[GitHub] [flink] lirui-apache commented on a change in pull request #13144: [FLINK-15853][hive][table-planner-blink] Use the new type inference f…

[GitBox <gi...@apache.org>]

lirui-apache commented on a change in pull request #13144:
URL: https://github.com/apache/flink/pull/13144#discussion_r475425845



##########
File path: flink-connectors/flink-connector-hive/src/main/java/org/apache/flink/table/functions/hive/HiveScalarFunction.java
##########
@@ -104,4 +142,62 @@ public Object eval(Object... args) {
 	 * Evaluation logical, args will be wrapped when is a single array.
 	 */
 	protected abstract Object evalInternal(Object[] args);
+
+	private Tuple2<Object[], DataType[]> getConstantArgAndTypes(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);
+			}
+		}
+		return Tuple2.of(constantArgs, inputTypes);
+	}
+
+	/**
+	 * Validate input argument types and decide result type.
+	 */
+	protected abstract DataType validateInputTypes(DataType[] argTypes) throws UDFArgumentException;
+
+	private class HiveUDFOutputStrategy implements TypeStrategy {
+
+		@Override
+		public Optional<DataType> inferType(CallContext callContext) {
+			Tuple2<Object[], DataType[]> constantArgAndTypes = getConstantArgAndTypes(callContext);
+			return Optional.ofNullable(getHiveResultType(constantArgAndTypes.f0, constantArgAndTypes.f1));
+		}
+	}
+
+	private class HiveUDFInputStrategy implements InputTypeStrategy {

Review comment:
       I think this is needed for input type validation. For example, according to the API contract, a `ValidationException` can be thrown if the input is invalid, but this should only happen during input inference rather than output inference.




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