Question

Please forgive my ignorance, but I wasn’t able to find an answer elsewhere.

I have the following code:

int value = 5;
Strategy s = new Strategy(convert(value));
mainClass.setStuff(s, value);

The Strategy is initialized with a number that is based on a conversion of “value”.
The mainClass uses the unconverted “value”.

What I would like to do is to simplify this by giving mainClass only the information which Strategy to use and with which unconverted value, whereupon mainClass should do the instantiation and initialization of the Strategy and process the value.

In C++ this would be possible with a template:

int value = 5;
mainClass.setStuff<Strategy>(value);

Can I make this work in Java somehow? It doesn’t seem to work with generics as unlike C++, Java cannot infer the type of the argument, so I can’t initialize Strategy.

Answer 1

Change the setStuff method signature to public <T extends Strategy> ReturnType setStuff(Class<T> clazz, int value). Then you can find the correct constructor and create your new instance.