Count non null fields in an object

Question

I have a UserProfile class which contains user\'s data as shown below:

class UserProfile {

  private String userId;
  private String displayNam         


        

Answer 1

You can simply a lot your code by creating a Stream over the given list of functions:

public static <T> long getNonNullFieldCount(T t, List<Function<? super T, ?>> functionList) {
    return functionList.stream().map(f -> f.apply(t)).filter(Objects::nonNull).count();
}

This will return the count of non-null fields returned by each function. Each function is mapped to the result of applying it to the given object and null fields are filtered out with the predicate Objects::nonNull.