001/* 002 * Copyright 2002-2017 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.messaging.simp.user; 018 019import java.util.concurrent.ScheduledFuture; 020 021import org.springframework.context.ApplicationListener; 022import org.springframework.messaging.Message; 023import org.springframework.messaging.MessageHandler; 024import org.springframework.messaging.MessagingException; 025import org.springframework.messaging.converter.MessageConverter; 026import org.springframework.messaging.simp.SimpMessageHeaderAccessor; 027import org.springframework.messaging.simp.SimpMessageType; 028import org.springframework.messaging.simp.SimpMessagingTemplate; 029import org.springframework.messaging.simp.broker.BrokerAvailabilityEvent; 030import org.springframework.scheduling.TaskScheduler; 031import org.springframework.util.Assert; 032 033/** 034 * {@code MessageHandler} that handles user registry broadcasts from other 035 * application servers and periodically broadcasts the content of the local 036 * user registry. 037 * 038 * <p>The aggregated information is maintained in a {@link MultiServerUserRegistry}. 039 * 040 * @author Rossen Stoyanchev 041 * @since 4.2 042 */ 043public class UserRegistryMessageHandler implements MessageHandler, ApplicationListener<BrokerAvailabilityEvent> { 044 045 private final MultiServerUserRegistry userRegistry; 046 047 private final SimpMessagingTemplate brokerTemplate; 048 049 private final String broadcastDestination; 050 051 private final TaskScheduler scheduler; 052 053 private final UserRegistryTask schedulerTask = new UserRegistryTask(); 054 055 private volatile ScheduledFuture<?> scheduledFuture; 056 057 private long registryExpirationPeriod = 20 * 1000; 058 059 060 /** 061 * Constructor. 062 * @param userRegistry the registry with local and remote user registry information 063 * @param brokerTemplate template for broadcasting local registry information 064 * @param broadcastDestination the destination to broadcast to 065 * @param scheduler the task scheduler to use 066 */ 067 public UserRegistryMessageHandler(MultiServerUserRegistry userRegistry, 068 SimpMessagingTemplate brokerTemplate, String broadcastDestination, TaskScheduler scheduler) { 069 070 Assert.notNull(userRegistry, "'userRegistry' is required"); 071 Assert.notNull(brokerTemplate, "'brokerTemplate' is required"); 072 Assert.hasText(broadcastDestination, "'broadcastDestination' is required"); 073 Assert.notNull(scheduler, "'scheduler' is required"); 074 075 this.userRegistry = userRegistry; 076 this.brokerTemplate = brokerTemplate; 077 this.broadcastDestination = broadcastDestination; 078 this.scheduler = scheduler; 079 } 080 081 082 /** 083 * Return the configured destination for broadcasting UserRegistry information. 084 */ 085 public String getBroadcastDestination() { 086 return this.broadcastDestination; 087 } 088 089 /** 090 * Configure the amount of time (in milliseconds) before a remote user 091 * registry snapshot is considered expired. 092 * <p>By default this is set to 20 seconds (value of 20000). 093 * @param milliseconds the expiration period in milliseconds 094 */ 095 @SuppressWarnings("unused") 096 public void setRegistryExpirationPeriod(long milliseconds) { 097 this.registryExpirationPeriod = milliseconds; 098 } 099 100 /** 101 * Return the configured registry expiration period. 102 */ 103 public long getRegistryExpirationPeriod() { 104 return this.registryExpirationPeriod; 105 } 106 107 108 @Override 109 public void onApplicationEvent(BrokerAvailabilityEvent event) { 110 if (event.isBrokerAvailable()) { 111 long delay = getRegistryExpirationPeriod() / 2; 112 this.scheduledFuture = this.scheduler.scheduleWithFixedDelay(this.schedulerTask, delay); 113 } 114 else { 115 ScheduledFuture<?> future = this.scheduledFuture; 116 if (future != null ){ 117 future.cancel(true); 118 this.scheduledFuture = null; 119 } 120 } 121 } 122 123 @Override 124 public void handleMessage(Message<?> message) throws MessagingException { 125 MessageConverter converter = this.brokerTemplate.getMessageConverter(); 126 this.userRegistry.addRemoteRegistryDto(message, converter, getRegistryExpirationPeriod()); 127 } 128 129 130 private class UserRegistryTask implements Runnable { 131 132 @Override 133 public void run() { 134 try { 135 SimpMessageHeaderAccessor accessor = SimpMessageHeaderAccessor.create(SimpMessageType.MESSAGE); 136 accessor.setHeader(SimpMessageHeaderAccessor.IGNORE_ERROR, true); 137 accessor.setLeaveMutable(true); 138 Object payload = userRegistry.getLocalRegistryDto(); 139 brokerTemplate.convertAndSend(getBroadcastDestination(), payload, accessor.getMessageHeaders()); 140 } 141 finally { 142 userRegistry.purgeExpiredRegistries(); 143 } 144 } 145 } 146 147}