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/*
* 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 org.apache.tuscany.sca.itest;
import java.util.Map;
import java.util.Timer;
import java.util.TimerTask;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import org.oasisopen.sca.ComponentContext;
import org.oasisopen.sca.RequestContext;
import org.oasisopen.sca.ServiceReference;
import org.oasisopen.sca.annotation.Callback;
import org.oasisopen.sca.annotation.Context;
import org.oasisopen.sca.annotation.Destroy;
import org.oasisopen.sca.annotation.Scope;
import org.oasisopen.sca.annotation.Service;
/**
* Sample Event Processor Service Implementation
*/
@Service(EventProcessorService.class)
@Scope("COMPOSITE")
public class EventProcessorServiceImpl implements EventProcessorService {
/**
* Reference to the callback
*
* **NB** This test makes the *DANGEROUS* assumption that there is only one client to
* this component and thus only one callback location. For a "real" COMPOSITE component,
* each client would need to be uniquely identified - this would need to be done using something
* like an ID on the service methods, which could be set by the client and used to identify
* a "session"
*/
private ServiceReference<EventProcessorCallBack> clientCallback = null;
/**
* Component context (injected)
*/
@Context
protected ComponentContext componentContext;
/**
* This map contains the call backs for each of the registered Event names
*/
private final Map<String, ServiceReference<EventProcessorCallBack>> eventListeners;
/**
* The list of all Event Generators we create
*/
private final EventGenerator[] allEventGenerators;
/**
* Constructor. Starts the Event Generators
*/
public EventProcessorServiceImpl() {
eventListeners = new ConcurrentHashMap<String, ServiceReference<EventProcessorCallBack>>();
// We will simulate an Event generator
allEventGenerators = new EventGenerator[2];
allEventGenerators[0] = new EventGenerator("FAST", 10); // Generate the FAST event every 10ms
allEventGenerators[1] = new EventGenerator("SLOW", 50); // Generate the SLOW event every 50ms
}
/**
* Registers the client to receive notifications for the specified event
*
* @param aEventName The name of the Event to register
*/
public void registerForEvent(String aEventName) {
// Register for the Event
eventListeners.put(aEventName, getClientCallback());
// Send the "register" started event to the client
receiveEvent(aEventName, "SameThread: Registered to receive notifications for " + aEventName);
}
private ServiceReference<EventProcessorCallBack> getClientCallback() {
if(clientCallback == null) {
RequestContext requestContext = componentContext.getRequestContext();
clientCallback = requestContext.getCallbackReference();
}
return clientCallback;
} // end method getClientCallback
/**
* Unregisters the client so it no longer receives notifications for the specified event
*
* @param aEventName The name of the Event to unregister
*/
public void unregisterForEvent(String aEventName) {
// Send the "register" started event to the client
receiveEvent(aEventName, "SameThread: Unregister from receiving notifications for " + aEventName);
eventListeners.remove(aEventName);
}
/**
* This method is called whenever the EventProcessorService receives an Event
*
* @param aEventName The name of the Event received
* @param aEventData The Event data
*/
private void receiveEvent(String aEventName, Object aEventData) {
// Get the listener for the Event
final ServiceReference<EventProcessorCallBack> callback = eventListeners.get(aEventName);
if (callback == null) {
//System.out.println("No registered listeners for " + aEventName);
return;
}
// Trigger the call back
// System.out.println("Notifying " + callback + " of event " + aEventName);
callback.getService().eventNotification(aEventName, aEventData);
// System.out.println("Done notify " + callback + " of event " + aEventName);
}
/**
* Shuts down the Event Processor
*/
@Destroy
public void shutdown() {
System.out.println("Shutting down the EventProcessor");
// Clear list of call back locations as we don't want to send any more notifications
eventListeners.clear();
// Stop the Event Generators
for (EventGenerator generator : allEventGenerators) {
generator.stop();
}
}
/**
* Utility class for generating Events
*/
private final class EventGenerator {
/**
* The Timer we are using to generate the events
*/
private final Timer timer = new Timer();
/**
* Lock object to ensure that we can cancel the timer cleanly.
*/
private final Object lock = new Object();
/**
* Constructor
*
* @param aEventName The name of the Event to generate
* @param frequencyInMilliseconds How frequently we should generate the Events
*/
private EventGenerator(String aEventName, int frequencyInMilliseconds) {
timer.schedule(new EventGeneratorTimerTask(aEventName),
frequencyInMilliseconds,
frequencyInMilliseconds);
}
/**
* Stop this Event Generator
*/
private void stop() {
synchronized (lock) {
timer.cancel();
}
}
/**
* The TimerTask that is invoked by the Timer for the EventGenerator
*/
private final class EventGeneratorTimerTask extends TimerTask {
/**
* The name of the Event we should generate
*/
private final String eventName;
/**
* Constructor
*
* @param aEventName The name of the Event we should generate
*/
private EventGeneratorTimerTask(String aEventName) {
eventName = aEventName;
}
/**
* Timer calls this method and it will generate an Event
*/
public void run() {
synchronized(lock) {
// System.out.println("Generating new event " + eventName);
receiveEvent(eventName, "Separate Thread Notification: " + UUID.randomUUID().toString());
}
}
}
}
}
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