OAuth requestToken for freelancer.com api

  /**
  * Configures the signature type, choose between header, querystring, etc. Defaults to Header
  *
  * @param scope The OAuth scope
  * @return the {@link ServiceBuilder} instance for method chaining
  */
  public ServiceBuilder signatureType(SignatureType type)
  {
     Preconditions.checkNotNull(type, "Signature type can't be null");
     this.signatureType = type;
    return this;
  }

  Service = new ServiceBuilder()
                    .provider(FreelancerApi.class)
                    .apiKey(consumer)
                    .apiSecret(secret)
                    .callback("oob")
                    .signatureType(SignatureType.QueryString)
                    .build();