不存在类型变量U的实例,因此Foo符合CompletionStage<U>

我已经做了几个小时了,但似乎无法解开这个问题。错误与此段代码有关:

错误本身是:

不存在类型变量U的实例,因此getusersforadccountresponse符合CompletionStage

在链的最开始 thenCompose s、 我擦掉了 return 使用IntelliJ的 “引入局部变量…” 查看整个链(包括第1118行)返回的类型的功能:

结果是

final CompletionStage<U> uCompletionStage = ...

但是您可以看到包含方法的返回类型是

public CompletionStage<GetUsersForAdAccountResponse> ...

GetUsersForAdAccountResponse ? (同样,通常 返回

我还尝试在每个 一路上,他们似乎都是对的。每个产生一个 CompletionStage<Foo> ,下一个 然后合成 Foo 并产生一个 CompletionStage<Bar> ,等等。(在一次代码重组中,我确实看到 CompletionStage<CompletionStage<Foo>> 但我认为那是我自己重写的作品。)

我不知道它是否有用,但这里是整个方法:

  @Override
  public CompletionStage<GetUsersForAdAccountResponse> getUsersForAdAccount(
      RequestContext context, GetUsersForAdAccountRequest request) {

    Uuid adAccountId = request.getAdAccountId();

    return verifyAuthorization(context,
        PortcullisTemplates.Action.GET_USERS_FOR_AD_ACCOUNT.getName(),
        portcullisTemplates.topOrganizationResource())
        .thenCompose(auditLogPrincipal -> jdbiExecutor.executeInTransaction(handler -> {

              // We purposely safeguard the account lookup as well behind Portcullis.
              AdAccountDao adAccountDao = handler.attach(AdAccountDao.class);
              if (adAccountDao.getAdAccountById(adAccountId) == null) {
                throw new ValidationException(SERVICE_NAME,
                    "Ad account not found: " + UuidUtils.toString(adAccountId));
              }

              AdAccountRoleUserMappingDao roleDao = handler.attach(AdAccountRoleUserMappingDao.class);

              List<String> roleNames = request.getRoleNamesList();
              return roleNames.isEmpty() ?
                     roleDao.getAdAccountRoleUserMappingsByAdAccount(adAccountId) :
                     roleDao.getAdAccountRoleUserMappingsByAdAccountAndRoles(adAccountId, roleNames);

        })).thenCompose(adAccountRoleUserMappings -> jdbiExecutor.execute(UserDao.class, userDao -> {
          return userDao
              .getUsersBy]UserIds(
                  adAccountRoleUserMappings.stream()
                      .map(AdAccountRoleUserMapping::userId)
                      .collect(Collectors.toList())
              ).stream()
                  .collect(Collectors.toMap(
                      User::userId,
                      user -> new EncryptedFieldsBuilder()
                          .firstName(user.encryptedFirstName())
                          .lastName(user.encryptedLastName())
                          .email(user.encryptedEmail())
                          .build()
              ));
        }).thenCompose(
            userEncryptedFields -> padlockService.decryptUserAccounts(userEncryptedFields)
        ).thenCompose(decryptedUsers -> GetUsersForAdAccountResponse.newBuilder()
            .addAllUserWithRole(
                adAccountRoleUserMappings.stream()
                    .filter(mapping -> decryptedUsers.containsKey(mapping.userId()))
                    .map(mapping -> UserWithRole.newBuilder()
                        .setAccount(decryptedUsers.get(mapping.userId()))
                        .setRoleName(mapping.roleName())
                        .build())
                    .collect(Collectors.toSet())
            ).build()
        ));
  }