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//---PACKAGE DECLARATION--- |
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package uk.ac.ukc.iscream.clientinterface; |
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//---IMPORTS--- |
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import uk.ac.ukc.iscream.util.*; |
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import uk.ac.ukc.iscream.componentmanager.*; |
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import uk.ac.ukc.iscream.core.*; |
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import uk.ac.ukc.iscream.client.*; |
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/** |
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* Acts as a Handler to a CORBA based client. |
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* |
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* !!! FUNDAMENTAL DESIGN PROBLEM !!! |
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* !!! Need a way to "shutdown" this class !!! |
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* |
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* @author $Author: tdb1 $ |
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* @version $Id: CorbaHandlerServant.java,v 1.1 2001/02/03 00:42:54 tdb1 Exp $ |
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*/ |
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class CorbaHandlerServant extends Thread implements CorbaHandlerOperations { |
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//---FINAL ATTRIBUTES--- |
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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: 1.1 $"; |
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//---STATIC METHODS--- |
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//---CONSTRUCTORS--- |
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/** |
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* Construct a new CorbaHandlerServant. |
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* |
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* @param packetSorter A reference to the PacketSorter in the component |
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* @param name The name of the client |
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* @param client A reference to the "servant" part of the connecting client. |
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*/ |
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public CorbaHandlerServant(PacketSorter packetSorter, String name, Client client) { |
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_packetSorter = packetSorter; |
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_clientName = name; |
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_hostList = ""; |
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_queue = new Queue(); |
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_client = client; |
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_logger.write(toString(), Logger.SYSINIT, "created"); |
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} |
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//---PUBLIC METHODS--- |
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/** |
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* This method loops round until we "shutdown" (not implemented yet). Inside |
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* the main loop we will first wait until the startData() method is called, |
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* then we'll send data constantly until stopData() is called. |
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*/ |
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public void run() { |
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// !!! OUGHT TO CHECK QUEUE START OF USE !!! |
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// get a queue |
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_queueID = _queue.getQueue(); |
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// we'll keep going until someone implements a "shutdown" :) |
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run = true; |
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while(run) { |
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// initially lock until someone tells us to start |
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synchronized(this) { |
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try { wait(); } catch(Exception e) {} |
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} |
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// loop sending data |
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while(_sendingData) { |
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try { |
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String xml = (String) _queue.get(_queueID); |
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// if it's not null (which could happen if we're "released") |
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// send it on to the client that we're connected to. |
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if(xml != null) { |
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_client.receiveXML(xml); |
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} |
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} |
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catch(InvalidQueueException e) { |
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// lets stop sending - maybe stop altogether ? |
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stopData(); |
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_logger.write(toString(), Logger.ERROR, "Queue failure: "+e); |
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} |
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} |
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// now, we've obviously been stopped, so we'll head back round this |
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// while loop until someone starts us again. |
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} |
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// if we get here we've been told to stop |
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_logger.write(toString(), Logger.SYSMSG, "Shutting Down"); |
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// remove ourselves from the queue |
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_queue.removeQueue(_queueID); |
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} |
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/** |
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* Start sending data to the client. |
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* |
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* @return a boolean stating whether the attempt to start succeeded |
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*/ |
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public boolean startData() { |
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if(!_sendingData) { |
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// register the Queue |
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_packetSorter.register(_queue, _hostList); |
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// mark the running flag |
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_sendingData = true; |
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// bump the loop |
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synchronized(this) { |
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try { notifyAll(); } catch(Exception e) {} |
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} |
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return true; |
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} |
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else { |
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return false; |
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} |
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} |
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/** |
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* Stop sending data to the client. |
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* |
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* @return a boolean stating whether the attempt to stop succeeded |
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*/ |
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public boolean stopData() { |
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if(_sendingData) { |
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// deregister the Queue |
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_packetSorter.deregister(_queue, _hostList); |
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// stop ourselves running |
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_sendingData = false; |
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// if the main loop is waiting for data it won't notice the |
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// above flag to stop. This bumps it out of the blocked get(). |
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_queue.releaseQueue(_queueID); |
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return true; |
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} |
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else { |
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return false; |
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} |
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} |
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/** |
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* Sets the host list for the Client to the requested semi-colon separated |
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* list of hostnames. This will only succeed if we are not sending data. |
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* |
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* @param hostList A semi-colon separated list of hostnames to use. |
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* @return Whether the request succeeded. |
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*/ |
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public boolean setHostList(String hostList) { |
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if(!_sendingData) { |
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_hostList = hostList; |
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return true; |
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} |
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else { |
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return false; |
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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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//---PRIVATE METHODS--- |
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//---ACCESSOR/MUTATOR METHODS--- |
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//---ATTRIBUTES--- |
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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 = ClientInterfaceMain.NAME; |
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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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* A reference to the Configuration Manager the system is using |
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*/ |
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private ConfigurationManager _configManager = ReferenceManager.getInstance().getCM(); |
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/** |
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* A reference to the PacketSorter. |
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*/ |
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private PacketSorter _packetSorter; |
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/** |
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* The host list the Client has requested |
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*/ |
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private String _hostList; |
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/** |
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* The name of the connected client. |
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*/ |
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private String _clientName; |
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/** |
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* Whether we are active and sending data. |
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*/ |
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private boolean _sendingData; |
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/** |
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* The Queue we'll use for buffering data to the client. |
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*/ |
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private Queue _queue; |
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/** |
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* The "servant" part of the client we're connected to. |
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*/ |
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private Client _client; |
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/** |
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* Our queue number within our Queue |
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*/ |
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private int _queueID; |
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/** |
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* The flag that dictates whether the main loop should *completely* exit |
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*/ |
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private boolean run; |
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//---STATIC ATTRIBUTES--- |
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} |