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*
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*
* - Redistributions in binary form must reproduce the above copyright
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*
* - Neither the name of Oracle nor the names of its
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*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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*/
/*
* This source code is provided to illustrate the usage of a given feature
* or technique and has been deliberately simplified. Additional steps
* required for a production-quality application, such as security checks,
* input validation and proper error handling, might not be present in
* this sample code.
*/
import java.io.*;
import java.net.*;
import java.lang.Byte;
/**
* Simple Java "server" using the Poller class
* to multiplex on incoming connections. Note
* that handoff of events, via linked Q is not
* actually be a performance booster here, since
* the processing of events is cheaper than
* the overhead in scheduling/executing them.
* Although this demo does allow for concurrency
* in handling connections, it uses a rather
* primitive "gang scheduling" policy to keep
* the code simpler.
*/
public class PollingServer
{
public final static int MAXCONN = 10000;
public final static int PORTNUM = 4444;
public final static int BYTESPEROP = 10;
/**
* This synchronization object protects access to certain
* data (bytesRead,eventsToProcess) by concurrent Consumer threads.
*/
private final static Object eventSync = new Object();
private static InputStream[] instr = new InputStream[MAXCONN];
private static int[] mapping = new int[65535];
private static LinkedQueue linkedQ = new LinkedQueue();
private static int bytesRead = 0;
private static int bytesToRead;
private static int eventsToProcess=0;
public PollingServer(int concurrency) {
Socket[] sockArr = new Socket[MAXCONN];
long timestart, timestop;
short[] revents = new short[MAXCONN];
int[] fds = new int[MAXCONN];
int bytes;
Poller Mux;
int serverFd;
int totalConn=0;
int connects=0;
System.out.println ("Serv: Initializing port " + PORTNUM);
try {
ServerSocket skMain = new ServerSocket (PORTNUM);
/*
* Create the Poller object Mux, allow for up to MAXCONN
* sockets/filedescriptors to be polled.
*/
Mux = new Poller(MAXCONN);
serverFd = Mux.add(skMain, Poller.POLLIN);
Socket ctrlSock = skMain.accept();
BufferedReader ctrlReader =
new BufferedReader(new InputStreamReader(ctrlSock.getInputStream()));
String ctrlString = ctrlReader.readLine();
bytesToRead = Integer.valueOf(ctrlString).intValue();
ctrlString = ctrlReader.readLine();
totalConn = Integer.valueOf(ctrlString).intValue();
System.out.println("Receiving " + bytesToRead + " bytes from " +
totalConn + " client connections");
timestart = System.currentTimeMillis();
/*
* Start the consumer threads to read data.
*/
for (int consumerThread = 0;
consumerThread < concurrency; consumerThread++ ) {
new Consumer(consumerThread).start();
}
/*
* Take connections, read Data
*/
int numEvents=0;
while ( bytesRead < bytesToRead ) {
int loopWaits=0;
while (eventsToProcess > 0) {
synchronized (eventSync) {
loopWaits++;
if (eventsToProcess <= 0) break;
try { eventSync.wait(); } catch (Exception e) {e.printStackTrace();};
}
}
if (loopWaits > 1)
System.out.println("Done waiting...loops = " + loopWaits +
" events " + numEvents +
" bytes read : " + bytesRead );
if (bytesRead >= bytesToRead) break; // may be done!
/*
* Wait for events
*/
numEvents = Mux.waitMultiple(100, fds, revents);
synchronized (eventSync) {
eventsToProcess = numEvents;
}
/*
* Process all the events we got from Mux.waitMultiple
*/
int cnt = 0;
while ( (cnt < numEvents) && (bytesRead < bytesToRead) ) {
int fd = fds[cnt];
if (revents[cnt] == Poller.POLLIN) {
if (fd == serverFd) {
/*
* New connection coming in on the ServerSocket
* Add the socket to the Mux, keep track of mapping
* the fdval returned by Mux.add to the connection.
*/
sockArr[connects] = skMain.accept();
instr[connects] = sockArr[connects].getInputStream();
int fdval = Mux.add(sockArr[connects], Poller.POLLIN);
mapping[fdval] = connects;
synchronized(eventSync) {
eventsToProcess--; // just processed this one!
}
connects++;
} else {
/*
* We've got data from this client connection.
* Put it on the queue for the consumer threads to process.
*/
linkedQ.put(new Integer(fd));
}
} else {
System.out.println("Got revents[" + cnt + "] == " + revents[cnt]);
}
cnt++;
}
}
timestop = System.currentTimeMillis();
System.out.println("Time for all reads (" + totalConn +
" sockets) : " + (timestop-timestart));
// Tell the client it can now go away
byte[] buff = new byte[BYTESPEROP];
ctrlSock.getOutputStream().write(buff,0,BYTESPEROP);
// Tell the cunsumer threads they can exit.
for (int cThread = 0; cThread < concurrency; cThread++ ) {
linkedQ.put(new Integer(-1));
}
} catch (Exception exc) { exc.printStackTrace(); }
}
/*
* main ... just check if a concurrency was specified
*/
public static void main (String args[])
{
int concurrency;
if (args.length == 1)
concurrency = java.lang.Integer.valueOf(args[0]).intValue();
else
concurrency = Poller.getNumCPUs() + 1;
PollingServer server = new PollingServer(concurrency);
}
/*
* This class is for handling the Client data.
* The PollingServer spawns off a number of these based upon
* the number of CPUs (or concurrency argument).
* Each just loops grabbing events off the queue and
* processing them.
*/
class Consumer extends Thread {
private int threadNumber;
public Consumer(int i) { threadNumber = i; }
public void run() {
byte[] buff = new byte[BYTESPEROP];
int bytes = 0;
InputStream instream;
while (bytesRead < bytesToRead) {
try {
Integer Fd = (Integer) linkedQ.take();
int fd = Fd.intValue();
if (fd == -1) break; /* got told we could exit */
/*
* We have to map the fd value returned from waitMultiple
* to the actual input stream associated with that fd.
* Take a look at how the Mux.add() was done to see how
* we stored that.
*/
int map = mapping[fd];
instream = instr[map];
bytes = instream.read(buff,0,BYTESPEROP);
} catch (Exception e) { System.out.println(e.toString()); }
if (bytes > 0) {
/*
* Any real server would do some synchronized and some
* unsynchronized work on behalf of the client, and
* most likely send some data back...but this is a
* gross oversimplification.
*/
synchronized(eventSync) {
bytesRead += bytes;
eventsToProcess--;
if (eventsToProcess <= 0) {
eventSync.notify();
}
}
}
}
}
}
}