Java tutorial
/* * Copyright (c) 2015, WSO2 Inc. (http://www.wso2.org) All Rights Reserved. * * Licensed 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.wso2.carbon.registry.caching.invalidator.connection; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.wso2.carbon.registry.caching.invalidator.impl.ConfigurationManager; import org.wso2.carbon.registry.caching.invalidator.impl.GlobalCacheInvalidationEvent; import org.wso2.carbon.registry.caching.invalidator.internal.CacheInvalidationDataHolder; import org.wso2.carbon.context.PrivilegedCarbonContext; import javax.cache.CacheManager; import javax.cache.Caching; import javax.jms.BytesMessage; import javax.jms.Connection; import javax.jms.ConnectionFactory; import javax.jms.Destination; import javax.jms.JMSException; import javax.jms.Message; import javax.jms.MessageConsumer; import javax.jms.MessageListener; import javax.jms.MessageProducer; import javax.jms.Session; import javax.jms.TopicSession; import javax.naming.Context; import javax.naming.InitialContext; import javax.naming.NamingException; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.ObjectInputStream; import java.util.Properties; public class JMSNotification implements InvalidNotification, MessageListener { // Setup the pub/sub connection, session // Send the msg (byte stream) private static Connection connection = null; private static Destination destination = null; private static final Log log = LogFactory.getLog(JMSNotification.class); @Override public void createConnection(Properties config) { try { Properties props = new Properties(); props.put(Context.INITIAL_CONTEXT_FACTORY, config.getProperty("initialContextFactory")); props.put(Context.PROVIDER_URL, config.getProperty("providerUrl")); props.put(Context.SECURITY_PRINCIPAL, config.getProperty("securityPrincipal")); props.put(Context.SECURITY_CREDENTIALS, config.getProperty("securityCredentials")); props.put("topic.cacheInvalidateTopic", config.getProperty("cacheInvalidateTopic")); InitialContext jndi = new InitialContext(props); ConnectionFactory connectionFactory = (ConnectionFactory) jndi.lookup("ConnectionFactory"); destination = (Destination) jndi.lookup("cacheInvalidateTopic"); connection = connectionFactory.createConnection(config.getProperty("securityPrincipal"), config.getProperty("securityCredentials")); connection.start(); } catch (NamingException | JMSException e) { log.error("Global cache invalidation: Error message broker initialization", e); } } @Override public void closeConnection() { if (connection != null) { try { connection.close(); } catch (JMSException e) { log.error("Global cache invalidation: Error in closing connection", e); } } } @Override public void publish(Object message) { Session pubSession = null; try { if (connection != null) { pubSession = connection.createSession(false, TopicSession.AUTO_ACKNOWLEDGE); MessageProducer publisher = pubSession.createProducer(destination); BytesMessage bytesMessage = pubSession.createBytesMessage(); bytesMessage.writeBytes((byte[]) message); publisher.send(bytesMessage); } } catch (JMSException e) { log.error("Global cache invalidation: Error in publishing the message", e); } finally { if (pubSession != null) { try { pubSession.close(); } catch (JMSException e) { log.error("Global cache invalidation: Error in publishing the message", e); } } } } @Override public void subscribe() { try { Session subSession = connection.createSession(false, TopicSession.AUTO_ACKNOWLEDGE); MessageConsumer messageConsumer = subSession.createConsumer(destination); messageConsumer.setMessageListener(this); connection.start(); log.info("Global cache invalidation is online"); } catch (JMSException e) { log.error("Global cache invalidation: Error in subscribing to topic", e); } } @Override public void onMessage(Message message) { BytesMessage bytesMessage = (BytesMessage) message; byte[] data; try { data = new byte[(int) bytesMessage.getBodyLength()]; for (int i = 0; i < (int) bytesMessage.getBodyLength(); i++) { data[i] = bytesMessage.readByte(); } log.debug("Cache invalidation message received: " + new String(data)); } catch (JMSException jmsException) { log.error("Error while reading the received message", jmsException); return; } boolean isCoordinator = false; if (CacheInvalidationDataHolder.getConfigContext() != null) { isCoordinator = CacheInvalidationDataHolder.getConfigContext().getAxisConfiguration() .getClusteringAgent().isCoordinator(); } if (isCoordinator) { PrivilegedCarbonContext.startTenantFlow(); try { log.debug("Global cache invalidation: deserializing data to object"); GlobalCacheInvalidationEvent event = (GlobalCacheInvalidationEvent) deserialize(data); log.debug("Global cache invalidation: deserializing complete"); if (!ConfigurationManager.getSentMsgBuffer().contains(event.getUuid().trim())) { // Ignore own messages PrivilegedCarbonContext.getThreadLocalCarbonContext().setTenantId(event.getTenantId(), true); CacheManager cacheManager = Caching.getCacheManagerFactory() .getCacheManager(event.getCacheManagerName()); if (cacheManager != null) { if (cacheManager.getCache(event.getCacheName()) != null) { cacheManager.getCache(event.getCacheName()).remove(event.getCacheKey()); log.debug("Global cache invalidated: " + event.getCacheKey()); } else { log.error("Global cache invalidation: error cache is null"); } } else { log.error("Global cache invalidation: error cache manager is null"); } } else { // To resolve future performance issues ConfigurationManager.getSentMsgBuffer().remove(event.getUuid().trim()); log.debug("Global cache invalidation: own message ignored"); } } catch (Exception e) { log.error("Global cache invalidation: error local cache update", e); } finally { PrivilegedCarbonContext.endTenantFlow(); } } } private Object deserialize(byte[] bytes) throws IOException, ClassNotFoundException { ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(bytes); ObjectInputStream objectInputStream = new ObjectInputStream(byteArrayInputStream); return objectInputStream.readObject(); } }