NIAD-3432: Skeleton processing service now removes leading _ before performing XPath query

[chiaramapellimt]

What

This fix relates to this ticket: https://nhse-dsic.atlassian.net/browse/NIAD-3432
When processing large messages with a skeleton attachment, the adaptor takes the skeleton document ID from the ebXML reference and uses it to search for the matching node in the payload XML. However, EMIS and SystmOne both prefix their ebXML document IDs with a leading underscore, while the same ID appears without the underscore in the payload XML. This mismatch meant the XPath query never found a matching node, returning null and causing the NullPointerException and subsequent LARGE_MESSAGE_GENERAL_FAILURE.

Why

Strip the leading underscore from the document ID before executing the XPath query. This is a one-line change in SkeletonProcessingService.java and is safe for messages where the document ID has no leading underscore, as the operation is a no-op in that case.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Internal change (non-breaking change with no effect on the functionality affecting end users)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• I have performed a self-review of my code
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have updated the Changelog with details of my change in the UNRELEASED section if this change will affect end users
• A corresponding change has been made to the Mapping Documentation repository

[github-actions]

Looks good. All 2 mutations in this change were killed.

class	surviving	killed
💯uk.nhs.adaptors.pss.translator.service.SkeletonProcessingService	0	2

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• Arcmutate licence valid until 2028-03-02 (yyyy/mm/dd) (non-commercial use only)
• Project uses Spring, but the Arcmutate Spring plugin is not present.

[github-actions]

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