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  • C# compiler fails to recognize a class is implementing an interface

    - by Freek
    The following code fails to compile (using VS2010) and I don't see why. The compiler should be able to infer that List is 'compatible' (sorry for lack of a better word) with IEnumerable, but somehow it doesn't. What am I missing here? interface ITest { void Test(); } class TestClass : ITest { public void Test() { } } class Program { static void Test(IEnumerable<ITest> tests) { foreach(var t in tests) { Console.WriteLine(t); } } static void Main(string[] args) { var lst = new List<TestClass>(); Test(lst); // fails, why? Test(lst.Select(t=>t as ITest)); //success Test(lst.ToArray()); // success } }

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  • Calling inheriting class methods via interface.

    - by Stacey
    Given the scenario... interface IBase{ void Process(int value); } abstract class Base : IBase { public virtual void Process(int value){ throw new NotImplementedException(); } } class Implemented: Base, IBase { public void Process(int value) { // .. some code here.. } } I'm trying to write a loop similar to the following. foreach( Base b in CollectionOfImplemented ) { b.Process( // something will go here // ); } Trying this, it keeps calling Base.Process, instead of Implemented.Process; but the type in the collection is Implemented, not Base. Boxing it seems to work, but I was hoping to see if I could find a more intelligent approach to it, since the Collection will contain other types of objects that also inherit from Base.

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  • Cross platform, Interactive text-based interface with command completion

    - by trojanfoe
    Does anyone know of a C++ library that will provide a text-based interactive interface? I want to create two versions of an application; a console based program that will perform whatever actions are given on the command line or interactively at the console as well as a GUI based program (Mac Cocoa and Windows MFC). Both versions will share a common C++ backend. For the console based program I would like similar history abilities to readline (which I cannot use as this application will be closed source) with command completion (Tab-activated for example). Perhaps there is something like this already available?

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  • Design classes/interface to support methods returning different types

    - by Nayn
    Hi, I have classes as below. public interface ITest <T> { public T MethodHere(); } public class test1 implements ITest<String> { String MethodHere(){ return "Bla"; } } public class test2 implements ITest<Integer> { Integer MethodHere(){ return Integer.valueOf(2); } } public class ITestFactory { public static ITest getInstance(int type) { if(type == 1) return new test1(); else if(type == 2) return new test2(); } } There is a warning in the factory class that ITest is used as raw type. What modification should I do to get rid of it? Thanks Nayn

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  • custom implementation of interface methods

    - by Renuka
    Hello all, I have a doubt in this scenario, I have posted some example code here.... public interface a{ public void m1(); public void m2(); public void m3(); . . . public void m100(); } public class A implements a{ public void m3(){ // implementation code } // Here i need to implement only m3() method but not all 100 methods //basically i have to implement all the other 99 methods // but here i don't want to either implement or provide skeleton declarations for all //remaining.... what should i do for compiling this ???? } Could anyone help this?

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  • How to implement fluent interface with a base class, in C++

    - by Vincenzo
    How can I implement this fluent interface in C++: class Base { public: Base& add(int x) { return *this; } } class Derived : public Base { public: Derived& minus(int x) { return *this; } } Derived d; d.add(1).minus(2).add(3).minus(4); Current code doesn't work since Base class doesn't know anything about Derived class, etc. I would be very thankful for a hint/suggestion.

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  • How should 4 decimals places behave, being simple yet powerful

    - by vener
    I have a UI question that troubled me on the best method to handle 4 decimal places for prices. In an table already cramped full of data, I would want to simplified the interface to make it not so cluttered. The actual current UI is shown below. http://i41.tinypic.com/bg5tub.jpg The problem is, for a unit price/units/D.Price and Dis.(Discount) to have 4 decimal places ($0.3459) is quite rare but it still happens (5 in 100 entries). This will result a lot of junk decimal places, cluttering up the interface. What is the best solution to this problem? In short, I want to declutter it yet maintain the precision. Note: This is web app

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  • C# creating a custom user interface

    - by CSharpInquisitor
    Hi, I have a SQL database holding a number of numeric and text values that get updated regularly. The exact number/type/names of these data points can change depending on the source of the database writes. I would like to create a user interface editor, where the user can add database points to the UI and arrange them and format them as they want. If a new point is added to the database they can right click on the UI and say "add this point" and choose from a list of database points. I'm looking for some pointers on where to start on creating this editor application, could something clever be done using XAML to dynamically create std WPF controls at runtime? Thanks in advance for any help, Si

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  • creating a custom user interface in WPF

    - by CSharpInquisitor
    I have a SQL database holding a number of numeric and text values that get updated regularly. The exact number/type/names of these data points can change depending on the source of the database writes. I would like to create a user interface editor, where the user can add database points to the UI and arrange them and format them as they want. If a new point is added to the database they can right click on the UI and say "add this point" and choose from a list of database points. I'm looking for some pointers on where to start on creating this editor application, could something clever be done using XAML to dynamically create std WPF controls at runtime?

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  • Drawing lines between windows just like in Interface Builder

    - by Koning Baard
    I have two windows, each with a round NSView: ------------------ ------------ |X-+ Oscillator | |X-+ Mixer | |----------------| |----------| | | | | | O | | O | | | | | | | | | ------------------ ------------ Both windows are in a seperate NIB. I want to be able to draw a line between the two round NSViews at runtime, using drag'n'drop, just like connecting IBOutlets in Interface Builder: ------------------ ------------ |X-+ Oscillator | |X-+ Mixer | |----------------| |----------| | | | | | O-------+-----+-----O | | | | | | | | | ------------------ ------------ I also want to be able to determine to which NSViews the NSViews are connected using the drawn lines. I need this to connect Oscillators to Mixers. I also want to be able to remove the connections by dragging into empty space. Can anyone explain me how to do this? Thanks.

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  • How to Activate VLC’s Web Interface, Control VLC From a Browser, & Use Any Smartphone as a Remote

    - by Chris Hoffman
    VLC includes a web interface, which you can enable to access your VLC player from a web browser, controlling playback from another device – particularly useful for a media center PC. VLC also offers a mobile web interface for smartphones. The web interface is turned off and locked down by default – you have to edit the web server’s .hosts file or VLC will disallow all incoming connections from other devices. How to Make Your Laptop Choose a Wired Connection Instead of Wireless HTG Explains: What Is Two-Factor Authentication and Should I Be Using It? HTG Explains: What Is Windows RT and What Does It Mean To Me?

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  • What are good reasons to use explicit interface implementation for the sole purpose of hiding members?

    - by Nathanus
    During one of my studies into the intricacies of C#, I came across an interesting passage concerning explicit interface implementation. While this syntax is quite helpful when you need to resolve name clashes, you can use explicit interface implementation simply to hide more "advanced" members from the object level. The difference between allowing the use of object.method() or requiring the casting of ((Interface)object).method() seems like mean-spirited obfuscation to my inexperienced eyes. The text noted that this will hide the method from Intellisense at the object level, but why would you want to do that if it was not necessary to avoid name conflicts?

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  • Blogger : refonte en profondeur de la plateforme de blogs de Google, la nouvelle interface sera développée avec Google Web Toolkit

    Google annonce une refonte en profondeur de la plateforme Blogger Sa nouvelle interface sera développée avec Google Web Toolkit Blogger, le célèbre service de publication Web racheté par Google en 2003, est sur le point d'avoir une refonte complète d'après son chef de produit Chang Kim. Il s'agit du changement d'interface le plus important de l'histoire du sixième plus grand site au monde qui s'enorgueillit de ses 400 millions de lecteurs et de ses 500 milliards de mots publiés, répartis sur un demi-milliard de billets de blog depuis la création du service. La nouvelle génération d'interface utilisateur de l'éditeur de billet et du tableau de bord (dashboard) de l'o...

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  • Should I implement an interface directly or have the superclass do it?

    - by c_maker
    Is there a difference between public class A extends AbstractB implements C {...} versus... public class A extends AbstractB {...} AbstractB implements C {...} I understand that in both cases, class A will end up conforming to the interface. In the second case, AbstractB can provide implementation for interface methods in C. Is that the only difference? If I do NOT want to provide an implementation for any of the interface methods in AbstractB, which style should I be using? Does using one or the other have some hidden 'documentation' purpose?

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  • Digia dévoile un nouveau concept d'interface homme-machine (IHM) en 3D pour les automobiles implémentée avec Qt

    Digia dévoile un nouveau concept d'interface homme-machine (IHM) en 3D pour les automobiles implémentée avec Qt Aux Qt Developer Days 2011 de Munich, Digia Qt Commercial a montré un nouveau concept d'interface homme-machine (IHM) en 3D pour les automobiles pour la prochaine version commerciale de Qt 4.8. Le concept sera utilisé comme une nouvelle plateforme d'innovation pour faciliter l'intégration et la présentation de nouvelles idées technologiques. Le principe d'interaction de l'IHM 3D est prévu pour la facilité et l'intuitivité de son utilisation. L'utilisateur est en mesure de contrôler l'interface utilisateur avec des gestes approximatifs au lieu de pointer précisément. Puisque le système m...

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  • How to make a css navigation menu "selected" option still clickable

    - by aslum
    So I have a fairly simple vertical CSS menu based off of UL. <ul class="vertnav"> <li><a href="unselected1.php">Item1</a></li> <li><a href="unselected2.php">Item2</a></li> <li><a href="selected.php" class="vertnavdown">Selected</a></li> </ul> I want three basic colors (say tan for default LI, orange for VERTNAVDOWN, and red for A:HOVER. However I can't seem to get the vertnavdown class to inherit right, and the .vertnav li a:visited overrides it every time. if I use !important to force it through I can't seem to also get the hover to work. Any suggestions? I thought I understood inheritance in CSS but I guess I don't. .vertnav{ list-style: none; margin: 0px; width: 172px; font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 11px; padding: 0px 0px 0px 0px; margin: 0px 0px 0px 0px; text-align: left; height: 45px; } .vertnav li{ margin: 0px; font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 11px; border-bottom: 0px none; border-right: 0px none; border-top: 1px solid #fff; border-left: 0px none; text-align: left; height: 45px; width: 172px; padding: 0px 0px 0px 0px; margin: 0px 0px 0px 0px; } .vertnav li a{ display: block; text-align: left; color: #666666; font-weight: bold; background-color: #FFEEC1; font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 11px; text-decoration: none; padding-top: 10px; padding-right: 0px; padding-bottom: 0px; padding-left: 15px; height: 45px; } .vertnav li a:visited{ display: block; text-align: left; color: #666666; background-color: #FFEEC1; font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 11px; font-weight: bold; text-decoration: none; padding-top: 10px; padding-right: 0px; padding-bottom: 0px; padding-left: 15px; height: 45px; } .vertnav li a:hover{ color: white; background-color: #ffbf0c; font-family: Verdana, Arial, Helvetica, sans-serif; height: 45px; text-decoration: none; font-weight: bold; } .vertnavdown a { display:block; color: #FFF; background-color: #ff9000; } .vertnavdown a:hover { background-color: #ffbf0c; } ^^^^^^^^^^^^^ Edited to add CSS. ^^^^^^

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  • Java multiple class compositing and boiler plate reduction

    - by h2g2java
    We all know why Java does/should not have multiple inheritance. So this is not questioning about what has already been debated till-cows-come-home. This discusses what we would do when we wish to create a class that has the characteristics of two or more other classes. Probably, most of us would do this to "inherit" from three classes. For simplicity, I left out the constructor.: class Car extends Vehicle { final public Transport transport; final public Machine machine; } So that, Car class directly inherits methods and objects of Vehicle class, but would have to refer to transport and machine explicitly to refer to objects instantiated in Transport and Machine. Car car = new Car(); car.drive(); // from Vehicle car.transport.isAmphibious(); // from Transport car.machine.getCO2Footprint(); // from Machine I thought this was a good idea until when I encounter frameworks that require setter and getter methods. For example, the XML <Car amphibious='false' footPrint='1000' model='Fordstatic999'/> would look for the methods setAmphibious(..), setFootPrint(..) and setModel(..). Therefore, I have to project the methods from Transport and Machine classes class Car extends Vehicle { final public Transport transport; final public Machine machine; public void setAmphibious(boolean b){ this.transport.setAmphibious(b); } public void setFootPrint(String fp){ this.machine.setFootPrint(fp); } } This is OK, if there were just a few characteristics. Right now, I am trying to adapt all of SmartGWT into GWT UIBinder, especially those classes that are not a GWT widget. There are lots of characteristics to project. Wouldn't it be nice if there exists some form of annotation framework that is like this: class Car extends Vehicle @projects {Transport @projects{Machine @projects Guzzler}} { /* No need to explicitly instantiate Transport, Machine or Guzzler */ .... } Where, in case of common names of characteristics exist, the characteristics of Machine would take precedence Guzzler's, and Transport's would have precedence over Machine's, and Vehicle's would have precedence over Transport's. The annotation framework would then instantiate Transport, Machine and Guzzler as hidden members of Car and expand to break-out the protected/public characteristics, in the precedence dictated by the @project annotation sequence, into actual source code or into byte-code. Preferably into byte-code. So that the setFootPrint method is found in both Machine and Guzzler, only that of Machine's would be projected. Questions: Don't you think this is a good idea to have such a framework? Does such a framework already exist? Tell me where/what. Is there an eclipse plugin that does it? Is there a proposal or plan anywhere that you know about such an annotation framework? It would be wonderful too, if the annotation/plugin framework lets me specify that boolean, int, or whatever else needs to be converted from String and does the conversion/parsing for me too. Please advise, somebody. I hope wording of my question was clear enough. Thx. Edited: To avoid OO enthusiasts jumping to conclusion, I have renamed the title of this question.

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  • Why is the this-pointer needed to access inherited attributes?

    - by Shadow
    Hi, assume the following class is given: class Base{ public: Base() {} Base( const Base& b) : base_attr(b.base_attr) {} void someBaseFunction() { .... } protected: SomeType base_attr; }; When I want a class to inherit from this one and include a new attribute for the derived class, I would write: class Derived: public Base { public: Derived() {} Derived( const Derived& d ) : derived_attr(d.derived_attr) { this->base_attr = d.base_attr; } void SomeDerivedFunction() { .... } private: SomeOtherType derived_attr; }; This works for me (let's ignore eventually missing semicolons or such please). However, when I remove the "this-" in the copy constructor of the derived class, the compiler complains that "'base_attr' was not declared in this scope". I thought that, when inheriting from a class, the protected attributes would then also be accessible directly. I did not know that the "this-" pointer was needed. I am now confused if it is actually correct what I am doing there, especially the copy-constructor of the Derived-class. Because each Derived object is supposed to have a base_attr and a derived_attr and they obviously need to be initialized/set correctly. And because Derived is inheriting from Base, I don't want to explicitly include an attribute named "base_attr" in the Derived-class. IMHO doing so would generally destroy the idea behind inheritance, as everything would have to be defined again. EDIT Thank you all for the quick answers. I completely forgot the fact that the classes actually are templates. Please, see the new examples below, which are actually compiling when including "this-" and are failing when omiting "this-" in the copy-constructor of the Derived-class: Base-class: #include <iostream> template<class T> class Base{ public: Base() : base_attr(0) {} Base( const Base& b) : base_attr(b.base_attr) {} void baseIncrement() { ++base_attr; } void printAttr() { std::cout << "Base Attribute: " << base_attr << std::endl; } protected: T base_attr; }; Derived-class: #include "base.hpp" template< class T > class Derived: public Base<T>{ public: Derived() : derived_attr(1) {} Derived( const Derived& d) : derived_attr(d.derived_attr) { this->base_attr = d.base_attr; } void derivedIncrement() { ++derived_attr; } protected: T derived_attr; }; and for completeness also the main function: #include "derived.hpp" int main() { Derived<int> d; d.printAttr(); d.baseIncrement(); d.printAttr(); Derived<int> d2(d); d2.printAttr(); return 0; }; I am using g++-4.3.4. Although I understood now that it seems to come from the fact that I use template-class definitions, I did not quite understand what is causing the problem when using templates and why it works when not using templates. Could someone please further clarify this?

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  • bidirectional OneToOne Mapping : From Entity to subclass and from superclass to Entity?

    - by Teocali
    I'm trying to establish a tricky bidirectional OneToOne mapping in hibernate. I got the following classes : @Entity @Inheritance(strategy = InheritanceType.JOINED) public class Parent { @OneToOne private AnotherEntity anotherEntity; } @Entity public class Child1 extends Parent{} @Entity public class Child2 extends Parent{} @Entity public class AnotherEntity { @OneToOne(mappedBy = "anotherEntity") private Child1 child1; @OneToOne(mappedBy = "anotherEntity") private Child1 child2; } The problem here is when I'm launching the application : I got the following message : org.hibernate.MappingException: property [anotherEntity] not found on entity [Child1] at org.hibernate.mapping.PersistentClass.getRecursiveProperty(PersistentClass.java:429) at org.hibernate.mapping.PersistentClass.getReferencedProperty(PersistentClass.java:369) at org.hibernate.cfg.Configuration.originalSecondPassCompile(Configuration.java:1614) at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1362) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1727) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1778) at org.springframework.orm.hibernate4.LocalSessionFactoryBuilder.buildSessionFactory(LocalSessionFactoryBuilder.java:189) at org.springframework.orm.hibernate4.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:350) at org.springframework.orm.hibernate4.LocalSessionFactoryBean.afterPropertiesSet(LocalSessionFactoryBean.java:335) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1514) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1452) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:567) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:913) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:464) at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:631) at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:588) at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:645) at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:508) at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:449) at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:133) at javax.servlet.GenericServlet.init(GenericServlet.java:160) at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1266) at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1185) at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1080) at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5015) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5302) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:895) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:871) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:615) at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:962) at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:536) at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1471) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:301) at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:836) at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:761) at org.apache.catalina.manager.ManagerServlet.check(ManagerServlet.java:1436) at org.apache.catalina.manager.ManagerServlet.deploy(ManagerServlet.java:673) at org.apache.catalina.manager.ManagerServlet.doPut(ManagerServlet.java:431) at javax.servlet.http.HttpServlet.service(HttpServlet.java:644) at javax.servlet.http.HttpServlet.service(HttpServlet.java:722) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:581) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:662) One obvious solution would be to move the anotherEntity field to Child1 and Child2, but it would mean lose the link from Parent to AnotherEntity. Any help welcome.

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  • I never really understood: what is Application Binary Interface (ABI)?

    - by claws
    I never clearly understood what is an ABI. I'm sorry for such a lengthy question. I just want to clearly understand things. Please don't point me to wiki article, If could understand it, I wouldn't be here posting such a lengthy post. This is my mindset about different interfaces: TV remote is an interface between user and TV. It is an existing entity but useless (doesn't provide any functionality) by itself. All the functionality for each of those buttons on the remote is implemented in the Television set. Interface: It is a "existing entity" layer between the functionality and consumer of that functionality. An, interface by itself is doesn't do anything. It just invokes the functionality lying behind. Now depending on who the user is there are different type of interfaces. Command Line Interface(CLI) commands are the existing entities, consumer is the user and functionality lies behind. functionality: my software functionality which solves some purpose to which we are describing this interface. existing entities: commands consumer: user Graphical User Interface(GUI) window,buttons etc.. are the existing entities, again consumer is the user and functionality lies behind. functionality: my software functionality which solves some purpose to which we are describing this interface. existing entities: window,buttons etc.. consumer: user Application Programming Interface(API) functions or to be more correct, interfaces (in interfaced based programming) are the existing entities, consumer here is another program not a user. and again functionality lies behind this layer. functionality: my software functionality which solves some purpose to which we are describing this interface. existing entities: functions, Interfaces(array of functions). consumer: another program/application. Application Binary Interface (ABI) Here is my problem starts. functionality: ??? existing entities: ??? consumer: ??? I've wrote few softwares in different languages and provided different kind of interfaces (CLI, GUI, API) but I'm not sure, if I ever, provided any ABI. http://en.wikipedia.org/wiki/Application_binary_interface says: ABIs cover details such as data type, size, and alignment; the calling convention, which controls how functions' arguments are passed and return values retrieved; the system call numbers and how an application should make system calls to the operating system; Other ABIs standardize details such as the C++ name mangling,[2] . exception propagation,[3] and calling convention between compilers on the same platform, but do not require cross-platform compatibility. Who needs these details? Please don't say, OS. I know assembly programming. I know how linking & loading works. I know what exactly happens inside. Where did C++ name mangling come in between? I thought we are talking at the binary level. Where did languages come in between? anyway, I've downloaded the [PDF] System V Application Binary Interface Edition 4.1 (1997-03-18) to see what exactly it contains. Well, most of it didn't make any sense. Why does it contain 2 chapters (4th & 5th) which describe the ELF file format.Infact, these are the only 2 significant chapters that specification. Rest of all the chapters "Processor Specific". Anyway, I thought that it is completely different topic. Please don't say that ELF file format specs are the ABI. It doesn't qualify to be Interface according to the definition. I know, since we are talking at such low level it must be very specific. But I'm not sure how is it "Instruction Set Architecture(ISA)" specific? Where can I find MS Window's ABI? So, these are the major queries that are bugging me.

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  • MVC - Cocoa interface - Cocoa Design pattern book

    - by Idan
    So I started reading this book: http://www.amazon.com/Cocoa-Design-Patterns-Erik-Buck/dp/0321535022 On chapter 2 it explains about the MVC design pattern and gives and example which I need some clarification to. The simple example shows a view with the following fields: hourlyRate, WorkHours, Standarthours , salary. The example is devided into 3 parts : View - contains some text fiels and a table (the table contains a list of employees' data). Controller - comprised of NSArrayController class (contains an array of MyEmployee) Model - MyEmployee class which describes an employee. MyEmployee class has one method which return the salary according to the calculation logic, and attributes in accordance with the view UI controls. MyEmployee inherits from NSManagedObject. Few things i'm not sure of : 1. Inside the MyEmplpyee class implemenation file, the calculation method gets the class attributes using sentence like " [[self valueForKey:@"hourlyRate"] floatValue];" Howevern, inside the header there is no data member named hourlyRate or any of the view fields. I'm not quite sure how does it work, and how it gets the value from the right view field. (does it have to be the same name as the field name in the view). maybe the conncetion is made somehow using the Interface builder and was not shown in the book ? and more important: 2. how does it seperate the view from the model ? let's say ,as the book implies might happen, I decide one day to remove one of the fields in the view. as far as I understand, that means changing the way the salary method works in MyEmplpyee (cause we have one field less) , and removing one attribute from the same calss. So how is that separate the View from the Model if changing one reflect on the other ? I guess I get something wrong... Any comments ? Thanks

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  • Moq: Unable to cast to interface

    - by Pickels
    Hello, earlier today I asked this question. So since moq creates it's own class from an interface I wasn't able to cast it to a different class. So it got me wondering what if I created a ICustomPrincipal and tried to cast to that. This is how my mocks look: var MockHttpContext = new Mock<HttpContextBase>(); var MockPrincipal = new Mock<ICustomPrincipal>(); MockHttpContext.SetupGet(h => h.User).Returns(MockPrincipal.Object); In the method I am trying to test the follow code gives the error(again): var user = (ICustomPrincipal)httpContext.User; The error is the following: Unable to cast object of type 'IPrincipalProxy4081807111564298854aabfc890edcc8' to type 'MyProject.Web.ICustomPrincipal'. I guess I still need some practice with interfaces and moq but shouldn't I be able to cast the class that moq created back to ICustomPrincipal? I know httpContext.User returns an IPrincipal so maybe something gets lost there? Well if anybody can help me I would appreciate that. Pickels Edit: As requested the full code of the method I am testing. It's still not finished but this is what I have so far: public bool AuthorizeCore(HttpContextBase httpContext) { if (httpContext == null) { throw new ArgumentNullException("httpContext"); } var user = (ICustomPrincipal)httpContext.User; if (!user.Identity.IsAuthenticated) { return false; } return true; }

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  • Cannot find interface declaration for 'UIResponder'

    - by lfe-eo
    Hi all, I am running into this issue when trying to compile code for an iPhone app that I inherited from a previous developer. I've poked around on a couple forums and it seems like the culprit may be a circular #import somewhere. First - Is there any easy way to find if this is the case/find what files the loop is in? Second - Its definitely possible this isn't the problem. This is the full error (truncated file paths so its easier to view here): In file included from [...]/Frameworks/UIKit.framework/Headers/UIView.h:9, from [...]/Frameworks/UIKit.framework/Headers/UIActivityIndicatorView.h:8, from [...]/Frameworks/UIKit.framework/Headers/UIKit.h:11, from /Users/wbs/Documents/EINetIPhone/EINetIPhone_Prefix.pch:13: [...]/Frameworks/UIKit.framework/Headers/UIResponder.h:15: error: expected ')' before 'UIResponder' [...]/Frameworks/UIKit.framework/Headers/UIResponder.h:17: error: expected '{' before '-' token [...]/Frameworks/UIKit.framework/Headers/UIResponder.h:42: warning: '@end' must appear in an @implementation context [...]/Frameworks/UIKit.framework/Headers/UIResponder.h:51: error: expected ':' before ';' token [...]/Frameworks/UIKit.framework/Headers/UIResponder.h:58: error: cannot find interface declaration for 'UIResponder' As you can see, there are other errors alongside this one. These seem to be simple syntax errors, however, they appear in one of Apple's UIKit files (not my own) so I am seriously doubting that Apple's code is truly producing these errors. I'm stumped as to how to solve this issue. If anyone has any ideas of things I could try or ways/places I could get more info on the problem, I'd really appreciate it. I'm very new to Obj-C and iPhone coding.

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  • Static method , Abstract method , Interface method comparision ?

    - by programmerist
    When i choose these methods? i can not decide which one i must prefer or when will i use one of them?which one give best performance? First Type Usage public abstract class _AccessorForSQL { public virtual bool Save(string sp, ListDictionary ld, CommandType cmdType); public virtual bool Update(); public virtual bool Delete(); public virtual DataSet Select(); } class GenAccessor : _AccessorForSQL { DataSet ds; DataTable dt; public override bool Save(string sp, ListDictionary ld, CommandType cmdType) { } public override bool Update() { return true; } public override bool Delete() { return true; } public override DataSet Select() { DataSet dst = new DataSet(); return dst; } Second Type Usage Also i can write it below codes: public class GenAccessor { public Static bool Save() { } public Static bool Update() { } public Static bool Delete() { } } Third Type Usage Also i can write it below codes: public interface IAccessorForSQL { bool Delete(); bool Save(string sp, ListDictionary ld, CommandType cmdType); DataSet Select(); bool Update(); } public class _AccessorForSQL : IAccessorForSQL { private DataSet ds; private DataTable dt; public virtual bool Save(string sp, ListDictionary ld, CommandType cmdType) { } } } I can use first one below usage: GenAccessor gen = New GenAccessor(); gen.Save(); I can use second one below usage: GenAccessor.Save(); Which one do you prefer? When will i use them? which time i need override method ? which time i need static method?

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  • Designing a fluid Javascript interface to abstract away the asynchronous nature of AJAX

    - by Anurag
    How would I design an API to hide the asynchronous nature of AJAX and HTTP requests, or basically delay it to provide a fluid interface. To show an example from Twitter's new Anywhere API: // get @ded's first 20 statuses, filter only the tweets that // mention photography, and render each into an HTML element T.User.find('ded').timeline().first(20).filter(filterer).each(function(status) { $('div#tweets').append('<p>' + status.text + '</p>'); }); function filterer(status) { return status.text.match(/photography/); } vs this (asynchronous nature of each call is clearly visible) T.User.find('ded', function(user) { user.timeline(function(statuses) { statuses.first(20).filter(filterer).each(function(status) { $('div#tweets').append('<p>' + status.text + '</p>'); }); }); }); It finds the user, gets their tweet timeline, filters only the first 20 tweets, applies a custom filter, and ultimately uses the callback function to process each tweet. I am guessing that a well designed API like this should work like a query builder (think ORMs) where each function call builds the query (HTTP URL in this case), until it hits a looping function such as each/map/etc., the HTTP call is made and the passed in function becomes the callback. An easy development route would be to make each AJAX call synchronous, but that's probably not the best solution. I am interested in figuring out a way to make it asynchronous, and still hide the asynchronous nature of AJAX.

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