fhir-path-custom-functions.md

This FHIR converter library includes custom FHIR Path functions that can be used in expressions evaluated by the FHIRPathUtils class. Alternatively, you can pass in the custom FHIR Path functions directly to your FHIR Path Engine.

For the most up-to-date list of custom functions please refer to the code in the CustomFHIRFunctions.kt file.

Usage

Kotlin

val bundle = Bundle() // Read or populate your bundle

val context = CustomContext(bundle, bundle, mutableMapOf("diagnostic" to "Bundle.entry.resource.ofType(DiagnosticReport)"))
val result1 = FhirPathUtils.evaluate(context, bundle, bundle, "%diagnostic")
if (result1.isNotEmpty()) {
    // Set the first Diagnostic Report as our focus for our next evaluation
    val result2: List<Base> = FhirPathUtils.evaluate(context, result1[0], bundle, "%resource.status")
}

Java

Bundle bundle = new Bundle(); // Read or populate your bundle

Map<String, String> constants = new HashMap<>(Map.of("diagnostic", "Bundle.entry.resource.ofType(DiagnosticReport)"));
CustomContext context = new CustomContext(bundle, bundle, constants);
List<Base> result1 = FhirPathUtils.INSTANCE.evaluate(context, bundle, bundle, "%diagnostic");
if (!result1.isEmpty()) {
    // Set the first Diagnostic Report as our focus for our next evaluation
    List<Base> result2 = FhirPathUtils.INSTANCE.evaluate(context, result1.get(0), bundle, "%resource.status");
}