Cloud Spanner: Make Spanner value classes serializable

google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerImpl.java

@@ -81,6 +81,7 @@
 import io.grpc.Context;
 import io.grpc.ManagedChannel;
 import java.io.IOException;
+import java.io.Serializable;
 import java.util.AbstractList;
 import java.util.ArrayList;
 import java.util.BitSet;
@@ -1511,6 +1512,8 @@ public Transaction call() throws Exception {
    * @param <R> the type of row data
    */
   private static class BaseStruct<R> extends Struct {
+    private static final long serialVersionUID = -1850257565078946587L;
+
     protected final Type type;
     protected final List<Object> rowData;
 
@@ -1838,6 +1841,8 @@ private SpannerException yieldError(SpannerException e) {
   }
 
   private static class GrpcStruct extends BaseStruct<List<Object>> {
+    private static final long serialVersionUID = -2067943506736181881L;
+
     GrpcStruct(Type type, List<Object> rowData) {
       super(type, rowData);
     }
@@ -1898,29 +1903,15 @@ private static Object decodeArrayValue(Type elementType, ListValue listValue) {
       switch (elementType.getCode()) {
         case BOOL:
           // Use a view: element conversion is virtually free.
-          return Lists.transform(
-              listValue.getValuesList(),
-              new Function<com.google.protobuf.Value, Boolean>() {
-                @Override
-                public Boolean apply(com.google.protobuf.Value input) {
-                  return input.getKindCase() == KindCase.NULL_VALUE ? null : input.getBoolValue();
-                }
-              });
+          return new BoolArray(listValue);
         case INT64:
           // For int64/float64 types, use custom containers.  These avoid wrapper object
           // creation for non-null arrays.
           return new Int64Array(listValue);
         case FLOAT64:
           return new Float64Array(listValue);
         case STRING:
-          return Lists.transform(
-              listValue.getValuesList(),
-              new Function<com.google.protobuf.Value, String>() {
-                @Override
-                public String apply(com.google.protobuf.Value input) {
-                  return input.getKindCase() == KindCase.NULL_VALUE ? null : input.getStringValue();
-                }
-              });
+          return new StringArray(listValue);
         case BYTES:
           {
             // Materialize list: element conversion is expensive and should happen only once.
@@ -2418,7 +2409,8 @@ private static NullPointerException throwNotNull(int columnIndex) {
    * {@code BigDecimal} respectively. Rather than construct new wrapper objects for each array
    * element, we use primitive arrays and a {@code BitSet} to track nulls.
    */
-  private abstract static class PrimitiveArray<T, A> extends AbstractList<T> {
+  private abstract static class PrimitiveArray<T, A> extends AbstractList<T> implements Serializable {
+    private static final long serialVersionUID = -3635424493234309483L;
     private final A data;
     private final BitSet nulls;
     private final int size;
@@ -2474,6 +2466,8 @@ A toPrimitiveArray(int columnIndex) {
   }
 
   private static class Int64Array extends PrimitiveArray<Long, long[]> {
+    private static final long serialVersionUID = -1119776393736089987L;
+
     Int64Array(ListValue protoList) {
       super(protoList);
     }
@@ -2499,6 +2493,8 @@ Long get(long[] array, int i) {
   }
 
   private static class Float64Array extends PrimitiveArray<Double, double[]> {
+    private static final long serialVersionUID = 615840120676713454L;
+
     Float64Array(ListValue protoList) {
       super(protoList);
     }
@@ -2522,4 +2518,44 @@ Double get(double[] array, int i) {
       return array[i];
     }
   }
+
+  private static class StringArray extends AbstractList<String> implements Serializable {
+    private static final long serialVersionUID = 695127243179520960L;
+    private final ListValue listValue;
+
+    private StringArray(ListValue listValue) {
+      this.listValue = listValue;
+    }
+
+    @Override
+    public String get(int index) {
+      com.google.protobuf.Value value = listValue.getValues(index);
+      return value.getKindCase() == KindCase.NULL_VALUE ? null : value.getStringValue();
+    }
+
+    @Override
+    public int size() {
+      return listValue.getValuesCount();
+    }
+  }
+
+  private static class BoolArray extends AbstractList<Boolean> implements Serializable {
+    private static final long serialVersionUID = -2850504708084921083L;
+    private final ListValue listValue;
+
+    private BoolArray(ListValue listValue) {
+      this.listValue = listValue;
+    }
+
+    @Override
+    public Boolean get(int index) {
+      com.google.protobuf.Value value = listValue.getValues(index);
+      return value.getKindCase() == KindCase.NULL_VALUE ? null : value.getBoolValue();
+    }
+
+    @Override
+    public int size() {
+      return listValue.getValuesCount();
+    }
+  }
 }

google-cloud-spanner/src/main/java/com/google/cloud/spanner/Statement.java

@@ -21,6 +21,8 @@
 
 import com.google.cloud.spanner.ReadContext.QueryAnalyzeMode;
 import com.google.common.collect.ImmutableMap;
+
+import java.io.Serializable;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
@@ -50,7 +52,9 @@
  *
  * <p>{@code Statement} instances are immutable.
  */
-public final class Statement {
+public final class Statement implements Serializable {
+  private static final long serialVersionUID = -1967958247625065259L;
+
   private final ImmutableMap<String, Value> parameters;
   private final String sql;
 

google-cloud-spanner/src/main/java/com/google/cloud/spanner/Struct.java

@@ -26,6 +26,8 @@
 import com.google.common.primitives.Booleans;
 import com.google.common.primitives.Doubles;
 import com.google.common.primitives.Longs;
+
+import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
@@ -41,7 +43,9 @@
  * <p>{@code Struct} instances are immutable.
  */
 @Immutable
-public abstract class Struct extends AbstractStructReader {
+public abstract class Struct extends AbstractStructReader implements Serializable {
+  private static final long serialVersionUID = 1698871272663044565L;
+
   // Only implementations within the package are allowed.
   Struct() {}
 
@@ -121,6 +125,8 @@ private void checkBindingInProgress(boolean expectInProgress) {
 
   /** Default implementation for test value structs produced by {@link Builder}. */
   private static class ValueListStruct extends Struct {
+    private static final long serialVersionUID = 1712981659934867577L;
+
     private final Type type;
     private final List<Value> values;
 

google-cloud-spanner/src/main/java/com/google/cloud/spanner/TimestampBound.java

@@ -24,6 +24,8 @@
 import com.google.protobuf.Duration;
 import com.google.protobuf.util.Durations;
 import com.google.spanner.v1.TransactionOptions;
+
+import java.io.Serializable;
 import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
@@ -115,10 +117,11 @@
  * @see Session#singleUseReadOnlyTransaction(TimestampBound)
  * @see Session#readOnlyTransaction(TimestampBound)
  */
-public final class TimestampBound {
+public final class TimestampBound implements Serializable {
   private static final TimestampBound STRONG_BOUND = new TimestampBound(Mode.STRONG, null, null);
   private static final TransactionOptions.ReadOnly STRONG_PROTO =
       TransactionOptions.ReadOnly.newBuilder().setStrong(true).build();
+  private static final long serialVersionUID = 9194565742651275731L;
 
   private final Mode mode;
   private final Timestamp timestamp;

google-cloud-spanner/src/main/java/com/google/cloud/spanner/Type.java

@@ -207,7 +207,9 @@ static Code fromProtoCode(TypeCode protoCode) {
   }
 
   /** Describes an individual field in a {@code STRUCT type}. */
-  public static final class StructField {
+  public static final class StructField implements Serializable {
+    private static final long serialVersionUID = 8640511292704408210L;
+
     private final String name;
     private final Type type;
 

google-cloud-spanner/src/test/java/com/google/cloud/spanner/GrpcResultSetTest.java

@@ -17,11 +17,15 @@
 package com.google.cloud.spanner;
 
 import static com.google.cloud.spanner.SpannerMatchers.isSpannerException;
+import static com.google.common.testing.SerializableTester.reserializeAndAssert;
 import static com.google.common.truth.Truth.assertThat;
 
 import com.google.cloud.ByteArray;
+import com.google.cloud.Date;
+import com.google.cloud.Timestamp;
 import com.google.cloud.spanner.spi.v1.SpannerRpc;
 import com.google.common.base.Function;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.protobuf.ByteString;
 import com.google.protobuf.NullValue;
@@ -588,4 +592,50 @@ private static ResultSetMetadata makeMetadata(Type rowType) {
     com.google.spanner.v1.Type typeProto = rowType.toProto();
     return ResultSetMetadata.newBuilder().setRowType(typeProto.getStructType()).build();
   }
+
+  @Test
+  public void serialization() throws Exception {
+    verifySerialization(Value.string("a"),
+            Value.string(null),
+            Value.bool(true),
+            Value.bool(null),
+            Value.int64(1),
+            Value.int64(null),
+            Value.float64(1.0),
+            Value.float64(null),
+            Value.bytes(ByteArray.fromBase64("abcd")),
+            Value.bytes(null),
+            Value.timestamp(Timestamp.ofTimeSecondsAndNanos(1, 2)),
+            Value.timestamp(null),
+            Value.date(Date.fromYearMonthDay(2017, 04, 17)),
+            Value.date(null),
+            Value.stringArray(ImmutableList.of("one", "two")),
+            Value.stringArray(null),
+            Value.boolArray(new boolean[]{true, false}),
+            Value.boolArray((boolean[]) null),
+            Value.int64Array(new long[]{1, 2, 3}),
+            Value.int64Array((long[]) null),
+            Value.timestampArray(ImmutableList.of(Timestamp.MAX_VALUE, Timestamp.MAX_VALUE)),
+            Value.timestampArray(null),
+            Value.dateArray(ImmutableList.of(
+                    Date.fromYearMonthDay(2017, 4, 17), Date.fromYearMonthDay(2017, 5, 18))),
+            Value.dateArray(null)
+    );
+  }
+
+  private void verifySerialization(Value... values) {
+    resultSet = new SpannerImpl.GrpcResultSet(stream, new NoOpListener(), QueryMode.NORMAL);
+    PartialResultSet.Builder builder = PartialResultSet.newBuilder();
+    List<Type.StructField> types = new ArrayList<>();
+    for (Value value : values) {
+      types.add(Type.StructField.of("f", value.getType()));
+      builder.addValues(value.toProto());
+    }
+    consumer.onPartialResultSet(
+            builder.setMetadata(makeMetadata(Type.struct(types)))
+                    .build());
+    consumer.onCompleted();
+    assertThat(resultSet.next()).isTrue();
+    reserializeAndAssert(resultSet.getCurrentRowAsStruct());
+  }
 }

google-cloud-spanner/src/test/java/com/google/cloud/spanner/StatementTest.java

@@ -16,6 +16,7 @@
 
 package com.google.cloud.spanner;
 
+import static com.google.common.testing.SerializableTester.reserializeAndAssert;
 import static com.google.common.truth.Truth.assertThat;
 
 import com.google.common.collect.ImmutableMap;
@@ -38,6 +39,7 @@ public void basic() {
     assertThat(stmt.getSql()).isEqualTo(sql);
     assertThat(stmt.getParameters()).isEmpty();
     assertThat(stmt.toString()).isEqualTo(sql);
+    reserializeAndAssert(stmt);
   }
 
   @Test

google-cloud-spanner/src/test/java/com/google/cloud/spanner/TimestampBoundTest.java

@@ -17,6 +17,7 @@
 package com.google.cloud.spanner;
 
 import static com.google.cloud.spanner.TimestampBound.Mode;
+import static com.google.common.testing.SerializableTester.reserializeAndAssert;
 import static com.google.common.truth.Truth.assertThat;
 
 import com.google.cloud.Timestamp;
@@ -37,6 +38,15 @@ public class TimestampBoundTest {
   private static final String TEST_TIME_ISO = "2015-10-12T15:14:54Z";
   @Rule public ExpectedException expectedException = ExpectedException.none();
 
+  @Test
+  public void serialization() throws Exception {
+    reserializeAndAssert(TimestampBound.strong());
+    reserializeAndAssert(TimestampBound.ofExactStaleness(10, TimeUnit.NANOSECONDS));
+    reserializeAndAssert(TimestampBound.ofMaxStaleness(100, TimeUnit.DAYS));
+    reserializeAndAssert(TimestampBound.ofMinReadTimestamp(Timestamp.now()));
+    reserializeAndAssert(TimestampBound.ofReadTimestamp(Timestamp.now()));
+  }
+
   @Test
   public void strong() {
     TimestampBound bound = TimestampBound.strong();