}
int protocolCode = ip4Packet.fetchProtocolCode().getValue();
long sourceIp = ip4Packet.fetchSourceIp().getValue();
long destIp = ip4Packet.fetchDestIp().getValue();
int sourcePort = tcpPacket.fetchSourcePort().getValue();
int destPort = tcpPacket.fetchDestPort().getValue();
int key = new HashCodeBuilder().append(protocolCode).append(sourceIp).append(destIp).append(sourcePort).append(destPort).toHashCode();
CotpPacketGroup group = groups.get(key);
if (group == null && !cotpPacket.isLastUnit()) {
group = new CotpPacketGroup(key);
groups.put(key, group);