fluentIterable2.java

public class FluentIterableExample {
        
        public static void main(String... args){
                List<Integer> input = generateInput();
                
                EvenFilter evenFilter = new EvenFilter();
                PowerFunction powerFunction = new PowerFunction(2);
                RangeFilter rangeFilter = new RangeFilter(17, 50);

                Optional<Double> result = FluentIterable.from(input).
                        filter(evenFilter).
                        transform(powerFunction).
                        firstMatch(rangeFilter);

                return result.or(Double.valueOf(0));
        }
        
        private static List<Integer> generateInput(){
                List<Integer> result = newLinkedList();
                for(int i=1; i<101; i++){
                        result.add(i);        
                }
                return result;
        }
        
}

class EvenFilter implements Predicate<Integer> {
    @Override
    public boolean apply(Integer integer) {
        return integer % 2 == 0;
    }
}

class PowerFunction implements Function<Integer, Double> {
    private final double root;

    public PowerFunction(double root) {
        this.root = root;
    }

    @Override
    public Double apply(Integer input) {
        return Math.pow(input, root);
    }
}

class RangeFilter implements Predicate<Double> {
    private final Range range;

    public RangeFilter(int start, int end) {
        this.range = Range.closed(Double.valueOf(start), Double.valueOf(end));
    }

    @Override
    public boolean apply(Double input) {
        return range.contains(input);
    }
}