Hi Team,

For FFD conversion from flat file to XML message in DataPower. We need to include the escape character "?" so that the character after the "?" symbol is treated as plain text instead of special delimiter for FFD.

How can we do that in FFD in DataPower?

The syntax in IIB DFDL is:
<xsd:annotation>
<dfdl:defineEscapeScheme name="escapeChar">
<dfdl:escapeScheme escapeKind="escapeCharacter">
<dfdl:property name="escapeCharacter">?</dfdl:property>
</dfdl:escapeScheme>
</dfdl:defineEscapeScheme>
</xsd:annotation>

We want to do similiar thing in DataPower FFD.

That is a bad idea.

FFDs are supported in DataPower only to be used with Contivo Analyst product (with a 10000$ seat license you likely do not have).
Hand crafted FFDs are not supported by default.

You can find few exception FFD types that are supported in these two WSTE webcasts:
https://www.ibm.com/support/pages/webcast-replay-non-xml-data-processing-websphere-datapower-soa-appliances-stylesheets-12-basics-and-encodings

https://www.ibm.com/support/pages/webcast-replay-non-xml-data-processing-websphere-datapower-soa-appliances-stylesheets-22-advanced
If what you want to do is not covered by those, then please stay away from using FFDs.
Any ticket you will open on this will be closed immediately as unsupported.

My rule of thumb:
For processing XML/JSON/binary use DataPower XSLT/GatewayScript/GatewayScript.

You can just read your input in GatewaScript with "session.input.readAsBuffer()" (in case input size is not >1GB).
Then you can validate "by hand" what you want by insppecting the read buffer.

------------------------------
Hermann Stamm-Wilbrandt
Compiler Level 3 support
IBM DataPower Gateways (⬚ᵈᵃᵗᵃ / ⣏⠆⡮⡆⢹⠁⡮⡆⡯⠂⢎⠆⡧⡇⣟⡃⡿⡃)
https://stamm-wilbrandt.de/en/blog/
------------------------------