将Java CompletionStage转换为等效的Scala

我正在尝试将下面的java代码转换为它的scala等价物

CompletionStage<GetXByKeyResponse> apiResponseF = appleClient.getAppleProperty(key);

CompletionStage<XContainer> xContainerF = apiResponseF.thenCompose(resp -> resp.fold(
    CompletableFuture::completedFuture,
    errorNotFound -> Futures.failedFuture(new Exception("some error")),
    errorInternalServerError -> Futures.failedFuture(new Exception("some error"))
    ));

return xContainerF;

折叠的定义

方法：

import java.util.function.Function;

    public <T> T fold(Function<XContainer, T> handleOk,
                Function<ServiceErrorResponse, T> handleNotFound,
                Function<ServiceErrorResponse, T> handleInternalServerError) {
            if (this instanceof Ok) {
                return handleOk.apply(((Ok) this).getValue());
            } else if (this instanceof NotFound) {
                return handleNotFound.apply(((NotFound) this).getValue());
            } else if (this instanceof InternalServerError) {
                return handleInternalServerError.apply(((InternalServerError) this).getValue());
            } else {
                throw new AssertionError("This is a bug!");
            }
        }

import java.util.function.function；
公共T形折叠（功能手柄），
函数handleNotFound，
函数handleInternalServerError）{
如果（此实例为Ok）{
return handleOk.apply（（（Ok）this.getValue（））；
}else if（未找到此实例）{
return handleNotFound.apply（（（NotFound）this.getValue（））；
}else if（此实例为InternalServerError）{
返回handleInternalServerError.apply（（（InternalServerError）this.getValue（））；
}否则{
抛出新的断言错误（“这是一个bug！”）；
}
}

import java.util.function.Function;

    public <T> T fold(Function<XContainer, T> handleOk,
                Function<ServiceErrorResponse, T> handleNotFound,
                Function<ServiceErrorResponse, T> handleInternalServerError) {
            if (this instanceof Ok) {
                return handleOk.apply(((Ok) this).getValue());
            } else if (this instanceof NotFound) {
                return handleNotFound.apply(((NotFound) this).getValue());
            } else if (this instanceof InternalServerError) {
                return handleInternalServerError.apply(((InternalServerError) this).getValue());
            } else {
                throw new AssertionError("This is a bug!");
            }
        }