Data Format Description Language (DFDL) v1.0 Specification
OGF Proposed Recommendation GFD-P-R.174, January 31, 2011


2.4 Validation Errors

Logical validation checks are constraints expressed in XSDL and they apply to the logical content of the infoset. Hence, parsing must successfully construct the infoset from the representation in order for validation checks to be meaningful. This implies that validation errors cannot affect the ability of a DFDL processor to successfully parse or unparse data.

DFDL processors may provide both validating and non-validating behaviors on either or both of parse and unparse. (A DFDL implementation could support validate on parse, but not support it on unparse and still be considered conforming.)

The behavior of a DFDL processor after a validation error is not specified by the DFDL language.

An unparse validation error is defined in terms of a parse validation error. Specifically, an unparse validation error occurs when the physical representation being output would generate a validation error when parsing the data representation using the same DFDL schema.

When resolving points of uncertainty, validation errors are ignored.

The following DFDL schema constructs are allowed in DFDL and are checked when validating:

  1. XSDL pattern facet - (for xs:string type elements only)

  2. XSDL minLength, maxLength

  3. XSDL minInclusive, minExclusive, maxInclusive, maxExclusive

  4. XSDL enumeration

  5. XSDL maxOccurs

Note that validation is distinct from the checking of DFDL assert or discriminator predicates. When a DFDL discriminator or assert is used to discriminate a choice or other point of uncertainty when parsing, then that assert or discriminator is essential to parsing and it is evaluated irrespective of whether validation is enabled or disabled.

Note that validation errors cannot be suppressed by points of uncertainty.


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