Copy Operator

, ,
1

Imported from previous forum

2

[ original email was from Darshan Khedekar - darshan.khedekar.ext@deutsche-boerse.com ]
Hi

If field is not sent and the oprator is copy does it copy the previous value from the (Msgtype,Tag) or from (Tag) only. ie Should the values be retained for MsgType+Tag combination or only for Tag?

Thanks and Regards
Darshan

3

That depends on how you’ve specified the dictionary.
David, could you chip in and provide a good explanation?

/Rolf

Hi

If field is not sent and the oprator is copy does it copy the previous
value from the (Msgtype,Tag) or from (Tag) only. ie Should the values be
retained for MsgType+Tag combination or only for Tag?

Thanks and Regards Darshan

4

The relevant section of the specifiaction is 6.3.1. It says that the previous value is the value of the entry in the specified dictionary having a specific key.

You can specify the dictionary through the dictionary attribute as in

If you don’t specify a dictionary, the global dictionary is used. The key is defaulted to the name of the field of the operator. It is possible to specify a key explicitly through the key attribute as in

Specifying an explicit key is useful when you want to have two fields with diferent names to share the same previous value.

Here are some examples


dictionary is “global” and key is “Foo”


dictionary is “type” and key is “Foo”. The type dictionary is specfic
to the current type as specified by the element in your
template.


dictionary is “template” and key is “Bar”.

dictionary is “template” and key is “Bar”. These two fields share
the same previous value with the key “Bar”. The template dictionary
is specific to the current template.

If you want to have “{MsgType, Tag}” as you described in your post, you shoud use

and to have “{Tag}” you shoud specifiy

Note that the dictionary attribute can be inherited in the concrete syntax, that means that it is possible to specfiy the dictionary for all fields in a template by just specifying the attribute at a higher level:

/David

That depends on how you’ve specified the dictionary. David, could you
chip in and provide a good explanation?

/Rolf

Hi

If field is not sent and the oprator is copy does it copy the previous
value from the (Msgtype,Tag) or from (Tag) only. ie Should the values
be retained for MsgType+Tag combination or only for Tag?

Thanks and Regards Darshan