Question

Something like this is what Im trying to achieve:

public Attribute<?> getAttribute(Class<? extends Attribute> attributeClass){
  for(Attribute attribute: attributes)
    if(attributeClass.isInstance(attribute)) return attributeClass.cast(attribute);
  return null;
}

where the Attribute< ?> is obviously the incorrect part.

I want the return type of this method to be of attributeClass, but I cant seem to figure out how to get that. I should note that I am aware that I could just use Attribute as a return type, but this method would be mostly called in this fashion:

AttributeType1 attributeType1 = getAttribute(AttributeType1.class);

…and I am trying to avoid having to cast every time.

Help appreciated.

Answer 1

this is what you need

public <T extends Attribute> T getAttribute(Class<T> attributeClass){

you need to specify the generic type before the return type