How to get the class of type variable in Java Generics

Question

I\'ve seen similar questions but they didnt help very much.

For instance I\'ve got this Generic Class:

public class ContainerTest
{

    public          


        

Answer 1

There is no "clean" way to get the Generic Type argument from within the class. Instead, a common pattern is to pass the Class of the Generic Type to the constructor and keep it as an inner property juste as done in the java.util.EnumMap implementation.

http://docs.oracle.com/javase/1.5.0/docs/api/java/util/EnumMap.html http://grepcode.com/file/repository.grepcode.com/java/root/jdk/openjdk/6-b14/java/util/EnumMap.java

public class ContainerTest<T> {

    Class<T> type;
    T t;

    public ContainerTest(Class<T> type) {
        this.type = type;
    }

    public void setT(T t) {
        this.t = t;
    }

    public T getT() {
        return t;
    }

    public void doSomething() {
        //There you can use "type" property.
    }
}