// ////// MetaData that deserves to be right here at the top level ////////
private void validateSchema(Schema schema) throws DDFException {
Set<String> columnSet = new HashSet<String>();
if (schema != null && schema.getColumns() != null) {
for (Column column : schema.getColumns()) {
if (columnSet.contains(column.getName())) {
throw new DDFException(String.format("Duplicated column name %s", column.getName()));
} else {
columnSet.add(column.getName());
}
}
}
}
