1 files changed, 103 insertions, 0 deletions
diff --git a/dotnet/Mammoth/Couscous/java/util/Optional.cs b/dotnet/Mammoth/Couscous/java/util/Optional.cs
new file mode 100644
index 0000000..f295688
--- /dev/null
+++ b/dotnet/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);
+        }
+    }
+}