org.springframework.messaging.converter

Class AbstractMessageConverter

java.lang.Object

org.springframework.messaging.converter.AbstractMessageConverter

All Implemented Interfaces:

MessageConverter

Direct Known Subclasses:

ByteArrayMessageConverter, MappingJackson2MessageConverter, StringMessageConverter

public abstract class AbstractMessageConverter
extends Object
implements MessageConverter

Abstract base class for MessageConverter implementations including support for common properties and a partial implementation of the conversion methods mainly to check if the converter supports the conversion based on the payload class and MIME type.

Since:

4.0

Author:

Rossen Stoyanchev

Field Summary

Fields

Modifier and Type	Field and Description
protected Log	logger

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractMessageConverter(Collection<MimeType> supportedMimeTypes) Construct an AbstractMessageConverter supporting multiple MIME types.
protected	AbstractMessageConverter(MimeType supportedMimeType) Construct an AbstractMessageConverter supporting a single MIME type.

Method Summary

Modifier and Type	Method and Description
protected boolean	canConvertFrom(Message<?> message, Class<?> targetClass)
protected boolean	canConvertTo(Object payload, MessageHeaders headers)
abstract Object	convertFromInternal(Message<?> message, Class<?> targetClass) Convert the message payload from serialized form to an Object.
abstract Object	convertToInternal(Object payload, MessageHeaders headers) Convert the payload object to serialized form.
Object	fromMessage(Message<?> message, Class<?> targetClass) Convert the payload of a Message from serialized form to a typed Object of the specified target class.
ContentTypeResolver	getContentTypeResolver() Return the configured ContentTypeResolver.
protected MimeType	getDefaultContentType(Object payload) Returns the default content type for the payload.
protected MimeType	getMimeType(MessageHeaders headers)
Class<?>	getSerializedPayloadClass() Return the configured preferred serialization payload class.
List<MimeType>	getSupportedMimeTypes() Return the supported MIME types.
boolean	isStrictContentTypeMatch() Whether content type resolution must produce a value that matches one of the supported MIME types.
void	setContentTypeResolver(ContentTypeResolver resolver) Configure the ContentTypeResolver to use to resolve the content type of an input message.
void	setSerializedPayloadClass(Class<?> payloadClass) Configure the preferred serialization class to use (byte[] or String) when converting an Object payload to a Message.
void	setStrictContentTypeMatch(boolean strictContentTypeMatch) Whether this converter should convert messages for which no content type could be resolved through the configured ContentTypeResolver.
protected abstract boolean	supports(Class<?> clazz) Whether the given class is supported by this converter.
protected boolean	supportsMimeType(MessageHeaders headers)
Message<?>	toMessage(Object payload, MessageHeaders headers) Create a Message whose payload is the result of converting the given payload Object to serialized form.

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected final Log logger

Constructor Detail

AbstractMessageConverter

protected AbstractMessageConverter(MimeType supportedMimeType)

Construct an AbstractMessageConverter supporting a single MIME type.

Parameters:

supportedMimeType - the supported MIME type

AbstractMessageConverter

protected AbstractMessageConverter(Collection<MimeType> supportedMimeTypes)

Construct an AbstractMessageConverter supporting multiple MIME types.

Parameters:

supportedMimeTypes - the supported MIME types

Method Detail

getSupportedMimeTypes

public List<MimeType> getSupportedMimeTypes()

Return the supported MIME types.

setContentTypeResolver

public void setContentTypeResolver(ContentTypeResolver resolver)

Configure the ContentTypeResolver to use to resolve the content type of an input message.

Note that if no resolver is configured, then strictContentTypeMatch should be left as false (the default) or otherwise this converter will ignore all messages.

By default, a DefaultContentTypeResolver instance is used.

getContentTypeResolver

public ContentTypeResolver getContentTypeResolver()

Return the configured ContentTypeResolver.

setStrictContentTypeMatch

public void setStrictContentTypeMatch(boolean strictContentTypeMatch)

Whether this converter should convert messages for which no content type could be resolved through the configured ContentTypeResolver. A converter can configured to be strict only when a contentTypeResolver is configured and the list of supportedMimeTypes is not be empty. then requires the content type of a message to be resolved When set to true, #supportsMimeType(MessageHeaders) will return false if the contentTypeResolver is not defined or if no content-type header is present.

isStrictContentTypeMatch

public boolean isStrictContentTypeMatch()

Whether content type resolution must produce a value that matches one of the supported MIME types.

setSerializedPayloadClass

public void setSerializedPayloadClass(Class<?> payloadClass)

Configure the preferred serialization class to use (byte[] or String) when converting an Object payload to a Message.

The default value is byte[].

Parameters:

payloadClass - either byte[] or String

getSerializedPayloadClass

public Class<?> getSerializedPayloadClass()

Return the configured preferred serialization payload class.

getDefaultContentType

protected MimeType getDefaultContentType(Object payload)

Returns the default content type for the payload. Called when toMessage(Object, MessageHeaders) is invoked without message headers or without a content type header.

By default, this returns the first element of the supportedMimeTypes, if any. Can be overridden in sub-classes.

Parameters:

payload - the payload being converted to message

Returns:

the content type, or null if not known

supports

protected abstract boolean supports(Class<?> clazz)

Whether the given class is supported by this converter.

Parameters:

clazz - the class to test for support

Returns:

true if supported; false otherwise

fromMessage

public final Object fromMessage(Message<?> message,
                                Class<?> targetClass)

Description copied from interface: MessageConverter

Convert the payload of a Message from serialized form to a typed Object of the specified target class. The MessageHeaders.CONTENT_TYPE header should indicate the MIME type to convert from.

If the converter does not support the specified media type or cannot perform the conversion, it should return null.

Specified by:

fromMessage in interface MessageConverter

Parameters:

message - the input message

targetClass - the target class for the conversion

Returns:

the result of the conversion, or null if the converter cannot perform the conversion

canConvertFrom

protected boolean canConvertFrom(Message<?> message,
                                 Class<?> targetClass)

convertFromInternal

public abstract Object convertFromInternal(Message<?> message,
                                           Class<?> targetClass)

Convert the message payload from serialized form to an Object.

toMessage

public final Message<?> toMessage(Object payload,
                                  MessageHeaders headers)

Description copied from interface: MessageConverter

Create a Message whose payload is the result of converting the given payload Object to serialized form. The optional MessageHeaders parameter may contain a MessageHeaders.CONTENT_TYPE header to specify the target media type for the conversion and it may contain additional headers to be added to the message.

If the converter does not support the specified media type or cannot perform the conversion, it should return null.

Specified by:

toMessage in interface MessageConverter

Parameters:

payload - the Object to convert

headers - optional headers for the message, may be null

Returns:

the new message or null if the converter does not support the Object type or the target media type

canConvertTo

protected boolean canConvertTo(Object payload,
                               MessageHeaders headers)

convertToInternal

public abstract Object convertToInternal(Object payload,
                                         MessageHeaders headers)

Convert the payload object to serialized form.

supportsMimeType

protected boolean supportsMimeType(MessageHeaders headers)

getMimeType

protected MimeType getMimeType(MessageHeaders headers)