public class DataFactory {

class SYNOP implements IDataSources {}
class WRF implements IDataSources {}

public abstract class Factory {
    public abstract IDataSources CreateModel();
}

public class SYNOPFactory extends Factory {

    @Override
    public IDataSources CreateModel() {
        return new SYNOP();
    }
}

public class WRFFactory extends Factory {

    @Override
    public IDataSources CreateModel() {
        return new WRF();
    }
}

public static void main(String[] args) {

    Factory factory = new WRFFactory();

}