SDK for Java

SDK for Java is a software development kit for development of web services which are capable of integrating with the JetPay-based payment solutions to perform pay-ins by using Payment Page. This section describes how to use SDK for Java to build pay-in experience from inside of your system.

SDK for Java is compatible with Java SE Development Kit 8 or higher. You can download SDK for Java from GitHub: https://github.com/Jetpay/paymentpage-sdk-java.

What can I do with SDK for Java?

SDK for Java allows you to do the following:

Calculate signature and generate request for opening the Payment Page checkout page
Check callback signatures and extract payment details from callbacks

What's inside?

SDK for Java contains the following:

Libraries for development and automated testing
Code samples in Java

Using SDK for Java

To start using SDK for Java you need to complete the following tasks:

Make sure you have you have ready your merchant ID and secret key obtained from JetPay.
1. If your company has never obtained any ID or secret key from JetPay, you need to submit an application for connecting to JetPay.
2. If your company already has an ID and a secret key to sign messages obtained from JetPay, you need to notify the JetPay technical support specialists that you want to use SDK for Java and consult with the customer support on how to arrange a test run.
Integrate the JetPay payment solution in your system:
1. Install the SDK for Java libraries into a directory inside your project.
2. Import the libraries you need into your system application.
Test and put your system in production mode.
1. Request test card numbers and test project ID from JetPay, debug and test your system.
2. Once testing is complete, request your production project ID from JetPay and put your system in production mode.

With any questions regarding usage of SDK for Java contact the JetPay technical support specialists at support@jetpay.kz.

Installing and importing libraries

You can install the SDK for Java libraries manually or by using automated procedures supported by the development environment you use.

The following steps describe how to manually install the SDK for Java libraries.

Download SDK for Java and pack the SDK files into a JAR file.
If your project directory does not contain a libs directory, create one and move the JAR file into the libs directory.
Import the file into your system project by using the procedures pertinent to your development environment.

Opening checkout page

The checkout page invocation request consists of a set of parameters, which are signed to secure the data transmitted to JetPay. SDK for Java allows you to seamlessly sign parameters and generate requests. To open the Payment Page checkout page by using SDK for Java do the following:

Create an instance of the Payment class and specify payment details.

Payment payment = new Payment('186', "pid_1555943554067");
             // Project ID and payment ID
             // Payment ID must be unique within your project scope
payment
      .setParam(Payment.PAYMENT_AMOUNT, 1001) // Amount in minor currency units
      .setParam(Payment.PAYMENT_CURRENCY, "EUR"); // Currency as per ISO-4217 alpha-3
      .setParam(Payment.PAYMENT_DESCRIPTION, "Test payment"); // Payment description (optional)

All the parameters in this example are required to perform any payment. You can also use any optional parameters available for Payment Page. For more information about the Payment Page invocation parameters, see Payment Page invocation parameters.

Create a gate instance and initiate it with the secret key you obtained from the JetPay technical support specialists. The secret key is required to sign invocation requests.
```
Gate gate = new Gate("<secret_key>");
   // Secret key you obtained from technical support service
```

Generate checkout page invocation request:

String paymentUrl = gate.getPurchasePaymentPageUrl("<pp_host>", payment);

Correct checkout page invocation request contains payment parameters and signature (abbreviated):

https://paymentpage.jetpay.kz/payment?signature=OEKRlLXKStyo
...%3D%3D&payment_id=1555943554067...123

Use the request in your system code to open the checkout page.

Here is an example of generating a URL for opening an English checkout page. The payment method selection page includes detailed payment information including amount, currency and short payment description.

Figure: Example of generating Payment Page invocation request

Payment payment = new Payment('186', "pid_1555943554067");
	 // Project ID and payment ID
	 // Payment ID must be unique within your project scope
payment
       .setParam(Payment.PAYMENT_AMOUNT, 1001)     // Amount in minor currency units
       .setParam(Payment.PAYMENT_CURRENCY, "EUR"); // Currency
	.setParam(Payment.PAYMENT_DESCRIPTION, "Test payment");  // Payment description
	.setParam(Payment.LANGUAGE_CODE, ("en");     // Language code to use in checkout page
Gate gate = new Gate("mySecret");   // Secret key
String paymentUrl = gate.getPurchasePaymentPageUrl("example.com", payment);  // Complete request with signature

Parsing callbacks

The JetPay payment platform sends payment results to the callback URL you specified when connecting to JetPay. Callback is an HTTP POST request that contains response data in JSON format. To extract payment information from JSON string do the following:

Create an instance of Gate with the secret key, if you did not it earlier.
```
Gate gate = new Gate("<secret_key>");
```
Create an instance of Callback by using the JSON string from the callback obtained from JetPay:
```
Callback callback = gate.handleCallback(data);
```
Use methods for extracting callback information. You can get either full payment information or request specific payment parameters:
```
callback.getPaymentId();             // Getting payment ID
callback.getPaymentStatus();         // Getting payment status
callback.getPayment();               // Getting payment body
```
By using SDK for Java, you can automatically check validity of callback signature. Below, you will find an example of callback that includes signature and payment results.

Figure: Sample payment callback

{
             "project_id": 186,       // Project ID
             "payment": {             // Payment details
             "id": "pid_1555943554067",       // Payment ID
             "type": "purchase",  // Payment type
             "status": "success", // Payment status
             "date": "2018-08-28T09:11:28+0000",  // Payment date and time
             "method": "online-thailand-banks", 
             "sum": {           // Payment amount and currency
             "amount": 1000,
             "currency": "EUR"
             },
             "description": "Test payment"  // Payment description
             },
             "account": {           // Payment instrument details
             "number": "431422******0056"
             },
             "operation": {     // The last operation within payment
             "id": 17839000001150,  // Operation ID
             "type": "sale",        // Operation type
             "status": "success",   // Operation status
             "date": "2018-08-28T09:11:28+0000", // Operation date and time
             "created_date": "2018-08-28T09:10:50+0000",
             "request_id": "2c8af331519833f2c96c4a1aaf60edfcffb...", // Request ID
             "sum_initial": {    // Initial payment amount and currency 
             "amount": 1000,
             "currency": "EUR"
             },
             "sum_converted": {
             // Payment amount and currency as per applicable project conversion rules
             "amount": 1000,
             "currency": "EUR"
             },
             "provider": {     // Payment details in payment system
             "id": 6,
             "payment_id": "15354474886323",
             "date": "2018-02-07T08:34:24+0000",
             "auth_code": "563253",
             "endpoint_id": 6
             },
             "code": "0",          // Unified response code
             "message": "Success" // User-readable response code
             },
              "signature": "22YlUIIgoppli/JX8w5F5+c2h12RXi81WLmgDx..."  // Signature
              }