Fix #76: handle lists of UDTs properly in ResultSet.getObject() methods

Author: maximevw

Diff for: CHANGELOG.md

@@ -14,6 +14,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 ### Fixed
 - Add codec for conversion between `Short` and CQL type `tinyint` (see issue
   [#76](https://github.com/ing-bank/cassandra-jdbc-wrapper/issues/76)).
+- Handle lists of User-Defined Types (UDT) properly when using `CassandraResultSet.getObject(String|int)` methods (see 
+  issue [#76](https://github.com/ing-bank/cassandra-jdbc-wrapper/issues/76)).
 
 ## [4.14.0] - 2024-12-24
 ### Added

Diff for: src/main/java/com/ing/data/cassandra/jdbc/CassandraResultSet.java

@@ -934,7 +934,10 @@ public Object getObject(final int columnIndex) throws SQLException {
                 final DataType elementsType = listType.getElementType();
                 final List<?> resultList;
 
-                if (elementsType instanceof TupleType) {
+                if (elementsType instanceof UserDefinedType) {
+                    resultList = this.currentRow.getList(columnIndex - 1,
+                        TypesMap.getTypeForComparator(DataTypeEnum.UDT.asLowercaseCql()).getType());
+                } else if (elementsType instanceof TupleType) {
                     resultList = this.currentRow.getList(columnIndex - 1,
                         TypesMap.getTypeForComparator(DataTypeEnum.TUPLE.asLowercaseCql()).getType());
                 } else {
@@ -1069,7 +1072,10 @@ public Object getObject(final String columnLabel) throws SQLException {
                 final DataType elementsType = listType.getElementType();
                 final List<?> resultList;
 
-                if (elementsType instanceof TupleType) {
+                if (elementsType instanceof UserDefinedType) {
+                    resultList = this.currentRow.getList(columnLabel,
+                        TypesMap.getTypeForComparator(DataTypeEnum.UDT.asLowercaseCql()).getType());
+                } else if (elementsType instanceof TupleType) {
                     resultList = this.currentRow.getList(columnLabel,
                         TypesMap.getTypeForComparator(DataTypeEnum.TUPLE.asLowercaseCql()).getType());
                 } else {

Diff for: src/test/java/com/ing/data/cassandra/jdbc/CollectionsUnitTest.java

@@ -38,6 +38,7 @@
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.instanceOf;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertInstanceOf;
@@ -356,6 +357,9 @@ void givenFrozenTypesSelectStatement_whenExecute_getExpectedResultSet() throws E
         assertEquals("test", udtValue.getString("value1"));
         assertTrue(udtValue.getBoolean("value2"));
 
+        // Check retrieving a list of UDTs does not throw an exception (see issue #76).
+        assertDoesNotThrow(() -> resultSet.getObject("innerUdt"));
+
         Object outerUdt = resultSet.getObject("outerUdt");
         assertInstanceOf(UdtValue.class, outerUdt);
         assertEquals(1, ((UdtValue) outerUdt).getInt("key"));