content: /*
   * Copyright (C) 2020 ActiveJ LLC.
   *
   * 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
   *
   * 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 io.activej.datastream.consumer;
  
  import io.activej.async.function.AsyncConsumer;
  import io.activej.common.annotation.StaticFactories;
  import io.activej.common.function.ConsumerEx;
  import io.activej.csp.consumer.ChannelConsumer;
  import io.activej.datastream.consumer.impl.*;
  import io.activej.datastream.processor.transformer.StreamTransformer;
  import io.activej.datastream.processor.transformer.StreamTransformers;
  import io.activej.datastream.supplier.StreamSupplier;
  import io.activej.promise.Promise;
  import io.activej.reactor.Reactor;
  
  import java.util.function.Consumer;
  
  @StaticFactories(StreamConsumer.class)
  public class StreamConsumers {
  	/**
  	 * Creates a consumer which does not consume anything.
  	 * Its acknowledgement completes when the supplier closes.
  	 */
  	public static <T> StreamConsumer<T> idle() {
  		return new Idle<>();
  	}
  
  	/**
  	 * Creates a consumer which consumes and ignores everything.
  	 * Its acknowledgement completes when the supplier closes.
  	 */
  	public static <T> StreamConsumer<T> skip() {
  		return new Skip<>();
  	}
  
  	/**
  	 * Creates a consumer which is already acknowledged.
  	 */
  	public static <T> StreamConsumer<T> acknowledged() {
  		return new Acknowledged<>();
  	}
  
  	/**
  	 * Creates a consumer which calls the provided {@link Consumer} with items
  	 * it receives.
  	 * Its acknowledgement completes when the supplier closes.
  	 */
  	public static <T> StreamConsumer<T> ofConsumer(ConsumerEx<T> consumer) {
  		return new OfConsumer<>(consumer);
  	}
  
  	/**
  	 * Creates a consumer that is in the closed state with given error set.
  	 */
  	public static <T> StreamConsumer<T> closingWithError(Exception e) {
  		return new ClosingWithError<>(e);
  	}
  
  	/**
  	 * Creates a consumer that waits until the promise completes
  	 * and then consumer items into the resulting consumer.
  	 */
  	public static <T> StreamConsumer<T> ofPromise(Promise<? extends StreamConsumer<T>> promise) {
  		if (promise.isResult()) return promise.getResult();
  		return new OfPromise<>(promise);
  	}
  
  	/**
  	 * Creates a consumer that streams the received items into a given {@link ChannelConsumer channel consumer}
  	 */
  	public static <T> StreamConsumer<T> ofChannelConsumer(ChannelConsumer<T> consumer) {
  		return new OfChannelConsumer<>(consumer);
  	}
  
  	/**
  	 * Creates a consumer which sends received items through the supplier received in the callback.
  	 * Acknowledge of that consumer will not be set until the promise received from the callback invocation completes.
  	 */
  	public static <T> StreamConsumer<T> ofSupplier(AsyncConsumer<StreamSupplier<T>> supplier) {
  		StreamTransformer<T, T> forwarder = StreamTransformers.identity();
  		Promise<Void> extraAcknowledge = supplier.accept(forwarder.getOutput());
  		StreamConsumer<T> result = forwarder.getInput();
  		if (extraAcknowledge == Promise.complete()) return result;
  		return result
  			.withAcknowledgement(ack -> ack.both(extraAcknowledge));
  	}
  
  	public static <T> StreamConsumer<T> ofAnotherReactor(Reactor anotherReactor, StreamConsumer<T> anotherReactorConsumer) {
  		if (Reactor.getCurrentReactor() == anotherReactor) {
  			return anotherReactorConsumer;
  		}
  		return new OfAnotherReactor<>(anotherReactor, anotherReactorConsumer);
  	}
  }
  