diff options
| author | Michael Williamson <mike@zwobble.org> | 2016-04-30 17:20:53 +0100 |
|---|---|---|
| committer | Michael Williamson <mike@zwobble.org> | 2016-04-30 17:20:53 +0100 |
| commit | ec5037c01868fecaec2eba89b975f3e53aded89a (patch) | |
| tree | e0d5a092419bace577a90eb29699f5be57f36078 /Mammoth/Couscous/java/util/Optional.cs | |
| parent | 17d1a1f710edd8dfb92e75bcd273e04cee7c8146 (diff) | |
Export from java-mammoth 5f538798b147f0e76
Diffstat (limited to 'Mammoth/Couscous/java/util/Optional.cs')
| -rw-r--r-- | Mammoth/Couscous/java/util/Optional.cs | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/Mammoth/Couscous/java/util/Optional.cs b/Mammoth/Couscous/java/util/Optional.cs new file mode 100644 index 0000000..f295688 --- /dev/null +++ b/Mammoth/Couscous/java/util/Optional.cs @@ -0,0 +1,103 @@ +using System; +using Mammoth.Couscous.java.util.function; + +namespace Mammoth.Couscous.java.util +{ + internal interface Optional<T> + { + bool isPresent(); + Optional<U> map<U>(Function<T, U> function); + Optional<U> flatMap<U>(Function<T, Optional<U>> function); + T orElse(T value); + T orElseGet(Supplier<T> supplier); + T orElseThrow<TException>(Supplier<TException> exceptionSupplier) where TException : Exception; + T get(); + void ifPresent(Consumer<T> consumer); + } + + internal class None<T> : Optional<T> { + public bool isPresent() { + return false; + } + + public Optional<U> map<U>(Function<T, U> function) { + return new None<U>(); + } + + public Optional<U> flatMap<U>(Function<T, Optional<U>> function) { + return new None<U>(); + } + + public T orElse(T value) { + return value; + } + + public T orElseGet(Supplier<T> supplier) { + return supplier.get(); + } + + public T orElseThrow<TException>(Supplier<TException> exceptionSupplier) where TException : Exception { + throw exceptionSupplier.get(); + } + + public T get() { + throw new NoSuchElementException(); + } + + public void ifPresent(Consumer<T> consumer) { + } + } + + internal class Some<T> : Optional<T> { + private readonly T _value; + + internal Some(T value) { + _value = value; + } + + public bool isPresent() { + return true; + } + + public Optional<U> map<U>(Function<T, U> function) { + return new Some<U>(function.apply(_value)); + } + + public Optional<U> flatMap<U>(Function<T, Optional<U>> function) { + return function.apply(_value); + } + + public T orElse(T value) { + return _value; + } + + public T orElseGet(Supplier<T> supplier) { + return _value; + } + + public T orElseThrow<TException>(Supplier<TException> exceptionSupplier) where TException : Exception { + return _value; + } + + public T get() { + return _value; + } + + public void ifPresent(Consumer<T> consumer) { + consumer.accept(_value); + } + } + + internal static class Optional + { + internal static Optional<T> empty<T>() + { + return new None<T>(); + } + + internal static Optional<T> of<T>(T value) + { + return new Some<T> (value); + } + } +} |
