private void validateFileSystemLoopException(Path start, Path... causes) {
try (Stream<Path> s = Files.walk(start, FileVisitOption.FOLLOW_LINKS)) {
try {
int count = s.mapToInt(p -> 1).reduce(0, Integer::sum);
fail("Should got FileSystemLoopException, but got " + count + "elements.");
} catch (UncheckedIOException uioe) {
IOException ioe = uioe.getCause();
if (ioe instanceof FileSystemLoopException) {
FileSystemLoopException fsle = (FileSystemLoopException) ioe;
boolean match = false;
for (Path cause : causes) {
if (fsle.getFile().equals(cause.toString())) {
match = true;
break;
}
}
assertTrue(match);
} else {
fail("Unexpected UncheckedIOException cause " + ioe.toString());
}
}
} catch (IOException ex) {
fail("Unexpected IOException " + ex);
}
}
public static void main(String... args) {
/*
-------------------------------------------------------------------------
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);
}
public void testBasic() {
try (Stream<Path> s = Files.list(testFolder)) {
Object[] actual = s.sorted().toArray();
assertEquals(actual, level1);
} catch (IOException ioe) {
fail("Unexpected IOException");
}
try (Stream<Path> s = Files.list(testFolder.resolve("empty"))) {
int count = s.mapToInt(p -> 1).reduce(0, Integer::sum);
assertEquals(count, 0, "Expect empty stream.");
} catch (IOException ioe) {
fail("Unexpected IOException");
}
}
public static void main(String[] args) {
// Page 45
// ========
IntStream.iterate(1, i -> i * 2).limit(10).forEachOrdered(System.out::println);
IntStream.range(1, 6).forEach(System.out::print); // prints 123456
// Page 46
// ========
List<Integer> intList = Arrays.asList(1, 2, 3);
OptionalDouble maxDistance =
intList.stream().map(i -> new Point(i % 3, i / 3)).mapToDouble(p -> p.distance(0, 0)).max();
DoubleStream ds =
intList.stream().map(i -> new Point(i % 3, i / 3)).mapToDouble(p -> p.distance(0, 0));
OptionalDouble maxDistance1 = ds.max();
// Page 48
// ========
Optional<Integer> max =
Arrays.asList(1, 2, 3, 4, 5).stream().map(i -> i + 1).max(Integer::compareTo);
// Page 49
// ========
OptionalInt max1 = IntStream.rangeClosed(1, 5).map(i -> i + 1).max();
DoubleStream ds1 = IntStream.rangeClosed(1, 10).asDoubleStream();
Stream<Integer> is = IntStream.rangeClosed(1, 10).boxed();
Stream<Integer> integerStream = Stream.of(1, 2);
IntStream is1 = integerStream.mapToInt(Integer::intValue);
}
