public Connection(String host, int port) {
server_port = port;
server_addr = host;
packets = new LinkedList<Packet>();
recv_worker = new RecvWorker();
recv_worker.start();
}
/**
* If this server has initiated the connection, then it gives up on the connection if it loses
* challenge. Otherwise, it keeps the connection.
*/
public boolean initiateConnection(Socket sock, Long sid) {
DataOutputStream dout = null;
try {
// Sending id and challenge
dout = new DataOutputStream(sock.getOutputStream());
dout.writeLong(self.getId());
dout.flush();
} catch (IOException e) {
LOG.warn("Ignoring exception reading or writing challenge: ", e);
closeSocket(sock);
return false;
}
// If lost the challenge, then drop the new connection
if (sid > self.getId()) {
LOG.info(
"Have smaller server identifier, so dropping the "
+ "connection: ("
+ sid
+ ", "
+ self.getId()
+ ")");
closeSocket(sock);
// Otherwise proceed with the connection
} else {
SendWorker sw = new SendWorker(sock, sid);
RecvWorker rw = new RecvWorker(sock, sid, sw);
sw.setRecv(rw);
SendWorker vsw = senderWorkerMap.get(sid);
if (vsw != null) vsw.finish();
senderWorkerMap.put(sid, sw);
if (!queueSendMap.containsKey(sid)) {
queueSendMap.put(sid, new ArrayBlockingQueue<ByteBuffer>(SEND_CAPACITY));
}
sw.start();
rw.start();
return true;
}
return false;
}
/**
* If this server receives a connection request, then it gives up on the new connection if it
* wins. Notice that it checks whether it has a connection to this server already or not. If it
* does, then it sends the smallest possible long value to lose the challenge.
*/
public boolean receiveConnection(Socket sock) {
Long sid = null;
try {
// Read server id
DataInputStream din = new DataInputStream(sock.getInputStream());
sid = din.readLong();
if (sid == QuorumPeer.OBSERVER_ID) {
/*
* Choose identifier at random. We need a value to identify
* the connection.
*/
sid = observerCounter--;
LOG.info("Setting arbitrary identifier to observer: " + sid);
}
} catch (IOException e) {
closeSocket(sock);
LOG.warn("Exception reading or writing challenge: " + e.toString());
return false;
}
// If wins the challenge, then close the new connection.
if (sid < self.getId()) {
/*
* This replica might still believe that the connection to sid is
* up, so we have to shut down the workers before trying to open a
* new connection.
*/
SendWorker sw = senderWorkerMap.get(sid);
if (sw != null) {
sw.finish();
}
/*
* Now we start a new connection
*/
LOG.debug("Create new connection to server: " + sid);
closeSocket(sock);
connectOne(sid);
// Otherwise start worker threads to receive data.
} else {
SendWorker sw = new SendWorker(sock, sid);
RecvWorker rw = new RecvWorker(sock, sid, sw);
sw.setRecv(rw);
SendWorker vsw = senderWorkerMap.get(sid);
if (vsw != null) vsw.finish();
senderWorkerMap.put(sid, sw);
if (!queueSendMap.containsKey(sid)) {
queueSendMap.put(sid, new ArrayBlockingQueue<ByteBuffer>(SEND_CAPACITY));
}
sw.start();
rw.start();
return true;
}
return false;
}
/*
* 读取对方的sid
*/
public boolean receiveConnection(Socket sock) {
Long sid = null;
try {
// Read server id
DataInputStream din = new DataInputStream(sock.getInputStream());
sid = din.readLong();
if (sid < 0) { // this is not a server id but a protocol version
// (see ZOOKEEPER-1633)
sid = din.readLong();
// next comes the #bytes in the remainder of the message
int num_remaining_bytes = din.readInt();
byte[] b = new byte[num_remaining_bytes];
// remove the remainder of the message from din
int num_read = din.read(b);
if (num_read != num_remaining_bytes) {
LOG.error(
"Read only "
+ num_read
+ " bytes out of "
+ num_remaining_bytes
+ " sent by server "
+ sid);
}
}
if (sid == QuorumPeer.OBSERVER_ID) {
/*
* Choose identifier at random. We need a value to identify the
* connection.
*/
sid = observerCounter--;
LOG.info("Setting arbitrary identifier to observer: " + sid);
}
} catch (IOException e) {
closeSocket(sock);
LOG.warn("Exception reading or writing challenge: " + e.toString());
return false;
}
// If wins the challenge, then close the new connection.
/*
* 只允许sid大的连接小的
*/
if (sid < self.getId()) {
/*
* This replica might still believe that the connection to sid is
* up, so we have to shut down the workers be fore trying to open a
* new connection.
*/
SendWorker sw = senderWorkerMap.get(sid);
if (sw != null) {
sw.finish();
}
/*
* Now we start a new connection
*/
LOG.debug("Create new connection to server: " + sid);
closeSocket(sock);
connectOne(sid);
// Otherwise start worker threads to receive data.
} else {
SendWorker sw = new SendWorker(sock, sid);
RecvWorker rw = new RecvWorker(sock, sid, sw);
sw.setRecv(rw);
SendWorker vsw = senderWorkerMap.get(sid);
if (vsw != null) vsw.finish();
senderWorkerMap.put(sid, sw);
if (!queueSendMap.containsKey(sid)) {
queueSendMap.put(sid, new ArrayBlockingQueue<ByteBuffer>(SEND_CAPACITY));
}
sw.start();
rw.start();
return true;
}
return false;
}