Java tutorial
/* * ALMA - Atacama Large Millimiter Array * (c) European Southern Observatory, 2009 * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package alma.acs.nc; import static alma.acs.nc.sm.generated.EventSubscriberAction.createConnection; import static alma.acs.nc.sm.generated.EventSubscriberAction.createEnvironment; import static alma.acs.nc.sm.generated.EventSubscriberAction.destroyConnection; import static alma.acs.nc.sm.generated.EventSubscriberAction.destroyEnvironment; import static alma.acs.nc.sm.generated.EventSubscriberAction.resumeConnection; import static alma.acs.nc.sm.generated.EventSubscriberAction.suspendConnection; import java.util.Collection; import java.util.HashMap; import java.util.Map; import java.util.concurrent.ArrayBlockingQueue; import java.util.concurrent.RejectedExecutionException; import java.util.concurrent.ThreadPoolExecutor; import java.util.concurrent.TimeUnit; import java.util.concurrent.atomic.AtomicLong; import java.util.logging.Logger; import org.apache.commons.scxml.ErrorReporter; import org.apache.commons.scxml.EventDispatcher; import org.apache.commons.scxml.SCInstance; import org.apache.commons.scxml.TriggerEvent; import alma.ACSErrTypeCommon.wrappers.AcsJBadParameterEx; import alma.ACSErrTypeCommon.wrappers.AcsJCORBAProblemEx; import alma.ACSErrTypeCommon.wrappers.AcsJCouldntPerformActionEx; import alma.ACSErrTypeCommon.wrappers.AcsJIllegalStateEventEx; import alma.ACSErrTypeCommon.wrappers.AcsJStateMachineActionEx; import alma.acs.container.ContainerServicesBase; import alma.acs.exceptions.AcsJException; import alma.acs.logging.MultipleRepeatGuard; import alma.acs.logging.RepeatGuard; import alma.acs.logging.RepeatGuard.Logic; import alma.acs.nc.sm.generated.EventSubscriberAction; import alma.acs.nc.sm.generated.EventSubscriberSignal; import alma.acs.nc.sm.generated.EventSubscriberSignalDispatcher; import alma.acs.nc.sm.generic.AcsScxmlActionDispatcher; import alma.acs.nc.sm.generic.AcsScxmlActionExecutor; import alma.acs.nc.sm.generic.AcsScxmlEngine; import alma.acs.util.StopWatch; import alma.acsErrTypeLifeCycle.wrappers.AcsJEventSubscriptionEx; import alma.acsnc.EventDescription; /** * Base class for an event subscriber, that can be used for both Corba NC and for in-memory test NC. * <p> * We will have to see if it can also be used for DDS-based events, or if the required modifications will be too heavy. * * @param <T> The event (base) type. If all events are of the same type then that type should be used; * otherwise a common base type for all events that may be sent on the given "channel" should be used, * such as <code>Object</code> or <code>IDLEntity</code>. */ public abstract class AcsEventSubscriberImplBase<T> implements AcsEventSubscriber<T>, AcsScxmlActionExecutor<EventSubscriberAction> { /** * A name that identifies the client of this NCSubscriber, to be used * both for logging and also (if applicable) as the supplier proxy name so that * looking at the proxy objects of the NC we can figure out who the clients are. */ protected final String clientName; protected final ContainerServicesBase services; /** * Provides access to the ACS logging system. */ protected final Logger logger; /** * State machine for the subscriber lifecycle. * It is not used for data handling itself, even though the measured overhead * of less than 0.2 ms per signal might allow this. */ protected final AcsScxmlEngine<EventSubscriberSignal, EventSubscriberAction> stateMachine; private static final String scxmlFileName = "/alma/acs/nc/sm/generated/EventSubscriberSCXML.xml"; protected final EventSubscriberSignalDispatcher stateMachineSignalDispatcher; /** * Event queue should hold at least two events to avoid unnecessary scary logs about slow receivers, * but must be short enough to get receivers to actually implement their own queue and discard mechanism * instead of relying on this ACS queue which may buffer events for a limited time and thus obscure the problem. * @see #eventHandlingExecutor */ public static final int EVENT_QUEUE_CAPACITY = 50; /** * Single-thread executor with a small queue (size given in {@link #EVENT_QUEUE_CAPACITY}, * used to stay responsive toward the NC even if receivers are slow. * The purpose is only to track down receivers that don't keep up with the event rate, and not to provide reliable event buffering, * see http://jira.alma.cl/browse/COMP-5767. * <p> * Errors are logged, using also fields {@link #numEventsDiscarded} and {@link #receiverTooSlowLogRepeatGuard}. * <p> * The difference of this mechanism compared to the logs controlled by {@link #processTimeLogRepeatGuard} is that * here we take into account the actual event rate and check whether the receiver can handle it, * whereas {@link #processTimeLogRepeatGuard} only compares the actual process times against pre-configured values. */ private ThreadPoolExecutor eventHandlingExecutor; /** * @see #eventHandlingExecutor */ private final AtomicLong numEventsDiscarded = new AtomicLong(0); /** * Throttles logs from {@link #logEventProcessingTooSlowForEventRate(long, String, long)}. */ private final RepeatGuard receiverTooSlowLogRepeatGuard; /** * Contains a generic receiver to be used by the * {@link #addGenericSubscription()} method. */ protected AcsEventSubscriber.GenericCallback genericReceiver; /** * Contains a list of receiver functions to be invoked when an event * of a particular type is received. * <p> * key = the event type (Java class derived from IDL struct). <br> * value = the matching event handler. */ protected final Map<Class<? extends T>, Callback<? extends T>> receivers = new HashMap<Class<? extends T>, Callback<? extends T>>(); /** * Contains a list of repeat guards for each different type of event. */ protected final MultipleRepeatGuard processTimeLogRepeatGuard; /** * Runtime access to the type parameter <T>. */ protected final Class<T> eventType; /** * @return <code>true</code> if events should be logged when they are received. */ protected abstract boolean isTraceEventsEnabled(); /** * Base class constructor, to be called from subclass ctor. * IMPORTANT: Subclasses MUST call "stateMachine.setUpEnvironment()" at the end of their constructors. * This is because Java does not support template method design for constructors * (see for example http://stackoverflow.com/questions/2906958/running-a-method-after-the-constructor-of-any-derived-class). * Since the subclasses are all meant to be produced within ACS I did not want to go for dirty tricks to work around this. * We also don't want to call a public init() method after constructing the subscriber. * <p> * Normally an ACS class such as container services will act as the factory for event subscriber objects, * but for exceptional cases it is also possible to create one stand-alone, * as long as the required parameters can be provided. * * @param services * To get ACS logger, access to the CDB, etc. * @param clientName * A name that identifies the client of this NCSubscriber. * TODO: Check if we still need this name to be specified separately from {@link services#getName()}. * @throws AcsJException * Thrown on any <I>really bad</I> error conditions encountered. */ public AcsEventSubscriberImplBase(ContainerServicesBase services, String clientName, Class<T> eventType) throws AcsJException { if (services == null) { AcsJBadParameterEx ex = new AcsJBadParameterEx(); ex.setParameter("services"); ex.setParameterValue("null"); throw ex; } this.services = services; if (clientName == null) { AcsJBadParameterEx ex = new AcsJBadParameterEx(); ex.setParameter("clientName"); ex.setParameterValue("null"); throw ex; } this.clientName = clientName; this.eventType = eventType; logger = services.getLogger(); // @TODO Set more realistic guarding parameters, e.g. max 1 identical log in 10 seconds processTimeLogRepeatGuard = new MultipleRepeatGuard(0, TimeUnit.SECONDS, 1, Logic.COUNTER, 100); // log slow receiver error only every 30 seconds or every 100 times, whatever comes first receiverTooSlowLogRepeatGuard = new RepeatGuard(30, TimeUnit.SECONDS, 100, Logic.OR); // set up the state machine AcsScxmlActionDispatcher<EventSubscriberAction> actionDispatcher = new AcsScxmlActionDispatcher<EventSubscriberAction>( logger, EventSubscriberAction.class); // As a design choice, we implement all SM actions directly here in this class and its subclasses. // The state machine framework expects an object per action, so that we must register ourselves for every action type. // We could do this as a for loop over EventSubscriberAction.values(), but better hardcode the registration // for every action type so that SM changes will be noticed more easily. actionDispatcher.registerActionHandler(createEnvironment, this); actionDispatcher.registerActionHandler(destroyEnvironment, this); actionDispatcher.registerActionHandler(createConnection, this); actionDispatcher.registerActionHandler(destroyConnection, this); actionDispatcher.registerActionHandler(suspendConnection, this); actionDispatcher.registerActionHandler(resumeConnection, this); // Here the AcsScxmlEngine constructor will load the scxml file and start the state machine stateMachine = new AcsScxmlEngine<EventSubscriberSignal, EventSubscriberAction>(scxmlFileName, logger, actionDispatcher, EventSubscriberSignal.class); // Convenience method to send events to the SM. // Usually meant to be used as a base class, but here we don't want to expose the SM to the user. stateMachineSignalDispatcher = new EventSubscriberSignalDispatcher() { @Override protected AcsScxmlEngine<EventSubscriberSignal, EventSubscriberAction> getScxmlEngine() { return stateMachine; } }; // Later at the end of the subclass ctor there should be the call to // stateMachine.setUpEnvironment(), leaving our state machine in state EnvironmentCreated } //////////////////////////////////////////////////////////////////////////////////////// /////////////////////// State machine ////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////////////////// /** * Dispatches the action enum to one of the action handler methods. * <p> * The overhead of implementing this method is the price we pay for avoiding reflection * and allowing flexible action implementation in the SM design. * @see alma.acs.nc.sm.generic.AcsScxmlActionExecutor#execute(java.lang.Enum, org.apache.commons.scxml.EventDispatcher, org.apache.commons.scxml.ErrorReporter, org.apache.commons.scxml.SCInstance, java.util.Collection) */ @Override public boolean execute(EventSubscriberAction action, EventDispatcher evtDispatcher, ErrorReporter errRep, SCInstance scInstance, Collection<TriggerEvent> derivedEvents) throws AcsJStateMachineActionEx { // logger.fine("Will handle action " + action.name()); boolean ret = true; switch (action) { case createEnvironment: createEnvironmentAction(evtDispatcher, errRep, scInstance, derivedEvents); break; case destroyEnvironment: destroyEnvironmentAction(evtDispatcher, errRep, scInstance, derivedEvents); break; case createConnection: createConnectionAction(evtDispatcher, errRep, scInstance, derivedEvents); break; case destroyConnection: destroyConnectionAction(evtDispatcher, errRep, scInstance, derivedEvents); break; case suspendConnection: suspendAction(evtDispatcher, errRep, scInstance, derivedEvents); break; case resumeConnection: resumeAction(evtDispatcher, errRep, scInstance, derivedEvents); break; default: ret = false; } // logger.fine("Done handling action " + action.name()); return ret; } /** * Subclass may override, but must call super.createEnvironmentAction(). */ protected void createEnvironmentAction(EventDispatcher evtDispatcher, ErrorReporter errRep, SCInstance scInstance, Collection<TriggerEvent> derivedEvents) throws AcsJStateMachineActionEx { // nada } /** * Subclass may override, but must call super.destroyEnvironmentAction(). */ protected void destroyEnvironmentAction(EventDispatcher evtDispatcher, ErrorReporter errRep, SCInstance scInstance, Collection<TriggerEvent> derivedEvents) throws AcsJStateMachineActionEx { } /** * Subclass may override, but must call super.createConnectionAction(). */ protected void createConnectionAction(EventDispatcher evtDispatcher, ErrorReporter errRep, SCInstance scInstance, Collection<TriggerEvent> derivedEvents) throws AcsJStateMachineActionEx { eventHandlingExecutor = new ThreadPoolExecutor(0, 1, 1L, TimeUnit.MINUTES, new ArrayBlockingQueue<Runnable>(EVENT_QUEUE_CAPACITY), services.getThreadFactory(), new ThreadPoolExecutor.AbortPolicy()); } /** * Handler for "destroyConnection" state machine action. * <p> * Shuts down the event queue. * Queued events may still be processed by the receivers afterwards, * but here we wait for up to 500 ms to log it if it is the case. * <p> * Further events delivered to {@link #processEventAsync(Object, EventDescription)} * will cause an exception there. * <p> * Subclass may override, but must call super.destroyConnectionAction(). */ protected void destroyConnectionAction(EventDispatcher evtDispatcher, ErrorReporter errRep, SCInstance scInstance, Collection<TriggerEvent> derivedEvents) throws AcsJStateMachineActionEx { eventHandlingExecutor.shutdown(); boolean queueOK = false; // just in case we want to report the success of this shutdown try { queueOK = eventHandlingExecutor.awaitTermination(500, TimeUnit.MILLISECONDS); } catch (InterruptedException ex) { // just leave queueOK == false } if (!queueOK) { // interrupted or timeout occurred, may still have events in the queue. Terminate with error message int remainingEvents = eventHandlingExecutor.getQueue().size(); logQueueShutdownError(500, remainingEvents); } } /** * Subclass may override, but must call super.suspendAction(). */ protected void suspendAction(EventDispatcher evtDispatcher, ErrorReporter errRep, SCInstance scInstance, Collection<TriggerEvent> derivedEvents) throws AcsJStateMachineActionEx { // nada } /** * Subclass may override, but must call super.resumeAction(). */ protected void resumeAction(EventDispatcher evtDispatcher, ErrorReporter errRep, SCInstance scInstance, Collection<TriggerEvent> derivedEvents) throws AcsJStateMachineActionEx { // nada } /** * Gets the configured (or default) max time that a receiver may take to process an event, * regardless of the actual event rate. */ protected abstract double getMaxProcessTimeSeconds(String eventName); /** * Logs an exception thrown by an event handler (user code). */ protected abstract void logEventReceiveHandlerException(String eventName, String receiverClassName, Throwable thr); /** * Logs the error that event processing time was exceeded. */ protected abstract void logEventProcessingTimeExceeded(String eventName, long logOcurrencesNumber); /** * Logs the error that the receiver cannot keep up with the actual event rate, * in spite of the small event buffering done. * * @param numEventsDiscarded The number of events that have actually been discarded since the last log. * Will often be 0 when we just warn about the queue filling up. * @param eventName */ protected abstract void logEventProcessingTooSlowForEventRate(long numEventsDiscarded, String eventName); /** * Logs or ignores the fact that an event was received for which no receiver could be found. * <p> * The subclass must know whether such a condition is expected or not, * e.g. because event filtering is set up outside of the subscriber * and only subscribed event types are expected to arrive. */ protected abstract void logNoEventReceiver(String eventName); /** * Logs the error that the local event buffer could not be emptied before shutting down the subscriber. */ protected abstract void logQueueShutdownError(int timeoutMillis, int remainingEvents); /** * Asynchronously calls {@link #processEvent(Object, EventDescription)}, * using {@link #eventHandlingExecutor}. * <p> * This method should be called from the subclass-specific method that receives the event, * for example <code>push_structured_event</code> in case of Corba NC. * <p> * This method is thread-safe. * * @param eventData (defined as <code>Object</code> instead of <code>T</code> to include data for generic subscription). * @param eventDesc event meta data */ protected void processEventAsync(final Object eventData, final EventDescription eventDesc) { // to avoid unnecessary scary logs, we tolerate previous events up to half the queue size boolean isReceiverBusyWithPreviousEvent = (eventHandlingExecutor.getQueue().size() > EVENT_QUEUE_CAPACITY / 2); // logger.info("Queue size: " + eventHandlingExecutor.getQueue().size()); boolean thisEventDiscarded = false; try { eventHandlingExecutor.execute(new Runnable() { public void run() { // here we call processEvent from the worker thread processEvent(eventData, eventDesc); } }); } catch (RejectedExecutionException ex) { // receivers have been too slow, queue is actually full, will drop data. thisEventDiscarded = true; numEventsDiscarded.incrementAndGet(); } if (thisEventDiscarded || isReceiverBusyWithPreviousEvent) { // receiverTooSlowLogRepeatGuard currently not thread-safe, therefore synchronize synchronized (receiverTooSlowLogRepeatGuard) { if (receiverTooSlowLogRepeatGuard.checkAndIncrement()) { // About numEventsDiscarded and concurrency: // That counter may have been incremented by other threads between the above RejectedExecutionException // and here. These threads are blocked now, and have not yet incremented the repeat guard. // This can lead to some harmless irregularities in how often we actually log the message. // What matters is that we report correctly the number of discarded events. logEventProcessingTooSlowForEventRate(numEventsDiscarded.getAndSet(0), eventData.getClass().getName()); } } } } /** * This method should be called from the subclass-specific method that receives the event, * for example <code>push_structured_event</code> in case of Corba NC, * or preferably via {@link #processEventAsync(Object, EventDescription)}. * <p> * No exception is allowed to be thrown by this method, even if the receiver implementation throws a RuntimeExecption * @param eventData (defined as <code>Object</code> instead of <code>T</code> to include data for generic subscription). * @param eventDesc */ protected void processEvent(Object eventData, EventDescription eventDesc) { Class<?> incomingEventType = eventData.getClass(); String eventName = incomingEventType.getName(); // figure out how much time this event has to be processed (according to configuration) double maxProcessTimeSeconds = getMaxProcessTimeSeconds(eventName); StopWatch profiler = new StopWatch(); // we give preference to a receiver that has registered for this event type T or a subtype if (eventType.isAssignableFrom(incomingEventType) && receivers.containsKey(incomingEventType)) { @SuppressWarnings("unchecked") T typedEventData = (T) eventData; Callback<? extends T> receiver = receivers.get(incomingEventType); profiler.reset(); try { _process(receiver, typedEventData, eventDesc); } catch (Throwable thr) { logEventReceiveHandlerException(eventName, receiver.getClass().getName(), thr); } double usedSecondsToProcess = (profiler.getLapTimeMillis() / 1000.0); // warn the end-user if the receiver is taking too long, using a repeat guard if (usedSecondsToProcess > maxProcessTimeSeconds && processTimeLogRepeatGuard.checkAndIncrement(eventName)) { logEventProcessingTimeExceeded(eventName, processTimeLogRepeatGuard.counterAtLastExecution(eventName)); } } // fallback to generic receive method else if (genericReceiver != null) { profiler.reset(); genericReceiver.receiveGeneric(eventData, eventDesc); double usedSecondsToProcess = (profiler.getLapTimeMillis() / 1000.0); // warn the end-user if the receiver is taking too long if (usedSecondsToProcess > maxProcessTimeSeconds && processTimeLogRepeatGuard.checkAndIncrement(eventName)) { logEventProcessingTimeExceeded(eventName, processTimeLogRepeatGuard.counterAtLastExecution(eventName)); } } // No receiver found. // This may be OK or not, depending on whether the subclass sets up filtering in the underlying notification framework // that ensures that only subscribed event types reach the subscriber. Subclass should decide if and how to report this. else { logNoEventReceiver(eventName); } } /** * "Generic helper method" to enforce type argument inference by the compiler, * see http://www.angelikalanger.com/GenericsFAQ/FAQSections/ProgrammingIdioms.html#FAQ207 */ private <U extends T> void _process(Callback<U> receiver, T eventData, EventDescription eventDescrip) { U castCorbaData = null; try { castCorbaData = receiver.getEventType().cast(eventData); } catch (ClassCastException ex) { // This should never happen and would be an ACS error logger.warning("Failed to deliver incompatible data '" + eventData.getClass().getName() + "' to subscriber '" + receiver.getEventType().getName() + "'. Fix data subscription handling in " + getClass().getName() + "!"); } // user code errors (runtime ex etc) we let fly up receiver.receive(castCorbaData, eventDescrip); } @Override public String getLifecycleState() { return stateMachine.getCurrentState(); } /** * Use only for unit testing! */ public boolean hasGenericReceiver() { return (genericReceiver != null); } /** * Use only for unit testing! */ public int getNumberOfReceivers() { return receivers.size(); } //////////////////////////////////////////////////////////////////////////////////////// ///////////////////////////// AcsEventSubscriber impl ////////////////////////////////// //////////////////////////////////////////////////////////////////////////////////////// /** * Subscribes to all events. The latest generic receiver displaces the previous one. * <p> * If in addition to this generic subscription we also have specific subscriptions via * {@link #addSubscription(Class, Callback)}, * then those more specific subscriptions will take precedence in receiving an event. * <p> * Notice though that any server-side filters previously created for the event type specific * subscriptions get deleted when calling this method, so that even after removing a generic * subscription the network performance gain of server-side filtering is lost. * @TODO: Couldn't this be fixed by creating the server-side filters on demand (see also javadoc class comment about lifecycle)? */ @Override public final void addGenericSubscription(GenericCallback receiver) throws AcsJEventSubscriptionEx { // First time we create the filter and set the receiver if (genericReceiver == null) { notifyFirstSubscription(null); } // After the filter is created, we just replace the receiver genericReceiver = receiver; } /** * Removes the generic receiver handler. * * @throws AcsJCORBAProblemEx */ @Override public final void removeGenericSubscription() throws AcsJEventSubscriptionEx { if (genericReceiver == null) { AcsJEventSubscriptionEx ex = new AcsJEventSubscriptionEx(); ex.setContext("Failed to remove generic subscription when not actually subscribed."); ex.setEventType("generic"); throw ex; } notifySubscriptionRemoved(null); genericReceiver = null; } @Override public final <U extends T> void addSubscription(Callback<U> receiver) throws AcsJEventSubscriptionEx { Class<U> subscribedEventType = receiver.getEventType(); if (subscribedEventType == null || !(eventType.isAssignableFrom(subscribedEventType))) { AcsJEventSubscriptionEx ex = new AcsJEventSubscriptionEx(); ex.setContext("Receiver is returning a null or invalid event type. " + "Check the getEventType() method implementation and try again."); ex.setEventType(subscribedEventType == null ? "null" : subscribedEventType.getName()); throw ex; } // First time we create the filter and set the receiver if (!receivers.containsKey(subscribedEventType)) { notifyFirstSubscription(subscribedEventType); } // After the filter is created, we just replace the corresponding receivers receivers.put(subscribedEventType, receiver); } @Override public final <U extends T> void removeSubscription(Class<U> structClass) throws AcsJEventSubscriptionEx { // Removing subscription from receivers list if (structClass != null) { if (receivers.containsKey(structClass)) { receivers.remove(structClass); notifySubscriptionRemoved(structClass); } else { AcsJEventSubscriptionEx ex = new AcsJEventSubscriptionEx(); ex.setContext("Trying to unsubscribe from an event type not being subscribed to."); ex.setEventType(structClass.getName()); throw ex; } } else { // Removing every type of event receivers.clear(); notifyNoSubscription(); } } @Override public final void startReceivingEvents() throws AcsJIllegalStateEventEx, AcsJCouldntPerformActionEx { try { stateMachineSignalDispatcher.startReceivingEvents(); } catch (AcsJStateMachineActionEx ex) { throw new AcsJCouldntPerformActionEx(ex); } } /** * @see alma.acs.nc.AcsEventSubscriber#disconnect() */ @Override public final void disconnect() throws AcsJIllegalStateEventEx, AcsJCouldntPerformActionEx { try { stateMachineSignalDispatcher.stopReceivingEvents(); } catch (AcsJIllegalStateEventEx ex) { // ignore. If the state is totally wrong then the subsequent cleanUpEnvironment // will also throw AcsJIllegalStateEventEx } catch (AcsJStateMachineActionEx ex) { throw new AcsJCouldntPerformActionEx(ex); } finally { // even after AcsJIllegalStateEventEx in stopReceivingEvents we want to do the second clean-up step try { stateMachineSignalDispatcher.cleanUpEnvironment(); } catch (AcsJStateMachineActionEx ex) { throw new AcsJCouldntPerformActionEx(ex); } } } @Override public final void suspend() throws AcsJIllegalStateEventEx, AcsJCouldntPerformActionEx { try { stateMachineSignalDispatcher.suspend(); } catch (AcsJStateMachineActionEx ex) { throw new AcsJCouldntPerformActionEx(ex); } } @Override public final void resume() throws AcsJIllegalStateEventEx, AcsJCouldntPerformActionEx { try { stateMachineSignalDispatcher.resume(); } catch (AcsJStateMachineActionEx ex) { throw new AcsJCouldntPerformActionEx(ex); } } //////////////////////////////////////////////////////////////////////////////////////// ///////////////////////// Subscription helper methods ////////////////////////////////// //////////////////////////////////////////////////////////////////////////////////////// /** * @param structClass Can be <code>null</code> in case of generic subscription. */ protected abstract void notifyFirstSubscription(Class<?> structClass) throws AcsJEventSubscriptionEx; /** * @param structClass * @throws AcsJEventSubscriptionEx */ protected abstract void notifySubscriptionRemoved(Class<?> structClass) throws AcsJEventSubscriptionEx; /** * */ protected abstract void notifyNoSubscription(); @Override public boolean isSuspended() { return stateMachine.isStateActive("EnvironmentCreated::Connected::Suspended"); } public final boolean isDisconnected() { return (stateMachine.isStateActive("EnvironmentCreated::Disconnected") || stateMachine.isStateActive("EnvironmentUnknown")); } }