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//---PACKAGE DECLARATION--- |
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package uk.ac.ukc.iscream.filter; |
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|
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//---IMPORTS--- |
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import java.io.*; |
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import java.net.*; |
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import java.util.*; |
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import uk.ac.ukc.iscream.core.*; |
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import uk.ac.ukc.iscream.componentmanager.*; |
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import uk.ac.ukc.iscream.filter.*; |
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import uk.ac.ukc.iscream.util.*; |
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|
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/** |
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* This class contains the main method to be run by |
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* the filterd. It harvests UDP traffic, and queues it. |
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* |
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* @author $Author: tdb1 $ |
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* @version $Id: UDPReader.java,v 1.13 2001/01/18 23:16:21 tdb1 Exp $ |
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*/ |
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public class UDPReader extends Thread{ |
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|
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//---FINAL ATTRIBUTES--- |
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|
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/** |
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* The current CVS revision of this class |
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*/ |
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public final String REVISION = "$Revision: 1.13 $"; |
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|
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/** |
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* The maximum size of a packet |
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*/ |
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private final int packetSizeLimit = 8192; |
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|
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//---STATIC METHODS--- |
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|
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//---CONSTRUCTORS--- |
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|
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/** |
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* Constructs a new UDPReader. |
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* |
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* @param port The port on which we listen for UDP data |
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* @param queue The queue which we are using |
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*/ |
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public UDPReader(int port, Queue queue){ |
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_port = port; |
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_queue = queue; |
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} |
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|
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//---PUBLIC METHODS--- |
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|
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/** |
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* The main method in the class. Reads and queues XML sent |
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* over UDP. |
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*/ |
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public void run() { |
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|
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// setup a Datagram socket |
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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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_logger.write(this.toString(), Logger.FATAL, "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.FATAL, "Could not start the UDPReader thread on port "+_port+"."); |
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return; |
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} |
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|
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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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|
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byte[] buf; |
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|
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// read UDP packets and queue them |
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boolean running = true; |
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while (running){ |
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try { |
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|
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// receive request and put it in the Queue |
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buf = new byte[packetSizeLimit]; |
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DatagramPacket packet = new DatagramPacket(buf, buf.length); |
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socket.receive(packet); |
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String xml = new String(packet.getData()); |
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_queue.add(xml); |
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} |
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catch (IOException e) { |
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_logger.write(this.toString(), Logger.WARNING, "This UDPReader thread has been shut down as an exception occured: "+e); |
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running = false; |
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} |
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} |
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socket.close(); |
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} |
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|
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/** |
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* Overrides the {@link java.lang.Object#toString() Object.toString()} |
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* method to provide clean logging (every class should have this). |
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* |
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* This uses the uk.ac.ukc.iscream.util.NameFormat class |
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* to format the toString() |
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* |
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* @return the name of this class and its CVS revision |
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*/ |
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public String toString() { |
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return FormatName.getName( |
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_name, |
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getClass().getName(), |
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REVISION); |
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} |
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|
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//---PRIVATE METHODS--- |
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|
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//---ACCESSOR/MUTATOR METHODS--- |
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|
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//---ATTRIBUTES--- |
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|
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/** |
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* This is the friendly identifier of the |
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* component this class is running in. |
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* eg, a Filter may be called "filter1", |
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* If this class does not have an owning |
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* component, a name from the configuration |
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* can be placed here. This name could also |
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* be changed to null for utility classes. |
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*/ |
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private String _name = FilterMain.NAME; |
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|
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/** |
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* This holds a reference to the |
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* system logger that is being used. |
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*/ |
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private Logger _logger = ReferenceManager.getInstance().getLogger(); |
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|
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/** |
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* The port that this reader is using |
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*/ |
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int _port; |
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|
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/** |
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* The Queue object |
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*/ |
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Queue _queue; |
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|
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//---STATIC ATTRIBUTES--- |
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|
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} |
