@Test
public void testHeadTail() {
List<Integer> ints = IntStreamEx.range(1000).boxed().toList();
checkShortCircuitCollector("tail(0)", Arrays.asList(), 0, ints::stream, MoreCollectors.tail(0));
checkCollector("tail(1)", Arrays.asList(999), ints::stream, MoreCollectors.tail(1));
checkCollector("tail(2)", Arrays.asList(998, 999), ints::stream, MoreCollectors.tail(2));
checkCollector("tail(500)", ints.subList(500, 1000), ints::stream, MoreCollectors.tail(500));
checkCollector("tail(999)", ints.subList(1, 1000), ints::stream, MoreCollectors.tail(999));
checkCollector("tail(1000)", ints, ints::stream, MoreCollectors.tail(1000));
checkCollector("tail(MAX)", ints, ints::stream, MoreCollectors.tail(Integer.MAX_VALUE));
checkShortCircuitCollector("head(0)", Arrays.asList(), 0, ints::stream, MoreCollectors.head(0));
checkShortCircuitCollector(
"head(1)", Arrays.asList(0), 1, ints::stream, MoreCollectors.head(1));
checkShortCircuitCollector(
"head(2)", Arrays.asList(0, 1), 2, ints::stream, MoreCollectors.head(2));
checkShortCircuitCollector(
"head(500)", ints.subList(0, 500), 500, ints::stream, MoreCollectors.head(500));
checkShortCircuitCollector(
"head(999)", ints.subList(0, 999), 999, ints::stream, MoreCollectors.head(999));
checkShortCircuitCollector("head(1000)", ints, 1000, ints::stream, MoreCollectors.head(1000));
checkShortCircuitCollector(
"head(MAX)", ints, 1000, ints::stream, MoreCollectors.head(Integer.MAX_VALUE));
checkShortCircuitCollector(
"head(10000)",
IntStreamEx.rangeClosed(1, 10000).boxed().toList(),
10000,
() -> Stream.iterate(1, x -> x + 1),
MoreCollectors.head(10000),
true);
}
@Test
public void testMapping() {
List<String> input = Arrays.asList("Capital", "lower", "Foo", "bar");
Collector<String, ?, Map<Boolean, Optional<Integer>>> collector =
MoreCollectors.partitioningBy(
str -> Character.isUpperCase(str.charAt(0)),
MoreCollectors.mapping(String::length, MoreCollectors.first()));
checkShortCircuitCollector(
"mapping", new BooleanMap<>(Optional.of(7), Optional.of(5)), 2, input::stream, collector);
Collector<String, ?, Map<Boolean, Optional<Integer>>> collectorLast =
MoreCollectors.partitioningBy(
str -> Character.isUpperCase(str.charAt(0)),
MoreCollectors.mapping(String::length, MoreCollectors.last()));
checkCollector(
"last", new BooleanMap<>(Optional.of(3), Optional.of(3)), input::stream, collectorLast);
input = Arrays.asList("Abc", "Bac", "Aac", "Abv", "Bbc", "Bgd", "Atc", "Bpv");
Map<Character, List<String>> expected =
EntryStream.of('A', Arrays.asList("Abc", "Aac"), 'B', Arrays.asList("Bac", "Bbc")).toMap();
AtomicInteger cnt = new AtomicInteger();
Collector<String, ?, Map<Character, List<String>>> groupMap =
Collectors.groupingBy(
s -> s.charAt(0),
MoreCollectors.mapping(
x -> {
cnt.incrementAndGet();
return x;
},
MoreCollectors.head(2)));
checkCollector("groupMap", expected, input::stream, groupMap);
cnt.set(0);
assertEquals(expected, input.stream().collect(groupMap));
assertEquals(4, cnt.get());
}
@Test
public void testGroupingByWithDomain() {
List<String> data = Arrays.asList("a", "foo", "test", "ququq", "bar", "blahblah");
Collector<String, ?, String> collector =
MoreCollectors.collectingAndThen(
MoreCollectors.groupingBy(
String::length,
IntStreamEx.range(10).boxed().toSet(),
TreeMap::new,
MoreCollectors.first()),
Object::toString);
checkShortCircuitCollector(
"groupingWithDomain",
"{0=Optional.empty, 1=Optional[a], 2=Optional.empty, 3=Optional[foo], 4=Optional[test], 5=Optional[ququq], "
+ "6=Optional.empty, 7=Optional.empty, 8=Optional[blahblah], 9=Optional.empty}",
data.size(),
data::stream,
collector);
Map<String, String> name2sex = new LinkedHashMap<>();
name2sex.put("Mary", "Girl");
name2sex.put("John", "Boy");
name2sex.put("James", "Boy");
name2sex.put("Lucie", "Girl");
name2sex.put("Fred", "Boy");
name2sex.put("Thomas", "Boy");
name2sex.put("Jane", "Girl");
name2sex.put("Ruth", "Girl");
name2sex.put("Melanie", "Girl");
Collector<Entry<String, String>, ?, Map<String, List<String>>> groupingBy =
MoreCollectors.groupingBy(
Entry::getValue,
StreamEx.of("Girl", "Boy").toSet(),
MoreCollectors.mapping(Entry::getKey, MoreCollectors.head(2)));
AtomicInteger counter = new AtomicInteger();
Map<String, List<String>> map =
EntryStream.of(name2sex).peek(c -> counter.incrementAndGet()).collect(groupingBy);
assertEquals(Arrays.asList("Mary", "Lucie"), map.get("Girl"));
assertEquals(Arrays.asList("John", "James"), map.get("Boy"));
assertEquals(4, counter.get());
Collector<Entry<String, String>, ?, Map<String, String>> groupingByJoin =
MoreCollectors.groupingBy(
Entry::getValue,
StreamEx.of("Girl", "Boy").toSet(),
MoreCollectors.mapping(
Entry::getKey, Joining.with(", ").maxChars(16).cutAfterDelimiter()));
counter.set(0);
Map<String, String> mapJoin =
EntryStream.of(name2sex).peek(c -> counter.incrementAndGet()).collect(groupingByJoin);
assertEquals("Mary, Lucie, ...", mapJoin.get("Girl"));
assertEquals("John, James, ...", mapJoin.get("Boy"));
assertEquals(7, counter.get());
}
@Test
public void testHeadParallel() {
List<Integer> expected = IntStreamEx.range(0, 2000, 2).boxed().toList();
List<Integer> expectedShort = Arrays.asList(0, 1);
for (int i = 0; i < 1000; i++) {
assertEquals(
"#" + i,
expectedShort,
IntStreamEx.range(1000).boxed().parallel().collect(MoreCollectors.head(2)));
assertEquals(
"#" + i,
expected,
IntStreamEx.range(10000)
.boxed()
.parallel()
.filter(x -> x % 2 == 0)
.collect(MoreCollectors.head(1000)));
}
assertEquals(
expectedShort, StreamEx.iterate(0, x -> x + 1).parallel().collect(MoreCollectors.head(2)));
}
@Test
public void testFlatMapping() {
{
Map<Integer, List<Integer>> expected =
IntStreamEx.rangeClosed(1, 100)
.boxed()
.toMap(x -> IntStreamEx.rangeClosed(1, x).boxed().toList());
Collector<Integer, ?, Map<Integer, List<Integer>>> groupingBy =
Collectors.groupingBy(
Function.identity(),
MoreCollectors.flatMapping(
x -> IntStream.rangeClosed(1, x).boxed(), Collectors.toList()));
checkCollector(
"flatMappingSimple", expected, () -> IntStreamEx.rangeClosed(1, 100).boxed(), groupingBy);
}
Function<Entry<String, List<String>>, Stream<String>> valuesStream =
e -> e.getValue() == null ? null : e.getValue().stream();
List<Entry<String, List<String>>> list =
EntryStream.of(
"a", Arrays.asList("bb", "cc", "dd"), "b", Arrays.asList("ee", "ff"), "c", null)
.append("c", Arrays.asList("gg"), "b", null, "a", Arrays.asList("hh"))
.toList();
{
Map<String, List<String>> expected =
EntryStream.of(list.stream())
.flatMapValues(l -> l == null ? null : l.stream())
.grouping();
checkCollector(
"flatMappingCombine",
expected,
list::stream,
Collectors.groupingBy(
Entry::getKey, MoreCollectors.flatMapping(valuesStream, Collectors.toList())));
AtomicInteger openClose = new AtomicInteger();
Collector<Entry<String, List<String>>, ?, Map<String, List<String>>> groupingBy =
Collectors.groupingBy(
Entry::getKey,
MoreCollectors.flatMapping(
valuesStream.andThen(
s -> {
if (s == null) return null;
openClose.incrementAndGet();
return s.onClose(openClose::decrementAndGet);
}),
Collectors.toList()));
checkCollector(
"flatMappingCombineClosed",
expected,
list::stream,
MoreCollectors.collectingAndThen(
groupingBy,
res -> {
assertEquals(0, openClose.get());
return res;
}));
boolean catched = false;
try {
Collector<Entry<String, List<String>>, ?, Map<String, List<String>>> groupingByException =
Collectors.groupingBy(
Entry::getKey,
MoreCollectors.flatMapping(
valuesStream.andThen(
s -> {
if (s == null) return null;
openClose.incrementAndGet();
return s.onClose(openClose::decrementAndGet)
.peek(
e -> {
if (e.equals("gg")) throw new IllegalArgumentException(e);
});
}),
Collectors.toList()));
list.stream()
.collect(
MoreCollectors.collectingAndThen(
groupingByException,
res -> {
assertEquals(0, openClose.get());
return res;
}));
} catch (IllegalArgumentException e1) {
assertEquals("gg", e1.getMessage());
catched = true;
}
assertTrue(catched);
}
{
Map<String, List<String>> expected =
EntryStream.of(
"a", Arrays.asList("bb"), "b", Arrays.asList("ee"), "c", Arrays.asList("gg"))
.toMap();
Collector<Entry<String, List<String>>, ?, List<String>> headOne =
MoreCollectors.flatMapping(valuesStream, MoreCollectors.head(1));
checkCollector(
"flatMappingSubShort",
expected,
list::stream,
Collectors.groupingBy(Entry::getKey, headOne));
checkShortCircuitCollector(
"flatMappingShort",
expected,
4,
list::stream,
MoreCollectors.groupingBy(Entry::getKey, StreamEx.of("a", "b", "c").toSet(), headOne));
AtomicInteger cnt = new AtomicInteger();
Collector<Entry<String, List<String>>, ?, List<String>> headPeek =
MoreCollectors.flatMapping(
valuesStream.andThen(s -> s == null ? null : s.peek(x -> cnt.incrementAndGet())),
MoreCollectors.head(1));
assertEquals(
expected, StreamEx.of(list).collect(Collectors.groupingBy(Entry::getKey, headPeek)));
assertEquals(3, cnt.get());
cnt.set(0);
assertEquals(
expected,
StreamEx.of(list)
.collect(
MoreCollectors.groupingBy(
Entry::getKey, StreamEx.of("a", "b", "c").toSet(), headPeek)));
assertEquals(3, cnt.get());
}
{
Map<String, List<String>> expected =
EntryStream.of(
"a",
Arrays.asList("bb", "cc"),
"b",
Arrays.asList("ee", "ff"),
"c",
Arrays.asList("gg"))
.toMap();
Collector<Entry<String, List<String>>, ?, List<String>> headTwo =
MoreCollectors.flatMapping(valuesStream, MoreCollectors.head(2));
checkCollector(
"flatMappingSubShort",
expected,
list::stream,
Collectors.groupingBy(Entry::getKey, headTwo));
AtomicInteger openClose = new AtomicInteger();
boolean catched = false;
try {
Collector<Entry<String, List<String>>, ?, Map<String, List<String>>> groupingByException =
Collectors.groupingBy(
Entry::getKey,
MoreCollectors.flatMapping(
valuesStream.andThen(
s -> {
if (s == null) return null;
openClose.incrementAndGet();
return s.onClose(openClose::decrementAndGet)
.peek(
e -> {
if (e.equals("gg")) throw new IllegalArgumentException(e);
});
}),
MoreCollectors.head(2)));
list.stream()
.collect(
MoreCollectors.collectingAndThen(
groupingByException,
res -> {
assertEquals(0, openClose.get());
return res;
}));
} catch (IllegalArgumentException e1) {
assertEquals("gg", e1.getMessage());
catched = true;
}
assertTrue(catched);
}
}
