| /* |
| * 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.beam.runners.core.metrics; |
| |
| import java.io.Serializable; |
| import java.util.Map; |
| import java.util.Objects; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.concurrent.ConcurrentMap; |
| import javax.annotation.Nullable; |
| import org.apache.beam.sdk.annotations.Experimental; |
| import org.apache.beam.sdk.annotations.Experimental.Kind; |
| import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.MoreObjects; |
| import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.Iterables; |
| |
| /** |
| * A map from {@code K} to {@code T} that supports getting or creating values associated with a key |
| * in a thread-safe manner. |
| */ |
| @Experimental(Kind.METRICS) |
| public class MetricsMap<K, T> implements Serializable { |
| |
| /** Interface for creating instances to populate the {@link MetricsMap}. */ |
| public interface Factory<K, T> extends Serializable { |
| /** |
| * Create an instance of {@code T} to use with the given {@code key}. |
| * |
| * <p>It must be safe to call this from multiple threads. |
| */ |
| T createInstance(K key); |
| } |
| |
| private final Factory<K, T> factory; |
| private final ConcurrentMap<K, T> metrics = new ConcurrentHashMap<>(); |
| |
| public MetricsMap(Factory<K, T> factory) { |
| this.factory = factory; |
| } |
| |
| /** Get or create the value associated with the given key. */ |
| public T get(K key) { |
| T metric = metrics.get(key); |
| if (metric == null) { |
| metric = factory.createInstance(key); |
| metric = MoreObjects.firstNonNull(metrics.putIfAbsent(key, metric), metric); |
| } |
| return metric; |
| } |
| |
| /** Get the value associated with the given key, if it exists. */ |
| @Nullable |
| public T tryGet(K key) { |
| return metrics.get(key); |
| } |
| |
| /** Return an iterable over the entries in the current {@link MetricsMap}. */ |
| public Iterable<Map.Entry<K, T>> entries() { |
| return Iterables.unmodifiableIterable(metrics.entrySet()); |
| } |
| |
| /** Return an iterable over the values in the current {@link MetricsMap}. */ |
| public Iterable<T> values() { |
| return Iterables.unmodifiableIterable(metrics.values()); |
| } |
| |
| @Override |
| public boolean equals(Object object) { |
| if (object instanceof MetricsMap) { |
| MetricsMap<?, ?> metricsMap = (MetricsMap<?, ?>) object; |
| return Objects.equals(metrics, metricsMap.metrics); |
| } |
| |
| return false; |
| } |
| |
| @Override |
| public int hashCode() { |
| return metrics.hashCode(); |
| } |
| } |