org.springframework.core.CoroutinesUtils Maven / Gradle / Ivy

/*
 * Copyright 2002-2021 the original author or authors.
 *
 * Licensed 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.springframework.core;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Objects;

import kotlin.Unit;
import kotlin.jvm.JvmClassMappingKt;
import kotlin.reflect.KClassifier;
import kotlin.reflect.KFunction;
import kotlin.reflect.full.KCallables;
import kotlin.reflect.jvm.ReflectJvmMapping;
import kotlinx.coroutines.BuildersKt;
import kotlinx.coroutines.CoroutineStart;
import kotlinx.coroutines.Deferred;
import kotlinx.coroutines.Dispatchers;
import kotlinx.coroutines.GlobalScope;
import kotlinx.coroutines.flow.Flow;
import kotlinx.coroutines.reactor.MonoKt;
import kotlinx.coroutines.reactor.ReactorFlowKt;
import org.reactivestreams.Publisher;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

/**
 * Utilities for working with Kotlin Coroutines.
 *
 * @author Sebastien Deleuze
 * @author Phillip Webb
 * @since 5.2
 */
public abstract class CoroutinesUtils {

	/**
	 * Convert a {@link Deferred} instance to a {@link Mono}.
	 */
	public static  Mono deferredToMono(Deferred source) {
		return MonoKt.mono(Dispatchers.getUnconfined(),
				(scope, continuation) -> source.await(continuation));
	}

	/**
	 * Convert a {@link Mono} instance to a {@link Deferred}.
	 */
	public static  Deferred monoToDeferred(Mono source) {
		return BuildersKt.async(GlobalScope.INSTANCE, Dispatchers.getUnconfined(),
				CoroutineStart.DEFAULT,
				(scope, continuation) -> MonoKt.awaitSingleOrNull(source, continuation));
	}

	/**
	 * Invoke a suspending function and converts it to {@link Mono} or
	 * {@link Flux}.
	 */
	public static Publisher invokeSuspendingFunction(Method method, Object target, Object... args) {
		KFunction function = Objects.requireNonNull(ReflectJvmMapping.getKotlinFunction(method));
		KClassifier classifier = function.getReturnType().getClassifier();
		Mono