Class ResponseBodyEmitterReturnValueHandler

java.lang.Object

org.springframework.web.servlet.mvc.method.annotation.ResponseBodyEmitterReturnValueHandler

All Implemented Interfaces:

HandlerMethodReturnValueHandler

public class ResponseBodyEmitterReturnValueHandler
extends Object
implements HandlerMethodReturnValueHandler

Handler for return values of type:

• ResponseBodyEmitter including sub-class SseEmitter and others.
• Reactive return types known to ReactiveAdapterRegistry.
• Any of the above wrapped with ResponseEntity.

Single-value reactive types are adapted to DeferredResult. Multi-value reactive types are adapted to ResponseBodyEmitter or SseEmitter as follows:

• SSE stream, if the element type is ServerSentEvent or if negotiated by content type.
• Text stream for a Publisher of CharSequence.
• A JSON stream if negotiated by content type to MediaType.APPLICATION_NDJSON.

Since:

4.2

Author:

Rossen Stoyanchev

Constructor Summary

Constructors

Constructor	Description
ResponseBodyEmitterReturnValueHandler(List<HttpMessageConverter<?>> messageConverters)	Simple constructor with reactive type support based on a default instance of ReactiveAdapterRegistry, SyncTaskExecutor, and ContentNegotiationManager with an Accept header strategy.
ResponseBodyEmitterReturnValueHandler(List<HttpMessageConverter<?>> messageConverters, ReactiveAdapterRegistry registry, TaskExecutor executor, ContentNegotiationManager manager)	Constructor that with added arguments to customize "reactive" type support.
ResponseBodyEmitterReturnValueHandler(List<HttpMessageConverter<?>> messageConverters, ReactiveAdapterRegistry registry, TaskExecutor executor, ContentNegotiationManager manager, List<ViewResolver> viewResolvers, @Nullable LocaleResolver localeResolver)	Constructor that with added arguments for view rendering.

Method Summary

Modifier and Type	Method	Description
void	handleReturnValue(@Nullable Object returnValue, MethodParameter returnType, ModelAndViewContainer mavContainer, NativeWebRequest webRequest)	Handle the given return value by adding attributes to the model and setting a view or setting the ModelAndViewContainer.setRequestHandled(boolean) flag to true to indicate the response has been handled directly.
boolean	supportsReturnType(MethodParameter returnType)	Whether the given method return type is supported by this handler.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ResponseBodyEmitterReturnValueHandler

public ResponseBodyEmitterReturnValueHandler(List<HttpMessageConverter<?>> messageConverters)

Simple constructor with reactive type support based on a default instance of ReactiveAdapterRegistry, SyncTaskExecutor, and ContentNegotiationManager with an Accept header strategy.

ResponseBodyEmitterReturnValueHandler

public ResponseBodyEmitterReturnValueHandler(List<HttpMessageConverter<?>> messageConverters,
 ReactiveAdapterRegistry registry,
 TaskExecutor executor,
 ContentNegotiationManager manager)

Constructor that with added arguments to customize "reactive" type support.

Parameters:

messageConverters - converters to write emitted objects with

registry - for reactive return value type support

executor - for blocking I/O writes of items emitted from reactive types

manager - for detecting streaming media types

Since:

5.0

ResponseBodyEmitterReturnValueHandler

public ResponseBodyEmitterReturnValueHandler(List<HttpMessageConverter<?>> messageConverters,
 ReactiveAdapterRegistry registry,
 TaskExecutor executor,
 ContentNegotiationManager manager,
 List<ViewResolver> viewResolvers,
 @Nullable LocaleResolver localeResolver)

Constructor that with added arguments for view rendering.

Parameters:

messageConverters - converters to write emitted objects with

registry - for reactive return value type support

executor - for blocking I/O writes of items emitted from reactive types

manager - for detecting streaming media types

viewResolvers - resolvers for fragment stream rendering

localeResolver - the LocaleResolver for fragment stream rendering

Since:

6.2

Method Details

supportsReturnType

public boolean supportsReturnType(MethodParameter returnType)

Description copied from interface: HandlerMethodReturnValueHandler

Whether the given method return type is supported by this handler.

Specified by:

supportsReturnType in interface HandlerMethodReturnValueHandler

Parameters:

returnType - the method return type to check

Returns:

true if this handler supports the supplied return type; false otherwise

handleReturnValue

public void handleReturnValue(@Nullable Object returnValue,
 MethodParameter returnType,
 ModelAndViewContainer mavContainer,
 NativeWebRequest webRequest)
                       throws Exception

Description copied from interface: HandlerMethodReturnValueHandler

Handle the given return value by adding attributes to the model and setting a view or setting the ModelAndViewContainer.setRequestHandled(boolean) flag to true to indicate the response has been handled directly.

Specified by:

handleReturnValue in interface HandlerMethodReturnValueHandler

Parameters:

returnValue - the value returned from the handler method

returnType - the type of the return value. This type must have previously been passed to HandlerMethodReturnValueHandler.supportsReturnType(MethodParameter) which must have returned true.

mavContainer - the ModelAndViewContainer for the current request

webRequest - the current request

Throws:

Exception - if the return value handling results in an error