public OperatorFactory createTableScanOperator(
Session session,
int operatorId,
PlanNodeId planNodeId,
String tableName,
String... columnNames)
{
checkArgument(session.getCatalog().isPresent(), "catalog not set");
checkArgument(session.getSchema().isPresent(), "schema not set");
QualifiedObjectName qualifiedTableName = new QualifiedObjectName(session.getCatalog().get(), session.getSchema().get(), tableName);
TableHandle tableHandle = metadata.getTableHandle(session, qualifiedTableName).orElse(null);
checkArgument(tableHandle != null, "Table %s does not exist", qualifiedTableName);
Map<String, ColumnHandle> allColumnHandles = metadata.getColumnHandles(session, tableHandle);
ImmutableList.Builder<ColumnHandle> columnHandlesBuilder = ImmutableList.builder();
ImmutableList.Builder<Type> columnTypesBuilder = ImmutableList.builder();
for (String columnName : columnNames) {
ColumnHandle columnHandle = allColumnHandles.get(columnName);
checkArgument(columnHandle != null, "Table %s does not have a column %s", tableName, columnName);
columnHandlesBuilder.add(columnHandle);
ColumnMetadata columnMetadata = metadata.getColumnMetadata(session, tableHandle, columnHandle);
columnTypesBuilder.add(columnMetadata.getType());
}
List<ColumnHandle> columnHandles = columnHandlesBuilder.build();
List<Type> columnTypes = columnTypesBuilder.build();