xrpl4j

A (limited) Java WebSocket client for the XRP ledger by Ripple.

With this library you can subscribe to the ledger's streams to get periodic notifications of server status, transactions, and ledgers.

To get a client:

XRPLedgerClient client = new XRPLedgerClient("wss://s1.ripple.com");
client.connectBlocking();

To subscribe to the transaction stream and ledger stream (this should implement StreamSubscriber):

client.subscribe(EnumSet.of(StreamSubscription.TRANSACTIONS, StreamSubscription.LEDGER), this);

Receive stream events in the subscriber:

@Override
public void onSubscription(StreamSubscription subscription, JSONObject message) {
    LOG.info("subscription returned a {} message", subscription.getMessageType());
    // handle transaction || ledger message
}

A complete example that sends two commands and subscribes to the transaction stream until it has received 100 transactions, then closes the client:

public static void main(String[] args) throws URISyntaxException, InterruptedException, InvalidStateException {

    // Get a client.
    XRPLedgerClient client = new XRPLedgerClient("wss://fh.xrpl.ws");
    client.connectBlocking(3000, TimeUnit.MILLISECONDS);
    
    // Send a command.
    client.sendCommand("ledger_current", (response) -> {
        LOG.info(response.toString(4));
    });

    // Send a command with parameters.
    Map<String, Object> parameters = new HashMap<>();
    parameters.put("ledger_index", "validated");
    client.sendCommand("ledger", parameters, (response) -> {
        LOG.info(response.toString(4));
    });

    // Subscribe to the transaction stream (add transactions to a list as they come in).
    List<String> transactions = new ArrayList<>();
    client.subscribe(EnumSet.of(StreamSubscription.TRANSACTIONS), (subscription, message) -> {
        LOG.info("Got message from subscription {}: {}", subscription.getMessageType(), message);
        transactions.add(message.toString());
    });

    // Tell the client to close when there are no more pending responses
    // for commands and all subscriptions have been unsubscribed.
    client.closeWhenComplete();

    // While we still have a connection check if the number of transactions received
    // has reached 100. If it has then unsubscribe from the transaction stream.
    // This should trigger automatic closing of the client, because of the previous
    // call to closeWhenComplete() (assuming all commands have been responded to).
    while (client.isOpen()) {
        LOG.info("Waiting for messages (transactions received: {})...", transactions.size());
        Thread.sleep(100);
        if (transactions.size() >= 100 && !client.getActiveSubscriptions().isEmpty()) {
            client.unsubscribe(client.getActiveSubscriptions());
        }
    }
}

smelis/xrpl4j

xrpl4j