/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership. The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License. You may obtain a copy of the License at
    * 
   *      http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package net.jini.lookup;
  
  import java.io.IOException;
  import java.rmi.RemoteException;
  import java.rmi.server.ExportException;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.concurrent.Callable;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.ConcurrentLinkedQueue;
  import java.util.concurrent.ConcurrentMap;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Future;
  import java.util.concurrent.FutureTask;
  import java.util.concurrent.LinkedBlockingQueue;
  import java.util.concurrent.PriorityBlockingQueue;
  import java.util.concurrent.RunnableFuture;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.concurrent.ScheduledThreadPoolExecutor;
  import java.util.concurrent.ThreadPoolExecutor;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicLong;
  import java.util.concurrent.locks.ReentrantReadWriteLock;
  import java.util.concurrent.locks.ReentrantReadWriteLock.ReadLock;
  import java.util.concurrent.locks.ReentrantReadWriteLock.WriteLock;
  import java.util.function.BiConsumer;
  import java.util.function.BiFunction;
  import java.util.logging.Level;
  import net.jini.config.ConfigurationException;
  import net.jini.core.constraint.MethodConstraints;
  import net.jini.core.constraint.RemoteMethodControl;
  import net.jini.core.entry.Entry;
  import net.jini.core.event.RemoteEvent;
  import net.jini.core.event.RemoteEventListener;
  import net.jini.core.event.UnknownEventException;
  import net.jini.core.lookup.ServiceEvent;
  import net.jini.core.lookup.ServiceID;
  import net.jini.core.lookup.ServiceItem;
  import net.jini.core.lookup.ServiceMatches;
  import net.jini.core.lookup.ServiceRegistrar;
  import net.jini.core.lookup.ServiceTemplate;
  import net.jini.export.Exporter;
  import net.jini.io.MarshalledInstance;
  import net.jini.jeri.AtomicILFactory;
  import net.jini.jeri.BasicJeriExporter;
  import net.jini.jeri.tcp.TcpServerEndpoint;
  import net.jini.security.TrustVerifier;
  import net.jini.security.proxytrust.ServerProxyTrust;
  import org.apache.river.concurrent.RC;
  import org.apache.river.concurrent.Ref;
  import org.apache.river.concurrent.Referrer;
  import org.apache.river.lookup.entry.LookupAttributes;
  import org.apache.river.proxy.BasicProxyTrustVerifier;
  import org.apache.river.thread.DependencyLinker;
  import org.apache.river.thread.ExtensibleExecutorService;
  import org.apache.river.thread.FutureObserver;
  import org.apache.river.thread.NamedThreadFactory;
  import org.apache.river.thread.ObservableFutureTask;
  
  /**
   * Internal implementation of the LookupCache interface. Instances of this class
   * are used in the blocking versions of ServiceDiscoveryManager.lookup() and are returned by
   * createLookupCache.
   */
  final class LookupCacheImpl implements LookupCache {
  
      private static final int ITEM_ADDED = 0;
      private static final int ITEM_REMOVED = 2;
      private static final int ITEM_CHANGED = 3;
      /* The listener that receives remote events from the lookup services */
      private final LookupListener lookupListener;
      /* Exporter for the remote event listener (lookupListener) */
      private volatile Exporter lookupListenerExporter;
      /* Proxy to the listener that receives remote events from lookups */
      private volatile RemoteEventListener lookupListenerProxy;
     /**
      * Task manager for the various tasks executed by this LookupCache
      */
     private volatile ExecutorService cacheTaskMgr;
     private volatile CacheTaskDependencyManager cacheTaskDepMgr;
     
     private volatile ExecutorService incomingEventExecutor;
     /* Flag that indicates if the LookupCache has been terminated. */
     private volatile boolean bCacheTerminated = false;
     /* Contains the ServiceDiscoveryListener's that receive local events */
     private final ReadLock sItemListenersRead;
     private final WriteLock sItemListenersWrite;
     private final Collection<ServiceDiscoveryListener> sItemListeners;
     /* Map from ServiceID to ServiceItemReg, this basically holds the replicated
      * filtered cache of ServiceRegistrar's, containing all the services
      * and attributes the client has registered interest in.
      * Regarding synchronization of state, all ServiceItemReg mutations 
      * are guarded using atoimc BiFunction's with computIfPresent calls,
      * now that mutations of ServiceItemReg are essentially atomic, the
      * next step would be to make ServiceItemReg immutable, and replace 
      * instead of mutate and decide on a sutiable identity, so that when a later
      * atomic operation occurring after filtering depends on an atomic
      * operation that preceded it, we can check whether an interleved atomic action
      * has occurred. At present interleaved atomic actions are prevented by
      * limiting access to a single thread for each EventReg in eventRegMap
      * for registration, events and lookup.  Removal from serviceIdMap only 
      * occurs through discard and insertion when newOldService is called
      * by RegisterListenerTask or HandleServiceEventTask, both occur
      * atomically and mutually exclusive (for an EventReg), hence mutating
      * atomic operations are unlikely to be interleaved, we also check that we 
      * have the same ServiceItemReg instance between dependant atomic operations.
      * and check whether a ServiceItemReg or EventReg has been discarded.
      * The atomic operations are separated by filtering, which may include 
      * remote calls. */
     private final ConcurrentMap<ServiceID, ServiceItemReg> serviceIdMap;
     /* Map from ProxyReg to EventReg: (proxyReg, {source,id,seqNo,lease})
      * This map is used to assist with managing event registrations with
      * each ServiceRegistar and replicating filtered state using ServiceEvents */
     private final ConcurrentMap<ProxyReg, EventReg> eventRegMap;
     /* Template current cache instance should use for primary matching */
     private final ServiceTemplate tmpl;
     /* Filter current cache instance should use for secondary matching */
     private final ServiceItemFilter filter;
     /* Desired lease duration to request from lookups' event mechanisms */
     private final long leaseDuration;
     /* Log the time when the cache gets created. This value is used to
      * calculate the time when the cache should expire.
      */
     private final long startTime;
     /**
      * For tasks waiting on verification events after service discard
      */
     private volatile ScheduledExecutorService serviceDiscardTimerTaskMgr;
     private final ConcurrentMap<ServiceID, Future> serviceDiscardFutures;
     /**
      * Whenever a ServiceIdTask is created in this cache, it is assigned a
      * unique sequence number to allow such tasks associated with the same
      * ServiceID to be executed in the order in which they were queued in the
      * TaskManager. This field contains the value of the sequence number
      * assigned to the most recently created ServiceIdTask.
      */
     private final AtomicLong taskSeqN;
     private final ServiceDiscoveryManager sdm;
     private final boolean useInsecureLookup;
 
     LookupCacheImpl(ServiceTemplate tmpl, ServiceItemFilter filter, 
             ServiceDiscoveryListener sListener, long leaseDuration,
             ServiceDiscoveryManager sdm, boolean useInsecureLookup) 
                                                     throws RemoteException 
     {
         this.useInsecureLookup = useInsecureLookup;
 	this.taskSeqN = new AtomicLong();
 	this.startTime = System.currentTimeMillis();
 	this.eventRegMap = new ConcurrentHashMap<ProxyReg, EventReg>();
 	this.serviceIdMap = new ConcurrentHashMap<ServiceID, ServiceItemReg>();
 	this.sItemListeners = new HashSet<ServiceDiscoveryListener>();
 	this.serviceDiscardFutures = RC.concurrentMap(new ConcurrentHashMap<Referrer<ServiceID>, Referrer<Future>>(), Ref.WEAK_IDENTITY, Ref.STRONG, 60000, 60000);
 	this.tmpl = tmpl.clone();
 	this.leaseDuration = leaseDuration;
 	this.filter = filter;
 	lookupListener = new LookupListener();
 	if (sListener != null) {
 	    sItemListeners.add(sListener);
 	}
 	this.sdm = sdm;
         ReentrantReadWriteLock rwl = new ReentrantReadWriteLock();
         sItemListenersRead = rwl.readLock();
         sItemListenersWrite = rwl.writeLock();
     } //end constructor
 
     private ExecutorService eventNotificationExecutor;
 
     /**
      * RemoteEventListener class that is registered with the proxy to
      * receive notifications from lookup services when any ServiceItem
      * changes (NOMATCH_MATCH, MATCH_NOMATCH, MATCH_MATCH)
      * 
      * TODO: implement RemoteMethodControl to allow the ServiceRegistrar
      * to place constraints on the LookupListener.
      */
     private final class LookupListener implements RemoteEventListener,
 	    ServerProxyTrust {
 
 	RemoteEventListener export() throws ExportException {
 	    return (RemoteEventListener) lookupListenerExporter.export(this);
 	}
 
 	@Override
 	public void notify(RemoteEvent evt) throws UnknownEventException,
 		java.rmi.RemoteException {
 	    if (!(evt instanceof ServiceEvent)) {
 		throw new UnknownEventException("ServiceEvent required,not: " + evt.toString());
 	    }
 	    notifyServiceMap((ServiceEvent) evt);
 	}
 
 	/**
 	 * Returns a <code>TrustVerifier</code> which can be used to verify that
 	 * a given proxy to this listener can be trusted.
 	 */
 	@Override
 	public TrustVerifier getProxyVerifier() {
 	    return new BasicProxyTrustVerifier(lookupListenerProxy);
 	} //end getProxyVerifier
     } //end class LookupCacheImpl.LookupListener
     
     /**
      * This task class, when executed, first registers to receive ServiceEvents
      * from the given ServiceRegistrar. If the registration process succeeds (no
      * RemoteExceptions), it then performs a lookup to query the given
      * ServiceRegistrar for a "snapshot" of its current state with respect to
      * services that match the given template.
      *
      * Note that the order of execution is important. That is, the lookup must
      * be executed only after registration for events has completed. This is
      * because when an entity registers with the event mechanism of a
      * ServiceRegistrar, the entity will only receive notification of events
      * that occur "in the future", after the registration is made. The entity
      * will not receive events about changes to the state of the
      * ServiceRegistrar that may have occurred before or during the registration
      * process.
      *
      * Thus, if the order of these tasks were reversed and lookup were to be
      * performed prior to the RegisterListenerTask, then the possibility exists
      * for the occurrence of a change in the ServiceRegistrar's state between
      * the time lookup retrieves a snapshot of that state, and the time the
      * event registration process has completed, resulting in an incorrect view
      * of the current state of the ServiceRegistrar.
      */
     private static final class RegisterListenerTask extends
 	    CacheTask {
 
 	final LookupCacheImpl cache;
 
 	public RegisterListenerTask(ProxyReg reg,
 		long seqN, LookupCacheImpl cache) {
 	    super(reg, seqN);
 	    this.cache = cache;
 	}
 
 	@Override
 	public boolean hasDeps() {
 	    return true;
 	}
 
 	@Override
 	public boolean dependsOn(CacheTask t) {
 	    if (t instanceof ProxyRegDropTask) {
 		ProxyReg r = getProxyReg();
 		if (r != null && r.equals(t.getProxyReg())) {
 		    if (t.getSeqN() < getSeqN()) {
 			return true;
 		    }
 		}
 	    }
 	    return false;
 	}
 
 	@Override
 	public void run() {
             if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER)){
                 ServiceDiscoveryManager.log(Level.FINER, 
                     "ServiceDiscoveryManager - RegisterListenerTask started");
             }
 	    long duration = cache.getLeaseDuration();
 	    if (duration < 0) {
 		return;
 	    }
 	    try {
 		EventReg eventReg
 			= cache.sdm.registerListener(
 				reg.getProxy(),
 				cache.tmpl,
 				cache.lookupListenerProxy,
 				duration
 			);
 		// eventReg is a new object not visible to other threads yet.
 		// It will be safely published using a ConcurrentMap, so
 		// we don't need to synchronize here.
 		/* Cancel the lease if the cache has been terminated */
 		if (cache.bCacheTerminated
 			|| Thread.currentThread().isInterrupted()) {
 		    // eventReg.lease is final and is already safely published
 		    cache.sdm.cancelLease(eventReg.lease);
 		} else {
                     eventReg.suspendEvents();
 		    EventReg existed
 			    = cache.eventRegMap.putIfAbsent(reg, eventReg);
 		    if (existed != null){ // A listener has already been registered.
 			cache.sdm.cancelLease(eventReg.lease);
 		    } else {
                         try {
                             /* Execute the lookup only if there were no problems */
                             cache.lookup(reg);
                         } finally {
                             synchronized (eventReg){
                                 eventReg.releaseEvents();
                                 eventReg.notify();
                             }
                         }
                     }
                     
 		} //endif
 	    } catch (Exception e) {
 		cache.sdm.fail(e,
 			reg.getProxy(),
 			this.getClass().getName(),
 			"run",
 			"Exception occurred while attempting to register with the lookup service event mechanism",
 			cache.bCacheTerminated
 		);
 	    } finally {
                 if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER)){
                     ServiceDiscoveryManager.log(Level.FINER, 
                         "ServiceDiscoveryManager - RegisterListenerTask completed");
                 }
 	    }
 	} //end run
     } //end class LookupCacheImpl.RegisterListenerTask
     
     /**
      * When the given registrar is discarded, this Task class is used to remove
      * the registrar from the various maps maintained by this cache.
      */
     private static final class ProxyRegDropTask extends CacheTask {
 
 	final LookupCacheImpl cache;
 	final EventReg eReg;
 
 	public ProxyRegDropTask(ProxyReg reg,
 		EventReg eReg,
 		long seqN,
 		LookupCacheImpl cache) {
 	    super(reg, seqN);
 	    this.cache = cache;
 	    this.eReg = eReg;
 	}
 
 	@Override
 	public void run() {
             if (ServiceDiscoveryManager.logger.isLoggable(Level.FINEST)){
                 ServiceDiscoveryManager.log(Level.FINEST, 
                     "ServiceDiscoveryManager - ProxyRegDropTask started");
             }
             // Maybe registrar was discarded before the RegisterLookupListener 
             // task completed?
             // That's ok this task should execute after RegisterLookupListener.
             synchronized (eReg){ //lease has already been cancelled by removeProxyReg or above.
                 while (eReg.eventsSuspended()) { 
                     // Lookup is in progress, due to non contiguous 
                     // event.
                     try {
                         eReg.wait(200L);
                     } catch (InterruptedException e){
                         Thread.currentThread().interrupt();
                     }
                 }
                 // We've woken up holding the lock on eReg, events and lookup
                 // cannot proceed until we release this lock.
                 // Before lookup can start adding state to the serviceIdMap
                 // it first checks the eReg is not discarded.
                 if (eReg.discard()) cache.eventRegMap.remove(reg, eReg);
             }
 	    /* For each itemReg in the serviceIdMap, disassociate the
 	     * lookup service referenced here from the itemReg; and
 	     * if the itemReg then has no more lookup services associated
 	     * with it, remove the itemReg from the map and send a
 	     * service removed event.
 	     */
 	    Iterator<Map.Entry<ServiceID, ServiceItemReg>> iter = cache.serviceIdMap.entrySet().iterator();
 	    while (iter.hasNext()) {
 		Map.Entry<ServiceID, ServiceItemReg> e = iter.next();
 		ServiceID srvcID = e.getKey();
                 DissociateLusCleanUpOrphan dlcl = new DissociateLusCleanUpOrphan(cache, reg.getProxy());
                 cache.serviceIdMap.computeIfPresent(srvcID, dlcl);
                 if (dlcl.itemRegProxy != null) {
                     cache.itemMatchMatchChange(srvcID, dlcl.itmReg, dlcl.itemRegProxy, dlcl.newItem, false);
                 } else if (dlcl.notify && dlcl.filteredItem != null) {
                     cache.removeServiceNotify(dlcl.filteredItem);
                 }
 	    } //end loop
             if (ServiceDiscoveryManager.logger.isLoggable(Level.FINEST)){
                 ServiceDiscoveryManager.log(Level.FINEST, 
                     "ServiceDiscoveryManager - ProxyRegDropTask completed");
             }
 	} //end run
 
 	@Override
 	public boolean hasDeps() {
 	    return true;
 	}
 
 	@Override
 	public boolean dependsOn(CacheTask t) {
 	    if (t instanceof RegisterListenerTask || t instanceof ProxyRegDropTask) {
 		ProxyReg r = getProxyReg();
 		if (r != null && r.equals(t.getProxyReg())) {
 		    if (t.getSeqN() < getSeqN()) {
 			return true;
 		    }
 		}
 	    }
 	    return false;
 	}
     } //end class LookupCacheImpl.ProxyRegDropTask
     
     /**
      * Task class used to determine whether or not to "commit" a service discard
      * request, increasing the chances that the service will eventually be
      * re-discovered. This task is also used to attempt a filter retry on an
      * item in which the cache's filter initially returned indefinite.
      */
     private static final class ServiceDiscardTimerTask implements Runnable {
 
 	private final ServiceID serviceID;
 	private final LookupCacheImpl cache;
 
 	public ServiceDiscardTimerTask(LookupCacheImpl cache, ServiceID serviceID) {
 	    this.serviceID = serviceID;
 	    this.cache = cache;
 	} //end constructor
 
 	@Override
 	public void run() {
             if (ServiceDiscoveryManager.logger.isLoggable(Level.FINEST)){
                 ServiceDiscoveryManager.log(Level.FINEST, 
                     "ServiceDiscoveryManager - ServiceDiscardTimerTask started");
             }
 	    try {
 		/* Exit if this cache has already been terminated. */
 		if (cache.bCacheTerminated) {
 		    return;
 		}
 		/* If the service ID is still contained in the serviceIdMap,
 		 * then a MATCH_NOMATCH event did not arrive, which is
 		 * interpreted here to mean that the service is still up.
 		 * The service ID will still be in the map if one (or both)
 		 * of the following is true:
 		 *  - the client discarded an unreachable service that never
 		 *    actually went down (so it's lease never expired, and
 		 *    a MATCH_NOMATCH event was never received)
 		 *  - upon applying the cache's filter to the service, the
 		 *    filter returned indefinite, and this task was queued
 		 *    to request that filtering be retried at a later time
 		 *
 		 * For the first case above, the service is "un-discarded" so
 		 * the service will be available to the client again. For the
 		 * second case, the filter is retried. If the service passes
 		 * the filter, the service is "un-discarded"; otherwise, it is
 		 * 'quietly' removed from the map (because a service removed
 		 * event was already sent when the service was originally
 		 * discarded.
 		 */
 		ServiceItemReg itemReg = cache.serviceIdMap.get(serviceID);
 		if (itemReg != null) {
                     // Refactoring strategy:
                     // read item and filter.
                     // compute atomically, check item undiscards and check
                     // that filtered item hasn't changed.
 		    //Discarded status hasn't changed
 		    ServiceItem itemToSend;
 		    if (!itemReg.isDiscarded()) return;
 		    ServiceItem item = null;
 		    ServiceItem filteredItem = null;
                     boolean addFilteredItemToMap = false;
                     boolean remove = false;
                     boolean notify = true;
 		    itemToSend = itemReg.getFilteredItem();
 		    if (itemToSend == null) {
 			item = itemReg.getItem();
 			filteredItem = item.clone();
 			//retry the filter
 			if (cache.useInsecureLookup){
 			    if (ServiceDiscoveryManager.filterPassed(filteredItem, cache.filter)) {
                                 addFilteredItemToMap = true;
 			    } else {
 				//'quietly' remove the item
                                 remove = true;
                                 notify = false;
 			    } //endif
 			} else {
 			    // We're dealing with a bootstrap proxy.
 			    // The filter may not be expecting a bootstrap proxy.
 			    try {
 				if(ServiceDiscoveryManager.filterPassed(filteredItem, cache.filter)){
                                     addFilteredItemToMap = true;
                                 } else {
                                     //'quietly' remove the item
                                     remove = true;
                                     notify = false;
                                 } //endif
 			    } catch (SecurityException ex){
                                 if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE)){
                                     ServiceDiscoveryManager.log(Level.FINE, 
                                         "Exception caught, while attempting to filter a bootstrap proxy", ex);
                                 }
 				try {
 				    filteredItem.service = ((ServiceProxyAccessor) filteredItem.service).getServiceProxy();
 				    if(ServiceDiscoveryManager.filterPassed(filteredItem, cache.filter)){
                                         addFilteredItemToMap = true;
                                     } else {
                                         //'quietly' remove the item
                                         remove = true;
                                         notify = false;
                                     } //endif
 				} catch (RemoteException ex1) {
 				    if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE)){
                                         ServiceDiscoveryManager.log(Level.FINE, 
                                             "Exception caught, while attempting to filter a bootstrap proxy", ex1);
                                     }
                                     //'quietly' remove the item
                                     remove = true;
                                     notify = false;
 				}
 			    } catch (ClassCastException ex){
 				if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE)){
                                     ServiceDiscoveryManager.log(Level.FINE, 
                                         "Exception caught, while attempting to filter a bootstrap proxy", ex);
                                 }
 				try {
 				    filteredItem.service = ((ServiceProxyAccessor) filteredItem.service).getServiceProxy();
 				    if(ServiceDiscoveryManager.filterPassed(filteredItem, cache.filter)){
                                         addFilteredItemToMap = true;
                                     } else {
                                         //'quietly' remove the item
                                         remove = true;
                                         notify = false;
                                     } //endif
 				} catch (RemoteException ex1) {
 				    if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE)){
                                         ServiceDiscoveryManager.log(Level.FINE, 
                                             "Exception caught, while attempting to filter a bootstrap proxy", ex1);
                                     }
                                     //'quietly' remove the item
                                     remove = true;
                                     notify = false;
 				}
 			    }
 			}
 		    } //endif
 		    /* Either the filter was retried and passed, in which case,
 		     * the filtered itemCopy was placed in the map and
 		     * "un-discarded"; or the
 		     * filter wasn't applied above (a non-null filteredItem
 		     * field in the itemReg in the map means that the filter
 		     * was applied at some previous time). In the latter case, the
 		     * service can now be "un-discarded", and a notification
 		     * that the service is now available can be sent for either case.
 		     */
                     AddOrRemove aor = 
                             new AddOrRemove(cache, item, filteredItem, 
                                     itemToSend, addFilteredItemToMap,
                                     remove, notify
                             );
                     cache.serviceIdMap.computeIfPresent(serviceID, aor);
 		    if (aor.notify) cache.addServiceNotify(aor.itemToSend);
 		}
 	    } finally {
                 if (ServiceDiscoveryManager.logger.isLoggable(Level.FINEST)){
                     ServiceDiscoveryManager.log(Level.FINEST, 
                         "ServiceDiscoveryManager - ServiceDiscardTimerTask completed");
                 }
 	    }
 	} //end run
     }
     
     /**
      * Used by ServiceDiscardTimerTask to make removal or add with unDiscard atomic.
      */
     private static class AddOrRemove 
             implements BiFunction<ServiceID, ServiceItemReg, ServiceItemReg> 
     {
         final LookupCacheImpl cache;
         final ServiceItem item;
         final ServiceItem filteredItem;
         final boolean addFilteredItemToMap;
         final boolean remove;
         boolean notify;
         ServiceItem itemToSend;
         
         AddOrRemove(LookupCacheImpl cache, ServiceItem item,
                 ServiceItem filteredItem, ServiceItem itemToSend, 
                 boolean addFilteredItemToMap, boolean remove, boolean notify)
         {
             this.cache = cache;
             this.item = item;
             this.filteredItem = filteredItem;
             this.itemToSend = itemToSend;
             this.addFilteredItemToMap = addFilteredItemToMap;
             this.remove = remove;
             this.notify = notify;
         }
         
         @Override
         public ServiceItemReg apply(ServiceID serviceID, ServiceItemReg itemReg) {
             if (!itemReg.unDiscard()){
                 notify = false;
                 return itemReg;
             } // Do nothing.
             /* Either the filter was retried and passed, in which case,
              * the filtered itemCopy was placed in the map and
              * "un-discarded"; or the
              * filter wasn't applied above (a non-null filteredItem
              * field in the itemReg in the map means that the filter
              * was applied at some previous time). In the latter case, the
              * service can now be "un-discarded", and a notification
              * that the service is now available can be sent for either case.
              */
             if (addFilteredItemToMap){
                 itemReg.replaceProxyUsedToTrackChange(null, item);
                 itemReg.setFilteredItem(filteredItem);
                 itemToSend = filteredItem;
                 return itemReg;
             } else if (remove){
                 return null;
             }
             return itemReg;
         }
         
     }
 
     // This method's javadoc is inherited from an interface of this class
     @Override
     public void terminate() {
 	synchronized (this) {
 	    if (bCacheTerminated) {
 		return; //allow for multiple terminations
 	    }
 	    bCacheTerminated = true;
 	} //end sync
 	sdm.removeLookupCache(this);
 	/* Terminate all tasks: first, terminate this cache's Executors*/
 	cacheTaskMgr.shutdownNow();
 	/* Terminate ServiceDiscardTimerTasks running for this cache */
 	serviceDiscardTimerTaskMgr.shutdownNow();
 	eventNotificationExecutor.shutdownNow();
 	/* Cancel all event registration leases held by this cache. */
 	Set set = eventRegMap.entrySet();
 	Iterator iter = set.iterator();
 	while (iter.hasNext()) {
 	    Map.Entry e = (Map.Entry) iter.next();
 	    EventReg eReg = (EventReg) e.getValue();
 	    sdm.cancelLease(eReg.lease);
 	} //end loop
 	/* Un-export the remote listener for events from lookups. */
 	try {
 	    lookupListenerExporter.unexport(true);
 	} catch (IllegalStateException e) {
             if (ServiceDiscoveryManager.logger.isLoggable(Level.FINEST)){
                 ServiceDiscoveryManager.log(
                     Level.FINEST, 
                     "IllegalStateException occurred while unexporting the cache's remote event listener",
                     e
                 );
             }
 	}
         incomingEventExecutor.shutdownNow();
         if (ServiceDiscoveryManager.logger.isLoggable(Level.FINEST)){
             ServiceDiscoveryManager.log(
                 Level.FINEST, 
                 "ServiceDiscoveryManager - LookupCache terminated"
             );
         }
     } //end LookupCacheImpl.terminate
 
     // This method's javadoc is inherited from an interface of this class
     @Override
     public ServiceItem lookup(ServiceItemFilter myFilter) {
 	checkCacheTerminated();
 	ServiceItem[] ret = getServiceItems(myFilter);
 	if (ret.length == 0) {
 	    return null;
 	}
 	// Maths.abs(Integer.MIN_VALUE) = -ve, so to avoid random
 	// hard to debug bugs, this has been changed.
 	int rand = sdm.random.nextInt(ret.length);
 	return ret[rand];
     } //end LookupCacheImpl.lookup
 
     // This method's javadoc is inherited from an interface of this class
     @Override
     public ServiceItem[] lookup(ServiceItemFilter myFilter, int maxMatches) {
 	checkCacheTerminated();
 	if (maxMatches < 1) {
 	    throw new IllegalArgumentException("maxMatches must be > 0");
 	}
 	ServiceItem[] sa = getServiceItems(myFilter);
 	int len = sa.length;
 	if (len == 0 || len <= maxMatches) return sa;
         List<ServiceItem> items = new LinkedList<ServiceItem>();
 	int rand = sdm.random.nextInt(Integer.MAX_VALUE) % len;
 	for (int i = 0; i < len; i++) {
 	    items.add(sa[(i + rand) % len]);
 	    if (items.size() == maxMatches) {
 		break;
 	    }
 	} //end loop
 	ServiceItem[] ret = new ServiceItem[items.size()];
 	items.toArray(ret);
 	return ret;
     } //end LookupCacheImpl.lookup
 
     // This method's javadoc is inherited from an interface of this class
     @Override
     public void discard(Object serviceReference) {
 	checkCacheTerminated();
 	/* Loop through the serviceIdMap, looking for the itemReg that
 	 * corresponds to given serviceReference. If such an itemReg
 	 * exists, and it's not already discarded, then queue a task
 	 * to discard the given serviceReference.
 	 */
 	Iterator<Map.Entry<ServiceID, ServiceItemReg>> iter = serviceIdMap.entrySet().iterator();
 	while (iter.hasNext()) {
 	    Map.Entry<ServiceID, ServiceItemReg> e = iter.next();
 	    ServiceItemReg itmReg = e.getValue();
             ServiceID sid = e.getKey();
             ServiceItem filteredItem = itmReg.getFilteredItem();
             if (filteredItem != null && (filteredItem.service).equals(serviceReference)) {
                 Discard dis = new Discard(this, itmReg, filteredItem, sdm.getDiscardWait());
                 serviceIdMap.computeIfPresent(sid, dis);
             }
 	} //end loop
     } //end LookupCacheImpl.discard
     
     private static class Discard 
             implements BiFunction<ServiceID, ServiceItemReg, ServiceItemReg>{
         
         LookupCacheImpl cache;
         ServiceItemReg expected;
         ServiceItem filteredItem;
         long discardWait;
         
         Discard(LookupCacheImpl cache, ServiceItemReg itmReg, ServiceItem filteredItem, long discardWait){
             this.cache = cache;
             this.expected = itmReg;
             this.filteredItem = filteredItem;
             this.discardWait = discardWait;
         }
 
         @Override
         public ServiceItemReg apply(ServiceID sid, ServiceItemReg itmReg) {
             if (!expected.equals(itmReg)) return itmReg;
             if (itmReg.discard()) {
                 Future f = 
                     cache.serviceDiscardTimerTaskMgr.schedule(
                         new ServiceDiscardTimerTask(cache, sid),
                         discardWait,
                         TimeUnit.MILLISECONDS
                     );
                 cache.serviceDiscardFutures.put(sid, f);
                 cache.removeServiceNotify(filteredItem);
             }
             return itmReg;
         }
     }
 
     /**
      * This method returns a <code>ServiceItem</code> array containing elements
      * that satisfy the following conditions: - is referenced by one of the
      * <code>itemReg</code> elements contained in the <code>serviceIdMap</code>
      * - is not currently discarded - satisfies the given
      * <code>ServiceItemFilter</code>
      *
      * Note that the <code>filter</code> parameter is a "2nd stage" filter. That
      * is, for each <code>itemReg</code> element in the
      * <code>serviceIdMap</code>, the "1st stage" filter corresponding to the
      * current instance of <code>LookupCache</code> has already been applied to
      * the <code>ServiceItem</code> referenced in that <code>itemReg</code>. The
      * <code>ServiceItemFilter</code> applied here is supplied by the entity
      * interacting with the cache, and provides a second filtering process.
      * Thus, this method applies the given <code>filter</code> parameter to the
      * <code>filteredItem</code> field (not the <code>item</code> field) of each
      * non-discarded <code>itemReg</code> element in the
      * <code>serviceIdMap</code>.
      *
      * This method returns all the instances of <code>ServiceItem</code> that
      * pass the given <code>filter</code>; and it discards all the items that
      * produce an indefinite result when that <code>filter</code> is applied.
      */
     private ServiceItem[] getServiceItems(ServiceItemFilter filter2) {
         FilteredItems items = new FilteredItems(this, filter2);
         serviceIdMap.forEach(items);
         return items.result();
     } //end LookupCacheImpl.getServiceItems
     
     private static class FilteredItems implements BiConsumer<ServiceID, ServiceItemReg> {
         
         private final List<ServiceItem> items;
         private final ServiceItemFilter filter2;
         private final LookupCacheImpl cache;
         
         FilteredItems(LookupCacheImpl cache, ServiceItemFilter filter2){
             this.items = new LinkedList<ServiceItem>();
             this.filter2 = filter2;
             this.cache = cache;
         }
 
         @Override
         public void accept(ServiceID sid, ServiceItemReg itemReg) {
 	    ServiceItem itemToFilter = itemReg.getFilteredItem();
             if ((itemToFilter == null) || (itemReg.isDiscarded())) return;
             /* Make a copy because the filter may change it to null */
             /* ServiceItemReg now performs defensive copy clone for us,
              * so we don't forget.
              */
             itemToFilter = itemToFilter.clone();
 	    /* Apply the filter */
 	    boolean pass = (filter2 == null) || (filter2.check(itemToFilter));
 	    /* Handle filter fail - skip to next item */
 	    if (!pass) return;
 	    /* Handle filter pass - add item to return set */
 	    if (itemToFilter.service != null) {
 		items.add(itemToFilter);
 		return;
 	    } //endif(pass)
 	    /* Handle filter indefinite - discard the item */
             Discard dis = 
                     new Discard(
                             cache, 
                             itemReg, 
                             itemToFilter, 
                             cache.sdm.getDiscardWait()
                     );
             cache.serviceIdMap.computeIfPresent(sid, dis);
         }
         
         ServiceItem[] result(){
             ServiceItem[] ret = new ServiceItem[items.size()];
             items.toArray(ret);
             return ret;
         }
         
     }
 
     ServiceItem [] processBootStrapProxys(Object [] proxys){
 	int length = proxys.length;
 	Collection<ServiceItem> result = new ArrayList<ServiceItem>(length);
 	for (int i = 0; i < length; i++){
 	    Object bootstrap;
 	    Entry [] attributes;
 	    ServiceID id;
 	    try {
 		bootstrap = sdm.bootstrapProxyPreparer.prepareProxy(proxys[i]);
 		attributes = ((ServiceAttributesAccessor) bootstrap).getServiceAttributes();
 		id = ((ServiceIDAccessor) bootstrap).serviceID();
 		result.add(new ServiceItem(id, bootstrap, attributes));
 	    } catch (IOException ex) { } //ignore
 	}
 	return result.toArray(new ServiceItem[result.size()]);
     }
     
     // This method's javadoc is inherited from an interface of this class
     @Override
     public void addListener(ServiceDiscoveryListener listener) {
 	checkCacheTerminated();
 	if (listener == null) {
 	    throw new NullPointerException("can't add null listener");
 	}
 	//No action is taken if not added according to LookupCache
 	ServiceItem[] items = getServiceItems(null);
         boolean added;
         sItemListenersWrite.lock();
         try {
             added = sItemListeners.add(listener);
         } finally {
             sItemListenersWrite.unlock();
         }
         if (added){
             for (int i = 0, l = items.length; i < l; i++) {
                 addServiceNotify(items[i], listener);
             } //end loop
         }
     } //end LookupCacheImpl.addListener
 
     // This method's javadoc is inherited from an interface of this class
     @Override
     public void removeListener(ServiceDiscoveryListener listener) {
 	checkCacheTerminated();
 	if (listener == null) {
 	    return;
 	}
         sItemListenersWrite.lock();
         try {
             sItemListeners.remove(listener);
         } finally {
             sItemListenersWrite.unlock();
         }
     } //end LookupCacheImpl.removeListener
 
     /**
      * Add a new ProxyReg to the lookupCache. Called by the constructor and the
      * DiscMgrListener's discovered() method.
      *
      * @param reg a ProxyReg to add.
      */
     public void addProxyReg(ProxyReg reg) {
 	RegisterListenerTask treg = new RegisterListenerTask(reg, taskSeqN.getAndIncrement(), this);
 	cacheTaskDepMgr.submit(treg);
     } //end LookupCacheImpl.addProxyReg
 
     /**
      * Remove a ProxyReg from the lookupCache. Called by DiscMgrListener's
      * discarded() method.
      *
      * @param reg a ProxyReg to remove.
      */
     public void removeProxyReg(ProxyReg reg) {
 	ProxyRegDropTask t;
 	//let the ProxyRegDropTask do the eventRegMap.remove
 	EventReg eReg = eventRegMap.get(reg);
 	if (eReg != null) {
 	    try {
 		sdm.leaseRenewalMgr.remove(eReg.lease);
 	    } catch (Exception e) {
                 if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER)){
                     ServiceDiscoveryManager.log(
                         Level.FINER, 
                         "exception occurred while removing an event registration lease",
                         e
                     );
                 }
 	    }
             t = new ProxyRegDropTask(reg, eReg, taskSeqN.getAndIncrement(), this);
             cacheTaskDepMgr.removeUselessTask(reg); //Possibly RegisterListenerTask before it commences execution.
             cacheTaskDepMgr.submit(t);
         } //endif
     } //end LookupCacheImpl.removeProxyReg
 
     /* Throws IllegalStateException if this lookup cache has been
      * terminated
      */
     private void checkCacheTerminated() {
 	sdm.checkTerminated();
 	if (bCacheTerminated) {
 	    throw new IllegalStateException("this lookup cache was terminated");
 	} //endif
     } //end LookupCacheImpl.checkCacheTerminated
     
     /**
      * Called by the lookupListener's notify() method
      * 
      * @param theEvent 
      */
     private void notifyServiceMap(ServiceEvent theEvent){
         if (theEvent.getSource() == null) {
 	    return;
 	}
         if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE)){
             ServiceDiscoveryManager.log(
                 Level.FINE, 
                 "HandleServiceEventTask submitted"
             );
         }
 	incomingEventExecutor.submit(new HandleServiceEventTask(this, theEvent));
     }
 
     /**
      * Task used to offload incoming ServiceEvents for LookupListener, so the
      * remote method call can return quickly.
      * 
      * This was initially made comparable for natural queue ordering, however
      * since events may be in network transit, while some are in the queue
      * and others are executing, it isn't a safe way to ensure any kind of
      * consistency or ordering.
      */
     private static class HandleServiceEventTask implements Runnable, Comparable {
         
         private final LookupCacheImpl cache;
         private final ServiceEvent theEvent;
         /* The following fields are only ever accessed by one thread at a time,
          * they are volatile to ensure visibility between threads */
         private volatile ProxyReg reg;
         private volatile EventReg eReg;
         private volatile long timestamp;
         private volatile ServiceItem item;
         
         HandleServiceEventTask(LookupCacheImpl cache, ServiceEvent event){
             this.cache = cache;
             this.theEvent = event;
         }
 
         @Override
         public void run() {
             if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER)){
                 ServiceDiscoveryManager.log(Level.FINER,"HandleServiceEventTask started");
             }
             try {
                 if (item == null){
                     if (cache.useInsecureLookup){
                         item = theEvent.getServiceItem();
                     } else {
                         //REMIND: Consider using the actual service proxy?  No, that
                         // would cause unnecessary download, need to allow clients the
                         // opportunity to filter first, then clients also need to
                         // prepare during filtering before actual service proxy is 
                         // safe for use.
                         Object proxy = theEvent.getBootstrapProxy();
                         if (proxy != null){
                             Entry [] attributes;
                             try {
                                 proxy = cache.sdm.bootstrapProxyPreparer.prepareProxy(proxy);
                                 /* A service that registers with a ServiceRegistrar may trigger a 
                                  * ServiceEvent before that service receives its ServiceID from
                                  * the ServiceRegistrar, which results in the ServiceIDAccessor
                                  * returning null, we're provided with the ServiceID anyway,
                                  * so we can avoid an unnecessary remote call.
                                  */
                                 attributes = ((ServiceAttributesAccessor)proxy).getServiceAttributes();
                                 item = new ServiceItem(theEvent.getServiceID(), proxy, attributes);
                             } catch (IOException ex) {
                                 if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE)){
                                     ServiceDiscoveryManager.log(
                                         Level.FINE, 
                                         "exception thrown while attempting to establish contact via a bootstrap proxy",
                                         ex
                                     );
                                 }
                                 // Item will be null.
                             }
                         }
                     }
                 }
                 /* Search eventRegMap for ProxyReg corresponding to event. */
                 FIND_ProxyReg: while (reg == null || eReg == null) {
                     Set<Map.Entry<ProxyReg, EventReg>> set = cache.eventRegMap.entrySet();
                     Iterator<Map.Entry<ProxyReg, EventReg>> iter = set.iterator();
                     while (iter.hasNext()) {
                         Map.Entry<ProxyReg, EventReg> e = iter.next();
                         eReg = e.getValue();
                         if (theEvent.getID() == eReg.eventID && theEvent.getSource().equals(eReg.source)) {
                             reg = e.getKey();
                             break FIND_ProxyReg;
                         } //endif
                     } //end loop
                     try {
                         cache.incomingEventExecutor.submit(this);
                         Thread.sleep(50L);
                         return;
                     } catch (InterruptedException ex) {
                         Thread.currentThread().interrupt();
                         return;
                     }
                 }
                 if (timestamp == 0){
                     timestamp = System.currentTimeMillis();
                 } else {
                     // We've done this before.
                     if (!cache.eventRegMap.containsKey(reg)) return; // Discarded.
                 }
                 long currentTime = System.currentTimeMillis();
                 long delta = 0;
                 boolean resubmit = false;
                 int waiting = 0;
                 synchronized (eReg){
                     if (eReg.discarded()) return;
                     if (eReg.nonContiguousEvent(theEvent.getSequenceNumber()) 
                         && (currentTime - timestamp < 500)) // 1/2 seconds.
                     {
                         resubmit = true;
                         eReg.notifyAll();
                     } else {
                         while (eReg.eventsSuspended()){ // We're next.
                             try {
                                 waiting ++;
                                 eReg.wait(100L);
                                 waiting --;
                                 if (eReg.discarded()) return;
                                 // Give priority to contiguous events.
                                 if (waiting > 0 && eReg.nonContiguousEvent(
                                                     theEvent.getSequenceNumber()))
                                 {
                                     eReg.notifyAll();
                                     resubmit = true;
                                     break;
                                 }
                             } catch (InterruptedException ex) {
                                 Thread.currentThread().interrupt();
                                 return;
                             }
                         }
                         if (!resubmit){
                             eReg.suspendEvents();
                             delta = eReg.updateSeqNo(theEvent.getSequenceNumber());
                         }
                     }
                 }
                 if (resubmit){ // To avoid churn and free up thread.
                     try {
                         cache.incomingEventExecutor.submit(this);
                         Thread.sleep(50L);
                     } catch (InterruptedException ex) {
                         Thread.currentThread().interrupt();
                         return;
                     }
                     return;
                 }
                 try {
                     cache.notifyServiceMap(delta,
                         theEvent.getServiceID(),
                         item,
                         theEvent.getTransition(),
                         reg);
                 } finally {
                     synchronized (eReg){
                         eReg.releaseEvents();
                         eReg.notifyAll();
                     }
                 }
             } catch (RuntimeException e){
                 if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER))
                     ServiceDiscoveryManager.log(Level.FINER, "HandleServiceEventTask threw a RuntimeException", e);
             } finally {
                 if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER))
                     ServiceDiscoveryManager.log(Level.FINER, "HandleServiceEventTask completed");
             }
         }
 
         @Override
         public int compareTo(Object o) {
             if (!(o instanceof HandleServiceEventTask)) return 0;
             HandleServiceEventTask that = (HandleServiceEventTask) o;
             long dif = this.theEvent.getSequenceNumber() - that.theEvent.getSequenceNumber();
             if (dif == 0) return 0;
             if (dif < 0) return -1; // Which means that.theEvent is larger than this.theEvent
             return 1;
         }
     }
     
     /**
      * Called by the HandleServiceEventTask. Checks the event sequence
      * number and, based on whether or not a "gap" is found in in the event
      * sequence, performs lookup (if a gap was found) or processes the event if
      * no gap was found.
      *
      * Recall that the Event specification states that if the sequence numbers
      * of two successive events differ by only 1, then one can be assured that
      * no events were missed. On the other hand, if the difference is greater
      * than 1 (the sequence contains a "gap"), then one or more events may -- or
      * may not -- have been missed. Thus, if a gap is found in the events,
      * although it's possible that no events were missed, this method takes the
      * conservative approach by assuming events were missed. When this method
      * determines that an event may have been missed, it requests a current
      * "snapshot" of the given ServiceRegistrar's state by performing lookup.
      * Since this method can safely assume that no events have been missed if it
      * finds no gaps in the event sequence, it can safely process the event
      * maintaining equivalent state to the registrar, that is finding and
      * filtering new services and filtering updated or changed existing
      * services.
      *
      * Note that when a lookup service is discovered, this utility registers
      * with that lookup service's event mechanism for service events related to
      * the services of interest. Upon registering with the event mechanism, a
      * data structure (of type EventReg) containing information about that
      * registration is placed in a Map for later processing when events do
      * arrive. If the timing is right, it is possible that a service event may
      * arrive between the time the registration is made and the time the
      * EventReg is stored in the map. Thus, this method may find that the
      * eventRegMap does not contain an element corresponding to the event this
      * method is currently processing. In that case, this method will do
      * nothing. It will simply return so that the service referenced in the
      * event can be discovered using the snapshot returned by the lookup method
      * that is ultimately c by the RegisterListenerTask (whose listener
      * registration caused this method to be invoked in the first place).
      */
     private void notifyServiceMap(long delta,
                                   ServiceID sid,
                                   ServiceItem item,
                                   int transition,
                                   ProxyReg reg) 
     {
 	/* Look for any gaps in the event sequence. */
         if (delta == 1) {
             //no gap, handle current event
             if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE)){
                 ServiceDiscoveryManager.log(
                     Level.FINE, 
                     "No gap, handle current ServiceEvent, ServiceID: {0} transition: {1}",
                     new Object[]{sid, transition}
                 );
             }
             /* Fix for Bug ID 4378751. The conditions described by that
              * bug involve a ServiceItem (corresponding to a previously
              * discovered service ID) having a null service field. A
              * null service field is due to an UnmarshalException caused
              * by a SecurityException that results from the lack of a
              * connection permission for the lookup service codebase
              * to the service's remote codebase. Skip this ServiceItem,
              * otherwise an un-expected serviceRemoved event will result
              * because the primary if-block will be unintentionally
              * entered due to the null service field in the ServiceItem.
              */
             if ((item != null) && (item.service == null)) {
                 return;
             }
             /* Handle the event by the transition type, and by whether
              * the associated ServiceItem is an old, previously discovered
              * item, or a newly discovered item.
              */
             if (transition == ServiceRegistrar.TRANSITION_MATCH_NOMATCH) 
             {
                 handleMatchNoMatch(reg.getProxy(), sid);
             } else if (transition == ServiceRegistrar.TRANSITION_NOMATCH_MATCH 
                     || transition == ServiceRegistrar.TRANSITION_MATCH_MATCH) 
             {
                 newOldService(reg, sid, item, transition == ServiceRegistrar.TRANSITION_MATCH_MATCH);
             } //endif(transition)
             return;
         } 
         if (delta == 0) {// Repeat event, ignore.
             if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE)){
                 ServiceDiscoveryManager.log(
                     Level.FINE, 
                     "Repeat ServiceEvent, ignore, ServiceID: {0} transition: {1}",
                     new Object[]{sid, transition}
                 );
             }
             return;
         } 
         if (delta < 0) { // Old event, ignore.
             if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE)){
                 ServiceDiscoveryManager.log(
                     Level.FINE, 
                     "Old ServiceEvent, ignore, ServiceID: {0} transition: {1}",
                     new Object[]{sid, transition}
                 );
             }
             return;
         } 
         //gap in event sequence, request snapshot
         if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE)){
             ServiceDiscoveryManager.log(
                 Level.FINE, 
                 "Gap in ServiceEvent sequence, performing lookup, ServiceID: {0} transition: {1}",
                 new Object[]{sid, transition}
             );
         }
         lookup(reg);
     }
     /**
      * Requests a "snapshot" of the given registrar's state.
      * 
      * Lookup is mutually exclusive with events.
      */
     private void lookup(ProxyReg reg) {
         ServiceRegistrar proxy = reg.getProxy();
         ServiceItem[] items;
         /* For the given lookup, get all services matching the tmpl */
         try {
             if (useInsecureLookup){
                 ServiceMatches matches = proxy.lookup(tmpl, Integer.MAX_VALUE);
                 items = matches.items;
             } else {
                 Object [] matches = ((SafeServiceRegistrar) proxy).lookUp(
 			tmpl, Integer.MAX_VALUE);
                 items = processBootStrapProxys(matches);
             }
         } catch (Exception e) {
             // ReRegisterGoodEquals test failure becomes more predictable
             // when fail is only called if decrement is successful.
             sdm.fail(e, proxy, this.getClass().getName(), "run", "Exception occurred during call to lookup", bCacheTerminated);
             return;
         }
         if (items == null) {
             throw new AssertionError("spec violation in queried lookup service: ServicesMatches instance returned by call to lookup() method contains null 'items' field");
         }
         /* Should we handle new and old items before cleaning up orphans? */
         /* 1. Cleanup "orphaned" itemReg's. */
         Iterator<Map.Entry<ServiceID, ServiceItemReg>> iter = serviceIdMap.entrySet().iterator();
         while (iter.hasNext()) {
             Map.Entry<ServiceID, ServiceItemReg> e = iter.next();
             ServiceID srvcID = e.getKey();
             ServiceItem itemInSnapshot = findItem(srvcID, items);
             if (itemInSnapshot != null) continue; //not an orphan
             if (Thread.currentThread().isInterrupted()) return; // skip
             DissociateLusCleanUpOrphan dlcl = new DissociateLusCleanUpOrphan(this, reg.getProxy());
             serviceIdMap.computeIfPresent(srvcID, dlcl);
             if (dlcl.itemRegProxy != null) {
                 itemMatchMatchChange(srvcID, dlcl.itmReg, dlcl.itemRegProxy, dlcl.newItem, false);
             } else if (dlcl.notify && dlcl.filteredItem != null) {
                 removeServiceNotify(dlcl.filteredItem);
             }
         } //end loop
         /* 2. Handle "new" and "old" items from the given lookup */
         for (int i = 0, l = items.length; i < l; i++) {
             /* Skip items with null service field (Bug 4378751) */
             if (items[i].service == null) {
                 continue;
             }
             if (items[i].serviceID == null  && !useInsecureLookup){
                 if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE))
                     ServiceDiscoveryManager.log(Level.FINE, 
                         "ServiceItem contained null serviceID field, attempting to retrieve again");
                 try {
                     ServiceID id = ((ServiceIDAccessor)items[i].service).serviceID();
                     // item hasn't been published (shared) yet, safe to mutate.
                     if (id == null) continue;
                     items[i].serviceID = id;
                 } catch ( IOException e){
                     if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE))
                         ServiceDiscoveryManager.log(Level.FINE, 
                             "ServiceItem contained null serviceID field, attempt to retrieve again failed, ignoring",
                             e);
                     continue;
                 }
             }
             newOldService(reg, items[i].serviceID, items[i], false);
         } //end loop
     }
 
     /**
      * Method used to process the service state ("snapshot"), matching this
      * cache's template, retrieved from the given lookup service.
      *
      * After retrieving the snapshot S, the lookup method calls this method for
      * each service referenced in S. This method determines if the given service
      * is an already-discovered service (is currently in this cache's
      * serviceIdMap), or is a new service. This method handles the service
      * differently, depending on whether the service is a new or old.
      *
      * a. if the item is old, then this method will: - compare the given item
      * from the snapshot to the UN-filtered item in given itemReg if(same
      * version but attributes have changed) send changed event else if( version
      * has changed ) send removed event followed by added event else do nothing
      * - apply the filter to the given item if(filter fails) send removed event
      * else if(filter passes) set the filtered item in the itemReg in the map
      * else if (filter is indefinite) discard item send removed event queue
      * another filter attempt for later b. if the given item is newly
      * discovered, then this task will: - create a new ServiceItemReg containing
      * the given item - place the new itemReg in the serviceIdMap - apply the
      * filter to the given item if(filter fails) remove the item from the map
      * but send NO removed event else if(filter passes) send added event for the
      * FILTERED item else if (filter is indefinite) discard item queue another
      * filter attempt for later but send NO removed event
      */
     
     private void newOldService(ProxyReg reg, ServiceID id, ServiceItem item, boolean matchMatchEvent) {
         if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE)){
             ServiceDiscoveryManager.log(
                 Level.FINE, 
                 "newOldService called, ServiceItem: {0}",
                 new Object[]{item}
             );
         }
         try {
             boolean previouslyDiscovered = false;
             ServiceItemReg itemReg;
             itemReg = serviceIdMap.get(id);
             if (itemReg == null) {
                 if (!eventRegMap.containsKey(reg)) {
                     /* reg must have been discarded, simply return */
                     if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER))
                         ServiceDiscoveryManager.log(
                             Level.FINER, 
                             "eventRegMap doesn't contain ProxyReg, returning, ServiceItem: {0}",
                             new Object[]{item}
                         );
                     return;
                 } //endif
                 // else
                 itemReg = new ServiceItemReg(reg.getProxy(), item);
                 ServiceItemReg existed = serviceIdMap.putIfAbsent(id, itemReg);
                 if (existed != null) {
                     itemReg = existed;
                     if (itemReg.isDiscarded()) {
                         if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER)){
                             ServiceDiscoveryManager.log(
                                 Level.FINER, 
                                 "newOldService, discarded returning, ServiceItem: {0}",
                                 new Object[]{item}
                             );
                         }
                         return;
                     }
                     if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER)){
                         ServiceDiscoveryManager.log(
                             Level.FINER, 
                             "newOldService, previously discovered, ServiceItem: {0}",
                             new Object[]{item}
                         );
                     }
                     previouslyDiscovered = true;
                 }
             } else if (itemReg.isDiscarded()) {
                 if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER)){
                     ServiceDiscoveryManager.log(
                         Level.FINER, 
                         "newOldService, discarded returning, ServiceItem: {0}",
                         new Object[]{item}
                     );
                 }
                 return;
             } else {
                  if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER)){
                     ServiceDiscoveryManager.log(
                         Level.FINER, 
                         "newOldService, previously discovered, ServiceItem: {0}",
                         new Object[]{item}
                     );
                 }
                 previouslyDiscovered = true;
             }
             if (previouslyDiscovered) {
                 //a. old, previously discovered item
                 itemMatchMatchChange(id, itemReg, reg.getProxy(), item, matchMatchEvent);
             } else {
                 //b. newly discovered item
                 ServiceItem newFilteredItem
                         = filterMaybeDiscard(id, itemReg, item, false);
 
                 if (newFilteredItem != null) {
                     addServiceNotify(newFilteredItem);
                 } //endif
             } //endif
         } catch (RuntimeException e) {
             if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE))
                 ServiceDiscoveryManager.log(Level.FINE, "Runtime exception thrown in newOldService call", e);
         } finally {
             if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER))
                 ServiceDiscoveryManager.log(Level.FINER, 
                         "newOldService call complete, ServiceItem: {0}",
                         new Object[]{item});
         }
     }
 
     /**
      * Returns the element in the given items array having the given ServiceID.
      */
     private ServiceItem findItem(ServiceID sid, ServiceItem[] items) {
 	if (items != null) {
 	    for (int i = 0, length = items.length; i < length; i++) {
 		if (sid.equals(items[i].serviceID)) {
 		    return items[i];
 		}
 	    } //end loop
 	} //endif
 	return null;
     } //end LookupCacheImpl.findItem
 
     /**
      * With respect to a given service (referenced by the parameter newItem), if
      * either an event has been received from the given lookup service
      * (referenced by the proxy parameter), or a snapshot of the given lookup
      * service's state has been retrieved, this method determines whether the
      * service's attributes have changed, or whether a new version of the
      * service has been registered. After the appropriate determination has been
      * made, this method applies the filter associated with the current cache
      * and sends the appropriate local ServiceDiscoveryEvent(s).
      *
      * This method is called under the following conditions: - when a new lookup
      * service is discovered, this method will be called for each previously
      * discovered service - when a gap in the events from a previously
      * discovered lookup service is discovered, this method will be called for
      * each previously discovered service - when a MATCH_MATCH event is
      * received, this method will be called for each previously discovered
      * service - when a NOMATCH_MATCH event is received, this method will be
      * called for each previously discovered service Note that this method is
      * never called when a MATCH_NOMATCH event is received; such an event is
      * always handled by the handleMatchNoMatch method.
      *
      * When this method is called, it may send one of the following events or
      * combination of events: - a service changed event - a service removed
      * event followed by a service added event - a service removed event
      *
      * A service removed event is sent when the service either fails the filter,
      * or the filter produces an indefinite result; in which case, the service
      * is also discarded.
      *
      * A service changed event is sent when the service passes the filter, and
      * it is determined that the service's attributes have changed. In this
      * case, the old and new service proxies are treated as the same if one of
      * the following conditions is met: - this method was called because of the
      * receipt of a MATCH_MATCH event - the old and new service proxies are
      * byte-wise fully equal (Note that the lookup service specification
      * guarantees that the proxies are the same when a MATCH_MATCH event is
      * received.)
      *
      * A service removed event followed by a service added event is sent when
      * the service passes the filter, and the conditions for which a service
      * changed event would be considered are not met; that is, this method was
      * not called because of the receipt of a MATCH_MATCH event; or the old and
      * new service proxies are not byte-wise fully equal.
      *
      * The if-else-block contained in this method implements the logic just
      * described. The parameter matchMatchEvent reflects the pertinent event
      * state that causes this method to be called. That is, either a MATCH_MATCH
      * event was received, or it wasn't, (and if it wasn't, then a full
      * byte-wise comparison is performed to determine whether the proxies are
      * still the same).
      *
      * To understand when the 'else' part of the if-else-block is executed,
      * consider the following conditions: - there is more than one lookup
      * service with which the service registers (ex. LUS-0 and LUS-1) - after
      * the service registers with LUS-0, a NOMATCH_MATCH event is received and
      * handled (so the service is now known to the cache) - before the service
      * registers with LUS-1, the service is replaced with a new version - the
      * NOMATCH_MATCH event resulting from the service's registration with LUS-1
      * is received BEFORE receiving the MATCH_NOMATCH/NOMATCH_MATCH event
      * sequence that will ultimately result from the re-registration of that new
      * version with LUS-0 When the above conditions occur, the NOMATCH_MATCH
      * event that resulted from the service's registration with LUS-1 will cause
      * this method to be invoked and the proxies to be fully compared (because
      * the event was not a MATCH_MATCH event); and since the old service proxy
      * and the new service proxy will not be fully equal, the else part of the
      * if-else-block will be executed.
      *
      * This method applies the filter only after the above comparisons and
      * determinations have been completed.
      */
     private void itemMatchMatchChange(ServiceID srvcID, ServiceItemReg itemReg, ServiceRegistrar proxy, ServiceItem newItem, boolean matchMatchEvent) {
 	/* Save the pre-event state. Update the post-event state after
 	 * applying the filter.
 	 */
         if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE)){
             ServiceDiscoveryManager.log(
                 Level.FINE, 
                 "itemMatchMatchChange called, ServiceID: {0} ",
                 new Object[]{srvcID}
             );
         }
         PreEventState pev = new PreEventState(proxy,itemReg,newItem,matchMatchEvent);
         ServiceItem newFilteredItem;
         serviceIdMap.computeIfPresent(srvcID, pev);
         if (pev.needToFilter){
             /* Now apply the filter, and send events if appropriate */
             newFilteredItem = filterMaybeDiscard(srvcID, itemReg, newItem, pev.notDiscarded);
             if (newFilteredItem != null) {
                 /* Passed the filter, okay to send event(s). */
                 if (pev.attrsChanged && pev.oldFilteredItem != null) {
                     changeServiceNotify(newFilteredItem, pev.oldFilteredItem);
                 }
                 if (pev.versionChanged) {
                     if (pev.notDiscarded && pev.oldFilteredItem != null) {
                         removeServiceNotify(pev.oldFilteredItem);
                     } //endif
                     addServiceNotify(newFilteredItem);
                 } //endif
             } //endif
         }
     }
     
     private static class PreEventState implements BiFunction<ServiceID, ServiceItemReg, ServiceItemReg> {
         
         private final ServiceRegistrar proxy;
         private final ServiceItemReg reg;
         private final ServiceItem newItem;
         private final boolean matchMatchEvent;
         ServiceItem oldItem;
 	ServiceItem oldFilteredItem;
 	boolean notDiscarded;
 	boolean attrsChanged = false;
 	boolean versionChanged = false;
         boolean needToFilter = false;
 	ServiceRegistrar proxyChanged = null;
 
         PreEventState(ServiceRegistrar proxy, ServiceItemReg reg, ServiceItem newItem, boolean matchMatchEvent){
             this.proxy = proxy;
             this.reg = reg;
             this.newItem = newItem;
             this.matchMatchEvent = matchMatchEvent;
         }
         
         @Override
         public ServiceItemReg apply(ServiceID t, ServiceItemReg itemReg) {
             boolean loggable = ServiceDiscoveryManager.logger.isLoggable(Level.FINER);
             if (! reg.equals(itemReg)) {
                 if (loggable)
                     ServiceDiscoveryManager.log(
                         Level.FINER, 
                         "PreEventState.apply, ServiceItemReg's not equal, returning. ServiceID: {0}",
                         new Object[]{t}
                     );
                 return itemReg;
             }
             notDiscarded = !itemReg.isDiscarded();
 	    oldItem = itemReg.getItem();
 	    oldFilteredItem = itemReg.getFilteredItem();
 	    if (itemReg.proxyNotUsedToTrackChange(proxy, newItem)) {
 		// not tracking
                 if (loggable)
                     ServiceDiscoveryManager.log(
                         Level.FINER, 
                         "PreEventState.apply, proxyNotUsedToTrackChange. ServiceID: {0}",
                         new Object[]{t}
                     );
 		if (matchMatchEvent) {
                     if (loggable)
                         ServiceDiscoveryManager.log(
                             Level.FINER, 
                             "PreEventState.apply, matchMatchEvent true returning. ServiceID: {0}",
                             new Object[]{t}
                         );
 		    return itemReg;
 		}
 		if (notDiscarded) {
                     if (loggable)
                         ServiceDiscoveryManager.log(
                             Level.FINER, 
                             "PreEventState.apply, notifyServiceRemoved true returning. ServiceID: {0}",
                             new Object[]{t}
                         );
 		    return itemReg;
 		}
                 if (loggable)
                     ServiceDiscoveryManager.log(
                         Level.FINER, 
                         "PreEventState.apply, proxyChanged = proxy. ServiceID: {0}",
                         new Object[]{t}
                     );
 		proxyChanged = proxy; // start tracking instead
 	    } //endif
 	    if (!notDiscarded) {
                 if (loggable)
                     ServiceDiscoveryManager.log(
                         Level.FINER, 
                         "PreEventState.apply, !notifyServiceRemoved, replacProxyUsedToTrackChange ServiceID: {0}",
                         new Object[]{t}
                     );
 		itemReg.replaceProxyUsedToTrackChange(proxyChanged, newItem);
 		itemReg.setFilteredItem(null);
 		itemReg.discard();
 		if (matchMatchEvent) {
 		    return itemReg;
 		}
 	    } //endif
 	    /* For an explanation of the logic of the following if-else-block,
 	     * refer to the method description above.
 	     */
 	    if (matchMatchEvent || sameVersion(newItem, oldItem)) {
 		if (!notDiscarded) {
                     if (loggable)
                         ServiceDiscoveryManager.log(
                             Level.FINER, 
                             "PreEventState.apply, matchMatchEvent || sameVersion && !notifyServiceRemoved return itemReg, no need to filter ServiceID: {0}",
                             new Object[]{t}
                         );
 		    return itemReg; 
 		}
 		/* Same version, determine if the attributes have changed.
 		 * But first, replace the new service proxy with the old
 		 * service proxy so the client always uses the old proxy
 		 * (at least, until the version is changed).
 		 */
 		//                newItem.service = oldItem.service; //Data race
 		/* Now compare attributes */
 		attrsChanged = !LookupAttributes.equal(newItem.attributeSets, oldItem.attributeSets);
 		if (!attrsChanged) {
                     if (loggable)
                         ServiceDiscoveryManager.log(
                             Level.FINER, 
                             "PreEventState.apply, matchMatchEvent || sameVersion && !attrsChanged return itemReg, no need to filter ServiceID: {0}",
                             new Object[]{t}
                         );
 		    return itemReg; //no change, no need to filter
 		}
 	    } else {
 		//(!matchMatchEvent && !same version) ==> re-registration
                 if (loggable)
                     ServiceDiscoveryManager.log(
                         Level.FINER, 
                         "PreEventState.apply, !matchMatchEvent &&! sameVersion ==> re-registrattion, versionChanged. ServiceID: {0}",
                         new Object[]{t}
                     );
 		versionChanged = true;
 	    } //endif
             if (loggable)
                 ServiceDiscoveryManager.log(
                     Level.FINER, 
                     "PreEventState.apply, need to filter true. ServiceID: {0}",
                     new Object[]{t}
                 );
             needToFilter = true;
             return itemReg;
         }
         
     }
 
     /**
      * Convenience method that performs a byte-wise comparison, including
      * codebases, of the services referenced by the given service items, and
      * returns the result. Since instances of RemoteMethodControl may
      * have different MethodConstraints and these affect marshaled bytes, we
      * ensure constraints are identical.
      * 
      * If the services cannot be compared, it is assumed
      * that the versions are not the same, and <code>false</code> is returned.
      */
     private static boolean sameVersion(ServiceItem item0, ServiceItem item1) {
 	boolean fullyEqual = false;
 	try {
 	    Object service0 = item0.service;
 	    Object service1 = item1.service;
 	    if (service0 instanceof RemoteMethodControl 
 		    && service1 instanceof RemoteMethodControl)
 	    {
 		MethodConstraints constraints = ((RemoteMethodControl)service0).getConstraints();
 		service1 = ((RemoteMethodControl) service1).setConstraints(constraints);
 	    }
 	    MarshalledInstance mi0 = new MarshalledInstance(service0);
 	    MarshalledInstance mi1 = new MarshalledInstance(service1);
 	    fullyEqual = mi0.fullyEquals(mi1);
 	} catch (IOException e) {
             if (ServiceDiscoveryManager.logger.isLoggable(Level.INFO)){
                 ServiceDiscoveryManager.log(
                     Level.INFO, 
                     "failure marshalling old and new services for equality check",
                     e
                 );
             }
 	}
 	return fullyEqual;
     } //end LookupCacheImpl.sameVersion
 
     /**
      * Gets the remaining time left on the current cache's "lifespan".
      */
     public long getLeaseDuration() {
 	if (leaseDuration == Long.MAX_VALUE) {
 	    return Long.MAX_VALUE;
 	}
 	return leaseDuration + startTime - System.currentTimeMillis();
     } //end LookupCacheImpl.getLeaseDuration
 
     /**
      * Sends a notification to all listeners when a ServiceItem has been added.
      */
     private void addServiceNotify(ServiceItem item) {
 	serviceNotifyDo(null, item, ITEM_ADDED);
     } //end LookupCacheImpl.addServiceNotify
 
     /**
      * Sends a notification to the given listener when a ServiceItem has been
      * added.
      */
     private void addServiceNotify(ServiceItem item, ServiceDiscoveryListener srvcListener) {
 	eventNotificationExecutor.execute(new ServiceNotifyDo(null, item, ITEM_ADDED, srvcListener, this));
 	if (ServiceDiscoveryManager.logger.isLoggable(Level.FINEST)) {
 	    try {
 		throw new Exception("Back Trace");
 	    } catch (Exception ex) {
 		ex.fillInStackTrace();
                 ServiceDiscoveryManager.log(
                     Level.FINEST, 
                     "Log back trace",
                     ex
                 );
 	    }
 	}
     } //end LookupCacheImpl.addServiceNotify
 
     /**
      * Sends a notification when a ServiceItem has been removed.
      */
     private void removeServiceNotify(ServiceItem item) {
 	serviceNotifyDo(item, null, ITEM_REMOVED);
     } //end LookupCacheImpl.removeServiceNotify
 
     /**
      * Sends a notification when a ServiceItem has been changed, but still
      * matches.
      */
     private void changeServiceNotify(ServiceItem newItem, ServiceItem oldItem) {
 	serviceNotifyDo(oldItem, newItem, ITEM_CHANGED);
     } //end LookupCacheImpl.changeServiceNotify
 
     /**
      * Common code for performing service notification to all listeners.
      */
     private void serviceNotifyDo(ServiceItem oldItem, ServiceItem item, int action) {
         sItemListenersRead.lock();
         try {
 	    if (sItemListeners.isEmpty()) {
 		return;
 	    }
 	    Iterator<ServiceDiscoveryListener> iter = sItemListeners.iterator();
 	    while (iter.hasNext()) {
 		ServiceDiscoveryListener sl = iter.next();
 		eventNotificationExecutor.execute(new ServiceNotifyDo(oldItem, item, action, sl, this));
 		if (ServiceDiscoveryManager.logger.isLoggable(Level.FINEST)) {
 		    try {
 			throw new Exception("Back Trace");
 		    } catch (Exception ex) {
 			ex.fillInStackTrace();
                         ServiceDiscoveryManager.log(
                             Level.FINEST, 
                             "Log back trace",
                             ex
                         );
 		    }
 		}
 	    } //end loop
 	} finally {
             sItemListenersRead.unlock();
         }
     } //end LookupCacheImpl.serviceNotifyDo
 
     /**
      * Common code for performing service notification to one listener in an
      * executor task thread.
      */
     private static class ServiceNotifyDo implements Runnable {
 
 	final ServiceItem oldItem;
 	final ServiceItem item;
 	final int action;
 	final ServiceDiscoveryListener sl;
 	final Object lookupCache;
 
 	ServiceNotifyDo(ServiceItem oldItem, ServiceItem item, int action, ServiceDiscoveryListener sl, LookupCache lookupCache) {
 	    this.oldItem = oldItem;
 	    this.item = item;
 	    this.action = action;
 	    this.sl = sl;
 	    this.lookupCache = lookupCache;
 	}
 	
 	@Override
 	public void run() {
 	    ServiceDiscoveryEvent event;
 	    try {
 		event = new ServiceDiscoveryEvent(lookupCache, oldItem, item);
 	    } catch (NullPointerException e) {
 		boolean lookupCacheNull = lookupCache == null;
 		boolean oldItemNull = oldItem == null;
 		boolean itemNull = item == null;
                 if (ServiceDiscoveryManager.logger.isLoggable(Level.INFO))
                     ServiceDiscoveryManager.log(
                         Level.INFO, 
                         "ServiceDiscoveryEvent constructor threw NullPointerException, lookupCache null? {0} oldItem null? {1} item null? {2}",
                         new Object[]{lookupCacheNull, oldItemNull, itemNull}
                     );
 		return;
 	    }
 	    switch (action) {
 		case ITEM_ADDED:
 		    sl.serviceAdded(event);
 		    break;
 		case ITEM_REMOVED:
 		    sl.serviceRemoved(event);
 		    break;
 		case ITEM_CHANGED:
 		    sl.serviceChanged(event);
 		    break;
 		default:
 		    throw new IllegalArgumentException("case must be one of the following: ITEM_ADDED, ITEM_REMOVED or ITEM_CHANGED");
 	    } //end switch(action)
 	}
     }
 
     void initCache() throws RemoteException {
 	/* Get the exporter for the remote event listener from the
 	 * configuration.
 	 */
 	try {
 	    Exporter defaultExporter = 
                 new BasicJeriExporter(TcpServerEndpoint.getInstance(0),
                     new AtomicILFactory(null, null, LookupCacheImpl.class.getClassLoader()),
 		    false,
 		    false
                 );
 	    lookupListenerExporter = 
                 sdm.thisConfig.getEntry(
                     ServiceDiscoveryManager.COMPONENT_NAME,
                     "eventListenerExporter",
                     Exporter.class, 
                     defaultExporter
                 );
 	} catch (ConfigurationException e) {
 	    // exception, use default
 	    ExportException e1 = new ExportException("Configuration exception while " + "retrieving exporter for " + "cache's remote event listener", e);
 	    throw e1;
 	}
 	/*
 	 * Executor dedicated to event notification.
 	 */
 	try {
 	    eventNotificationExecutor = 
                 sdm.thisConfig.getEntry(
                     ServiceDiscoveryManager.COMPONENT_NAME,
                     "eventNotificationExecutor",
                     ExecutorService.class
                 );
 	} catch (ConfigurationException e) {
 	    /* use default */
 	    eventNotificationExecutor = 
                     new ThreadPoolExecutor(1, 1, 15L, TimeUnit.SECONDS, 
                             new LinkedBlockingQueue<Runnable>(),
                             new NamedThreadFactory("SDM event notifier: " + toString(), false),
                             new ThreadPoolExecutor.CallerRunsPolicy());
 	}
 	/* Get a general-purpose task manager for this cache from the
 	 * configuration. This task manager will be used to manage the
 	 * various tasks executed by this instance of the lookup cache.
 	 */
 	try {
 	    cacheTaskMgr = sdm.thisConfig.getEntry(
                     ServiceDiscoveryManager.COMPONENT_NAME,
                     "cacheExecutorService",
                     ExecutorService.class
             );
 	} catch (ConfigurationException e) {
 	    /* use default */
 	    cacheTaskMgr = new ThreadPoolExecutor(3, 3, 15L, TimeUnit.SECONDS,
                     new LinkedBlockingQueue<Runnable>(),
                     new NamedThreadFactory("SDM lookup cache: " + toString(), false),
                     new ThreadPoolExecutor.CallerRunsPolicy()
             );
 	}
 	cacheTaskMgr = new ExtensibleExecutorService(cacheTaskMgr, new ExtensibleExecutorService.RunnableFutureFactory() {
 	    @Override
 	    public <T> RunnableFuture<T> newTaskFor(Runnable r, T value) {
 		if (r instanceof ObservableFutureTask) {
 		    return (RunnableFuture<T>) r;
 		}
 		return new CacheTaskWrapper<T>(r, value);
 	    }
 
 	    @Override
 	    public <T> RunnableFuture<T> newTaskFor(Callable<T> c) {
 		if (c instanceof ObservableFutureTask) {
 		    return (RunnableFuture<T>) c;
 		}
 		return new CacheTaskWrapper<T>(c);
 	    }
 	});
 	cacheTaskDepMgr = new CacheTaskDependencyManager(cacheTaskMgr);
 	/* Get a special-purpose task manager for this cache from the
 	 * configuration. That Executor will be used to manage the
 	 * various instances of the special-purpose task, executed by
 	 * this instance of the lookup cache, that waits on verification
 	 * events after a previousy discovered service has been discarded.
 	 */
 	try {
 	    serviceDiscardTimerTaskMgr = 
                 sdm.thisConfig.getEntry(
                     ServiceDiscoveryManager.COMPONENT_NAME,
                     "discardExecutorService",
                     ScheduledExecutorService.class
                 );
 	} catch (ConfigurationException e) {
 	    /* use default */
 	    serviceDiscardTimerTaskMgr = 
                 new ScheduledThreadPoolExecutor(
                     4,
                     new NamedThreadFactory("SDM discard timer: " + toString(), false)
                 );
 	}
         /* ExecutorService for processing incoming events.
          * 
          */
         try {
             incomingEventExecutor = sdm.thisConfig.getEntry(
                 ServiceDiscoveryManager.COMPONENT_NAME, 
                 "ServiceEventExecutorService", 
                 ExecutorService.class
             );
         } catch (ConfigurationException e){
             incomingEventExecutor = 
                 new ThreadPoolExecutor(1, 1, 15L, TimeUnit.SECONDS,
                     new PriorityBlockingQueue(256),
                     new NamedThreadFactory("SDM ServiceEvent: " + toString(), false),
                     new ThreadPoolExecutor.DiscardOldestPolicy()
                 );
         }
         incomingEventExecutor = new ExtensibleExecutorService(incomingEventExecutor,
             new ExtensibleExecutorService.RunnableFutureFactory()
             {
 
                 @Override
                 public <T> RunnableFuture<T> newTaskFor(Runnable r, T value) {
                     return new ComparableFutureTask<T>(r,value);
                 }
 
                 @Override
                 public <T> RunnableFuture<T> newTaskFor(Callable<T> c) {
                     return new ComparableFutureTask<T>(c);
                 }
                 
             }
         );
 	// Moved here from constructor to avoid publishing this reference
 	lookupListenerProxy = lookupListener.export();
         sdm.proxyRegSetRead.lock();
         try {
             Iterator<ProxyReg> it = sdm.proxyRegSet.iterator();
             while (it.hasNext()) {
                 addProxyReg(it.next());
             }
         } finally {
             sdm.proxyRegSetRead.unlock();
         }
             
     } //end LookupCacheImpl.initCache
     
     /**
      * This enables a BlockingPriorityQueue to arrange tasks in an
      * ExecutorService.
      * 
      * @param <V> 
      */
     private static class ComparableFutureTask<V> extends FutureTask<V> 
                                 implements Comparable<ComparableFutureTask> 
     {
         
         private final Object task;
 
         public ComparableFutureTask(Runnable runnable, V result) {
             super(runnable, result);
             task = runnable;
         }
         
         public ComparableFutureTask(Callable<V> callable){
             super(callable);
             task = callable;
         }
 
         @Override
         public int compareTo(ComparableFutureTask o) {
             if (task instanceof Comparable && o.task instanceof Comparable){
                 return ((Comparable)task).compareTo(o.task);
             }
             if (ServiceDiscoveryManager.logger.isLoggable(Level.FINEST))
                 ServiceDiscoveryManager.log(
                     Level.FINEST, 
                     "task not instanceof Comparable {0}",
                     new Object [] {task.getClass().getCanonicalName()}
                 );
             return 0;
         }
 
 	@Override
 	public int hashCode() {
 	    int hash = 3;
 	    hash = 89 * hash + (this.task != null ? this.task.hashCode() : 0);
 	    return hash;
 	}
 	
 	@Override
 	public boolean equals(Object o){
 	    if (!(o instanceof ComparableFutureTask)) return false;
 	    return this.task.equals(((ComparableFutureTask)o).task);
 	}
 
     }
 
     /**
      * Applies the first-stage <code>filter</code> associated with the current
      * instance of <code>LookupCache</code> to the given <code>item</code> and
      * returns the resulting filtered item if the <code>filter</code> is passed
      * (or is <code>null</code>); otherwise, returns <code>null</code> and sends
      * a service removed event if the <code>sendEvent</code> parameter is
      * <code>true</code>.
      * <p>
      * This method is called only when the <code>item</code> to be filtered
      * corresponds to an element that currently exists in the
      * <code>serviceIdMap</code>.
      * <p>
      * As described in the <code>ServiceItemFilter</code> specification, when
      * the <code>item</code> passes the <code>filter</code>, the
      * <code>service</code> field of the <code>item</code> is replaced with the
      * filtered form of the object previously contained in that field. In this
      * case, the <code>filteredItem</code> field of the corresponding
      * <code>ServiceItemReg</code> element of the <code>serviceIdMap</code> is
      * set to this new filtered item.
      * <p>
      * If the <code>filter</code> returns <code>indefinite</code>, then that
      * specification states that the <code>service</code> field is replaced with
      * <code>null</code>. In this case, the <code>filteredItem</code> field of
      * the corresponding <code>ServiceItemReg</code> element of the
      * <code>serviceIdMap</code> is left unchanged.
      */
     private ServiceItem filterMaybeDiscard(ServiceID srvcID, ServiceItemReg itemReg, ServiceItem item, boolean sendEvent) {
         if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE))
             ServiceDiscoveryManager.log(
                 Level.FINE,
                 "filterMaybeDiscard called, ServiceID: {0}", 
                 new Object [] {srvcID}
             );
 	if ((item == null) || (item.service == null)) {
             if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER))
                 ServiceDiscoveryManager.log(
                     Level.FINER,
                     "filterMaybeDiscard, item or service was null, returning null, ServiceID: {0}", 
                     new Object []{srvcID}
                 );
 	    return null;
 	}
         boolean addFilteredItemToMap = false;
         /* Make a copy to filter because the filter may modify it. */
         ServiceItem filteredItem = item.clone();
         boolean discardRetryLater = false;
         boolean pass = false;
 	if (filter == null) {
             pass = true;
 	    if (useInsecureLookup){
                 addFilteredItemToMap = true;
 	    } else {
 		try {
 		    filteredItem.service =
 			    ((ServiceProxyAccessor) filteredItem.service).getServiceProxy();
                     addFilteredItemToMap = true;
 		} catch (RemoteException ex) {
                     if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE))
                         ServiceDiscoveryManager.log(Level.FINE,
 			    "Exception thrown while trying to download service proxy",
 			    ex
                         );
                     discardRetryLater = true;
 		}
 	    }
 	} else { 
             if (useInsecureLookup){
                 pass = filter.check(filteredItem);
             } else {
                 try {
                     pass = filter.check(filteredItem);
                 } catch (SecurityException ex){ 
                     try {
                         // Filter didn't expect bootstrap proxy
                         filteredItem.service = ((ServiceProxyAccessor) filteredItem.service).getServiceProxy();
                         pass = filter.check(filteredItem);
                     } catch (RemoteException ex1) {
                         if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE))
                             ServiceDiscoveryManager.log(Level.FINE, 
                                 "Exception thrown while trying to download service proxy",
                                 ex1
                             );
                         discardRetryLater = true;
                     }
                 } catch (ClassCastException ex){
 		    try {
                         // Filter didn't expect bootstrap proxy
                         filteredItem.service = ((ServiceProxyAccessor) filteredItem.service).getServiceProxy();
                         pass = filter.check(filteredItem);
                     } catch (RemoteException ex1) {
                         if (ServiceDiscoveryManager.logger.isLoggable(Level.FINE))
                             ServiceDiscoveryManager.log(Level.FINE, 
                                 "Exception thrown while trying to download service proxy",
                                 ex1
                             );
                         discardRetryLater = true;
                     }
 		}
             }
             /* Handle filter pass */
             if (pass && !discardRetryLater && filteredItem.service != null) {
                 addFilteredItemToMap = true;
                 if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER))
                     ServiceDiscoveryManager.log(Level.FINER, 
                         "filterMaybeDiscard, filter passed, ServiceID: {0}", 
                         new Object[]{srvcID}
                     );
             } //endif(pass)
         }//endif
         PostEventState pes = 
                 new PostEventState(this, itemReg, item, filteredItem, sendEvent,
                         pass, discardRetryLater, addFilteredItemToMap, sdm.getDiscardWait());
         serviceIdMap.computeIfPresent(srvcID, pes);
         if (pes.notifyRemoved && pes.oldFilteredItem != null) {
             removeServiceNotify(pes.oldFilteredItem);
         }
         if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER))
             ServiceDiscoveryManager.log(Level.FINER, 
                 "filterMaybeDiscard, returning filtered ServiceItem: {0}",
                 new Object []{pes.filteredItemPass}
             );
 	return pes.filteredItemPass;
     } //end LookupCacheImpl.filterMaybeDiscard
     
     private static class PostEventState implements BiFunction<ServiceID, ServiceItemReg, ServiceItemReg> {
         
         ServiceItem filteredItemPass;
         ServiceItem oldFilteredItem = null;
         final ServiceItem item;
         final ServiceItem filteredItem;
         final boolean pass;
         final boolean discardRetryLater;
         final boolean sendEvent;
         final boolean addFilteredItemToMap;
         boolean notifyRemoved = false;
         final ServiceItemReg expected;
         final LookupCacheImpl cache;
         final long discardWait;
         
         PostEventState(LookupCacheImpl cache, ServiceItemReg itemReg,
                 ServiceItem item, ServiceItem filteredItem, boolean sendEvent,
                 boolean pass, boolean discardRetryLater,
                 boolean addFilteredItemToMap, long discardWait)
         {
             this.cache = cache;
             this.expected = itemReg;
             this.item = item;
             this.filteredItem = filteredItem;
             this.sendEvent = sendEvent;
             this.pass = pass;
             this.discardRetryLater = discardRetryLater;
             this.addFilteredItemToMap = addFilteredItemToMap;
             this.discardWait = discardWait;
         }
 
         @Override
         public ServiceItemReg apply(ServiceID id, ServiceItemReg itemReg) {
             if (!expected.equals(itemReg)) return itemReg;
             ServiceItemReg removeIfNull = itemReg;
             /* Handle filter fail */
             if (!pass && !discardRetryLater) {
                 if (itemReg != null) {
                     if (sendEvent) {
                         oldFilteredItem = itemReg.getFilteredItem();
                         notifyRemoved = true;
                         removeIfNull = null;
                     } else {
                         removeIfNull = null;
                     } //endif
                 } //endif
                 filteredItemPass = null;
             } //endif(fail)
             if (addFilteredItemToMap){
                 /**
                  * Replaces the <code>item</code> field of itemReg
                  * with the given <code>item</code> parameter; and sets the
                  * <code>filteredItem</code> field of itemReg to the value contained in
                  * the <code>filteredItem</code> parameter.
                  */
                 cache.cancelDiscardTask(id);
                 itemReg.replaceProxyUsedToTrackChange(null, item);
                 itemReg.setFilteredItem(filteredItem);
                 filteredItemPass = filteredItem;
             }
             /* Handle filter indefinite */
             if (discardRetryLater){
                 /**
                  * Sets a service
                  * removed event, and queues a <code>ServiceDiscardTimerTask</code> to retry
                  * the filter at a later time.
                  * If there's been any change in what is being discarded for
                  * filter retry, then update the item field in the map to
                  * capture that change; and set the filteredItem field to
                  * to null to guarantee that the filter is re-applied to
                  * that changed item.
                  */
                 if (itemReg.discard()) {
                     itemReg.replaceProxyUsedToTrackChange(null, item);
                     itemReg.setFilteredItem(null);
                     Future f = cache.serviceDiscardTimerTaskMgr.schedule(
                             new ServiceDiscardTimerTask(cache, item.serviceID),
                             discardWait,
                             TimeUnit.MILLISECONDS
                     );
                     cache.serviceDiscardFutures.put(item.serviceID, f);
                     if (sendEvent) {
                         notifyRemoved = true;
                     }
                 }
             }
             return removeIfNull;
         }
         
     }
 
     /**
      * Convenience method called (only when a TRANSITION_MATCH_NOMATCH event is
      * received) that removes the given <code>item</code> from the
      * <code>serviceIdMap</code> and wakes up the
      * <code>ServiceDiscardTimerTask</code> if the given <code>item</code> is
      * discarded; otherwise, sends a removed event.
      */
     private void handleMatchNoMatch(ServiceRegistrar proxy, ServiceID srvcID) {
         if (ServiceDiscoveryManager.logger.isLoggable(Level.FINER))
             ServiceDiscoveryManager.log(Level.FINER, 
                 "handleMatchNoMatch called, ServiceID: {0}",
                 new Object []{srvcID}
             );
         DissociateLusCleanUpOrphan dlcl = new DissociateLusCleanUpOrphan(this, proxy);
         serviceIdMap.computeIfPresent(srvcID, dlcl);
         if (dlcl.itemRegProxy != null) {
             itemMatchMatchChange(srvcID, dlcl.itmReg, dlcl.itemRegProxy, dlcl.newItem, false);
         } else if (dlcl.notify && dlcl.filteredItem != null) {
             removeServiceNotify(dlcl.filteredItem);
         }
     } //end LookupCacheImpl.handleMatchNoMatch
     
     /**
      * Atomic block of code.
      */
     private static class DissociateLusCleanUpOrphan 
              implements BiFunction<ServiceID, ServiceItemReg, ServiceItemReg> 
      {
 
         final LookupCacheImpl cache;
         boolean notify;
         final ServiceRegistrar proxy;
         ServiceRegistrar itemRegProxy;
         ServiceItemReg itmReg;
         ServiceItem newItem;
         ServiceItem filteredItem;
         
         DissociateLusCleanUpOrphan(LookupCacheImpl cache, ServiceRegistrar proxy){
             this.itmReg = null;
             this.notify = false;
             this.itemRegProxy = null;
             this.cache = cache;
             this.proxy = proxy;
             this.newItem = null;
             this.filteredItem = null;
         }
         
         @Override
         public ServiceItemReg apply(ServiceID srvcID, ServiceItemReg itemReg) {
             itmReg = itemReg;
             newItem = itemReg.removeProxy(proxy);
             filteredItem = itemReg.getFilteredItem();
             if (newItem != null) {
                 itemRegProxy = itemReg.getProxy();
             } 
             /**
              *
              */
             else if (itemReg.hasNoProxys()) {
                 if (itemReg.isDiscarded()) {
                     /* Remove item from map and wake up the discard task */
                     itmReg = null;
                     cache.cancelDiscardTask(srvcID);
                 } else {
                     //remove item from map and send removed event
                     notify = true;
                     itmReg = null;
                 } //endif
             } //endif
             return itmReg;
         }
     }
 
     /**
      * Wake up service discard task if running, else remove from mgr.
      */
     private void cancelDiscardTask(ServiceID sid) {
 	// Might need to record future's and cancel from there.
 	Future task = serviceDiscardFutures.get(sid);
 	if (task != null) {
 	    task.cancel(true);
 	}
     } //end LookupCacheImpl.cancelDiscardTask
 
     /**
      *      
      */
     final static class CacheTaskDependencyManager implements FutureObserver {
 
 	// CacheTasks pending completion.
 
 	private final ConcurrentLinkedQueue<CacheTaskWrapper> pending;
 	private final ExecutorService executor;
 
 	CacheTaskDependencyManager(ExecutorService e) {
 	    this.pending = new ConcurrentLinkedQueue<CacheTaskWrapper>();
 	    executor = e;
 	}
 
 	CacheTaskWrapper submit(Runnable t) {
 	    CacheTaskWrapper future = new CacheTaskWrapper(t, null);
 	    pending.offer(future);
 	    future.addObserver(this);
 	    if (t instanceof CacheTask && ((CacheTask) t).hasDeps()) {
 		List<FutureObserver.ObservableFuture> deps = new LinkedList<FutureObserver.ObservableFuture>();
 		Iterator<CacheTaskWrapper> it = pending.iterator();
 		while (it.hasNext()) {
 		    CacheTaskWrapper w = it.next();
 		    Object c = w.getTask();
 		    if (c instanceof CacheTask && ((CacheTask) t).dependsOn((CacheTask) c)) {
 			deps.add(w);
 		    }
 		}
 		if (deps.isEmpty()) {
 		    executor.submit(future);
                     if (ServiceDiscoveryManager.logger.isLoggable(Level.FINEST))
                         ServiceDiscoveryManager.log(
                             Level.FINEST, 
                             "ServiceDiscoveryManager {0} submitted to executor task queue",
                             new Object []{t.toString()}
                         );
 		} else {
 		    DependencyLinker linker = new DependencyLinker(executor, deps, future);
 		    linker.register();
                     if (ServiceDiscoveryManager.logger.isLoggable(Level.FINEST))
                         ServiceDiscoveryManager.log(
                                 Level.FINEST, 
                                 "ServiceDiscoveryManager {0} registered dependencies", 
                                 new Object [] {t.toString()}
                         );
 		}
 	    } else {
 		executor.submit(future);
                 if (ServiceDiscoveryManager.logger.isLoggable(Level.FINEST))
                     ServiceDiscoveryManager.log(Level.FINEST, 
                         "ServiceDiscoveryManager {0} submitted to executor task queue",
                         new Object []{t.toString()}
                     );
 	    }
 	    return future;
 	}
 
 	@Override
 	public void futureCompleted(Future e) {
 	    pending.remove(e);
 	    Object t;
 	    if (e instanceof CacheTaskWrapper) {
 		t = ((CacheTaskWrapper) e).getTask();
 	    } else {
 		t = e;
 	    }
             if (ServiceDiscoveryManager.logger.isLoggable(Level.FINEST))
                 ServiceDiscoveryManager.log(
                     Level.FINEST,
                     "ServiceDiscoveryManager {0} completed execution", 
                     new Object[]{t.toString()}
                 );
 	}
 
 	/**
 	 * Removes from the cache's task queue, all pending tasks associated
 	 * with the given ProxyReg. This method is called when the given
 	 * ProxyReg has been discarded.
 	 */
 	void removeUselessTask(ProxyReg reg) {
 	    Iterator<CacheTaskWrapper> it = pending.iterator();
 	    while (it.hasNext()) {
 		CacheTaskWrapper w = it.next();
 		Object t = w.getTask();
 		if (t instanceof CacheTask && ((CacheTask) t).isFromProxy(reg)) {
 		    w.cancel(true); // Also causes task to be removed
                     if (ServiceDiscoveryManager.logger.isLoggable(Level.FINEST))
                         ServiceDiscoveryManager.log(
                             Level.FINEST,
                             "ServiceDiscoveryManager {0} cancelled", 
                             new Object[]{t.toString()}
                         );
 		}
 	    } //end loop
 	} //end LookupCacheImpl.removeUselessTask
 
     }
 
     /**
      * ObservableFuture wrapper class for CacheTask's.
      *
      * @param <T>
      */
     final static class CacheTaskWrapper<T> extends ObservableFutureTask<T> {
 
 	private final Object task;
 
 	CacheTaskWrapper(Runnable r, T result) {
 	    super(r, result);
 	    task = r;
 	}
 
 	CacheTaskWrapper(Callable<T> c) {
 	    super(c);
 	    task = c;
 	}
 
 	Object getTask() {
 	    return task;
 	}
 
     }
 
     /**
      * Class for implementing register/lookup/notify/dropProxy/discard tasks
      */
     abstract static class CacheTask implements Runnable {
 
 	protected final ProxyReg reg;
 	protected volatile long thisTaskSeqN;
 
 	protected CacheTask(ProxyReg reg, long seqN) {
 	    this.reg = reg;
 	    this.thisTaskSeqN = seqN;
             if (ServiceDiscoveryManager.logger.isLoggable(Level.FINEST))
                 ServiceDiscoveryManager.log(
                     Level.FINEST,
                     "ServiceDiscoveryManager {0} constructed", 
                     new Object[]{toString()}
                 );
 	} //end constructor
 	/* check if the task is on a specific ProxyReg, return true if it is */
 
 	public boolean isFromProxy(ProxyReg reg) {
 	    if (this.reg == null) {
 		return false;
 	    }
 	    return (this.reg).equals(reg);
 	} //end isFromProxy
 
 	/**
 	 * Returns the ProxyReg associated with this task (if any).
 	 */
 	public ProxyReg getProxyReg() {
 	    return reg;
 	} //end ProxyReg
 
 	/**
 	 * Returns the unique sequence number of this task.
 	 */
 	public long getSeqN() {
 	    return thisTaskSeqN;
 	} //end getSeqN
 
 	public abstract boolean hasDeps();
 
 	public boolean dependsOn(CacheTask task) {
 	    return false;
 	}
     } //end class CacheTask
 }