Combinators in Guava libraries

Do you want to use combinators in Java code? Guava libraries provide them for you.

Iterators.filter(unfiltered, predicate);
Iterators.transform(fromIterator, function);

Maps.filterKeys(unfiltered, keyPredicate);
Maps.filterValues(unfiltered, valuePredicate);
Maps.filterEntries(unfiltered, entryPredicate)
Maps.transformValues(fromMap, function);

Lists.transform(fromList, function);

Sets.filter(unfiltered, predicate);

See official document for detail.

• FunctionalExplained - guava-libraries

But sadly, there is no reduce & fold in Guava.

• Issue 218 - guava-libraries - Add a fold method for Iterables - Guava: Google Core Libraries for Java 1.6+ - Google Project Hosting