abstract

All I want to do is make sure that child classes of the class Item implement a static method and I want this to be checked at compile time to avoid runtime errors. abstract classes with static methods don't seem to work: ERROR: A static member cannot be marked as override, virtual, or abstract public abstract class Item { public static abstract Item GetHistoricalItem(int id, DateTime pastDateTime); } public class Customer : Item { public static override Customer GetHistoricalItem(int id, DateTime pastDateTime) { return new Customer(); } } public class Address : Item { public static override

I am interating through classes in a Jar file and wish to find those which are not abstract. I can solve this by instantiating the classes and trapping InstantiationException but that has a performance hit as some classes have heavy startup. I can't find anything obviously like isAbstract() in the Class.java docs. It'll have abstract as one of its modifiers when you call getModifiers() on the class object. This link should help. Modifier.isAbstract( someClass.getModifiers() ); Also: http://java.sun.com/javase/6/docs/api/java/lang/reflect/Modifier.html http://java.sun.com/javase/6/docs/api/java

What's the best practice to define an abstract instance attribute, but not as a property? I would like to write something like: class AbstractFoo(metaclass=ABCMeta): @property @abstractmethod def bar(self): pass class Foo(AbstractFoo): def __init__(self): self.bar = 3 Instead of: class Foo(AbstractFoo): def __init__(self): self._bar = 3 @property def bar(self): return self._bar @bar.setter def setbar(self, bar): self._bar = bar @bar.deleter def delbar(self): del self._bar Properties are handy, but for simple attribute requiring no computation they are an overkill. This is especially important

I've be fiddling around with ui-router today in trying to better understand the scaffolding in Ionic and one thing that I noticed was that they give the abstracted state of "tabs" a url. The only times I've ever used abstract states, I used an empty string as the url and I notice that if I've ever accidentally attempted to navigate to an abstracted state (as opposed to the child state) I get the error: Cannot transition to abstract state '[insertAbstractStateHere]' edit: "Moreover, in experimenting, when I try to assign a url to my abstract state (outside of Ionic) and still render the nested

Is it possible to simulate abstract base class in JavaScript? What is the most elegant way to do it? Say, I want to do something like: - var cat = new Animal('cat'); var dog = new Animal('dog'); cat.say(); dog.say(); It should output: 'bark', 'meow' One simple way to create an abstract class is this: /** @constructor @abstract */ var Animal = function() { if (this.constructor === Animal) { throw new Error("Can't instantiate abstract class!"); } // Animal initialization... }; /** @abstract */ Animal.prototype.say = function() { throw new Error("Abstract method!"); } The Animal "class" and the

I am getting a compile time error with Java: MyClass is not abstract and does not override abstract method onClassicControllerRemovedEvent( wiiusej.wiiusejevents.wiiuseapievents.ClassicControllerRemovedEvent) in wiiusejevents.utils.WiimoteListener) Here is the class: import wiiusej.WiiUseApiManager; import wiiusej.Wiimote; import wiiusej.wiiusejevents.physicalevents.ExpansionEvent; import wiiusej.wiiusejevents.physicalevents.IREvent; import wiiusej.wiiusejevents.physicalevents.MotionSensingEvent; import wiiusej.wiiusejevents.physicalevents.WiimoteButtonsEvent; import wiiusej.wiiusejevents