code: public static short translateBucketAcl(AccessControlList acl, String userId) {
      short mode = (short) 0;
      for (Grant grant : acl.getGrantsAsList()) {
        Permission perm = grant.getPermission();
        Grantee grantee = grant.getGrantee();
        if (perm.equals(Permission.Read)) {
          if (isUserIdInGrantee(grantee, userId)) {
            // If the bucket is readable by the user, add r and x to the owner mode.
            mode |= (short) 0500;
          }
        } else if (perm.equals(Permission.Write)) {
          if (isUserIdInGrantee(grantee, userId)) {
            // If the bucket is writable by the user, +w to the owner mode.
            mode |= (short) 0200;
          }
        } else if (perm.equals(Permission.FullControl)) {
          if (isUserIdInGrantee(grantee, userId)) {
            // If the user has full control to the bucket, +rwx to the owner mode.
            mode |= (short) 0700;
          }
        }
      }
      return mode;
    }
docs: Translates S3 bucket ACL to Alluxio owner mode.
  
  @param acl the acl of S3 bucket
  @param userId the S3 user id of the Alluxio owner
  @return the translated posix mode in short format