/*
 * Copyright 2002-2019 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.
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package org.springframework.web.servlet.config.annotation;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.Callable;

import org.springframework.core.task.AsyncTaskExecutor;
import org.springframework.core.task.SimpleAsyncTaskExecutor;
import org.springframework.lang.Nullable;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import org.springframework.web.context.request.async.CallableProcessingInterceptor;
import org.springframework.web.context.request.async.DeferredResult;
import org.springframework.web.context.request.async.DeferredResultProcessingInterceptor;

Helps with configuring options for asynchronous request processing.
Author:
Rossen Stoyanchev
Since:
3.2/**
 * Helps with configuring options for asynchronous request processing.
 *
 * @author Rossen Stoyanchev
 * @since 3.2
 */
public class AsyncSupportConfigurer {

	@Nullable
	private AsyncTaskExecutor taskExecutor;

	@Nullable
	private Long timeout;

	private final List<CallableProcessingInterceptor> callableInterceptors = new ArrayList<>();

	private final List<DeferredResultProcessingInterceptor> deferredResultInterceptors = new ArrayList<>();


	
The provided task executor is used to:

Handle Callable controller method return values. 
Perform blocking writes when streaming to the response
through a reactive (e.g. Reactor, RxJava) controller method return value.

By default only a SimpleAsyncTaskExecutor is used. However when using the above two use cases, it's recommended to configure an executor backed by a thread pool such as ThreadPoolTaskExecutor. 
Params:
taskExecutor – the task executor instance to use by default/**
	 * The provided task executor is used to:
	 * <ol>
	 * <li>Handle {@link Callable} controller method return values.
	 * <li>Perform blocking writes when streaming to the response
	 * through a reactive (e.g. Reactor, RxJava) controller method return value.
	 * </ol>
	 * <p>By default only a {@link SimpleAsyncTaskExecutor} is used. However when
	 * using the above two use cases, it's recommended to configure an executor
	 * backed by a thread pool such as {@link ThreadPoolTaskExecutor}.
	 * @param taskExecutor the task executor instance to use by default
	 */
	public AsyncSupportConfigurer setTaskExecutor(AsyncTaskExecutor taskExecutor) {
		this.taskExecutor = taskExecutor;
		return this;
	}

	
Specify the amount of time, in milliseconds, before asynchronous request
handling times out. In Servlet 3, the timeout begins after the main request
processing thread has exited and ends when the request is dispatched again
for further processing of the concurrently produced result.
If this value is not set, the default timeout of the underlying
implementation is used.
Params:
timeout – the timeout value in milliseconds/**
	 * Specify the amount of time, in milliseconds, before asynchronous request
	 * handling times out. In Servlet 3, the timeout begins after the main request
	 * processing thread has exited and ends when the request is dispatched again
	 * for further processing of the concurrently produced result.
	 * <p>If this value is not set, the default timeout of the underlying
	 * implementation is used.
	 * @param timeout the timeout value in milliseconds
	 */
	public AsyncSupportConfigurer setDefaultTimeout(long timeout) {
		this.timeout = timeout;
		return this;
	}

	
Configure lifecycle interceptors with callbacks around concurrent request execution that starts when a controller returns a Callable. 
Params:
interceptors – the interceptors to register/**
	 * Configure lifecycle interceptors with callbacks around concurrent request
	 * execution that starts when a controller returns a
	 * {@link java.util.concurrent.Callable}.
	 * @param interceptors the interceptors to register
	 */
	public AsyncSupportConfigurer registerCallableInterceptors(CallableProcessingInterceptor... interceptors) {
		this.callableInterceptors.addAll(Arrays.asList(interceptors));
		return this;
	}

	
Configure lifecycle interceptors with callbacks around concurrent request execution that starts when a controller returns a DeferredResult. 
Params:
interceptors – the interceptors to register/**
	 * Configure lifecycle interceptors with callbacks around concurrent request
	 * execution that starts when a controller returns a {@link DeferredResult}.
	 * @param interceptors the interceptors to register
	 */
	public AsyncSupportConfigurer registerDeferredResultInterceptors(
			DeferredResultProcessingInterceptor... interceptors) {

		this.deferredResultInterceptors.addAll(Arrays.asList(interceptors));
		return this;
	}


	@Nullable
	protected AsyncTaskExecutor getTaskExecutor() {
		return this.taskExecutor;
	}

	@Nullable
	protected Long getTimeout() {
		return this.timeout;
	}

	protected List<CallableProcessingInterceptor> getCallableInterceptors() {
		return this.callableInterceptors;
	}

	protected List<DeferredResultProcessingInterceptor> getDeferredResultInterceptors() {
		return this.deferredResultInterceptors;
	}

}