import java.net.*;  // for Socket and ServerSocket
import java.io.*;   // for IOException

class PoolDispatcher implements Dispatcher {

  static final String NUMTHREADS = "8";        // Default thread pool size
  static final String THREADPROP = "Threads";  // Name of thread property

  private int numThreads;           // Number of threads in pool

  public PoolDispatcher() {
    // Get the number of threads from the System properties or take the default
    numThreads = Integer.parseInt(System.getProperty(THREADPROP, NUMTHREADS));
  }

  public void startDispatching(final ServerSocket servSock, final Logger logger,
                               final ProtocolFactory protoFactory) {
    // Create N-1 threads, each running an iterative server
    for (int i = 0; i < (numThreads - 1); i++) { 
      Thread thread = new Thread() {
        public void run() {
          dispatchLoop(servSock, logger, protoFactory);
        }
      };
      thread.start();
      logger.writeEntry("Created and started Thread = " + thread.getName());
    }
    logger.writeEntry("Iterative server starting in main thread " + 
                    Thread.currentThread().getName());
    // Use main thread as Nth iterative servero
    dispatchLoop(servSock, logger, protoFactory);
    /* NOT REACHED */
  }

  private void dispatchLoop(ServerSocket servSock, Logger logger, 
                            ProtocolFactory protoFactory) {
    // Run forever, accepting and handling each connection
    for (;;) {
      try {
        Socket clntSock = servSock.accept();  // Block waiting for connection
        Runnable protocol = protoFactory.createProtocol(clntSock, logger);
        protocol.run();
      } catch (IOException e) {
        logger.writeEntry("Exception = " +  e.getMessage());
      }
    }
  }
}