private void projectionValidation(Fields projFields) {
if (projFields == null) {
return;
}
Fields allFields = this.getOutputFields();
for (String field : projFields) {
if (!allFields.contains(field)) {
throw new IllegalArgumentException(
"Trying to select non-existent field: '"
+ field
+ "' from stream containing fields fields: <"
+ allFields
+ ">");
}
}
}