Thanks Willem Jiang I agree to your comments. Camel's InOnly & InOut pattern does have their means, and it's not just for optimize;
Because we understand MEP as such, I think the low level Processor should always handle the MEP correctly, they should judge the MEP, and return the result by In or Out Message by the MEP is InOnly or InOut; But it seems not all Processor deal with MEP as such; for example the TransformProcessor never judge the MEP's value and always return result by Out Message; At first I think it's bug, but it seems not. So I am truly confused ......
