/*
 * Copyright 2002-2022 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.web.servlet.mvc.method.annotation;

import java.io.IOException;
import java.io.OutputStream;

/**
 * A controller method return value type for asynchronous request processing
 * where the application can write directly to the response {@code OutputStream}
 * without holding up the Servlet container thread.
 *
 * <p><strong>Note:</strong> when using this option it is highly recommended to
 * configure explicitly the TaskExecutor used in Spring MVC for executing
 * asynchronous requests. Both the MVC Java config and the MVC namespaces provide
 * options to configure asynchronous handling. If not using those, an application
 * can set the {@code taskExecutor} property of
 * {@link org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter
 * RequestMappingHandlerAdapter}.
 *
 * @author Rossen Stoyanchev
 * @since 4.2
 */
@FunctionalInterface
public interface StreamingResponseBody {

	/**
	 * A callback for writing to the response body.
	 * @param outputStream the stream for the response body
	 * @throws IOException an exception while writing
	 */
	void writeTo(OutputStream outputStream) throws IOException;

}
