private PDBTEW2Listener(PDBTExecSingleCltWrkInitSrv srv, Socket s) throws IOException {
_srv = srv;
_s = s;
_ois = new ObjectInputStream(_s.getInputStream());
_oos = new ObjectOutputStream(_s.getOutputStream());
_oos.flush();
}
/**
* there is an issue with this method: if it is called often enough, the <CODE>
* _s.sendUrgentData(0);</CODE> method that it invokes, will force the <CODE>_s</CODE> socket to
* close on the other end, at least on Windows systems. This behavior is due to the fact that
* OOB data handling is problematic since there are conflicting specifications in TCP.
* Therefore, it is required that the method is not called with high frequency (see the <CODE>
* PDBTExecSingleCltWrkInitSrv._CHECK_PERIOD_MSECS</CODE> flag in this file.)
*
* @return true iff the worker is available to accept work according to all evidence.
*/
private synchronized boolean getAvailability() {
boolean res = _isAvail && _s != null && _s.isClosed() == false;
if (res && _OK2SendOOB) { // work-around the OOB data issue
// last test using OOB sending of data
try {
_OK2SendOOB = false; // indicates should not send OOB data until set to true
_s.sendUrgentData(0); // unfortunately, if this method is called often enough,
// it will cause the socket to close???
res = true;
} catch (IOException e) {
// e.printStackTrace();
utils.Messenger.getInstance()
.msg("PDBTExecSingleCltWrkInitSrv.getAvailability(): Socket has been closed", 0);
res = false;
_isAvail = false; // declare availability to false as well
// try graceful exit
try {
_s.shutdownOutput();
_s.close(); // Now we can close the Socket
} catch (IOException e2) {
// silently ignore
}
}
}
return res;
}
private void processException(Exception e) {
// e.printStackTrace();
try {
_ois.close();
_oos.close();
_s.close();
} catch (Exception e2) {
// e2.printStackTrace();
} finally {
synchronized (_srv) {
getWorkers().remove(_s);
utils.Messenger.getInstance()
.msg("PDBTExecSingleCltWrkInitSrv: Worker Network Connection Closed", 0);
}
_ois = null;
_oos = null;
_s = null;
}
}
private boolean isConnectionLost() {
return _s == null || _s.isClosed();
}
/**
* reads from the input stream the initialization command sent to it, sends back to the client
* an <CODE>OKReply</CODE> "ACK" msg, and then enters an infinite loop waiting to read from the
* input stream an <CODE>RRObject</CODE> obj that should really be of type <CODE>
* TaskObjectsExecutionRequest</CODE>, on which it executes its method <CODE>
* obj.runProtocol(_srv,_ois, _oos)</CODE>.
*/
public void run() {
// first, read from socket the worker-initialization object that will
// be broadcast for execution to every worker connecting to this server.
utils.Messenger mger = utils.Messenger.getInstance();
try {
mger.msg("PDBTEC2ListenerThread: waiting to read the init_cmd from client", 1);
RRObject initCmd = (RRObject) _ois.readObject();
mger.msg("PDBTEC2ListenerThread: done reading the init_cmd from client", 1);
setInitCmd(initCmd);
mger.msg("PDBTEC2ListenerThread: done setting the init_cmd", 2);
// send back to the clt an "ACK" message
_oos.writeObject(new OKReply());
_oos.flush();
mger.msg("PDBTEC2ListenerThread: done sending OKReply through the socket", MIN_PRIORITY);
} catch (Exception e) { // client closed connection
// e.printStackTrace();
try {
_ois.close();
_oos.close();
_s.close();
} catch (Exception e2) {
// e2.printStackTrace();
}
mger.msg("PDBTEC2ListenerThread: Client Network Connection Closed", 0);
System.exit(-1);
}
while (true) {
try {
mger.msg("PDBTEC2ListenerThread.run(): waiting to read an RRObject...", 2);
// 1. read from socket input
RRObject obj = (RRObject) _ois.readObject(); // obj is an TaskObjectsExecutionRequest
mger.msg("PDBTEC2ListenerThread.run(): RRObject read", 2);
// 2. take appropriate action
try {
obj.runProtocol(_srv, _ois, _oos);
} catch (PDBatchTaskExecutorException e) {
mger.msg(
"PDBTEC2ListenerThread.run(): calling obj.runProtocol() "
+ "issued PDBatchTaskExecutorException, will try one more time.",
1);
secondChance(obj);
} catch (
IOException e) { // worker somehow failed, give srv one more shot, then notify client
mger.msg(
"PDBTEC2ListenerThread.run(): calling obj.runProtocol() "
+ "issued IOException, will try one more time.",
1);
secondChance(obj);
}
} catch (Exception e) { // client closed connection
// e.printStackTrace();
try {
_ois.close();
_oos.close();
_s.close();
} catch (Exception e2) {
// e2.printStackTrace();
}
mger.msg(
"PDBTExecSingleCltWrkInitSrv: Client Network Connection Closed "
+ "(exception '"
+ e
+ "' caught)",
0);
System.exit(-1);
}
}
}