How to filter list using Predicate [duplicate]

Question

private static class FilterByStringContains implements Predicate<String> {
        private String filterString;
        private FilterByStringContains(final String filterString) {
            this.filterString = filterString;
        }
        @Override
        public boolean apply(final String string) {
            return string.contains(filterString);
        }
    }

I have a list of Strings, I want to filter it by the specified String so the returned value contains a list of only the specified strings. I was going to use a predicate as above but not sure how to apply this to filter a list

Answer 1

I'm assuming the Predicate here is from Guava? If so, you could use Iterables.filter:

Iterable<String> filtered = Iterables.filter(original, predicate);

Then build a list from that if you wanted:

List<String> filteredCopy = Lists.newArrayList(filtered);

... but I'd only suggest copying it to another list if you actually want it as a list. If you're just going to iterate over it (and only once), stick to the iterable.

Answer 2

How about using Guava's filter method or Apache commons' filter method? Guava's method returns a view of the collection, whereas Apache Commons' modifies the collection in-place. Don't reinvent the wheel!