src/main/java/at/ac/tuwien/sbc/valesriegler/xvsm/SpaceListener.java

   1 package at.ac.tuwien.sbc.valesriegler.xvsm;
   2
   3 import java.io.Serializable;
   4 import java.util.Date;
   5 import java.util.List;
   6 import java.util.Timer;
   7 import java.util.TimerTask;
   8 import java.util.concurrent.atomic.AtomicBoolean;
   9
  10 import org.mozartspaces.notifications.Notification;
  11 import org.mozartspaces.notifications.NotificationListener;
  12 import org.mozartspaces.notifications.Operation;
  13 import org.slf4j.Logger;
  14 import org.slf4j.LoggerFactory;
  15
  16 /**
  17  *
  18  * The SpaceListener provides the {@link NotificationListener} interface.
  19  * <p />
  20  * In {@link SpaceListener#getEntries()} a method for reading the entities, that are normally expected from the notification,
  21  * must be supplied. Thus, it's possible in {@link SpaceListener#startHandlingAbsenceOfNotifications()} to start a timer and to
  22  * execute the actions, which are normally triggered by the notification, with space objects read from {@link SpaceListener#getEntries()}.
  23  * If {@link SpaceListener#lookAround} is true the timer periodically checks if the corresponding {@link AbstractXVSMConnector#timeOflastOperation} is old enough (= the agent is idle for some time)
  24  * and possibly executes the action as a result.
  25  *
  26  * @author Gregor Riegler <gregor DOT riegler AT gmail DOT com>
  27  *
  28  */
  29 public abstract class SpaceListener implements NotificationListener {
  30         private static final Logger log = LoggerFactory
  31                         .getLogger(SpaceListener.class);
  32
  33         protected boolean lookAround = true;
  34         protected long timeout = 3000;
  35         protected AtomicBoolean inNotification = new AtomicBoolean(true);
  36
  37         @Override
  38         public void entryOperationFinished(Notification arg0, Operation arg1,
  39                         List<? extends Serializable> entries) {
  40                 synchronized (AbstractXVSMConnector.lockObject) {
  41                         AbstractXVSMConnector.timeOflastOperation.set(new Date().getTime());
  42                         try {
  43                                 log.info("I am running a notification now!");
  44                                 inNotification.set(true);
  45                                 onEntriesWritten(entries);
  46                         } catch (Exception e) {
  47 //                              e.printStackTrace();
  48                         }
  49
  50                 }
  51         }
  52
  53         abstract List<? extends Serializable> getEntries() throws Exception;
  54
  55         abstract void onEntriesWritten(List<? extends Serializable> entries)
  56                         throws Exception;
  57
  58         public void startHandlingAbsenceOfNotifications() {
  59                 if(!lookAround) return;
  60                 AbstractXVSMConnector.timeOflastOperation.set(new Date().getTime() + 3500);
  61
  62                 Timer timer = new Timer();
  63
  64                 timer.schedule(new SpaceTask(), 3000, 3000);
  65         }
  66
  67         class SpaceTask extends TimerTask {
  68
  69                 @Override
  70                 public void run() {
  71                         if(new Date().getTime()-timeout <= AbstractXVSMConnector.timeOflastOperation.get()) {
  72                                 return;
  73                         }
  74                         synchronized(AbstractXVSMConnector.lockObject) {
  75                                 try {
  76                                         AbstractXVSMConnector.timeOflastOperation.set(new Date().getTime());
  77                                         log.info("Timer task running");
  78
  79                                         List<? extends Serializable> entries = getEntries();
  80                                         if(entries.size() != 0) {
  81                                                 log.info("{} entries in timer", entries.size());
  82                                                 inNotification.set(false);
  83                                                 onEntriesWritten(entries);
  84                                         } else {
  85                                                 log.info("No entries in timer!");
  86                                         }
  87                                 } catch (Exception e) {
  88                                         log.info(e.getMessage());
  89 //                                      e.printStackTrace();
  90                                 }
  91
  92                         }
  93
  94                 }
  95         }
  96
  97 }
  98
  99
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