Question

In my Java application, i need some sort of multiple-selection from a list,is there any way except a self implemented funktion like this:

private List<T> list = someListClass(); //Contains the data

public List<T> getByKey(Key key){
   List<T> returnList = someListClass();
   for(Element e : list){
      if(e.qualifiedBy(key)) returnList.add(e);
   }
   return returnList;
}

Answer 1

Your method is fine.

With Java8 lambdas, the above will be easier to write:

public List<T> getByKey(Key key){
    return list.stream().filter(e -> e.qualifiedBy(key)).into(someListClass());
}

But before that, what you have is the simplest thing.