Java tutorial
/** * 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.hcatalog.messaging.jms; import org.apache.commons.lang.StringUtils; import org.apache.hcatalog.common.HCatConstants; import org.apache.hcatalog.messaging.HCatEventMessage; import org.apache.hcatalog.messaging.MessageFactory; import javax.jms.JMSException; import javax.jms.Message; import javax.jms.TextMessage; /** * Helper Utility to assist consumers of HCat Messages in extracting * message-content from JMS messages. */ public class MessagingUtils { /** * Method to return HCatEventMessage contained in the JMS message. * @param message The JMS Message instance * @return The contained HCatEventMessage */ public static HCatEventMessage getMessage(Message message) { try { String messageBody = ((TextMessage) message).getText(); String eventType = message.getStringProperty(HCatConstants.HCAT_EVENT); String messageVersion = message.getStringProperty(HCatConstants.HCAT_MESSAGE_VERSION); String messageFormat = message.getStringProperty(HCatConstants.HCAT_MESSAGE_FORMAT); if (StringUtils.isEmpty(messageBody) || StringUtils.isEmpty(eventType)) throw new IllegalArgumentException( "Could not extract HCatEventMessage. " + "EventType and/or MessageBody is null/empty."); return MessageFactory.getDeserializer(messageFormat, messageVersion).getHCatEventMessage(eventType, messageBody); } catch (JMSException exception) { throw new IllegalArgumentException("Could not extract HCatEventMessage. ", exception); } } // Prevent construction. private MessagingUtils() { } }