PingMessage.java

package org.ripple.power.txns.btc;

import java.io.EOFException;
import java.nio.ByteBuffer;

/**
 * <p>A 'ping' message is sent to test network connectivity to a node.  Upon receiving a ping,
 * the node responds with a pong.</p>
 *
 * <p>Ping Message</p>
 * <pre>
 *   Size       Field               Description
 *   ====       =====               ===========
 *   8 bytes    Nonce               Random value
 * </pre>
 */
public class PingMessage {

    /**
     * Send a 'ping' message to a peer
     *
     * @param       peer                Destination peer
     * @return                          'ping' message
     */
    public static Message buildPingMessage(Peer peer) {
        //
        // We will use the current time as the nonce
        //
        SerializedBuffer msgBuffer = new SerializedBuffer(8).putLong(System.currentTimeMillis());
        //
        // Build the message
        //
        ByteBuffer buffer = MessageHeader.buildMessage("ping", msgBuffer);
        return new Message(buffer, peer, MessageHeader.MessageCommand.PING);
    }

    /**
     * Process a 'ping' message
     *
     * @param       msg                 Message
     * @param       inBuffer            Input buffer
     * @param       msgListener         Message listener
     * @throws      EOFException        End-of-data while processing input stream
     */
    public static void processPingMessage(Message msg, SerializedBuffer inBuffer, MessageListener msgListener)
                                        throws EOFException {
        //
        // BIP0031 adds the 'pong' message and requires an 8-byte nonce in the 'ping'
        // message.  If we receive a 'ping' without a payload, we do not return a
        // 'pong' since the client has not implemented BIP0031.
        //
        if (inBuffer.available() >= 8) {
            //
            // Get the nonce from the 'ping' message
            //
            long nonce = inBuffer.getLong();
            //
            // Notify the message listener
            //
            msgListener.processPing(msg, nonce);
        }
    }
}