lirui-apache commented on a change in pull request #13144:
URL: https://github.com/apache/flink/pull/13144#discussion_r480038553
##########
File path:
flink-connectors/flink-connector-hive/src/main/java/org/apache/flink/table/functions/hive/HiveScalarFunction.java
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@@ -104,4 +114,66 @@ public Object eval(Object... args) {
* Evaluation logical, args will be wrapped when is a single array.
*/
protected abstract Object evalInternal(Object[] args);
+
+ private void setArguments(CallContext callContext) {
+ DataType[] inputTypes =
callContext.getArgumentDataTypes().toArray(new DataType[0]);
+ Object[] constantArgs = new Object[inputTypes.length];
+ for (int i = 0; i < constantArgs.length; i++) {
+ if (callContext.isArgumentLiteral(i)) {
+ constantArgs[i] = callContext.getArgumentValue(
+ i,
ClassLogicalTypeConverter.getDefaultExternalClassForType(inputTypes[i].getLogicalType()))
+ .orElse(null);
+ }
+ }
+ this.constantArguments = constantArgs;
+ this.argTypes = inputTypes;
+ }
+
+ /**
+ * Infer return type of this function call.
+ */
+ protected abstract DataType inferReturnType() throws
UDFArgumentException;
+
+ private class HiveUDFOutputStrategy implements TypeStrategy {
+
+ @Override
+ public Optional<DataType> inferType(CallContext callContext) {
+ setArguments(callContext);
+ try {
+ return Optional.of(inferReturnType());
+ } catch (UDFArgumentException e) {
+ throw new FlinkHiveUDFException(e);
+ }
+ }
+ }
+
+ private class HiveUDFInputStrategy implements InputTypeStrategy {
+
+ @Override
+ public ArgumentCount getArgumentCount() {
+ return ConstantArgumentCount.any();
+ }
+
+ @Override
+ public Optional<List<DataType>> inferInputTypes(CallContext
callContext, boolean throwOnFailure) {
+ setArguments(callContext);
+ try {
+ inferReturnType();
+ } catch (UDFArgumentException e) {
+ if (throwOnFailure) {
+ throw new ValidationException(
+ String.format("Cannot
find a suitable Hive function from %s for the input arguments",
+
hiveFunctionWrapper.getClassName()), e);
+ } else {
+ return Optional.empty();
+ }
+ }
+ return Optional.of(callContext.getArgumentDataTypes());
+ }
+
+ @Override
+ public List<Signature> getExpectedSignatures(FunctionDefinition
definition) {
+ return
Collections.singletonList(Signature.of(Signature.Argument.of("*")));
Review comment:
I'm not sure whether it's possible to get all the valid signatures for a
hive function. Some hive function supports implicit type conversion, e.g. a
function that operates on string values may take numeric input as well. I'll
double check.
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