/// <summary>
/// Perform the Invariant based validation for this rule
/// </summary>
/// <param name="invariantRule"></param>
/// <param name="model"></param>
/// <param name="result">The OperationOutcome that will have the validation results appended</param>
/// <param name="context">Describes the context in which a validation check is performed.</param>
/// <returns></returns>
public static bool ValidateInvariantRule(ValidationContext context, ElementDefinition.ConstraintComponent invariantRule, ITypedElement model, OperationOutcome result)
{
string expression = invariantRule.GetStringExtension("http://hl7.org/fhir/StructureDefinition/structuredefinition-expression");
try
{
// No FhirPath extension
if (string.IsNullOrEmpty(expression))
{
result.Issue.Add(new OperationOutcome.IssueComponent()
{
Code = OperationOutcome.IssueType.Invariant,
Severity = OperationOutcome.IssueSeverity.Warning,
Details = new CodeableConcept(null, invariantRule.Key, "Unable to validate without a FhirPath expression"),
Diagnostics = expression
});
return(true);
}
// Ensure the FHIR extensions are registered
Hl7.Fhir.FhirPath.ElementNavFhirExtensions.PrepareFhirSymbolTableFunctions();
if (model.Predicate(expression, new EvaluationContext(model)))
{
return(true);
}
result.Issue.Add(new OperationOutcome.IssueComponent()
{
Code = OperationOutcome.IssueType.Invariant,
Severity = OperationOutcome.IssueSeverity.Error,
Details = new CodeableConcept(null, invariantRule.Key, invariantRule.Human),
Diagnostics = expression
});
return(false);
}
catch (Exception ex)
{
result.Issue.Add(new OperationOutcome.IssueComponent()
{
Code = OperationOutcome.IssueType.Invariant,
Severity = OperationOutcome.IssueSeverity.Fatal,
Details = new CodeableConcept(null, invariantRule.Key, "FATAL: Unable to process the invariant rule: " + invariantRule.Key + " " + expression),
Diagnostics = String.Format("FhirPath: {0}\r\nError: {1}", expression, ex.Message)
});
return(false);
}
}