org.springframework.http.codec

Interface HttpMessageWriter<T>

Type Parameters:

T - the type of objects in the input stream

All Known Implementing Classes:

EncoderHttpMessageWriter, FormHttpMessageWriter, MultipartHttpMessageWriter, PartHttpMessageWriter, ProtobufHttpMessageWriter, ResourceHttpMessageWriter, ServerSentEventHttpMessageWriter

public interface HttpMessageWriter<T>

Strategy for encoding a stream of objects of type <T> and writing the encoded stream of bytes to an ReactiveHttpOutputMessage.

Since:

5.0

Author:

Rossen Stoyanchev, Arjen Poutsma, Sebastien Deleuze

Method Summary

Modifier and Type	Method and Description
boolean	canWrite(ResolvableType elementType, MediaType mediaType) Whether the given object type is supported by this writer.
List<MediaType>	getWritableMediaTypes() Return the list of media types supported by this Writer.
default List<MediaType>	getWritableMediaTypes(ResolvableType elementType) Return the list of media types supported by this Writer for the given type of element.
reactor.core.publisher.Mono<Void>	write(Publisher<? extends T> inputStream, ResolvableType elementType, MediaType mediaType, ReactiveHttpOutputMessage message, Map<String,Object> hints) Write a given stream of object to the output message.
default reactor.core.publisher.Mono<Void>	write(Publisher<? extends T> inputStream, ResolvableType actualType, ResolvableType elementType, MediaType mediaType, ServerHttpRequest request, ServerHttpResponse response, Map<String,Object> hints) Server-side only alternative to write(Publisher, ResolvableType, MediaType, ReactiveHttpOutputMessage, Map) with additional context available.

Method Detail

getWritableMediaTypes

List<MediaType> getWritableMediaTypes()

Return the list of media types supported by this Writer. The list may not apply to every possible target element type and calls to this method should typically be guarded via canWrite(elementType, null). The list may also exclude media types supported only for a specific element type. Alternatively, use getWritableMediaTypes(ResolvableType) for a more precise list.

Returns:

the general list of supported media types

getWritableMediaTypes

default List<MediaType> getWritableMediaTypes(ResolvableType elementType)

Return the list of media types supported by this Writer for the given type of element. This list may differ from getWritableMediaTypes() if the Writer doesn't support the element type, or if it supports it only for a subset of media types.

Parameters:

elementType - the type of element to encode

Returns:

the list of media types supported for the given class

Since:

5.3.4

canWrite

boolean canWrite(ResolvableType elementType,
                 @Nullable
                 MediaType mediaType)

Whether the given object type is supported by this writer.

Parameters:

elementType - the type of object to check

mediaType - the media type for the write (possibly null)

Returns:

true if writable, false otherwise

write

reactor.core.publisher.Mono<Void> write(Publisher<? extends T> inputStream,
                                        ResolvableType elementType,
                                        @Nullable
                                        MediaType mediaType,
                                        ReactiveHttpOutputMessage message,
                                        Map<String,Object> hints)

Write a given stream of object to the output message.

Parameters:

inputStream - the objects to write

elementType - the type of objects in the stream which must have been previously checked via canWrite(ResolvableType, MediaType)

mediaType - the content type for the write (possibly null to indicate that the default content type of the writer must be used)

message - the message to write to

hints - additional information about how to encode and write

Returns:

indicates completion or error

write

default reactor.core.publisher.Mono<Void> write(Publisher<? extends T> inputStream,
                                                ResolvableType actualType,
                                                ResolvableType elementType,
                                                @Nullable
                                                MediaType mediaType,
                                                ServerHttpRequest request,
                                                ServerHttpResponse response,
                                                Map<String,Object> hints)

Server-side only alternative to write(Publisher, ResolvableType, MediaType, ReactiveHttpOutputMessage, Map) with additional context available.

Parameters:

actualType - the actual return type of the method that returned the value; for annotated controllers, the MethodParameter can be accessed via ResolvableType.getSource().

elementType - the type of Objects in the input stream

mediaType - the content type to use (possibly null indicating the default content type of the writer should be used)

request - the current request

response - the current response

Returns:

a Mono that indicates completion of writing or error