CSV file column validation

Question

I've implemented an apex algorithm to upload a CSV file into Salesforce. In the CSV file there are 7 necessary columns and I keep all of them in a list of strings:

private List<String> necessaryColumns = new `List<String>` {'column01' , 'column02', 'column03', 'column04', 'column05', 'column06', 'column07'};

I need to validate by column names.

I do not need to check the amount of columns.

If one of the 7 columns is missing in the CSV file, then I need to show a warning message to the users.

Please advise how to validate by column name?

Answer 1

You can do this using set intersection:

Set<String> columnsInFile = new Set<String>(LIST_OF_COLUMNS);

if (!columnsInFile.containsAll(necessaryColumns)) {
    // Do error handling here.
}

containsAll returns false if the given Set does not contain all of the items in the List passed.