org.springframework.http.converter.protobuf

Class ProtobufHttpMessageConverter

java.lang.Object

org.springframework.http.converter.AbstractHttpMessageConverter<Message>

org.springframework.http.converter.protobuf.ProtobufHttpMessageConverter

All Implemented Interfaces:

HttpMessageConverter<Message>

public class ProtobufHttpMessageConverter
extends AbstractHttpMessageConverter<Message>

An HttpMessageConverter that can read and write Protobuf com.google.protobuf.Message using Google Protocol buffers.

By default it supports "application/json", "application/xml", "text/plain" and "application/x-protobuf" while writing also supports "text/html"

To generate Message Java classes you need to install the protoc binary.

Tested against Protobuf version 2.5.0.

Since:

4.1

Author:

Alex Antonov, Brian Clozel

Field Summary

Fields

Modifier and Type	Field and Description
static java.nio.charset.Charset	DEFAULT_CHARSET
private ExtensionRegistry	extensionRegistry
private static java.util.concurrent.ConcurrentHashMap<java.lang.Class<?>,java.lang.reflect.Method>	methodCache
static MediaType	PROTOBUF
static java.lang.String	X_PROTOBUF_MESSAGE_HEADER
static java.lang.String	X_PROTOBUF_SCHEMA_HEADER

Fields inherited from class org.springframework.http.converter.AbstractHttpMessageConverter

logger

Constructor Summary

Constructors

Constructor and Description
ProtobufHttpMessageConverter() Construct a new instance.
ProtobufHttpMessageConverter(ExtensionRegistryInitializer registryInitializer) Construct a new instance with an ExtensionRegistryInitializer that allows the registration of message extensions.

Method Summary

Modifier and Type	Method and Description
protected boolean	canWrite(MediaType mediaType) This method overrides the parent implementation, since this HttpMessageConverter can also produce MediaType.HTML "text/html" ContentType.
private java.nio.charset.Charset	getCharset(HttpHeaders headers)
private java.nio.charset.Charset	getCharset(MediaType contentType)
protected MediaType	getDefaultContentType(Message message) Returns the default content type for the given type.
private Message.Builder	getMessageBuilder(java.lang.Class<? extends Message> clazz) Create a new Message.Builder instance for the given class.
protected Message	readInternal(java.lang.Class<? extends Message> clazz, HttpInputMessage inputMessage) Abstract template method that reads the actual object.
private void	setProtoHeader(HttpOutputMessage response, Message message) Set the "X-Protobuf-*" HTTP headers when responding with a message of content type "application/x-protobuf"
protected boolean	supports(java.lang.Class<?> clazz) Indicates whether the given class is supported by this converter.
protected void	writeInternal(Message message, HttpOutputMessage outputMessage) Abstract template method that writes the actual body.

Methods inherited from class org.springframework.http.converter.AbstractHttpMessageConverter

addDefaultHeaders, canRead, canRead, canWrite, getContentLength, getSupportedMediaTypes, read, setSupportedMediaTypes, write

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_CHARSET

public static final java.nio.charset.Charset DEFAULT_CHARSET

PROTOBUF

public static final MediaType PROTOBUF

X_PROTOBUF_SCHEMA_HEADER

public static final java.lang.String X_PROTOBUF_SCHEMA_HEADER

See Also:

Constant Field Values

X_PROTOBUF_MESSAGE_HEADER

public static final java.lang.String X_PROTOBUF_MESSAGE_HEADER

See Also:

Constant Field Values

methodCache

private static final java.util.concurrent.ConcurrentHashMap<java.lang.Class<?>,java.lang.reflect.Method> methodCache

extensionRegistry

private ExtensionRegistry extensionRegistry

Constructor Detail

ProtobufHttpMessageConverter

public ProtobufHttpMessageConverter()

Construct a new instance.

ProtobufHttpMessageConverter

public ProtobufHttpMessageConverter(ExtensionRegistryInitializer registryInitializer)

Construct a new instance with an ExtensionRegistryInitializer that allows the registration of message extensions.

Method Detail

supports

protected boolean supports(java.lang.Class<?> clazz)

Description copied from class: AbstractHttpMessageConverter

Indicates whether the given class is supported by this converter.

Specified by:

supports in class AbstractHttpMessageConverter<Message>

Parameters:

clazz - the class to test for support

Returns:

true if supported; false otherwise

readInternal

protected Message readInternal(java.lang.Class<? extends Message> clazz,
                               HttpInputMessage inputMessage)
                        throws java.io.IOException,
                               HttpMessageNotReadableException

Description copied from class: AbstractHttpMessageConverter

Abstract template method that reads the actual object. Invoked from AbstractHttpMessageConverter.read(java.lang.Class<? extends T>, org.springframework.http.HttpInputMessage).

Specified by:

readInternal in class AbstractHttpMessageConverter<Message>

Parameters:

clazz - the type of object to return

inputMessage - the HTTP input message to read from

Returns:

the converted object

Throws:

java.io.IOException - in case of I/O errors

HttpMessageNotReadableException - in case of conversion errors

getCharset

private java.nio.charset.Charset getCharset(HttpHeaders headers)

getMessageBuilder

private Message.Builder getMessageBuilder(java.lang.Class<? extends Message> clazz)
                                   throws java.lang.Exception

Create a new Message.Builder instance for the given class.

This method uses a ConcurrentHashMap for caching method lookups.

Throws:

java.lang.Exception

canWrite

protected boolean canWrite(MediaType mediaType)

This method overrides the parent implementation, since this HttpMessageConverter can also produce MediaType.HTML "text/html" ContentType.

Overrides:

canWrite in class AbstractHttpMessageConverter<Message>

Parameters:

mediaType - the media type to write, can be null if not specified. Typically the value of an Accept header.

Returns:

true if the supported media types are compatible with the media type, or if the media type is null

writeInternal

protected void writeInternal(Message message,
                             HttpOutputMessage outputMessage)
                      throws java.io.IOException,
                             HttpMessageNotWritableException

Description copied from class: AbstractHttpMessageConverter

Abstract template method that writes the actual body. Invoked from AbstractHttpMessageConverter.write(T, org.springframework.http.MediaType, org.springframework.http.HttpOutputMessage).

Specified by:

writeInternal in class AbstractHttpMessageConverter<Message>

Parameters:

message - the object to write to the output message

outputMessage - the HTTP output message to write to

Throws:

java.io.IOException - in case of I/O errors

HttpMessageNotWritableException - in case of conversion errors

getCharset

private java.nio.charset.Charset getCharset(MediaType contentType)

setProtoHeader

private void setProtoHeader(HttpOutputMessage response,
                            Message message)

Set the "X-Protobuf-*" HTTP headers when responding with a message of content type "application/x-protobuf"

Note: outputMessage.getBody() should not have been called before because it writes HTTP headers (making them read only).

getDefaultContentType

protected MediaType getDefaultContentType(Message message)

Description copied from class: AbstractHttpMessageConverter

Returns the default content type for the given type. Called when AbstractHttpMessageConverter.write(T, org.springframework.http.MediaType, org.springframework.http.HttpOutputMessage) is invoked without a specified content type parameter.

By default, this returns the first element of the supportedMediaTypes property, if any. Can be overridden in subclasses.

Overrides:

getDefaultContentType in class AbstractHttpMessageConverter<Message>

Parameters:

message - the type to return the content type for

Returns:

the content type, or null if not known