Chain of Map method references

Question

I'm working with Twitter4J. But the question I'm asking is more general. I want to access the user id of a given tweet. Currently, I have the following two options:

//Option 1 stream.map(status -> status.getUser().getId())       .forEach(System.out::println);  //Option 2: stream.map(Status::getUser)       .map(User:getId)       .forEach(System.out::println); 

I don't like the lambda expression in the first option, nor being forced to call two maps in the second one. Is there a way to make a chain of method references? I know that Status::getUser::getId does not work, but am wondering if there is an alternative.

Answer 1

Nope, these are the two ways of doing it. Anything else would end up being only less clear.

But, since you asked, here are some options.

static<T,U,R> Function<T,R> chain(         Function<? super T, ? extends U> f1,         Function<? super U, ? extends R> f2) {     return t -> f2.apply(f1.apply(t)); }  stream.map(chain(Status::getUser, User::getId)) 

Or

static<T,R> Function<T,R> func(Function<T,R> f) {     return f; }  stream.map(func(Status::getUser).andThen(User::getId))