GenericType is a utility class that considerably eases the resolution of generic type information at runtime.
Author: Michael Karneim
Project Homepage: http://github.com/mkarneim/generictype
Given you have an interface that extends the generic interface Collection:
public interface MyCollection extends Collection<String> {
}
You can see that the value of the generic type parameter is String.
But do you know how to access this value using reflection?
Actually it's possible because the value is compiled into the class file of MyCollection.
But if you try to write some code that can resolve it, you'll possibly realize that this not a simple task. I stumbled upon this problem during my work on Beanfabrics. And it took me quite a while to write some code that can do it.
Finally I created this repository with my solution called GenericType.
First choose the type variable you are interested by using standard reflection:
TypeVariable E = Collection.class.getTypeParameters()[0];
Then create an instance of GenericType with a reference to MyCollection.
GenericType classType = new GenericType(MyCollection.class);
And now you can access the actual value of the type parameter:
GenericType typeParam = classType.getTypeParameter(E);
Assert.assertEquals( String.class, typeParam.asClass());
For downloading a binary distribution please visit the download page.
GenericType is open source, and it is distributed under the terms of the LGPL license. Please read the license.txt.
Give me some feedback if you can't include a LGPL library into you project. I will be happy to add other OS licences if required.
- Java 6
For some examples please have a look at the unit tests.