| /* |
| * 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.stratos.messaging.message.receiver.cluster.status; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.stratos.common.threading.StratosThreadPool; |
| import org.apache.stratos.messaging.broker.subscribe.EventSubscriber; |
| import org.apache.stratos.messaging.listener.EventListener; |
| import org.apache.stratos.messaging.message.receiver.StratosEventReceiver; |
| import org.apache.stratos.messaging.util.MessagingUtil; |
| |
| |
| /** |
| * A thread for receiving instance notifier information from message broker. |
| */ |
| public class ClusterStatusEventReceiver extends StratosEventReceiver { |
| private static final Log log = LogFactory.getLog(ClusterStatusEventReceiver.class); |
| private final ClusterStatusEventMessageDelegator messageDelegator; |
| private final ClusterStatusEventMessageListener messageListener; |
| private EventSubscriber eventSubscriber; |
| private static volatile ClusterStatusEventReceiver instance; |
| |
| private ClusterStatusEventReceiver() { |
| // TODO: make pool size configurable |
| this.executorService = StratosThreadPool.getExecutorService("clusterstatus-event-receiver", 100); |
| ClusterStatusEventMessageQueue messageQueue = new ClusterStatusEventMessageQueue(); |
| this.messageDelegator = new ClusterStatusEventMessageDelegator(messageQueue); |
| this.messageListener = new ClusterStatusEventMessageListener(messageQueue); |
| execute(); |
| } |
| |
| public void addEventListener(EventListener eventListener) { |
| messageDelegator.addEventListener(eventListener); |
| } |
| |
| public static ClusterStatusEventReceiver getInstance () { |
| if (instance == null) { |
| synchronized (ClusterStatusEventReceiver.class) { |
| if (instance == null) { |
| instance = new ClusterStatusEventReceiver(); |
| } |
| } |
| } |
| |
| return instance; |
| } |
| |
| private void execute() { |
| try { |
| // Start topic subscriber thread |
| eventSubscriber = new EventSubscriber(MessagingUtil.Topics.CLUSTER_STATUS_TOPIC.getTopicName(), messageListener); |
| executorService.execute(eventSubscriber); |
| |
| if (log.isDebugEnabled()) { |
| log.debug("InstanceNotifier event message receiver thread started"); |
| } |
| |
| // Start instance notifier event message delegator thread |
| executorService.execute(messageDelegator); |
| if (log.isDebugEnabled()) { |
| log.debug("InstanceNotifier event message delegator thread started"); |
| } |
| |
| |
| } catch (Exception e) { |
| if (log.isErrorEnabled()) { |
| log.error("InstanceNotifier receiver failed", e); |
| } |
| } |
| } |
| |
| public void terminate() { |
| eventSubscriber.terminate(); |
| messageDelegator.terminate(); |
| } |
| |
| public boolean isSubscribed() { |
| return ((eventSubscriber != null) && (eventSubscriber.isSubscribed())); |
| } |
| } |