fixes #499

main/commons/src/main/java/org/cryptomator/common/Optionals.java

@@ -1,6 +1,7 @@
 package org.cryptomator.common;
 
 import java.util.Optional;
+import java.util.function.Function;
 
 public final class Optionals {
 
@@ -14,4 +15,16 @@ public final class Optionals {
 		}
 	}
 
+	/**
+	 * Returns a function that is equivalent to the input function but immediately gets the value of the returned optional when invoked.
+	 * 
+	 * @param <T> the type of the input to the function
+	 * @param <R> the type of the result of the function
+	 * @param optionalFunction An input function {@code Function<Foo, Optional<Bar>>}
+	 * @return A {@code Function<Foo, Bar>}, that may throw an NoSuchElementException, if the original function returns an empty optional.
+	 */
+	public static <T, R> Function<T, R> unwrap(Function<T, Optional<R>> optionalFunction) {
+		return t -> optionalFunction.apply(t).get();
+	}
+
 }