The Activator class within the root System namespace is pretty powerful. There are a lot of overloads for passing parameters to the constructor and such. Check out the documentation at: http://msdn.microsoft.com/en-us/library/system.activator.createinstance.aspx or (new path) https://docs.microsoft.com/en-us/dotnet/api/system.activator.createinstance Here are some simple examples:
I’d like to be able to introspect a C++ class for its name, contents (i.e. members and their types) etc. I’m talking native C++ here, not managed C++, which has reflection. I realise C++ supplies some limited information using RTTI. Which additional libraries (or other techniques) could supply this information?
Like answered before, you should use: Another way, which is sometimes prefered, is calling the getter dynamically. example code: Also be aware that when your class inherits from another class, you need to recursively determine the Field. for instance, to fetch all Fields of a given class;
After type erasure, all that is known about T is that it is some subclass of Object. You need to specify some factory to create instances of T. One approach could use a Supplier<T>: Usage might look like this: Alternatively, you can provide a Class<T> object, and then use reflection.
I have to ask a question in return: is your GenSet “checked” or “unchecked”? What does that mean? Checked: strong typing. GenSet knows explicitly what type of objects it contains (i.e. its constructor was explicitly called with a Class<E> argument, and methods will throw an exception when they are passed arguments that are not of type E. See Collections.checkedCollection.-> in that case, you should … Read more
You’re invoking the method with the class, but you need an instance of it. Try this:
You’ve added an extra level of abstraction by calling the method with reflection. The reflection layer wraps any exception in an InvocationTargetException, which lets you tell the difference between an exception actually caused by a failure in the reflection call (maybe your argument list wasn’t valid, for example) and a failure within the method called. Just unwrap the … Read more
The name reflection is used to describe code which is able to inspect other code in the same system (or itself). For example, say you have an object of an unknown type in Java, and you would like to call a ‘doSomething’ method on it if one exists. Java’s static typing system isn’t really designed … Read more