| /* |
| * 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.flink.statefun.flink.core.feedback; |
| |
| import java.util.Objects; |
| import java.util.concurrent.ConcurrentHashMap; |
| |
| /** |
| * HandOffChannelBroker. |
| * |
| * <p>It is used together with the co-location constrain so that two tasks can access the same |
| * "hand-off" channel, and communicate directly (not via the network stack) by simply passing |
| * references in one direction. |
| * |
| * <p>To obtain a feedback channel one must first obtain an {@link SubtaskFeedbackKey} and simply |
| * call {@link #get()}. A channel is removed from this broker on a call to {@link |
| * FeedbackChannel#close()}. |
| */ |
| public final class FeedbackChannelBroker { |
| |
| private static final FeedbackChannelBroker INSTANCE = new FeedbackChannelBroker(); |
| |
| private final ConcurrentHashMap<SubtaskFeedbackKey<?>, FeedbackChannel<?>> channels = |
| new ConcurrentHashMap<>(); |
| |
| public static FeedbackChannelBroker get() { |
| return INSTANCE; |
| } |
| |
| @SuppressWarnings({"unchecked"}) |
| public <V> FeedbackChannel<V> getChannel(SubtaskFeedbackKey<V> key) { |
| Objects.requireNonNull(key); |
| |
| FeedbackChannel<?> channel = channels.computeIfAbsent(key, FeedbackChannelBroker::newChannel); |
| |
| return (FeedbackChannel<V>) channel; |
| } |
| |
| @SuppressWarnings("resource") |
| void removeChannel(SubtaskFeedbackKey<?> key) { |
| channels.remove(key); |
| } |
| |
| private static <V> FeedbackChannel<V> newChannel(SubtaskFeedbackKey<V> key) { |
| FeedbackQueue<V> queue = new LockFreeBatchFeedbackQueue<>(); |
| return new FeedbackChannel<>(key, queue); |
| } |
| } |