overloading

问题 This question already has answers here : Is Method Overloading considered polymorphism? [closed] (8 answers) Closed 5 years ago . I was studying about static and dynamic polymorphism and got these links: http://guruzon.com/1/oop-concepts/polymorphism/what-is-polymorphism-example-tutorial-uml-diagram-notation http://www.coderanch.com/t/379004/java/java/static-polymorphism-dynamic-polymorphism http://javarevisited.blogspot.in/2011/08/what-is-polymorphism-in-java-example.html In all these links

问题 Wanna do the following: BootStrap { def init = {servletContext -> ........ MyDomainClass.metaClass.save = {-> delegate.extraSave() //////// how to call original save() here? } } ......... } P.S. MyDomainClass#extraSave is defined as public void extraSave(){.....} 回答1: First of all, Bootstrap.groovy may not be the best place to do this kind of metaprogramming. The problem with this approach is that the changes to the classes will be applied when the application starts, but you may lose these

问题 Is there a good, generic, way to do the following without resorting to a second method or lots of casts - I want to keep the API as light as possible and it seems ok to me OO-wise: class Foo { public T Bar<T>() where T: IAlpha { /* blahblahblah */ } public T Bar<T>() where T: IBeta { /* blahblahblah */ } } interface IAlpha { string x {set;} } interface IBeta { string y {set;} } thanks 回答1: You can't overload a method by return value only (generic or not). Additionally, it would be impossible

问题 When I call the EntryPoint with a parameter of type TemplateA, I always receive an exception, since the first overload is always called. What I expected to happen is that the most specific method (second overload) will be called due to dynamic binding. Any ideas why? private object _obj; public void EntryPoint(object p) { myFunc(p); } //first overload private void myFunc(object container) { throw new NotImplementedException(); } //second overload private void myFunc(TemplateA template) { _obj

问题 Below is a transcript of what I've tried and what happens. I'm looking for how to call a specific overload along with an explanation of why the following does not work. If your answer is "you should use this commandlet instead" or "call it twice" please understand when I don't accept your answer. PS C:\> [System.IO.Path]::Combine("C:\", "foo") C:\foo PS C:\> [System.IO.Path]::Combine("C:\", "foo", "bar") Cannot find an overload for "Combine" and the argument count: "3". At line:1 char:26 +

问题 I'm trying to get my head around ad-hoc polymorphism in haskell, that is having the same function provide different behaviour for different argument types. But while the following test code compiles {-# LANGUAGE MultiParamTypeClasses #-} class MyClass a b where foo :: a -> b instance MyClass Bool Int where foo True = 0 foo False = 1 instance MyClass Double Double where foo x = -x if I try to call it using something like foo True ghci yells at me: No instance for (MyClass Bool b0) arising from

问题 I am having a problem in my DSL with overloaded generic methods resulting in the compiler wanting me to add explicit parameter types: def alpha[T](fun: Int => T): String = fun(33).toString def beta [T](fun: Int => T): String = fun(66).toString def beta [T](thunk: => T): String = thunk.toString alpha { _ + 11 } // ok beta { _ + 22 } // "error: missing parameter type for expanded function" beta { _: Int => _ + 22 } // ok... ouch. Any chance I can get rid of the the clutter in the last line?

问题 The following C++ program compiles without errors: void f(char){} void f(signed char){} void f(unsigned char){} int main(){} The wchar_t version of the same program does not: void f(wchar_t){} void f(signed wchar_t){} void f(unsigned wchar_t){} int main(){} error: redefinition of ‘void f(wchar_t)’ void f(signed wchar_t){} It seems that wchar_t is unsigned . Why is there an inconsistency in overloading? 回答1: The char s are all distinct types and can be overloaded [basic.fundamental] / 1 [...]

问题 I like to overload methods to support more and more default cases. What is the performance impact of method overloading? From your experience, is it advisable to overload methods? What is the limit? What are the workarounds? 回答1: Overloading has no impact on performance; it's resolved by the compiler at compile-time. As for design guidance, see the design guidelines: http://msdn.microsoft.com/en-us/library/ms229029.aspx 回答2: If you're using C# 4.0 you can save your fingers some work and use

问题 So as the title implies my question is a bit odd and complicated. I know what I'm about to do breaks all the rules of "good" programming practices but hey, what's life if we don't live a little? So what I did was create the following program. (Note this was part of a larger experiment to really try and understand generics so some of the function names maybe a bit out of order) import java.util.*; public class GenericTestsClean { public static void test2() { BigCage<Animal> animalCage=new