fixed problem with nested arrays

Author: chernser

jdbc-v2/src/main/java/com/clickhouse/jdbc/internal/JdbcUtils.java

@@ -229,6 +229,8 @@ public static Object convert(Object value, Class<?> type, ClickHouseColumn colum
         try {
             if (type.isInstance(value)) {
                 return value;
+            } else if (type != java.sql.Array.class && value instanceof List<?>) {
+                return convertList((List<?>) value, type);
             } else if (type == String.class) {
                 return value.toString();
             } else if (type == Boolean.class || type == boolean.class) {
@@ -268,15 +270,14 @@ public static Object convert(Object value, Class<?> type, ClickHouseColumn colum
                 if (column != null && column.getArrayBaseColumn() != null) {
                     ClickHouseDataType baseType = column.getArrayBaseColumn().getDataType();
                     Object[] convertedValues = convertArray(arrayValue.getArrayOfObjects(),
-                            JdbcUtils.convertToJavaClass(column.getArrayBaseColumn().getDataType()));
+                            JdbcUtils.convertToJavaClass(baseType));
                     return new Array(convertedValues, baseType.getName(), baseType.getVendorTypeNumber());
                 }
                 return new Array(arrayValue.getArrayOfObjects(), "Unknown", JDBCType.OTHER.getVendorTypeNumber());
             } else if (type == java.sql.Array.class && value instanceof List<?>) {
-
                 if (column != null && column.getArrayBaseColumn() != null) {
                     ClickHouseDataType baseType = column.getArrayBaseColumn().getDataType();
-                    return new Array(convertList((List<?>) value, JdbcUtils.convertToJavaClass(column.getArrayBaseColumn().getDataType())),
+                    return new Array(convertList((List<?>) value, JdbcUtils.convertToJavaClass(baseType)),
                             baseType.getName(), JdbcUtils.CLICKHOUSE_TO_SQL_TYPE_MAP.getOrDefault(baseType, JDBCType.OTHER).getVendorTypeNumber());
                 }
                 // base type is unknown. all objects should be converted
@@ -301,6 +302,9 @@ public static Object[] convertList(List<?> values, Class<?> type) throws SQLExce
         if (values == null) {
             return null;
         }
+        if (values.isEmpty()) {
+            return new Object[0];
+        }
 
         Object[] convertedValues = new Object[values.size()];
         for (int i = 0; i < values.size(); i++) {

jdbc-v2/src/test/java/com/clickhouse/jdbc/DataTypeTests.java

@@ -1000,6 +1000,23 @@ public void testArrayTypes() throws SQLException {
         }
     }
 
+    @Test(groups = { "integration" })
+    public void testNestedArrays() throws Exception {
+        try (Connection conn = getJdbcConnection()) {
+            try (Statement stmt = conn.createStatement()) {
+                try (ResultSet rs = stmt.executeQuery("SELECT [['a', 'b'], ['c', 'd']] as value")) {
+                    assertTrue(rs.next());
+                    Array arrayHolder = (Array) rs.getObject(1);
+                    Object[] array = (Object[]) arrayHolder.getArray();
+                    Object[] subArray1 =  (Object[]) array[0];
+                    assertEquals(subArray1, new Object[]{ "a", "b"} );
+                    Object[] subArray2 =  (Object[]) array[1];
+                    assertEquals(subArray2, new Object[]{ "c", "d"} );
+                }
+            }
+        }
+    }
+
     @Test(groups = { "integration" })
     public void testMapTypes() throws SQLException {
         runQuery("CREATE TABLE test_maps (order Int8, "

jdbc-v2/src/test/java/com/clickhouse/jdbc/internal/JdbcUtilsTest.java

@@ -1,12 +1,10 @@
 package com.clickhouse.jdbc.internal;
 
 import com.clickhouse.client.api.data_formats.internal.BinaryStreamReader;
-import com.clickhouse.client.api.data_formats.internal.InetAddressConverter;
 import com.clickhouse.data.ClickHouseColumn;
 import org.testng.annotations.Test;
 
 import java.math.BigDecimal;
-import java.net.Inet6Address;
 import java.sql.SQLException;
 import java.util.Arrays;
 import java.util.List;