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List<String> reports = codes.stream()
.map(
Switch.defaultCase(code -> "Unknwown code " + code)
.single(0, code -> "Success")
// ...
.build())
.collect(Collectors.toList()); |
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Envoyé par BugFactory
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1 2 3 4 | public interface SwitchExpression <T, R> extends Function<T, R>
{
// unchanged
} |
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1 2 3 4 5 | @Override
public R apply(T value)
{
return resolve(value);
} |
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | @Test
public void StreamMapTest()
{
// switcher could have been written in the map method of the Stream.of(),
// but it's defined here for readability only.
SwitchExpression<Integer, String> switcher = Switch.<Integer, String> start()
.defaultCase(v -> "ODD")
.predicate(v -> v % 2 == 0, v -> "EVEN")
.build();
// just to check thats everything is fine
assertNotNull(switcher, "cannot build the switcher");
// let's run the Stream.map which will call the switcher.
// the switcher implements Function <R, T> and its apply(T t) method.
List<String> result = Stream.of(0, 1, 2, 3, 4, 5, 6, 7, 8, 9)
.map(switcher)
.collect(Collectors.toList());
// few tests on the list
assertNotNull(result, "the returned list is null, which is unacceptable!");
assertEquals(10, result.size(), "the returned list size is wrong, which is totally unacceptable!");
// then lets count the EVEN and the ODD to verify the switcher behavior inside a Stream.map().
Map<String, Long> statistics = result.stream().collect(Collectors.groupingBy(String::toString, Collectors.counting()));
assertNotNull(statistics, "the returned map is null, which is unbelievable!");
assertEquals(5L, statistics.get("ODD").longValue());
assertEquals(5L, statistics.get("EVEN").longValue());
// it's working!
} |
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