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/*
* 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.dubbo.registry.zookeeper;
import org.apache.dubbo.common.threadpool.manager.FrameworkExecutorRepository;
import org.apache.dubbo.common.utils.ConcurrentHashSet;
import org.apache.dubbo.registry.RegistryNotifier;
import org.apache.dubbo.registry.client.ServiceDiscovery;
import org.apache.dubbo.registry.client.ServiceInstance;
import org.apache.dubbo.registry.client.event.ServiceInstancesChangedEvent;
import org.apache.dubbo.registry.client.event.listener.ServiceInstancesChangedListener;
import org.apache.dubbo.rpc.model.ScopeModelUtil;
import org.apache.curator.framework.api.CuratorWatcher;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CountDownLatch;
import static org.apache.zookeeper.Watcher.Event.EventType.NodeChildrenChanged;
import static org.apache.zookeeper.Watcher.Event.EventType.NodeDataChanged;
/**
* Zookeeper {@link ServiceDiscovery} Change {@link CuratorWatcher watcher} only interests in
* {@link Watcher.Event.EventType#NodeChildrenChanged} and {@link Watcher.Event.EventType#NodeDataChanged} event types,
* which will multicast a {@link ServiceInstancesChangedEvent} when the service node has been changed.
*
* @since 2.7.5
*/
public class ZookeeperServiceDiscoveryChangeWatcher implements CuratorWatcher {
private Set listeners = new ConcurrentHashSet<>();
private final ZookeeperServiceDiscovery zookeeperServiceDiscovery;
private final RegistryNotifier notifier;
private volatile boolean keepWatching = true;
private final String serviceName;
private final String path;
private CountDownLatch latch;
public ZookeeperServiceDiscoveryChangeWatcher(ZookeeperServiceDiscovery zookeeperServiceDiscovery,
String serviceName,
String path,
CountDownLatch latch) {
this.zookeeperServiceDiscovery = zookeeperServiceDiscovery;
this.serviceName = serviceName;
this.path = path;
this.latch = latch;
this.notifier = new RegistryNotifier(zookeeperServiceDiscovery.getUrl(), zookeeperServiceDiscovery.getDelay(),
ScopeModelUtil.getFrameworkModel(zookeeperServiceDiscovery.getUrl().getScopeModel()).getBeanFactory()
.getBean(FrameworkExecutorRepository.class).getServiceDiscoveryAddressNotificationExecutor()) {
@Override
protected void doNotify(Object rawAddresses) {
listeners.forEach(listener -> listener.onEvent((ServiceInstancesChangedEvent) rawAddresses));
}
};
}
@Override
public void process(WatchedEvent event) throws Exception {
try {
latch.await();
} catch (InterruptedException e) {
}
Watcher.Event.EventType eventType = event.getType();
if (NodeChildrenChanged.equals(eventType) || NodeDataChanged.equals(eventType)) {
if (shouldKeepWatching()) {
zookeeperServiceDiscovery.reRegisterWatcher(this);
List instanceList = zookeeperServiceDiscovery.getInstances(serviceName);
notifier.notify(new ServiceInstancesChangedEvent(serviceName, instanceList));
}
}
}
public String getPath() {
return path;
}
public void addListener(ServiceInstancesChangedListener listener) {
listeners.add(listener);
}
public Set getListeners() {
return listeners;
}
public boolean shouldKeepWatching() {
return keepWatching;
}
public void stopWatching() {
this.keepWatching = false;
}
public void setLatch(CountDownLatch latch) {
this.latch = latch;
}
public String getServiceName() {
return serviceName;
}
}