pulsar-client-reactive-adapter/src/main/java/org/apache/pulsar/reactive/client/internal/adapter/AdapterImplementationFactory.java

/*
 * 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
 *
 *   https://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.pulsar.reactive.client.internal.adapter;

import java.util.Iterator;
import java.util.ServiceLoader;
import java.util.concurrent.CompletableFuture;
import java.util.function.Supplier;

import org.apache.pulsar.client.api.PulsarClient;
import org.apache.pulsar.reactive.client.adapter.ProducerCacheProvider;
import org.apache.pulsar.reactive.client.adapter.ProducerCacheProviderFactory;
import org.apache.pulsar.reactive.client.api.ReactiveMessageSenderCache;
import org.apache.pulsar.reactive.client.api.ReactivePulsarClient;
import reactor.core.publisher.Mono;

/**
 * Adapter implementation for {@link ReactivePulsarClient} based on {@link PulsarClient}.
 */
public final class AdapterImplementationFactory {

	private AdapterImplementationFactory() {

	}

	private static final ProducerCacheProviderFactory PRODUCER_CACHE_PROVIDER_FACTORY;

	static {
		Iterator<ProducerCacheProviderFactory> iterator = ServiceLoader.load(ProducerCacheProviderFactory.class)
				.iterator();
		if (iterator.hasNext()) {
			PRODUCER_CACHE_PROVIDER_FACTORY = iterator.next();
		}
		else {
			PRODUCER_CACHE_PROVIDER_FACTORY = null;
		}
	}

	/**
	 * Creates a ReactivePulsarClient which will lazily call the provided supplier to get
	 * an instance of a Pulsar Client when needed.
	 * @param pulsarClientSupplier the supplier to use for getting a Pulsar Client
	 * instance
	 * @return a ReactivePulsarClient instance
	 */
	public static ReactivePulsarClient createReactivePulsarClient(Supplier<PulsarClient> pulsarClientSupplier) {
		return new ReactivePulsarResourceAdapterPulsarClient(new ReactivePulsarResourceAdapter(pulsarClientSupplier));
	}

	/**
	 * Adapts a {@link CompletableFuture} returned by the {@link PulsarClient} operations
	 * to a {@link Mono}.
	 * @param futureSupplier supplier of the {@link CompletableFuture}
	 * @param <T> the internal type
	 * @return the adapted {@link Mono}
	 */
	public static <T> Mono<T> adaptPulsarFuture(Supplier<? extends CompletableFuture<T>> futureSupplier) {
		return PulsarFutureAdapter.adaptPulsarFuture(futureSupplier);
	}

	/**
	 * Creates a {@link ReactiveMessageSenderCache} adapting the provided
	 * {@link ProducerCacheProvider}.
	 * @param producerCacheProvider a ProducerCacheProvider instance
	 * @return a ReactiveMessageSenderCache instance
	 */
	public static ReactiveMessageSenderCache createCache(ProducerCacheProvider producerCacheProvider) {
		return new ProducerCache(producerCacheProvider);
	}

	/**
	 * Creates a {@link ReactiveMessageSenderCache}. If a
	 * {@link ProducerCacheProviderFactory} can be loaded by the {@link ServiceLoader}, it
	 * is used to supply a {@link ProducerCacheProvider} from which the
	 * {@link ReactiveMessageSenderCache} is adapted. Otherwise, the
	 * {@link ReactiveMessageSenderCache} is adapted from a new
	 * {@link ConcurrentHashMapProducerCacheProvider} instance.
	 * @return a ReactiveMessageSenderCache instance
	 */
	public static ReactiveMessageSenderCache createCache() {
		return new ProducerCache((PRODUCER_CACHE_PROVIDER_FACTORY != null) ? PRODUCER_CACHE_PROVIDER_FACTORY.get()
				: new ConcurrentHashMapProducerCacheProvider());
	}

}