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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.client;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.function.ThrowableAction;
import org.apache.dubbo.common.logger.Logger;
import org.apache.dubbo.common.logger.LoggerFactory;
import org.apache.dubbo.common.utils.Page;
import org.apache.dubbo.event.Event;
import org.apache.dubbo.event.EventDispatcher;
import org.apache.dubbo.registry.client.event.ServiceDiscoveryDestroyedEvent;
import org.apache.dubbo.registry.client.event.ServiceDiscoveryDestroyingEvent;
import org.apache.dubbo.registry.client.event.ServiceDiscoveryExceptionEvent;
import org.apache.dubbo.registry.client.event.ServiceDiscoveryInitializedEvent;
import org.apache.dubbo.registry.client.event.ServiceDiscoveryInitializingEvent;
import org.apache.dubbo.registry.client.event.ServiceInstancePreRegisteredEvent;
import org.apache.dubbo.registry.client.event.ServiceInstancePreUnregisteredEvent;
import org.apache.dubbo.registry.client.event.ServiceInstanceRegisteredEvent;
import org.apache.dubbo.registry.client.event.ServiceInstanceUnregisteredEvent;
import org.apache.dubbo.registry.client.event.listener.ServiceInstancesChangedListener;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.atomic.AtomicBoolean;
import static java.util.Optional.empty;
import static java.util.Optional.of;
/**
* The decorating implementation of {@link ServiceDiscovery} to published the {@link Event Dubbo event} when some actions are
* executing, including:
*
* - Lifecycle actions:
*
*
*
* Action
* before
* After
*
*
*
*
* {@link #INITIALIZE_ACTION start}
* {@link ServiceDiscoveryInitializingEvent}
* {@link ServiceDiscoveryInitializedEvent}
*
*
* {@link #DESTROY_ACTION stop}
* {@link ServiceDiscoveryDestroyingEvent}
* {@link ServiceDiscoveryDestroyedEvent}
*
*
*
* - Registration actions:
*
*
*
* Action
* before
* After
*
*
*
*
* {@link #REGISTER_ACTION register}
* {@link ServiceInstancePreRegisteredEvent}
* {@link ServiceInstanceRegisteredEvent}
*
*
* {@link #UPDATE_ACTION update}
* N/A
* N/A
*
*
* {@link #UNREGISTER_ACTION unregister}
* N/A
* N/A
*
*
*
*
*
* @see ServiceDiscovery
* @see ServiceDiscoveryInitializingEvent
* @see ServiceDiscoveryInitializedEvent
* @see ServiceInstancePreRegisteredEvent
* @see ServiceInstanceRegisteredEvent
* @see ServiceDiscoveryDestroyingEvent
* @see ServiceDiscoveryDestroyedEvent
* @since 2.7.5
*/
final class EventPublishingServiceDiscovery implements ServiceDiscovery {
/**
* @see ServiceInstancePreRegisteredEvent
* @see ServiceInstanceRegisteredEvent
*/
protected static final String REGISTER_ACTION = "register";
protected static final String UPDATE_ACTION = "update";
protected static final String UNREGISTER_ACTION = "unregister";
/**
* @see ServiceDiscoveryInitializingEvent
* @see ServiceDiscoveryInitializedEvent
*/
protected static final String INITIALIZE_ACTION = "initialize";
/**
* @see ServiceDiscoveryDestroyingEvent
* @see ServiceDiscoveryDestroyedEvent
*/
protected static final String DESTROY_ACTION = "destroy";
protected final EventDispatcher eventDispatcher = EventDispatcher.getDefaultExtension();
protected final AtomicBoolean initialized = new AtomicBoolean(false);
protected final AtomicBoolean destroyed = new AtomicBoolean(false);
protected final Logger logger = LoggerFactory.getLogger(getClass());
private final ServiceDiscovery serviceDiscovery;
protected EventPublishingServiceDiscovery(ServiceDiscovery serviceDiscovery) {
if (serviceDiscovery == null) {
throw new NullPointerException("The ServiceDiscovery argument must not be null!");
}
this.serviceDiscovery = serviceDiscovery;
}
@Override
public final void register(ServiceInstance serviceInstance) throws RuntimeException {
assertDestroyed(REGISTER_ACTION);
assertInitialized(REGISTER_ACTION);
executeWithEvents(
of(new ServiceInstancePreRegisteredEvent(serviceDiscovery, serviceInstance)),
() -> serviceDiscovery.register(serviceInstance),
of(new ServiceInstanceRegisteredEvent(serviceDiscovery, serviceInstance))
);
}
@Override
public final void update(ServiceInstance serviceInstance) throws RuntimeException {
assertDestroyed(UPDATE_ACTION);
assertInitialized(UPDATE_ACTION);
executeWithEvents(
empty(),
() -> serviceDiscovery.update(serviceInstance),
empty()
);
}
@Override
public final void unregister(ServiceInstance serviceInstance) throws RuntimeException {
assertDestroyed(UNREGISTER_ACTION);
assertInitialized(UNREGISTER_ACTION);
executeWithEvents(
of(new ServiceInstancePreUnregisteredEvent(this, serviceInstance)),
() -> serviceDiscovery.unregister(serviceInstance),
of(new ServiceInstanceUnregisteredEvent(this, serviceInstance))
);
}
@Override
public Set getServices() {
return serviceDiscovery.getServices();
}
@Override
public List getInstances(String serviceName) throws NullPointerException {
return serviceDiscovery.getInstances(serviceName);
}
@Override
public Page getInstances(String serviceName, int offset, int pageSize) throws NullPointerException, IllegalArgumentException {
return serviceDiscovery.getInstances(serviceName, offset, pageSize);
}
@Override
public Page getInstances(String serviceName, int offset, int pageSize, boolean healthyOnly) throws NullPointerException, IllegalArgumentException {
return serviceDiscovery.getInstances(serviceName, offset, pageSize, healthyOnly);
}
@Override
public Map> getInstances(Iterable serviceNames, int offset, int requestSize) throws NullPointerException, IllegalArgumentException {
return serviceDiscovery.getInstances(serviceNames, offset, requestSize);
}
@Override
public String toString() {
return serviceDiscovery.toString();
}
@Override
public void addServiceInstancesChangedListener(ServiceInstancesChangedListener listener) throws NullPointerException, IllegalArgumentException {
serviceDiscovery.addServiceInstancesChangedListener(listener);
eventDispatcher.addEventListener(listener);
}
@Override
public URL getUrl() {
return serviceDiscovery.getUrl();
}
@Override
public ServiceInstance getLocalInstance() {
return serviceDiscovery.getLocalInstance();
}
@Override
public void initialize(URL registryURL) {
assertDestroyed(INITIALIZE_ACTION);
if (isInitialized()) {
if (logger.isWarnEnabled()) {
logger.warn("It's ignored to start current ServiceDiscovery, because it has been started.");
}
return;
}
executeWithEvents(
of(new ServiceDiscoveryInitializingEvent(this, serviceDiscovery)),
() -> serviceDiscovery.initialize(registryURL),
of(new ServiceDiscoveryInitializedEvent(this, serviceDiscovery))
);
// doesn't start -> started
initialized.compareAndSet(false, true);
}
@Override
public void destroy() {
assertDestroyed(DESTROY_ACTION);
executeWithEvents(
of(new ServiceDiscoveryDestroyingEvent(this, serviceDiscovery)),
serviceDiscovery::destroy,
of(new ServiceDiscoveryDestroyedEvent(this, serviceDiscovery))
);
// doesn't stop -> stopped
destroyed.compareAndSet(false, true);
}
protected final void executeWithEvents(Optional beforeEvent,
ThrowableAction action,
Optional afterEvent) {
beforeEvent.ifPresent(this::dispatchEvent);
try {
action.execute();
} catch (Throwable e) {
logger.error("Execute action throws and dispatch a ServiceDiscoveryExceptionEvent.", e);
dispatchEvent(new ServiceDiscoveryExceptionEvent(this, serviceDiscovery, e));
}
afterEvent.ifPresent(this::dispatchEvent);
}
private void dispatchEvent(Event event) {
eventDispatcher.dispatch(event);
}
public final boolean isInitialized() {
return initialized.get();
}
public final boolean isDestroyed() {
return destroyed.get();
}
protected void assertDestroyed(String action) throws IllegalStateException {
if (isDestroyed()) {
throw new IllegalStateException("The action[" + action + "] is rejected, because the ServiceDiscovery is destroyed already.");
}
}
protected void assertInitialized(String action) throws IllegalStateException {
if (!isInitialized()) {
throw new IllegalStateException("The action[" + action + "] is rejected, because the ServiceDiscovery is not initialized yet.");
}
}
}