/**
* Construct a datagram with the given flag. <br>
* <br>
* Note: This method *depends* on the values of `remotePort', `remoteAddress', `myPort',
* `myAddress' and `sequenceNo'. Failing to set these before calling this method causes undefined
* behaviour. Also note that if you want to set values to something else than the default, you
* must construct the packet manually or alter the returned object.<br>
* <br>
* This method also increments the sequenceNo.<br>
* <br>
* This method sets the following fields:
*
* <ol>
* <li>Remote address
* <li>Remote port
* <li>Local address
* <li>Local port
* <li>Flag
* <li>Sequence no.
* <li>Payload to null.
* </ol>
*
* @param flag Flag for the packet, see {@link KtnDatagram.Flag}. Setting this to
* KtnDatagram.Flag.NONE constructs a packet with no flag or data, and makes no sense.
* @return Initialised flagged datagram.
*/
protected KtnDatagram constructInternalPacket(Flag flag) {
KtnDatagram packet = new KtnDatagram();
packet.setDest_port(remotePort);
packet.setDest_addr(remoteAddress);
packet.setSrc_addr(myAddress);
packet.setSrc_port(myPort);
packet.setFlag(flag);
packet.setSeq_nr(nextSequenceNo++);
packet.setPayload(null);
return packet;
}
/**
* Construct a datagram with the given payload. <br>
* <br>
* Note: This method *depends* on the values of `remotePort', `remoteAddress', `myPort',
* `myAddress' and `sequenceNo'. Failing to set these before calling this method causes undefined
* behaviour. Also note that if you want to set values to something else than the default, you
* must construct the packet manually or alter the returned object.<br>
* <br>
* This method also increments the sequenceNo.<br>
* <br>
* This method sets the following fields:
*
* <ol>
* <li>Remote address
* <li>Remote port
* <li>Local address
* <li>Local port
* <li>Flag to NONE.
* <li>Sequence no.
* <li>Payload.
* </ol>
*
* @param payload Payload for packet, can not be null.
* @return Initialised datagram.
*/
protected KtnDatagram constructDataPacket(String payload) {
if (payload == null) throw new IllegalArgumentException("Payload can not be null.");
KtnDatagram packet = new KtnDatagram();
packet.setDest_port(remotePort);
packet.setDest_addr(remoteAddress);
packet.setSrc_addr(myAddress);
packet.setSrc_port(myPort);
packet.setFlag(Flag.NONE);
packet.setSeq_nr(nextSequenceNo++);
packet.setPayload(payload);
return packet;
}