Added NullType support

table/src/main/java/tech/ydb/table/result/impl/ProtoNullValueReader.java

@@ -0,0 +1,35 @@
+package tech.ydb.table.result.impl;
+
+import tech.ydb.proto.ValueProtos;
+import tech.ydb.table.values.proto.ProtoType;
+import tech.ydb.table.values.proto.ProtoValue;
+
+
+/**
+ * @author Aleksandr Gorshenin
+ */
+final class ProtoNullValueReader extends AbstractValueReader {
+    static final ProtoNullValueReader INSTANCE = new ProtoNullValueReader();
+
+    private ProtoNullValueReader() { }
+
+    @Override
+    protected ValueProtos.Type getProtoType() {
+        return ProtoType.getNull();
+    }
+
+    @Override
+    protected ValueProtos.Value getProtoValue() {
+        return ProtoValue.nullValue();
+    }
+
+    @Override
+    protected void setProtoValue(ValueProtos.Value value) {
+        // skip
+    }
+
+    @Override
+    public void toString(StringBuilder sb) {
+        sb.append("Null");
+    }
+}

table/src/main/java/tech/ydb/table/result/impl/ProtoValueReaders.java

@@ -63,6 +63,8 @@ static AbstractValueReader forTypeImpl(ValueProtos.Type type) {
                 return variantReader(type);
             case VOID_TYPE:
                 return ProtoVoidValueReader.INSTANCE;
+            case NULL_TYPE:
+                return ProtoNullValueReader.INSTANCE;
             default:
                 throw new IllegalStateException("unsupported type: " + type);
         }

table/src/main/java/tech/ydb/table/values/NullType.java

@@ -0,0 +1,36 @@
+package tech.ydb.table.values;
+
+
+import tech.ydb.proto.ValueProtos;
+import tech.ydb.table.values.proto.ProtoType;
+
+
+/**
+ * @author Aleksandr Gorshenin
+ */
+public final class NullType implements Type {
+
+    private static final NullType INSTANCE = new NullType();
+
+    private NullType() {
+    }
+
+    public static NullType of() {
+        return NullType.INSTANCE;
+    }
+
+    @Override
+    public Kind getKind() {
+        return Kind.NULL;
+    }
+
+    @Override
+    public String toString() {
+        return "Null";
+    }
+
+    @Override
+    public ValueProtos.Type toPb() {
+        return ProtoType.getNull();
+    }
+}

table/src/main/java/tech/ydb/table/values/NullValue.java

@@ -0,0 +1,35 @@
+package tech.ydb.table.values;
+
+import tech.ydb.proto.ValueProtos;
+import tech.ydb.table.values.proto.ProtoValue;
+
+
+/**
+ * @author Aleksandr Gorshenin
+ */
+public class NullValue implements Value<NullType> {
+
+    private static final NullValue INSTANCE = new NullValue();
+
+    private NullValue() {
+    }
+
+    public static NullValue of() {
+        return INSTANCE;
+    }
+
+    @Override
+    public String toString() {
+        return "Null";
+    }
+
+    @Override
+    public NullType getType() {
+        return NullType.of();
+    }
+
+    @Override
+    public ValueProtos.Value toPb() {
+        return ProtoValue.nullValue();
+    }
+}

table/src/main/java/tech/ydb/table/values/Type.java

@@ -47,6 +47,7 @@ enum Kind {
         DICT,
         VARIANT,
         VOID,
+        NULL,
         PG_TYPE;
     }
 }

table/src/main/java/tech/ydb/table/values/proto/ProtoType.java

@@ -10,6 +10,7 @@
 import tech.ydb.table.values.DecimalType;
 import tech.ydb.table.values.DictType;
 import tech.ydb.table.values.ListType;
+import tech.ydb.table.values.NullType;
 import tech.ydb.table.values.OptionalType;
 import tech.ydb.table.values.PgType;
 import tech.ydb.table.values.PrimitiveType;
@@ -32,6 +33,10 @@ public class ProtoType {
         .setVoidType(NullValue.NULL_VALUE)
         .build();
 
+    private static final ValueProtos.Type NULL = ValueProtos.Type.newBuilder()
+        .setNullType(NullValue.NULL_VALUE)
+        .build();
+
     private static final ValueProtos.Type BOOL = primitiveType(PrimitiveTypeId.BOOL);
     private static final ValueProtos.Type INT_8 = primitiveType(PrimitiveTypeId.INT8);
     private static final ValueProtos.Type UINT_8 = primitiveType(PrimitiveTypeId.UINT8);
@@ -334,6 +339,10 @@ public static ValueProtos.Type getVoid() {
         return VOID;
     }
 
+    public static ValueProtos.Type getNull() {
+        return NULL;
+    }
+
     public static ValueProtos.Type getPgType(int oid, int typlen, int typmod) {
         return ValueProtos.Type.newBuilder()
                 .setPgType(ValueProtos.PgType.newBuilder()
@@ -417,6 +426,9 @@ public static Type fromPb(ValueProtos.Type type) {
             case VOID_TYPE:
                 return VoidType.of();
 
+            case NULL_TYPE:
+                return NullType.of();
+
             case PG_TYPE:
                 ValueProtos.PgType pgType = type.getPgType();
                 return PgType.of(pgType.getOid(), pgType.getTyplen(), pgType.getTypmod());

table/src/main/java/tech/ydb/table/values/proto/ProtoValue.java

@@ -16,7 +16,6 @@
 
 import com.google.common.collect.Maps;
 import com.google.protobuf.ByteString;
-import com.google.protobuf.NullValue;
 import com.google.protobuf.UnsafeByteOperations;
 
 import tech.ydb.proto.ValueProtos;
@@ -25,6 +24,7 @@
 import tech.ydb.table.values.DecimalValue;
 import tech.ydb.table.values.DictType;
 import tech.ydb.table.values.ListType;
+import tech.ydb.table.values.NullValue;
 import tech.ydb.table.values.OptionalType;
 import tech.ydb.table.values.PrimitiveType;
 import tech.ydb.table.values.PrimitiveValue;
@@ -36,6 +36,8 @@
 import tech.ydb.table.values.VariantType;
 import tech.ydb.table.values.VoidValue;
 
+import static tech.ydb.table.values.Type.Kind.VOID;
+
 
 /**
  * @author Sergey Polovko
@@ -50,11 +52,15 @@ public class ProtoValue {
     private static final ValueProtos.Value EMPTY = ValueProtos.Value.newBuilder().build();
 
     private static final ValueProtos.Value EMPTY_OPTIONAL = ValueProtos.Value.newBuilder()
-        .setNullFlagValue(NullValue.NULL_VALUE)
+        .setNullFlagValue(com.google.protobuf.NullValue.NULL_VALUE)
         .build();
 
     private static final ValueProtos.Value VOID = ValueProtos.Value.newBuilder()
-        .setNullFlagValue(NullValue.NULL_VALUE)
+        .setNullFlagValue(com.google.protobuf.NullValue.NULL_VALUE)
+        .build();
+
+    private static final ValueProtos.Value NULL = ValueProtos.Value.newBuilder()
+        .setNullFlagValue(com.google.protobuf.NullValue.NULL_VALUE)
         .build();
 
     private ProtoValue() { }
@@ -650,6 +656,12 @@ public static ValueProtos.Value voidValue() {
         return VOID;
     }
 
+    // -- null value --
+
+    public static ValueProtos.Value nullValue() {
+        return NULL;
+    }
+
     // -- from proto --
 
     public static Value<?> fromPb(Type type, ValueProtos.Value value) {
@@ -749,6 +761,9 @@ public static Value<?> fromPb(Type type, ValueProtos.Value value) {
             case VOID:
                 return VoidValue.of();
 
+            case NULL:
+                return NullValue.of();
+
             default:
                 throw new IllegalStateException("unknown type kind: " + type.getKind());
         }

table/src/test/java/tech/ydb/table/integration/NullReadTest.java

@@ -0,0 +1,57 @@
+package tech.ydb.table.integration;
+
+import org.junit.Assert;
+import org.junit.ClassRule;
+import org.junit.Test;
+
+import tech.ydb.table.SessionRetryContext;
+import tech.ydb.table.impl.SimpleTableClient;
+import tech.ydb.table.query.DataQueryResult;
+import tech.ydb.table.result.ResultSetReader;
+import tech.ydb.table.result.ValueReader;
+import tech.ydb.table.rpc.grpc.GrpcTableRpc;
+import tech.ydb.table.transaction.TxControl;
+import tech.ydb.table.values.NullType;
+import tech.ydb.table.values.NullValue;
+import tech.ydb.table.values.PrimitiveType;
+import tech.ydb.test.junit4.GrpcTransportRule;
+
+/**
+ *
+ * @author Aleksandr Gorshenin
+ */
+public class NullReadTest {
+    @ClassRule
+    public static final GrpcTransportRule YDB_TRANSPORT = new GrpcTransportRule();
+    private static final SessionRetryContext CTX = SessionRetryContext.create(SimpleTableClient.newClient(
+            GrpcTableRpc.useTransport(YDB_TRANSPORT)
+    ).build()).build();
+
+    @Test
+    public void nullReadTest() {
+        DataQueryResult result = CTX.supplyResult(
+                s -> s.executeDataQuery("SELECT '1' AS p1, 123 AS p2, NULL AS p3", TxControl.serializableRw())
+        ).join().getValue();
+
+        Assert.assertEquals(1, result.getResultSetCount());
+
+        ResultSetReader rs = result.getResultSet(0);
+        Assert.assertTrue(rs.next());
+
+        ValueReader p1 = rs.getColumn("p1");
+        ValueReader p2 = rs.getColumn("p2");
+        ValueReader p3 = rs.getColumn("p3");
+
+        Assert.assertNotNull(p1);
+        Assert.assertNotNull(p2);
+        Assert.assertNotNull(p3);
+
+        Assert.assertSame(PrimitiveType.Bytes, p1.getType());
+        Assert.assertSame(PrimitiveType.Int32, p2.getType());
+        Assert.assertSame(NullType.of(), p3.getType());
+
+        Assert.assertArrayEquals(new byte[] { '1' }, p1.getBytes());
+        Assert.assertEquals(123, p2.getInt32());
+        Assert.assertSame(NullValue.of(), p3.getValue());
+    }
+}

table/src/test/java/tech/ydb/table/integration/TableQueryTest.java

@@ -6,8 +6,12 @@
 
 import javax.annotation.Nonnull;
 
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.ClassRule;
+import org.junit.Test;
+
 import tech.ydb.core.StatusCode;
-import tech.ydb.core.UnexpectedResultException;
 import tech.ydb.table.SessionRetryContext;
 import tech.ydb.table.description.TableDescription;
 import tech.ydb.table.impl.SimpleTableClient;
@@ -21,11 +25,6 @@
 import tech.ydb.table.values.StructValue;
 import tech.ydb.test.junit4.GrpcTransportRule;
 
-import org.junit.Assert;
-import org.junit.BeforeClass;
-import org.junit.ClassRule;
-import org.junit.Test;
-
 
 public class TableQueryTest {
     @ClassRule
@@ -172,11 +171,11 @@ public void testReadRowsEmptyColumns() {
         ).join().getValue().getResultSetReader();
 
         Assert.assertTrue(rsr.next());
-        Assert.assertEquals(rsr.getColumn("series_id").getUint64(), 1);
+        Assert.assertEquals(1, rsr.getColumn("series_id").getUint64());
         Assert.assertEquals("Once I rose above the noise and confusion", rsr.getColumn("title").getText());
         Assert.assertEquals("Carry on my wayward son", rsr.getColumn("series_info").getText());
         Assert.assertTrue(rsr.next());
-        Assert.assertEquals(rsr.getColumn("series_id").getUint64(), 2);
+        Assert.assertEquals(2, rsr.getColumn("series_id").getUint64());
         Assert.assertEquals("There'll be peace when you are done", rsr.getColumn("title").getText());
         Assert.assertEquals("Lay your weary head to rest", rsr.getColumn("series_info").getText());
         Assert.assertFalse(rsr.next());