001/** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.activemq.advisory; 018 019import java.util.EventObject; 020 021import javax.jms.Destination; 022 023import org.apache.activemq.command.ConsumerId; 024 025/** 026 * An event when the number of consumers on a given destination changes. 027 * 028 * 029 */ 030public abstract class ConsumerEvent extends EventObject { 031 private static final long serialVersionUID = 2442156576867593780L; 032 private final Destination destination; 033 private final ConsumerId consumerId; 034 private final int consumerCount; 035 036 public ConsumerEvent(ConsumerEventSource source, Destination destination, ConsumerId consumerId, int consumerCount) { 037 super(source); 038 this.destination = destination; 039 this.consumerId = consumerId; 040 this.consumerCount = consumerCount; 041 } 042 043 public ConsumerEventSource getAdvisor() { 044 return (ConsumerEventSource) getSource(); 045 } 046 047 public Destination getDestination() { 048 return destination; 049 } 050 051 /** 052 * Returns the current number of consumers active at the time this advisory was sent. 053 * 054 * Note that this is not the number of consumers active when the consumer started consuming. 055 * It is usually more vital to know how many consumers there are now - rather than historically 056 * how many there were when a consumer started. So if you create a {@link ConsumerListener} 057 * after many consumers have started, you will receive a ConsumerEvent for each consumer. However the 058 * {@link #getConsumerCount()} method will always return the current active consumer count on each event. 059 */ 060 public int getConsumerCount() { 061 return consumerCount; 062 } 063 064 public ConsumerId getConsumerId() { 065 return consumerId; 066 } 067 068 public abstract boolean isStarted(); 069}