/*
* 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.cloudstack.mom.inmemory;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import javax.ejb.Local;
import javax.naming.ConfigurationException;
import org.apache.cloudstack.framework.events.Event;
import org.apache.cloudstack.framework.events.EventBus;
import org.apache.cloudstack.framework.events.EventBusException;
import org.apache.cloudstack.framework.events.EventSubscriber;
import org.apache.cloudstack.framework.events.EventTopic;
import org.apache.log4j.Logger;
import com.cloud.utils.Pair;
import com.cloud.utils.component.ManagerBase;
@Local(value = EventBus.class)
public class InMemoryEventBus extends ManagerBase implements EventBus {
private static final Logger s_logger = Logger.getLogger(InMemoryEventBus.class);
private final static ConcurrentHashMap<UUID, Pair<EventTopic, EventSubscriber>> subscribers;
static {
subscribers = new ConcurrentHashMap<UUID, Pair<EventTopic, EventSubscriber>>();
}
@Override
public boolean configure(String name, Map<String, Object> params) throws ConfigurationException {
_name = name;
return true;
}
@Override
public void setName(String name) {
_name = name;
}
@Override
public UUID subscribe(EventTopic topic, EventSubscriber subscriber) throws EventBusException {
if (subscriber == null || topic == null) {
throw new EventBusException("Invalid EventSubscriber/EventTopic object passed.");
}
UUID subscriberId = UUID.randomUUID();
subscribers.put(subscriberId, new Pair<EventTopic, EventSubscriber>(topic, subscriber));
return subscriberId;
}
@Override
public void unsubscribe(UUID subscriberId, EventSubscriber subscriber) throws EventBusException {
if (subscriberId == null) {
throw new EventBusException("Cannot unregister a null subscriberId.");
}
if (subscribers.isEmpty()) {
throw new EventBusException("There are no registered subscribers to unregister.");
}
if (!subscribers.containsKey(subscriberId)) {
throw new EventBusException("No subscriber found with subscriber id " + subscriberId);
} else {
subscribers.remove(subscriberId);
}
}
@Override
public void publish(Event event) throws EventBusException {
if (subscribers == null || subscribers.isEmpty()) {
return; // no subscriber to publish to, so just return
}
for (UUID subscriberId : subscribers.keySet()) {
Pair<EventTopic, EventSubscriber> subscriberDetails = subscribers.get(subscriberId);
// if the event matches subscribers interested event topic then call back the subscriber with the event
if (isEventMatchesTopic(event, subscriberDetails.first())) {
EventSubscriber subscriber = subscriberDetails.second();
subscriber.onEvent(event);
}
}
}
@Override
public String getName() {
return _name;
}
@Override
public boolean start() {
return true;
}
@Override
public boolean stop() {
return true;
}
public int totalSubscribers() {
return subscribers.size();
}
private String replaceNullWithWildcard(String key) {
if (key == null || key.isEmpty()) {
return "*";
} else {
return key;
}
}
private boolean isEventMatchesTopic(Event event, EventTopic topic) {
String eventTopicSource = replaceNullWithWildcard(topic.getEventSource());
eventTopicSource = eventTopicSource.replace(".", "-");
String eventSource = replaceNullWithWildcard(event.getEventSource());
eventSource = eventSource.replace(".", "-");
if (!eventTopicSource.equals("*") && !eventSource.equals("*") && !eventTopicSource.equalsIgnoreCase(eventSource)) {
return false;
}
String eventTopicCategory = replaceNullWithWildcard(topic.getEventCategory());
eventTopicCategory = eventTopicCategory.replace(".", "-");
String eventCategory = replaceNullWithWildcard(event.getEventCategory());
eventCategory = eventCategory.replace(".", "-");
if (!eventTopicCategory.equals("*") && !eventCategory.equals("*") && !eventTopicCategory.equalsIgnoreCase(eventCategory)) {
return false;
}
String eventTopicType = replaceNullWithWildcard(topic.getEventType());
eventTopicType = eventTopicType.replace(".", "-");
String eventType = replaceNullWithWildcard(event.getEventType());
eventType = eventType.replace(".", "-");
if (!eventTopicType.equals("*") && !eventType.equals("*") && !eventTopicType.equalsIgnoreCase(eventType)) {
return false;
}
String eventTopicResourceType = replaceNullWithWildcard(topic.getResourceType());
eventTopicResourceType = eventTopicResourceType.replace(".", "-");
String resourceType = replaceNullWithWildcard(event.getResourceType());
resourceType = resourceType.replace(".", "-");
if (!eventTopicResourceType.equals("*") && !resourceType.equals("*") && !eventTopicResourceType.equalsIgnoreCase(resourceType)) {
return false;
}
String resourceUuid = replaceNullWithWildcard(event.getResourceUUID());
resourceUuid = resourceUuid.replace(".", "-");
String eventTopicresourceUuid = replaceNullWithWildcard(topic.getResourceUUID());
eventTopicresourceUuid = eventTopicresourceUuid.replace(".", "-");
if (!resourceUuid.equals("*") && !eventTopicresourceUuid.equals("*") && !resourceUuid.equalsIgnoreCase(eventTopicresourceUuid)) {
return false;
}
return true;
}
}