/*
 * Copyright 2002-2016 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
 *
 *      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.springframework.http;

import java.util.function.Supplier;

import org.reactivestreams.Publisher;
import reactor.core.publisher.Mono;

import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferFactory;

A "reactive" HTTP output message that accepts output as a Publisher. 
Typically implemented by an HTTP request on the client-side or an
HTTP response on the server-side.
Author:
Arjen Poutsma, Sebastien Deleuze
Since:
5.0/**
 * A "reactive" HTTP output message that accepts output as a {@link Publisher}.
 *
 * <p>Typically implemented by an HTTP request on the client-side or an
 * HTTP response on the server-side.
 *
 * @author Arjen Poutsma
 * @author Sebastien Deleuze
 * @since 5.0
 */
public interface ReactiveHttpOutputMessage extends HttpMessage {

	
Return a DataBufferFactory that can be used to create the body. 
See Also:
writeWith(Publisher<? extends DataBuffer>)
Returns:
a buffer factory/**
	 * Return a {@link DataBufferFactory} that can be used to create the body.
	 * @return a buffer factory
	 * @see #writeWith(Publisher)
	 */
	DataBufferFactory bufferFactory();

	
Register an action to apply just before the HttpOutputMessage is committed.
Note: the supplied action must be properly deferred, e.g. via Mono.defer or Mono.fromRunnable, to ensure it's executed in the right order, relative to other actions. 
Params:
action – the action to apply/**
	 * Register an action to apply just before the HttpOutputMessage is committed.
	 * <p><strong>Note:</strong> the supplied action must be properly deferred,
	 * e.g. via {@link Mono#defer} or {@link Mono#fromRunnable}, to ensure it's
	 * executed in the right order, relative to other actions.
	 * @param action the action to apply
	 */
	void beforeCommit(Supplier<? extends Mono<Void>> action);

	
Whether the HttpOutputMessage is committed.
/**
	 * Whether the HttpOutputMessage is committed.
	 */
	boolean isCommitted();

	
Use the given Publisher to write the body of the message to the underlying HTTP layer. 
Params:
body – the body content publisher
Returns:
a Mono that indicates completion or error/**
	 * Use the given {@link Publisher} to write the body of the message to the
	 * underlying HTTP layer.
	 * @param body the body content publisher
	 * @return a {@link Mono} that indicates completion or error
	 */

	Mono<Void> writeWith(Publisher<? extends DataBuffer> body);

	
Use the given Publisher of Publishers to write the body of the HttpOutputMessage to the underlying HTTP layer, flushing after each Publisher<DataBuffer>. 
Params:
body – the body content publisher
Returns:
a Mono that indicates completion or error/**
	 * Use the given {@link Publisher} of {@code Publishers} to write the body
	 * of the HttpOutputMessage to the underlying HTTP layer, flushing after
	 * each {@code Publisher<DataBuffer>}.
	 * @param body the body content publisher
	 * @return a {@link Mono} that indicates completion or error
	 */
	Mono<Void> writeAndFlushWith(Publisher<? extends Publisher<? extends DataBuffer>> body);

	
Indicate that message handling is complete, allowing for any cleanup or end-of-processing tasks to be performed such as applying header changes made via HttpMessage.getHeaders() to the underlying HTTP message (if not applied already). 
This method should be automatically invoked at the end of message
processing so typically applications should not have to invoke it.
If invoked multiple times it should have no side effects.
Returns:
a Mono that indicates completion or error/**
	 * Indicate that message handling is complete, allowing for any cleanup or
	 * end-of-processing tasks to be performed such as applying header changes
	 * made via {@link #getHeaders()} to the underlying HTTP message (if not
	 * applied already).
	 * <p>This method should be automatically invoked at the end of message
	 * processing so typically applications should not have to invoke it.
	 * If invoked multiple times it should have no side effects.
	 * @return a {@link Mono} that indicates completion or error
	 */
	Mono<Void> setComplete();

}