| /** |
| * 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 |
| * <p> |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * <p> |
| * 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.hadoop.hdds.server.events; |
| |
| import java.util.HashSet; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Set; |
| import java.util.UUID; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.function.Predicate; |
| import java.util.stream.Collectors; |
| |
| import org.apache.hadoop.ozone.lease.Lease; |
| import org.apache.hadoop.ozone.lease.LeaseAlreadyExistException; |
| import org.apache.hadoop.ozone.lease.LeaseExpiredException; |
| import org.apache.hadoop.ozone.lease.LeaseManager; |
| import org.apache.hadoop.ozone.lease.LeaseNotFoundException; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * Event watcher the (re)send a message after timeout. |
| * <p> |
| * Event watcher will send the tracked payload/event after a timeout period |
| * unless a confirmation from the original event (completion event) is arrived. |
| * |
| * @param <TIMEOUT_PAYLOAD> The type of the events which are tracked. |
| * @param <COMPLETION_PAYLOAD> The type of event which could cancel the |
| * tracking. |
| */ |
| @SuppressWarnings("CheckStyle") |
| public abstract class EventWatcher<TIMEOUT_PAYLOAD extends |
| IdentifiableEventPayload, |
| COMPLETION_PAYLOAD extends IdentifiableEventPayload> { |
| |
| private static final Logger LOG = LoggerFactory.getLogger(EventWatcher.class); |
| |
| private final Event<TIMEOUT_PAYLOAD> startEvent; |
| |
| private final Event<COMPLETION_PAYLOAD> completionEvent; |
| |
| private final LeaseManager<UUID> leaseManager; |
| |
| protected final Map<UUID, TIMEOUT_PAYLOAD> trackedEventsByUUID = |
| new ConcurrentHashMap<>(); |
| |
| protected final Set<TIMEOUT_PAYLOAD> trackedEvents = new HashSet<>(); |
| |
| public EventWatcher(Event<TIMEOUT_PAYLOAD> startEvent, |
| Event<COMPLETION_PAYLOAD> completionEvent, |
| LeaseManager<UUID> leaseManager) { |
| this.startEvent = startEvent; |
| this.completionEvent = completionEvent; |
| this.leaseManager = leaseManager; |
| |
| } |
| |
| public void start(EventQueue queue) { |
| |
| queue.addHandler(startEvent, this::handleStartEvent); |
| |
| queue.addHandler(completionEvent, (completionPayload, publisher) -> { |
| UUID uuid = completionPayload.getUUID(); |
| try { |
| handleCompletion(uuid, publisher); |
| } catch (LeaseNotFoundException e) { |
| //It's already done. Too late, we already retried it. |
| //Not a real problem. |
| LOG.warn("Completion event without active lease. UUID={}", uuid); |
| } |
| }); |
| |
| } |
| |
| private synchronized void handleStartEvent(TIMEOUT_PAYLOAD payload, |
| EventPublisher publisher) { |
| UUID identifier = payload.getUUID(); |
| trackedEventsByUUID.put(identifier, payload); |
| trackedEvents.add(payload); |
| try { |
| Lease<UUID> lease = leaseManager.acquire(identifier); |
| try { |
| lease.registerCallBack(() -> { |
| handleTimeout(publisher, identifier); |
| return null; |
| }); |
| |
| } catch (LeaseExpiredException e) { |
| handleTimeout(publisher, identifier); |
| } |
| } catch (LeaseAlreadyExistException e) { |
| //No problem at all. But timer is not reset. |
| } |
| } |
| |
| private synchronized void handleCompletion(UUID uuid, |
| EventPublisher publisher) throws LeaseNotFoundException { |
| leaseManager.release(uuid); |
| TIMEOUT_PAYLOAD payload = trackedEventsByUUID.remove(uuid); |
| trackedEvents.remove(payload); |
| onFinished(publisher, payload); |
| } |
| |
| private synchronized void handleTimeout(EventPublisher publisher, |
| UUID identifier) { |
| TIMEOUT_PAYLOAD payload = trackedEventsByUUID.remove(identifier); |
| trackedEvents.remove(payload); |
| onTimeout(publisher, payload); |
| } |
| |
| |
| /** |
| * Check if a specific payload is in-progress. |
| */ |
| public synchronized boolean contains(TIMEOUT_PAYLOAD payload) { |
| return trackedEvents.contains(payload); |
| } |
| |
| public synchronized boolean remove(TIMEOUT_PAYLOAD payload) { |
| try { |
| leaseManager.release(payload.getUUID()); |
| } catch (LeaseNotFoundException e) { |
| LOG.warn("Completion event without active lease. UUID={}", |
| payload.getUUID()); |
| } |
| trackedEventsByUUID.remove(payload.getUUID()); |
| return trackedEvents.remove(payload); |
| |
| } |
| |
| abstract void onTimeout(EventPublisher publisher, TIMEOUT_PAYLOAD payload); |
| |
| abstract void onFinished(EventPublisher publisher, TIMEOUT_PAYLOAD payload); |
| |
| public List<TIMEOUT_PAYLOAD> getTimeoutEvents( |
| Predicate<? super TIMEOUT_PAYLOAD> predicate) { |
| return trackedEventsByUUID.values().stream().filter(predicate) |
| .collect(Collectors.toList()); |
| } |
| } |