Metapath function support needed for adding or improving FedRAMP constraints

[Gabeblis]

This is a ...

improvement - something could be better

This relates to ...

• the FedRAMP OSCAL Registry
• the FedRAMP OSCAL baselines
• the Guide to OSCAL-based FedRAMP Content
• the Guide to OSCAL-based FedRAMP System Security Plans (SSP)
• the Guide to OSCAL-based FedRAMP Security Assessment Plans (SAP)
• the Guide to OSCAL-based FedRAMP Security Assessment Results (SAR)
• the Guide to OSCAL-based FedRAMP Plan of Action and Milestones (POA&M)
• the FedRAMP SSP OSCAL Template (JSON or XML Format)
• the FedRAMP SAP OSCAL Template (JSON or XML Format)
• the FedRAMP SAR OSCAL Template (JSON or XML Format)
• the FedRAMP POA&M OSCAL Template (JSON or XML Format)
• the FedRAMP OSCAL Validations

User Story

As a developer working on writing constraints, I want metaschema-java to support crucial XPath functions,
so that I can proceed with implementing and validating constraints without being blocked.

Goals

Enable support for the following XPath functions in metaschema-java:

• Function substring- functions are not implemented in Metapath processor metaschema-framework/metaschema-java#132
• Function normalize-space() is not implemented in Metapath processor metaschema-framework/metaschema-java#133
• Function matches() is not implemented in Metapath processor metaschema-framework/metaschema-java#134
• Function tokenize() is not implemented in Metapath processor metaschema-framework/metaschema-java#135

Dependencies

No response

Acceptance Criteria

• All FedRAMP Documents Related to OSCAL Adoption (https://github.com/GSA/fedramp-automation) affected by the changes in this issue have been updated.
• A Pull Request (PR) is submitted that fully addresses the goals of this User Story. This issue is referenced in the PR.

Other information

Currently, the development of several constraints is halted because metaschema-java lacks support for essential XPath functions. These functions are critical to writing and validating certain constraints in our schema. Without them, we are unable to proceed with development and testing, leading to delays in the project timeline. This user story aims to ensure that metaschema-java provides the necessary support for these XPath functions to unblock development and enable the proper writing of constraints.

[wandmagic]

filter would also be great

[aj-stein-gsa]

I am gonna work on a cross-reference issue in metaschema-java so these functions and their capabilities "bubble up" into oscal-cli soon enough and we can update the version in the container spec.

Thank you gentlemen, updates incoming! 😎