mbeckerle commented on a change in pull request #273: WIP: Add User Defined
Functions Capability
URL: https://github.com/apache/incubator-daffodil/pull/273#discussion_r332225188
##########
File path:
daffodil-core/src/main/scala/org/apache/daffodil/dpath/Expression.scala
##########
@@ -1870,6 +1871,47 @@ case class FunctionCallExpression(functionQNameString:
String, expressions: List
case (RefQName(_, "unsignedByte", XSD), args) =>
XSConverterExpr(functionQNameString, functionQName, args,
NodeInfo.UnsignedByte)
+ case (RefQName(Some(_), _, _), args) => {
+ val namespace = functionQName.namespace.toString()
+ val fName = functionQName.local
+
+ lazy val udfservice = {
+ val a = UDFService
+ a.warnings.map { w => SDW(WarnID.UserDefinedFunction, w) }
+ val allErrors = a.errors.mkString("\n\n")
+ SDE(s"Function unknown: fname[${fName}]
fnamespace[${namespace}].\n$allErrors")
+ a
+ }
+
+ val fcObject = udfservice.udfs.lookupFunctionClass(namespace, fName)
+
+ if (fcObject == null) {
+ SDE("Function not found: fname[%s] fnamespace[%s]. Currently
registered UDFs:\n%s", fName, namespace, udfservice.allFunctionClasses)
+ }
+
+ val fcClassType = fcObject.getClass
+
+ val paramTypesReturnTypeTuple: Array[(Array[Class[_]], Class[_])] =
fcClassType.getMethods.collect {
+ case p if p.getName == "evaluate" => (p.getParameterTypes,
p.getReturnType)
+ }
+
+ if (paramTypesReturnTypeTuple.isEmpty) {
+ SDE("Missing evaluate method for function provided: name[%s]
namespace[%s]", fName, namespace)
+ }
+
+ if (paramTypesReturnTypeTuple.length > 1) {
+ SDE("Only one evaluate method allowed per function class: name[%s]
namespace[%s]", fName, namespace)
+ }
+
+ val paramTypes: Array[Class[_]] = paramTypesReturnTypeTuple.head._1
+ val retType: Class[_] = paramTypesReturnTypeTuple.head._2
+
Review comment:
Brandon, how could they use a UDF as a variable? A UDF has no state. Or
rather, it SHOULD have no state. There are no guarantees that the UDF instance
is preserved from one call to the next. It gets initialized, but you can't
count on storing information in them and then retrieving it, as that would then
end up exposing state across backtracking, etc.
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