| /** |
| * 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.curator.x.discovery.details; |
| |
| import com.google.common.base.Function; |
| import com.google.common.base.Preconditions; |
| import com.google.common.collect.Lists; |
| import com.google.common.collect.Maps; |
| import org.apache.curator.utils.CloseableExecutorService; |
| import org.apache.curator.utils.CloseableUtils; |
| import org.apache.curator.framework.CuratorFramework; |
| import org.apache.curator.framework.listen.ListenerContainer; |
| import org.apache.curator.framework.recipes.cache.ChildData; |
| import org.apache.curator.framework.recipes.cache.PathChildrenCache; |
| import org.apache.curator.framework.recipes.cache.PathChildrenCacheEvent; |
| import org.apache.curator.framework.recipes.cache.PathChildrenCacheListener; |
| import org.apache.curator.utils.ZKPaths; |
| import org.apache.curator.x.discovery.ServiceCache; |
| import org.apache.curator.x.discovery.ServiceInstance; |
| import java.io.IOException; |
| import java.util.List; |
| import java.util.concurrent.ConcurrentMap; |
| import java.util.concurrent.Executor; |
| import java.util.concurrent.Executors; |
| import java.util.concurrent.ThreadFactory; |
| import java.util.concurrent.atomic.AtomicReference; |
| |
| public class ServiceCacheImpl<T> implements ServiceCache<T>, PathChildrenCacheListener |
| { |
| private final ListenerContainer<ServiceCacheListener> listenerContainer = new ListenerContainer<ServiceCacheListener>(); |
| private final ServiceDiscoveryImpl<T> discovery; |
| private final AtomicReference<State> state = new AtomicReference<State>(State.LATENT); |
| private final PathChildrenCache cache; |
| private final ConcurrentMap<String, ServiceInstance<T>> instances = Maps.newConcurrentMap(); |
| |
| private enum State |
| { |
| LATENT, |
| STARTED, |
| STOPPED |
| } |
| |
| private static CloseableExecutorService convertThreadFactory(ThreadFactory threadFactory) |
| { |
| Preconditions.checkNotNull(threadFactory, "threadFactory cannot be null"); |
| return new CloseableExecutorService(Executors.newSingleThreadExecutor(threadFactory)); |
| } |
| |
| ServiceCacheImpl(ServiceDiscoveryImpl<T> discovery, String name, ThreadFactory threadFactory) |
| { |
| this(discovery, name, convertThreadFactory(threadFactory)); |
| } |
| |
| ServiceCacheImpl(ServiceDiscoveryImpl<T> discovery, String name, CloseableExecutorService executorService) |
| { |
| Preconditions.checkNotNull(discovery, "discovery cannot be null"); |
| Preconditions.checkNotNull(name, "name cannot be null"); |
| Preconditions.checkNotNull(executorService, "executorService cannot be null"); |
| |
| this.discovery = discovery; |
| |
| cache = new PathChildrenCache(discovery.getClient(), discovery.pathForName(name), true, false, executorService); |
| cache.getListenable().addListener(this); |
| } |
| |
| @Override |
| public List<ServiceInstance<T>> getInstances() |
| { |
| return Lists.newArrayList(instances.values()); |
| } |
| |
| @Override |
| public void start() throws Exception |
| { |
| Preconditions.checkState(state.compareAndSet(State.LATENT, State.STARTED), "Cannot be started more than once"); |
| |
| cache.start(true); |
| for ( ChildData childData : cache.getCurrentData() ) |
| { |
| addInstance(childData, true); |
| } |
| discovery.cacheOpened(this); |
| } |
| |
| @Override |
| public void close() throws IOException |
| { |
| Preconditions.checkState(state.compareAndSet(State.STARTED, State.STOPPED), "Already closed or has not been started"); |
| |
| listenerContainer.forEach |
| ( |
| new Function<ServiceCacheListener, Void>() |
| { |
| @Override |
| public Void apply(ServiceCacheListener listener) |
| { |
| discovery.getClient().getConnectionStateListenable().removeListener(listener); |
| return null; |
| } |
| } |
| ); |
| listenerContainer.clear(); |
| |
| CloseableUtils.closeQuietly(cache); |
| |
| discovery.cacheClosed(this); |
| } |
| |
| @Override |
| public void addListener(ServiceCacheListener listener) |
| { |
| listenerContainer.addListener(listener); |
| discovery.getClient().getConnectionStateListenable().addListener(listener); |
| } |
| |
| @Override |
| public void addListener(ServiceCacheListener listener, Executor executor) |
| { |
| listenerContainer.addListener(listener, executor); |
| discovery.getClient().getConnectionStateListenable().addListener(listener, executor); |
| } |
| |
| @Override |
| public void removeListener(ServiceCacheListener listener) |
| { |
| listenerContainer.removeListener(listener); |
| discovery.getClient().getConnectionStateListenable().removeListener(listener); |
| } |
| |
| @Override |
| public void childEvent(CuratorFramework client, PathChildrenCacheEvent event) throws Exception |
| { |
| boolean notifyListeners = false; |
| switch ( event.getType() ) |
| { |
| case CHILD_ADDED: |
| case CHILD_UPDATED: |
| { |
| addInstance(event.getData(), false); |
| notifyListeners = true; |
| break; |
| } |
| |
| case CHILD_REMOVED: |
| { |
| instances.remove(instanceIdFromData(event.getData())); |
| notifyListeners = true; |
| break; |
| } |
| } |
| |
| if ( notifyListeners ) |
| { |
| listenerContainer.forEach |
| ( |
| new Function<ServiceCacheListener, Void>() |
| { |
| @Override |
| public Void apply(ServiceCacheListener listener) |
| { |
| listener.cacheChanged(); |
| return null; |
| } |
| } |
| ); |
| } |
| } |
| |
| private String instanceIdFromData(ChildData childData) |
| { |
| return ZKPaths.getNodeFromPath(childData.getPath()); |
| } |
| |
| private void addInstance(ChildData childData, boolean onlyIfAbsent) throws Exception |
| { |
| String instanceId = instanceIdFromData(childData); |
| ServiceInstance<T> serviceInstance = discovery.getSerializer().deserialize(childData.getData()); |
| if ( onlyIfAbsent ) |
| { |
| instances.putIfAbsent(instanceId, serviceInstance); |
| } |
| else |
| { |
| instances.put(instanceId, serviceInstance); |
| } |
| cache.clearDataBytes(childData.getPath(), childData.getStat().getVersion()); |
| } |
| } |