/**
* Returns selected columns as a bool array with true value set for specified column names.
* The result will contain number of elements equal to flattened number of columns.
* For example:
* selectedColumns - a,b,c
* allColumns - a,b,c,d
* If column c is a complex type, say list<string> and other types are primitives then result will
* be [false, true, true, true, true, true, false]
* Index 0 is the root element of the struct which is set to false by default, index 1,2
* corresponds to columns a and b. Index 3,4 correspond to column c which is list<string> and
* index 5 correspond to column d. After flattening list<string> gets 2 columns.
*
* @param selectedColumns - comma separated list of selected column names
* @param schema - object schema
* @return - bool array with true value set for the specified column names
*/
public static bool[] includeColumns(string selectedColumns, TypeDescription schema)
{
int numFlattenedCols = schema.getMaximumId();
bool[] results = new bool[numFlattenedCols + 1];
if ("*".Equals(selectedColumns))
{
for (int i = 0; i < results.Length; i++)
{
results[i] = true;
}
return(results);
}
if (selectedColumns != null &&
schema.getCategory() == Category.STRUCT)
{
IList <string> fieldNames = schema.getFieldNames();
IList <TypeDescription> fields = schema.getChildren();
foreach (string column in selectedColumns.Split((',')))
{
TypeDescription col = findColumn(column, fieldNames, fields);
if (col != null)
{
for (int i = col.getId(); i <= col.getMaximumId(); ++i)
{
results[i] = true;
}
}
}
}
return(results);
}