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import java.util.*; |
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// This class contains the main method to be run by |
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// the filter children. It harvests UDP traffic |
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// the filter children. It harvests UDP traffic. |
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// |
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// |
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public class UDPReader { |
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public class UDPReader extends Thread{ |
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public static void main(String[] args) throws IOException { |
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// It is normal to use this constructor in preference |
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// to any other in this class. |
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public UDPReader(int port, Logger logger){ |
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this.logger = logger; |
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this.port = port; |
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} |
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public UDPReader(Logger logger){ |
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this(4589, logger); |
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} |
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// default UDP listening port. |
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int port = 4589; |
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final int packetSizeLimit = 8192; |
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public void run() { |
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// Allow the user to choose their own port number. |
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if (args.length == 1){ |
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try { |
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port = new Integer(args[0]).intValue(); |
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} |
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catch (Exception e){ |
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// If something went wrong, use the default again. |
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port = 4589; |
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} |
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} |
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DatagramSocket socket = null; |
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try { |
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socket = new DatagramSocket(port); |
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} |
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catch (BindException e){ |
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System.out.println("Some other process is already listening on port "+port+"."); |
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System.out.println("Please specify another port number on the command line."); |
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System.exit(0); |
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logger.write(this.toString(), Logger.SYSMSG, "Could not start the UDPReader thread on port "+port+" as this port was already in use."); |
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return; |
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} |
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catch (Exception e){ |
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logger.write(this.toString(), Logger.SYSMSG, "Could not start the UDPReader thread on port "+port+"."); |
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return; |
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} |
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System.out.println("UDPReader ready and listening for UDP packets on port "+port); |
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logger.write(this.toString(), Logger.SYSMSG, "UDPReader thread ready and listening for UDP packets on port "+port); |
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byte[] buf; |
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UDPReaderThread t = new UDPReaderThread(); |
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boolean running = true; |
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while (running){ |
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System.gc(); |
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try { |
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buf = new byte[packetSizeLimit]; |
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// receive request |
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DatagramPacket packet = new DatagramPacket(buf, buf.length); |
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socket.receive(packet); |
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UDPReaderThread t = new UDPReaderThread(); |
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t.run(packet); |
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} |
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catch (IOException e) { |
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System.out.println("An exception occured in the UDPReader!"); |
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e.printStackTrace(); |
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logger.write(this.toString(), Logger.SYSMSG, "The UDPReader thread has been shut down as an exception occured: "+e); |
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return; |
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} |
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} |
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socket.close(); |
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} |
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Logger logger; |
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int port; |
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final int packetSizeLimit = 8192; |
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} |
