Package org.springframework.messaging.converter

Class CompositeMessageConverter

java.lang.Object

org.springframework.messaging.converter.CompositeMessageConverter

All Implemented Interfaces:

MessageConverter, SmartMessageConverter

public class CompositeMessageConverter
extends Object
implements SmartMessageConverter

A MessageConverter that delegates to a list of registered converters to be invoked until one of them returns a non-null result.

As of 4.2.1, this composite converter implements SmartMessageConverter in order to support the delegation of conversion hints.

Since:

4.0

Author:

Rossen Stoyanchev, Juergen Hoeller

Constructor Summary

Constructors

Constructor	Description
CompositeMessageConverter(Collection<MessageConverter> converters)	Create an instance with the given converters.

Method Summary

Modifier and Type	Method	Description
Object	fromMessage(Message<?> message, Class<?> targetClass)	Convert the payload of a Message from a serialized form to a typed Object of the specified target class.
Object	fromMessage(Message<?> message, Class<?> targetClass, Object conversionHint)	A variant of MessageConverter.fromMessage(Message, Class) which takes an extra conversion context as an argument, allowing to take, for example, annotations on a payload parameter into account.
List<MessageConverter>	getConverters()	Return the underlying list of delegate converters.
Message<?>	toMessage(Object payload, MessageHeaders headers)	Create a Message whose payload is the result of converting the given payload Object to serialized form.
Message<?>	toMessage(Object payload, MessageHeaders headers, Object conversionHint)	A variant of MessageConverter.toMessage(Object, MessageHeaders) which takes an extra conversion context as an argument, allowing to take, for example, annotations on a return type into account.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Details

CompositeMessageConverter

public CompositeMessageConverter(Collection<MessageConverter> converters)

Create an instance with the given converters.

Method Details

fromMessage

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

Description copied from interface: MessageConverter

Convert the payload of a Message from a 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

fromMessage

@Nullable
public Object fromMessage(Message<?> message,
 Class<?> targetClass,
 @Nullable
 Object conversionHint)

Description copied from interface: SmartMessageConverter

A variant of MessageConverter.fromMessage(Message, Class) which takes an extra conversion context as an argument, allowing to take, for example, annotations on a payload parameter into account.

Specified by:

fromMessage in interface SmartMessageConverter

Parameters:

message - the input message

targetClass - the target class for the conversion

conversionHint - an extra object passed to the MessageConverter, for example, the associated MethodParameter (may be null}

Returns:

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

See Also:

• MessageConverter.fromMessage(Message, Class)

toMessage

@Nullable
public Message<?> toMessage(Object payload,
 @Nullable
 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

toMessage

@Nullable
public Message<?> toMessage(Object payload,
 @Nullable
 MessageHeaders headers,
 @Nullable
 Object conversionHint)

Description copied from interface: SmartMessageConverter

A variant of MessageConverter.toMessage(Object, MessageHeaders) which takes an extra conversion context as an argument, allowing to take, for example, annotations on a return type into account.

Specified by:

toMessage in interface SmartMessageConverter

Parameters:

payload - the Object to convert

headers - optional headers for the message (may be null)

conversionHint - an extra object passed to the MessageConverter, for example, the associated MethodParameter (may be null}

Returns:

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

See Also:

• MessageConverter.toMessage(Object, MessageHeaders)

getConverters

public List<MessageConverter> getConverters()

Return the underlying list of delegate converters.

toString

public String toString()

Overrides:

toString in class Object