/**
* invoke as: <CODE>
* java -cp <classpath> parallel.distributed.PDBTExecSingleCltWrkInitSrv [workers_port(7890)] [client_port(7891)]
* </CODE>
*
* @param args String[]
*/
public static void main(String[] args) {
int wport = 7890; // default port
int cport = 7891;
if (args.length > 0) {
try {
wport = Integer.parseInt(args[0]);
} catch (Exception e) {
e.printStackTrace();
usage();
System.exit(-1);
}
if (args.length > 1) {
try {
cport = Integer.parseInt(args[1]);
} catch (Exception e) {
e.printStackTrace();
usage();
System.exit(-1);
}
}
}
PDBTExecSingleCltWrkInitSrv server = new PDBTExecSingleCltWrkInitSrv(wport, cport);
try {
server.run();
} catch (Exception e) {
e.printStackTrace();
System.err.println("Server exits due to exception.");
}
}
/**
* creates a server socket listening on the port specified in the parameter of the constructor,
* and waits for a single incoming client connection which it handles by invoking the <CODE>
* addNewClientConnection(s)</CODE> method of the enclosing server, and then the thread exits.
*/
public void run() {
try {
ServerSocket ss = new ServerSocket(_port);
System.out.println("Srv: Now Accepting Single Client Connection");
// while (true) {
try {
Socket s = ss.accept();
System.out.println("Srv: Client Added to the Network");
addNewClientConnection(s);
System.out.println("Srv: finished adding client connection");
} catch (Exception e) {
// e.printStackTrace();
System.err.println("Client Connection failed, exiting...");
System.exit(-1);
}
// }
} catch (IOException e) {
// e.printStackTrace();
utils.Messenger.getInstance()
.msg(
"PDBTExecSingleCltWrkInitSrv.C2Thread.run(): "
+ "Failed to create Server Socket, Server exiting.",
0);
System.exit(-1);
}
}
/**
* creates a server socket listening on port specified in the object constructor, and then
* enters an infinite loop waiting for incoming socket connection requests representing a worker
* process attempting to connect to this server, which it handles via the enclosing server's
* <CODE>addNewWorkerConnection(s)</CODE> method.
*/
public void run() {
try {
ServerSocket ss = new ServerSocket(_port);
System.out.println("Srv: Now Accepting Worker Connections");
while (true) {
try {
Socket s = ss.accept();
System.out.println("Srv: Incoming New Worker Connection to the Network");
System.out.println(
"Srv: Thread may have to wait if an init_cmd has not yet arrived from the client");
addNewWorkerConnection(s);
System.out.println("Srv: finished adding new worker connection to the _workers");
} catch (Exception e) {
utils.Messenger.getInstance()
.msg(
"PDBTExecSingleCltWrkInitSrv.W2Thread.run(): "
+ "An error occured while adding new worker connection",
2);
// e.printStackTrace();
}
}
} catch (IOException e) {
// e.printStackTrace();
utils.Messenger.getInstance()
.msg(
"PDBTExecSingleCltWrkInitSrv.W2Thread.run(): "
+ "Failed to create Server Socket, Server exiting.",
0);
System.exit(-1);
}
}
/**
* 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);
}
}
}