feat: adds getValue to ResultSet (#1073)

* feat: adds getValue method to result set

Adds a generic getValue method to the result set. It can be used to
retrieve any type from the database.

* feat: removes custom int64 and float64 arrays

* feat: fixes clirr checks

Clirr does not support java 8 default implementations, so it thinks this
are breaking changes. These in fact are not breaking changes, since we
provide implementations in the interfaces.

* test: fixes GrpcResultSet serialize test

* feat: implements getValueInternal in result set

Adds a less intrusive implementation of getValueInternal for the
AbstractResultSet.

* fix: fixes struct value decoding

Uses the correct type for decoding structs from the result set

* feat: makes the structArray method public

Makes it public the method  to retrieve an array of structs from a Value

* test: adds tests for value literals

* feat: accepts null in arrays for getValue

* feat: allows nulls in values from result sets

* docs: fixes java doc for getValue

Author: thiagotnunes

google-cloud-spanner/clirr-ignored-differences.xml

@@ -592,4 +592,17 @@
     <className>com/google/cloud/spanner/AsyncTransactionManager$CommitTimestampFuture</className>
     <method>java.lang.Object get()</method>
   </difference>
+
+  <!-- Adds getValue to ResultSet -->
+  <!-- These are not breaking changes, since we provide default interface implementation -->
+  <difference>
+    <differenceType>7012</differenceType>
+    <className>com/google/cloud/spanner/StructReader</className>
+    <method>com.google.cloud.spanner.Value getValue(int)</method>
+  </difference>
+  <difference>
+    <differenceType>7012</differenceType>
+    <className>com/google/cloud/spanner/StructReader</className>
+    <method>com.google.cloud.spanner.Value getValue(java.lang.String)</method>
+  </difference>
 </differences>

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

@@ -28,6 +28,7 @@
 import com.google.cloud.ByteArray;
 import com.google.cloud.Date;
 import com.google.cloud.Timestamp;
+import com.google.cloud.spanner.Type.StructField;
 import com.google.cloud.spanner.spi.v1.SpannerRpc;
 import com.google.cloud.spanner.v1.stub.SpannerStubSettings;
 import com.google.common.annotations.VisibleForTesting;
@@ -679,6 +680,62 @@ protected Date getDateInternal(int columnIndex) {
       return (Date) rowData.get(columnIndex);
     }
 
+    @Override
+    protected Value getValueInternal(int columnIndex) {
+      final List<Type.StructField> structFields = getType().getStructFields();
+      final StructField structField = structFields.get(columnIndex);
+      final Type columnType = structField.getType();
+      final boolean isNull = rowData.get(columnIndex) == null;
+      switch (columnType.getCode()) {
+        case BOOL:
+          return Value.bool(isNull ? null : getBooleanInternal(columnIndex));
+        case INT64:
+          return Value.int64(isNull ? null : getLongInternal(columnIndex));
+        case NUMERIC:
+          return Value.numeric(isNull ? null : getBigDecimalInternal(columnIndex));
+        case FLOAT64:
+          return Value.float64(isNull ? null : getDoubleInternal(columnIndex));
+        case STRING:
+          return Value.string(isNull ? null : getStringInternal(columnIndex));
+        case BYTES:
+          return Value.bytes(isNull ? null : getBytesInternal(columnIndex));
+        case TIMESTAMP:
+          return Value.timestamp(isNull ? null : getTimestampInternal(columnIndex));
+        case DATE:
+          return Value.date(isNull ? null : getDateInternal(columnIndex));
+        case STRUCT:
+          return Value.struct(isNull ? null : getStructInternal(columnIndex));
+        case ARRAY:
+          switch (columnType.getArrayElementType().getCode()) {
+            case BOOL:
+              return Value.boolArray(isNull ? null : getBooleanListInternal(columnIndex));
+            case INT64:
+              return Value.int64Array(isNull ? null : getLongListInternal(columnIndex));
+            case NUMERIC:
+              return Value.numericArray(isNull ? null : getBigDecimalListInternal(columnIndex));
+            case FLOAT64:
+              return Value.float64Array(isNull ? null : getDoubleListInternal(columnIndex));
+            case STRING:
+              return Value.stringArray(isNull ? null : getStringListInternal(columnIndex));
+            case BYTES:
+              return Value.bytesArray(isNull ? null : getBytesListInternal(columnIndex));
+            case TIMESTAMP:
+              return Value.timestampArray(isNull ? null : getTimestampListInternal(columnIndex));
+            case DATE:
+              return Value.dateArray(isNull ? null : getDateListInternal(columnIndex));
+            case STRUCT:
+              return Value.structArray(
+                  columnType.getArrayElementType(),
+                  isNull ? null : getStructListInternal(columnIndex));
+            default:
+              throw new IllegalArgumentException(
+                  "Invalid array value type " + this.type.getArrayElementType());
+          }
+        default:
+          throw new IllegalArgumentException("Invalid value type " + this.type);
+      }
+    }
+
     @Override
     protected Struct getStructInternal(int columnIndex) {
       return (Struct) rowData.get(columnIndex);
@@ -1280,6 +1337,11 @@ protected Date getDateInternal(int columnIndex) {
     return currRow().getDateInternal(columnIndex);
   }
 
+  @Override
+  protected Value getValueInternal(int columnIndex) {
+    return currRow().getValueInternal(columnIndex);
+  }
+
   @Override
   protected boolean[] getBooleanArrayInternal(int columnIndex) {
     return currRow().getBooleanArrayInternal(columnIndex);

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

@@ -49,6 +49,10 @@ public abstract class AbstractStructReader implements StructReader {
 
   protected abstract Date getDateInternal(int columnIndex);
 
+  protected Value getValueInternal(int columnIndex) {
+    throw new UnsupportedOperationException("method should be overwritten");
+  }
+
   protected abstract boolean[] getBooleanArrayInternal(int columnIndex);
 
   protected abstract List<Boolean> getBooleanListInternal(int columnIndex);
@@ -197,6 +201,18 @@ public Date getDate(String columnName) {
     return getDateInternal(columnIndex);
   }
 
+  @Override
+  public Value getValue(int columnIndex) {
+    checkNonNull(columnIndex, columnIndex);
+    return getValueInternal(columnIndex);
+  }
+
+  @Override
+  public Value getValue(String columnName) {
+    int columnIndex = getColumnIndex(columnName);
+    return getValueInternal(columnIndex);
+  }
+
   @Override
   public boolean[] getBooleanArray(int columnIndex) {
     checkNonNullOfType(columnIndex, Type.array(Type.bool()), columnIndex);

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

@@ -333,4 +333,16 @@ public List<Struct> getStructList(String columnName) {
     checkValidState();
     return delegate.get().getStructList(columnName);
   }
+
+  @Override
+  public Value getValue(int columnIndex) {
+    checkValidState();
+    return delegate.get().getValue(columnIndex);
+  }
+
+  @Override
+  public Value getValue(String columnName) {
+    checkValidState();
+    return delegate.get().getValue(columnName);
+  }
 }

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

@@ -273,6 +273,16 @@ public Date getDate(String columnName) {
       return getCurrentRowAsStruct().getDate(columnName);
     }
 
+    @Override
+    public Value getValue(int columnIndex) {
+      return getCurrentRowAsStruct().getValue(columnIndex);
+    }
+
+    @Override
+    public Value getValue(String columnName) {
+      return getCurrentRowAsStruct().getValue(columnName);
+    }
+
     @Override
     public boolean[] getBooleanArray(int columnIndex) {
       return getCurrentRowAsStruct().getBooleanArray(columnIndex);

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

@@ -207,6 +207,11 @@ protected Date getDateInternal(int columnIndex) {
       return values.get(columnIndex).getDate();
     }
 
+    @Override
+    protected Value getValueInternal(int columnIndex) {
+      return values.get(columnIndex);
+    }
+
     @Override
     protected Struct getStructInternal(int columnIndex) {
       return values.get(columnIndex).getStruct();

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

@@ -132,6 +132,16 @@ public interface StructReader {
   /** Returns the value of a non-{@code NULL} column with type {@link Type#date()}. */
   Date getDate(String columnName);
 
+  /** Returns the value of a nullable column as a {@link Value}. */
+  default Value getValue(int columnIndex) {
+    throw new UnsupportedOperationException("method should be overwritten");
+  }
+
+  /** Returns the value of a nullable column as a {@link Value}. */
+  default Value getValue(String columnName) {
+    throw new UnsupportedOperationException("method should be overwritten");
+  }
+
   /**
    * Returns the value of a non-{@code NULL} column with type {@code Type.array(Type.bool())}.
    *

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

@@ -543,7 +543,7 @@ private Value() {}
    *
    * @throws IllegalStateException if {@code isNull()} or the value is not of the expected type
    */
-  abstract List<Struct> getStructArray();
+  public abstract List<Struct> getStructArray();
 
   @Override
   public String toString() {

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/DirectExecuteResultSet.java

@@ -23,6 +23,7 @@
 import com.google.cloud.spanner.SpannerException;
 import com.google.cloud.spanner.Struct;
 import com.google.cloud.spanner.Type;
+import com.google.cloud.spanner.Value;
 import com.google.common.base.Preconditions;
 import com.google.spanner.v1.ResultSetStats;
 import java.math.BigDecimal;
@@ -231,6 +232,18 @@ public Date getDate(String columnName) {
     return delegate.getDate(columnName);
   }
 
+  @Override
+  public Value getValue(int columnIndex) {
+    Preconditions.checkState(nextCalledByClient, MISSING_NEXT_CALL);
+    return delegate.getValue(columnIndex);
+  }
+
+  @Override
+  public Value getValue(String columnName) {
+    Preconditions.checkState(nextCalledByClient, MISSING_NEXT_CALL);
+    return delegate.getValue(columnName);
+  }
+
   @Override
   public boolean[] getBooleanArray(int columnIndex) {
     Preconditions.checkState(nextCalledByClient, MISSING_NEXT_CALL);

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ReplaceableForwardingResultSet.java

@@ -25,6 +25,7 @@
 import com.google.cloud.spanner.SpannerExceptionFactory;
 import com.google.cloud.spanner.Struct;
 import com.google.cloud.spanner.Type;
+import com.google.cloud.spanner.Value;
 import com.google.common.base.Preconditions;
 import com.google.spanner.v1.ResultSetStats;
 import java.math.BigDecimal;
@@ -231,6 +232,18 @@ public Date getDate(String columnName) {
     return delegate.getDate(columnName);
   }
 
+  @Override
+  public Value getValue(int columnIndex) {
+    checkClosed();
+    return delegate.getValue(columnIndex);
+  }
+
+  @Override
+  public Value getValue(String columnName) {
+    checkClosed();
+    return delegate.getValue(columnName);
+  }
+
   @Override
   public boolean[] getBooleanArray(int columnIndex) {
     checkClosed();