Guava: how to combine filter and transform?

Question

I have a collection of Strings, and I would like to convert it to a collection of strings were all empty or null Strings are removed and all others are trimmed.

I can do

Answer 1

In the upcoming latest version(12.0) of Guava, there will be a class named FluentIterable. This class provides the missing fluent API for this kind of stuff.

Using FluentIterable, you should be able doing something like this:

final Collection filtered = FluentIterable
    .from(tokens)
    .transform(new Function() {
       @Override
       public String apply(final String input) {
         return input == null ? "" : input.trim();
       }
     })
    .filter(new Predicate() {
       @Override
       public boolean apply(final String input) {
         return !Strings.isNullOrEmpty(input);
       }
     })
   .toImmutableList();