import inspect def test2(): frame = inspect.currentframe().f_back cls = frame.[?something here?] # cls here should == B (class) c = C() c.test() Basically, C is child of B, B is child of A. Then we create c of type C. Then the call to c.test() actually calls B.test() (via inheritance), which calls to test2(). test2() can get the parent frame frame; code reference to method via frame.f_code; self via frame.f_locals['self']; but type(frame.f_locals['self']) is C (of course), but not B, where method is defined. Any way to get B?

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  • PHP: friend classes and ungreedy caller function/class

    - by avetis.kazarian
    Is there any way to get the caller function with something else than debug_backtrace()? I'm looking for a less greedy way to simulate scopes like friend or internal. Let's say I have a class A and a class B. Until now, I've been using debug_backtrace(), which is too greedy (IMHO). I thought of something like this: <?php class A { public function __construct(B $callerObj) {} } class B { public function someMethod() { $obj = new A($this); } } ?> It might be OK if you want to limit it to one specific class, but let's say I have 300 classes, and I want to limit it to 25 of them? One way could be using an interface to aggregate: public function __construct(CallerInterface $callerObj) But it's still an ugly code. Moreover, you can't use that trick with static classes. Have any better idea?

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  • Ruby: Locate class definition at run time?

    - by Thor Thurn
    I'm having an odd probably with rails right now... a class is being defined somewhere, and I can't find it. Grepping for "class ClassName" hasn't managed to locate it, but it's definitely there when I load up the rails console. It's just a vanilla class inheriting from Object with nothing else defined... quite boring. So, what I'd like is a way to figure out where this class constant was originally defined from the rails console. Something to print out the value of '__ FILE __' when this class was declared, in other words. I feel like some type of metaprogramming should make this possible.

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  • Trying to understand the usage of class_eval

    - by eMxyzptlk
    Hello everyone, I'm using the rails-settings gem, and I'm trying to understand how you add functions to ActiveRecord classes (I'm building my own library for card games), and I noticed that this gem uses one of the Meta-programming techniques to add the function to the ActiveRecord::Base class (I'm far from Meta-programming master in ruby, but I'm trying to learn it) module RailsSettings class Railtie < Rails::Railtie initializer 'rails_settings.initialize', :after => :after_initialize do Railtie.extend_active_record end end class Railtie def self.extend_active_record ActiveRecord::Base.class_eval do def self.has_settings class_eval do def settings RailsSettings::ScopedSettings.for_thing(self) end scope :with_settings, :joins => "JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND settings.thing_type = '#{self.base_class.name}')", :select => "DISTINCT #{self.table_name}.*" scope :with_settings_for, lambda { |var| { :joins => "JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND settings.thing_type = '#{self.base_class.name}') AND settings.var = '#{var}'" } } scope :without_settings, :joins => "LEFT JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND settings.thing_type = '#{self.base_class.name}')", :conditions => 'settings.id IS NULL' scope :without_settings_for, lambda { |var| { :joins => "LEFT JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND settings.thing_type = '#{self.base_class.name}') AND settings.var = '#{var}'", :conditions => 'settings.id IS NULL' } } end end end end end end What I don't understand is why he uses class_eval on ActiveRecord::Base, wasn't it easier if he just open the ActiveRecord::Base class and define the functions? Specially that there's nothing dynamic in the block (What I mean by dynamic is when you do class_eval or instance_eval on a string containing variables) something like this: module ActiveRecord class Base def self.has_settings class_eval do def settings RailsSettings::ScopedSettings.for_thing(self) end scope :with_settings, :joins => "JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND settings.thing_type = '#{self.base_class.name}')", :select => "DISTINCT #{self.table_name}.*" scope :with_settings_for, lambda { |var| { :joins => "JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND settings.thing_type = '#{self.base_class.name}') AND settings.var = '#{var}'" } } scope :without_settings, :joins => "LEFT JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND settings.thing_type = '#{self.base_class.name}')", :conditions => 'settings.id IS NULL' scope :without_settings_for, lambda { |var| { :joins => "LEFT JOIN settings ON (settings.thing_id = #{self.table_name}.#{self.primary_key} AND settings.thing_type = '#{self.base_class.name}') AND settings.var = '#{var}'", :conditions => 'settings.id IS NULL' } } end end end end I understand the second class_eval (before the def settings) is to define functions on the fly on every class that 'has_settings' right ? Same question here, I think he could use "def self.settings" instead of "class_eval.... def settings", no ?

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