Java SDK

To create payments, you need to link your server to our platform via one of our integration methods.
Our Java SDK library is the ideal solution to connect to our platform if you prefer to do so with your own stand-alone system using Java language.

Choosing the Java SDK, you can:

• Access all functionalities of our RESTful API in a compact, convenient and customisable way.
• Use all server-sided integration methods of our platform (Hosted Checkout Page / Hosted Tokenization Page / Server-to-server).
• Make all payment processing-related API calls (i.e. CreateHostedCheckout, CreatePayment, RefundPayment and many more).

To take full advantage of this SDK, make sure you meet these requirements:

• Java 8 or higher
• Maven/Gradle

Download the newest version of Java library and follow the installation instructions. You can download and install the latest version of the Java SDK by:

• Using Maven Repository
  Make sure to select the latest version.
  
  
• Using Gradle
  Make sure to select the latest version.
  
  
• Downloading the source code of the SDK from GitHub and installing our library manually on your system.

Find more details on GitHub. Also, check out all available SDK objects and properties in our Full API Reference. Once you are all set, read the next chapters on how to prepare and use the SDK.

Initialisation

To connect your system to our platform by using the SDK, you need to initialise it at first.

Initialising requires you to:

• Create test/live account.
• Create properties file:
  

  
  onlinePayments.api.integrator=CompanyName
  onlinePayments.api.endpoint.host=ProperApiEndpoint
   # The properties below are optional and use the given values by default
  onlinePayments.api.endpoint.scheme=https
  onlinePayments.api.endpoint.port=-1
  onlinePayments.api.connectTimeout=10000
  onlinePayments.api.socketTimeout=10000
  onlinePayments.api.maxConnections=10
  onlinePayments.api.https.protocols=TLSv1.2
  onlinePayments.api.authorizationType=V1HMAC

• Create an API Key and API Secret for the PSPID you wish to use for transaction processing.
• Initialise an instance of Client using the API Key / API Secret to set up the connection to our test/live platform.

After initialisation, you can start processing transactions via your PSPID. Learn how this works in the dedicated chapter.

Have a look at code samples of two connection methods covering the steps mentioned above:

1. By using created properties file
   

   
   private ClientInterface client;
   
   private MerchantClientInterface merchantClient;
   
   public void initialiseSdk () {
    URI propertiesUri = getClass().getClassLoader().getResource("paymentprovider.properties").toURI();
    client = Factory.createClient(propertiesUri, "apiKey", "apiSecret");
    merchantClient = client.merchant("PSPID");
   }
   

2. By using CommunicatorConfiguration
   

   
   CommunicatorConfiguration communicatorConfiguration =
   
    new CommunicatorConfiguration()
           .withApiKeyId("apiKey")
           .withSecretApiKey("apiSecret")
           .withApiEndpoint(URI.create("apiEndpoint"))
           .withIntegrator("integrator")
           .withAuthorizationType(AuthorizationType.V1HMAC);
   client = Factory.createClient(communicatorConfiguration);
   clientMerchant = client.merchant("PSPID");
   

The following table provides an overview of the arguments accepted by the individual instances:

After you have initialised the SDK, you can send requests to our platform via your PSPID. Learn how to do this in the next chapter .

Use SDK

After the successful initialisation of the Client instance, you gain full access to our RESTful API. It enables you to:

• Send requests for new transactions for any of our server integration methods.
• Get your transactions’ current status.
• Perform maintenance requests (i.e., captures, refunds) on existing transactions.

Check out our test cases in GitHub, including full code samples, and our Full API Reference to learn what is possible.

Below you may find some of the most common actions you can perform:

• Create new transactions
• Get transaction status
• Perform maintenance operation

Create new transactions

To create a new transaction, you can use either the Client or MerchantClient instance for any of our integration methods to create a new transaction. It can be done through:

• Routing the request to your PSPID on our platform (for Client).
• Creating a request for the respective integration method.

Below you can find code samples related to particular integration methods:

• Hosted Checkout Page
• Hosted Tokenization Page
• Server-to-server

Hosted Checkout Page

To use this integration method, you need to create a CreateHostedCheckoutRequest call. It must contain at least an Order object.

/* 
 *… Initialisation....
 */
CreateHostedCheckoutRequest checkoutRequest = new CreateHostedCheckoutRequest();

// The request with an example object of the AmountOfMoney
checkoutRequest.withOrder(new Order()
        .withAmountOfMoney(new AmountOfMoney()
                .withAmount(100L)
                .withCurrencyCode("EUR")));
CreateHostedCheckoutResponse response = hostedCheckoutClient.createHostedCheckout(checkoutRequest);

This call returns a CreateHostedCheckout response. Store the hostedCheckoutId and RETURNMAC it contains, as well as any other information relevant for you. You will need these for steps described in the following chapters.

This response also contains a partialRedirectURL.

You have to concatenate the base URL "https://payment." with partialRedirectURL according to the formula

https://payment. + partialRedirectURL

and perform redirection of your customer to this URL. Once the customer visits the Hosted Checkout Page, the payment process continues there.

Hosted Tokenization Page

To use this integration method, you need to

• Create and upload a template as described in our Hosted Tokenization Page guide

CreateHostedTokenizationRequest hostedTokenizationRequest = new CreateHostedTokenizationRequest();
CreateHostedTokenizationRequest createHostedTokenizationRequest = hostedTokenizationRequest.withVariant("YourTemplate.html"); 
CreateHostedTokenizationResponse hostedTokenizationResponse = merchantClient.hostedTokenization() 
        .createHostedTokenization(createHostedTokenizationRequest);

From CreateHostedTokenizationResponse retrieve hostedTokenizationId and partialRedirectUrl. Use the partialRedirectUrl for the iframe and the hostedTokenizationId or tokenId (see infobox) to create the actual payment via Server-to-server integration method.

GetHostedTokenizationResponse getHostedTokenizationResponse = initializer.getClientMerchant().hostedTokenization().getHostedTokenization(hostedTokenizationId);
String tokenId = getHostedTokenizationResponse.getToken().getId();

// The example object of the AmountOfMoney 
AmountOfMoney amount = new AmountOfMoney() 
      .withAmount(100L) 
      .withCurrencyCode("EUR"); 

Order order = new Order().withAmountOfMoney(amount);
CardPaymentMethodSpecificInput paymentInput = new CardPaymentMethodSpecificInput().withToken(tokenId);

CreatePaymentRequest requestBody = new CreatePaymentRequest()
        .withCardPaymentMethodSpecificInput(paymentInput)
        .withOrder(order);
CreatePaymentResponse response = initializer.getClientMerchant().payments().createPayment(requestBody);

Server-to-server

A minimum paymentResponse requires you to set at least an Order object and a payment method:

// The example object of the AmountOfMoney 
AmountOfMoney amountOfMoney = new AmountOfMoney() 
        .withAmount(100L) 
        .withCurrencyCode("EUR"); 
Order order = new Order().withAmountOfMoney(amountOfMoney); 
 
// To get more test card data visit the website: Find more test data here 
Card card = new Card() 
         .withCvv("123") 
         .withCardNumber("5399999999999999") 
         .withCardholderName("Test Name") 
         .withExpiryDate("1236"); 
int paymentProductId = 3; 
 
PaymentsClientInterface paymentClient = merchantClient.payments(); 
CreatePaymentRequest createPaymentRequest = new CreatePaymentRequest(); 
 
CardPaymentMethodSpecificInput cardPaymentMethodSpecificInput = new CardPaymentMethodSpecificInput(); 
cardPaymentMethodSpecificInput.setCard(card); 
cardPaymentMethodSpecificInput.setPaymentProductId(paymentProductId) ; 
 
createPaymentRequest.setCardPaymentMethodSpecificInput(cardPaymentMethodSpecificInput); 
createPaymentRequest.setOrder(order); 
 
CreatePaymentResponse createPaymentResponse = paymentClient.createPayment(createPaymentRequest);

Get transaction status

Our RESTful API allows you to request a transaction’s status anytime by one of our GET calls:

• GetHostedCheckout
• GetPaymentDetails
• GetCaptures
• GetRefunds

A GetPaymentDetails request looks like this:

PaymentResponse paymentResponse = merchantClient.payments().getPaymentDetails(paymentId);

For more information about statuses visit the status documentation page.

Perform maintenance operation

To perform follow-up actions on existing transactions (i.e. captures or refunds), use our CapturePayment or RefundPayment API call respectively:

CapturePayment

/* 
 *… Initialisation....
 */
 MerchantClientInterface merchantClient;

 // Here you get paymentId you can use in further code
 String paymentId = createPaymentResponse.getPayment().getId();
 CapturePaymentRequest capturePaymentRequest = new CapturePaymentRequest();
 capturePaymentRequest.withAmount(amount);
 capturePaymentRequest.setIsFinal(true);

 merchantClient.payments().capturePayment(paymentId, capturePaymentRequest);

RefundPayment

/*  
 *… Initialisation.... 
 */ 
MerchantClientInterface merchantClient;
String paymentId;
RefundRequest refundRequest = new RefundRequest();
// The example object of the AmountOfMoney
AmountOfMoney amountOfMoney = new AmountOfMoney()
        .withAmount(100L)
        .withCurrencyCode("EUR");
refundRequest.setAmountOfMoney(amountOfMoney);
// Get RefundResponse object
RefundResponse refundResponse = merchantClient.payments().refundPayment(paymentId, refundRequest);

Handle exceptions

If a transaction is rejected, our platform provides detailed information with an Exception instance. The affiliated HTTP status code also help you troubleshoot the error.

You can encounter two types of exceptions: transaction exceptions and HTTP exceptions.

Transaction exceptions

This kind of exception refers to transaction requests that are technically correct but were rejected by your customer’s issuer or your acquirer. If the transaction is returned in the exception, it means that it was created in our systems but not successfully processed.

/*
 * Initialization....
 */


CreatePaymentRequest createPaymentRequest = new CreatePaymentRequest(); 
String paymentId; 
try { 
    CreatePaymentResponse createPaymentResponse = paymentClient.createPayment(createPaymentRequest); 
    paymentId = createPaymentResponse.getPayment().getId(); 
} catch (DeclinedPaymentException e) { 
 
    PaymentResponse payment = e.getCreatePaymentResult().getPayment(); 
    paymentId = payment.getId(); 
    String paymentStatus = payment.getStatus(); 
    handleError(payment); 
} 
PaymentResponse paymentResponse = merchantClient.payments().getPayment(paymentId); 
 
// Your code to check transaction status and handle errors 
if (isNotSuccessful(paymentResponse)) { 
    handleError(paymentResponse); 
} 

/*
 * Initialization....
 */


String paymentId = createPaymentResponse.getPayment().getId(); 
String refundId; 
 
RefundRequest refundRequest = new RefundRequest(); 
 
try { 
    RefundResponse refundResponse = merchantClient.payments().refundPayment(paymentId, refundRequest); 
    refundId = refundResponse.getId(); 
} catch (DeclinedRefundException e) { 
    RefundResponse refundResult = e.getRefundResult(); 
    handleError(refundResult); 
} 
RefundsResponse refundResponse = merchantClient.payments().getRefunds(paymentId); 
 
// Your code to check transaction status and handle errors 
if (isNotSuccessful(refundResponse, refundId)) { 
    handleError(refundResponse); 
} 

HTTP exceptions

This kind of exception refers to various problems caused by technical errors in the API call or payment request.

You can combine any of the following code snippets with this standard CreatePayment request:

/* 
 *…. Initialisation....
 */

CreatePaymentRequest createPaymentRequest = new CreatePaymentRequest(); 
 
// The example object of the AmountOfMoney 
AmountOfMoney amountOfMoney = new AmountOfMoney() 
        .withAmount(100L) 
        .withCurrencyCode("EUR"); 
 
Order order = new Order().withAmountOfMoney(amountOfMoney); 
 
CardPaymentMethodSpecificInput cardPaymentMethodSpecificInput = new CardPaymentMethodSpecificInput(); 
 
// The example object of the Card – you can find test cards on 
// /documentation/test-cases/ 
Card card = new Card() 
         .withCvv("123") 
         .withCardNumber("5399999999999999") 
         .withCardholderName("Test Name") 
         .withExpiryDate("1236"); 
 
cardPaymentMethodSpecificInput.setCard(card); 
cardPaymentMethodSpecificInput.setPaymentProductId(3); 
 
createPaymentRequest.setCardPaymentMethodSpecificInput(cardPaymentMethodSpecificInput); 
 
try { 
    CreatePaymentResponse createPaymentResponse = paymentClient.createPayment(createPaymentRequest); 
} 
catch (ApiException e) { 
    // Refer to the list below to see how specific implementations of ApiException can be handled. 
}

catch (ValidationException e) { 
    System.err.println("Input validation error"); 
    for (APIError error : e.getErrors()) { 
        if (error.getPropertyName() == null) { 
            System.err.println(error.getCode() + ": " + error.getMessage()); 
    } else { 
            System.err.println(error.getPropertyName() + ": " + error.getCode() + ": " + error.getMessage()); 
        }
    }
}

catch (AuthorizationException e) { 
    System.err.println("Authorization error"); 
    for (APIError error : e.getErrors()) { 
        System.err.println(error.getCode() + ": " + error.getMessage()); 
    }
}

catch (IdempotenceException e) { 
    System.err.println("Idempotence error:"); 
    for (APIError error : e.getErrors()) { 
        System.err.println(error.getCode() + ": " + error.getMessage()); 
    }
}

catch (ReferenceException e) { 
    System.err.println("Incorrect object reference:"); 
    for (APIError error : e.getErrors()) { 
        System.err.println(error.getCode() + ": " + error.getMessage()); 
    }
}

catch (DirectException e) { 
    System.err.println("Error occurred at Direct or a downstream partner/acquirer:"); 
    for (APIError error : e.getErrors()) { 
        System.err.println(error.getCode() + ": " + error.getMessage()); 
    }
}

catch (ApiException e) { 
    System.err.println("Platform error: "); 
    for (APIError error : e.getErrors()) { 
        System.err.println(error.getCode() + ": " + error.getMessage()); 
    }
}

catch (CommunicationException e) { 
    System.err.println("Communication exception: " + e.getMessage()); 
}

HTTP status codes

All our exceptions are linked to one or more HTTP status codes, indicating the root cause for many possible errors.

IdempotenceException
ReferenceException

ReferenceException

DirectException

DirectException

DirectException

ApiException

Additional Features

The SDK has a lot more to offer. Have a look at the following features, as they will help you build the perfect solution.

• Get available payment methods
• Send idempotent requests
• Use logging
• Connection pooling
• Customise communication
• Webhooks

Get available payment methods

Before you initiate the actual payment process, you send a GetPaymentProducts request to our platform. The response contains a list of available payment methods in your PSPID. Depending on your customers’ preferences, you can offer a selection on our Hosted Checkout Page or on your own webshop environment using subsequent CreatePayment requests.

/* 
 *…. Initialisation....
 */

// Prepare the request to get all active payment methods in your PSPID 
var queryParams = new GetPaymentProductsParams() 
    .withCountryCode("FR") 
    .withCurrencyCode("EUR"); 
 
// Send the request and get the response 
GetPaymentProductsResponse paymentProductResponse = merchantClient.products().getPaymentProducts(queryParams); 

Send idempotent requests

One of the main REST API features is its ability to detect and prevent sending requests (i.e. payment requests) accidentally twice. The SDK makes it very easy for you to ensure that you send only unique – idempotent – requests to our platform.

Use the additional argument paymentContext and set its property named idempotence to a CreatePayment request. The SDK will send an X-GCS-Idempotence-Key header with the idempotence key as its value.

If you send requests this way to our platform, we will check the following

• If you send subsequent request with the same idempotence key, the response contains an X-GCS-Idempotence-Request-Timestamp header. The SDK will set the idempotenceRequestTimestamp property of the paymentContext argument.
• If the first request is not finished yet, the RESTful Server API returns a  409 status code. Then the SDK throws an IdempotenceException with the original idempotence key and the idempotence request timestamp.

/* 
 *…. Initialisation....
 */

CreatePaymentRequest createPaymentRequest = new CreatePaymentRequest(); 
 
String idempotenceKey = "YourKeyForThePayment"; 
 
var callContext = new CallContext(); 
callContext.withIdempotenceKey(idempotenceKey); 
 
try { 
   var createPaymentResponse = merchantClient.payments().createPayment(createPaymentRequest, callContext); 
} catch (IdempotenceException e) { 
   // a request with the same idempotenceKey is still in progress, try again after a short pause 
   // e.getIdempotenceRequestTimestamp() contains the value of the 
   // X-GCS-Idempotence-Request-Timestamp header 
} finally { 
   Long idempotenceRequestTimestamp = callContext.getIdempotenceRequestTimestamp(); 
   // idempotenceRequestTimestamp contains the value of the 
   // X-GCS-Idempotence-Request-Timestamp header 
   // if idempotenceRequestTimestamp is not empty, this was not the first request 
}

Use logging

The SDK supports logging of requests, responses, and exceptions of the API communication. These can be helpful for troubleshooting or tracing individual steps in the payment flow.

To use this logging feature, you should implement the CommunicatorLogger interface.

The SDK offers two implementations of the logging feature:

• System.out (SysOutCommunicatorLogger)
• java.util.logging.Logger (JdkCOmmunicatorLogger)

You can enable/disable the logging by calling the enableLogging method on a ClientInterface object and provide the logger as an argument. You can subsequently disable the logger by calling the disableLogging method:

ClientInterface client = Factory.createClient(propertiesUrl.toURI(), "apiKeyId", "secretApiKey");

CommunicatorLogger logger = new JdkCommunicatorLogger(Logger.getLogger(...), Level.INFO);
client.enableLogging(logger);
//... Do some calls
client.disableLogging();

Connection pooling

You can manage your network resources by limiting the number of possible connections the SDK creates and maintains. The Client instances created as discussed in the Initialise SDK chapter will have their own connection pool. The Client instances created with the same Communicator object share a connection pool.

If you use multiple Client instances to share a single connection pool, make sure to follow these steps:

1. Create a shared Communicator . You can use the com.onlinepayments.Factory class.
2. Create Client instances with that Communicator.

/* 
 *…. Initialisation....
 */

/* Initialisation... */  
// Communicator instance 


Communicator communicator = Factory.createCommunicator(propertiesUrl.toURI(), "apiKeyId", "secretApiKey"); 
// create one or more clients using the shared communicator 
ClientInterface client = Factory.createClient(communicator); 

Customise communication

A ClientInterface uses a Communicator to communicate with our platform. Communicator implementations transform a request object to a HTTP request and a HTTP response to a response object. If needed, you can extend this class. To instantiate a ClientInterface that uses your own implementation of Communicator, you can use the following code snippet:

Communicator communicator = new YourCommunicator();
ClientInterface client = Factory.createClient(communicator);

Providing your own implementation is not necessary for most cases. The functionality of the com.onlinepayments.defaultimpl.DefaultCommunicator is built on classes: Authenticator, Connection, Marshaller and MetaDataProvider. The implementation of these classes can easily be extended or replaced to fit your needs.

Marshaller is used to marshal / unmarshal request and response objects to and from JSON, which you should not change. The other modules needed to communicate with the our platform are:

• The RESTful Server API endpoint URI.
• A Connection for one or more HTTP connections to our server.
• An Authenticator, to sign your requests.
• A MetaDataProvider, constructing the header with your server’s meta data.

For your convenience, the CommunicatorBuilder class is provided to easily replace one or more of these modules. For example, to instantiate a ClientInterface that uses your own implementation of Connection, you can use the following code snippet:

/* 
 *…. Initialisation....
 */

Connection connection = new YourConnection();  
Communicator communicator = Factory.createCommunicatorBuilder(propertiesUrl.toURI(), "apiKeyId", "secretApiKey").withConnection(connection).build();  
ClientInterface client = Factory.createClient(communicator);

Webhooks

The part of the SDK that handles the webhooks support is called the webhooks helper. It transparently handles both validation of signatures against the event bodies sent by the webhooks system (including finding the secret key for key IDs - not to be confused with the API Key and API Secret), and unmarshalling of these bodies to objects. This allows you to focus on the essentials, without going through all the additional information and extracting the desired ones by yourself. To learn more about webhooks, read our dedicated guide. 

Provide secret keys

Configure the "WebhooksKey" / "WebhooksKeySecret" and your server webhooks endpoints in the Merchant Portal:

String keyId = "WebhooksKey";
String secretKey = "WebhooksKeySecret";

Use InMemorySecretKeyStore.INSTANCE.storeSecretKey(keyId, secretKey) to store a secret key for a key ID.

You can add or remove keys using the following functions:

• InMemorySecretKeyStore.INSTANCE.getSecretKey(keyId)
• InMemorySecretKeyStore.INSTANCE.removeSecretKey(keyId) to remove the stored secret key for a key ID.
• InMemorySecretKeyStore.INSTANCE.clear() to remove all stored secret keys.

If you require more advanced storage, e.g. using a database or file system, we recommend writing your own implementation.

Initialise webhooks helper

Using an implementation of com.onlinepayments.webhooks.SecretKeyStore, create an instance of com.onlinepayments.webhooks.WebhooksHelper:

WebhooksHelper helper = Webhooks.createHelper(InMemorySecretKeyStore. INSTANCE);

Use Webhooks helper

To process events received in a webhook, first call the unmarshal method of the WebhooksHelper object. It takes the following arguments:

• The body, as a string. This should be the raw body as received from the webhooks system.

  String bodyOfRequest = "JSON_Body_Of_The_Request";

• A list of request headers as received from the webhooks system. Below you will find an example of creating a list of request headers. It should contain the two headers for the keyId and the signature:
  
  

  // Retrieve the headers from the Webhook message, depends on your implementation.
  List<Header> webhookHeaders = request.getHeaders();
  
  // Transform the received headers
  List<RequestHeader> requestHeaders = new ArrayList<RequestHeader>();
  for (Header webhookHeader : webhookHeaders) {
      requestHeaders.add(new RequestHeader(webhookHeader.getName(), webhookHeader.getValue()));
  }

• Now you can use the webhook helper to unmarshal incoming events which allow you to process data in your application:
  
  

  try {
      WebhooksEvent event = helper.unmarshal(bodyOfRequest, requestHeaders);
  } catch (SignatureValidationException e) {
      // Your code to handle error
  }