/**
* Return a mutable {@code MessageHeaderAccessor} for the given message attempting to match the
* type of accessor used to create the message headers, or otherwise wrapping the message with a
* {@code MessageHeaderAccessor} instance.
*
* <p>This is for cases where a header needs to be updated in generic code while preserving the
* accessor type for downstream processing.
*
* @return an accessor of the required type (never {@code null})
* @since 4.1
*/
public static MessageHeaderAccessor getMutableAccessor(Message<?> message) {
if (message.getHeaders() instanceof MutableMessageHeaders) {
MutableMessageHeaders mutableHeaders = (MutableMessageHeaders) message.getHeaders();
MessageHeaderAccessor accessor = mutableHeaders.getMessageHeaderAccessor();
if (accessor != null) {
return (accessor.isMutable() ? accessor : accessor.createAccessor(message));
}
}
return new MessageHeaderAccessor(message);
}
