public static void main(String... args) {
/*
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From obj to ...
-------------------------------------------------------------------------
*/
Stream<String> streamOfStrings = Stream.of("un", "deux", "trois");
Function<String, StringBuilder> function = StringBuilder::new;
streamOfStrings.map(function) /*.forEach(System.out::println)*/;
streamOfStrings = Stream.of("un", "deux", "trois");
ToIntFunction<String> toIntFunction = String::length;
IntStream streamOfInts = streamOfStrings.mapToInt(toIntFunction);
streamOfStrings = Stream.of("un", "deux", "trois");
ToDoubleFunction<String> toDoubleFunction = String::length;
DoubleStream streamOfDoubles = streamOfStrings.mapToDouble(toDoubleFunction);
streamOfStrings = Stream.of("un", "deux", "trois");
ToLongFunction<String> toLongFunction = String::length;
LongStream streamOfLongs = streamOfStrings.mapToLong(toLongFunction);
/*
-------------------------------------------------------------------------
From int to ...
-------------------------------------------------------------------------
*/
IntUnaryOperator plusplus = i -> i++;
IntStream.of(1, 2, 3).map(plusplus)
/*.forEach(x->System.out.println(x))*/ ;
IntFunction<String> intFunction = i -> "" + i;
IntStream.of(1, 2, 3).mapToObj(intFunction)
/*.forEach(System.out::println)*/ ;
IntToDoubleFunction itdf = i -> i;
IntStream.of(1, 2, 3).mapToDouble(itdf)
/*.forEach(System.out::println)*/ ;
IntToLongFunction itlf = i -> i;
IntStream.of(1, 2, 3).mapToLong(itlf)
/*.forEach(System.out::println)*/ ;
/*
-------------------------------------------------------------------------
From long to ...
-------------------------------------------------------------------------
*/
LongUnaryOperator times = l -> l * l;
LongStream.of(1L, 2L, 3L).map(times)
/*.forEach(System.out::println)*/ ;
LongFunction<String> lf = l -> "toto";
LongStream.of(1L, 2L, 3L).mapToObj(lf);
/*
-------------------------------------------------------------------------
From double to ...
-------------------------------------------------------------------------
*/
DoubleToIntFunction dtif = d -> (int) d;
DoubleStream.of(1.3, 1.5, 1.6).mapToInt(dtif).forEach(System.out::println);
}
@Override
public LongStream perform(Stream<I> stream) {
return stream.mapToLong(function);
}