Csv

import java.io.IOError;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Csv {
    public static List<List<String >> readCsv(String filname) throws IOException,TooManyEntriesException{
        String contents = Files.readString(Path.of(filname), StandardCharsets.US_ASCII);
        String[] allRows = contents.split("\n");
        String header = allRows[0];
        String[] rows = Arrays.copyOfRange(allRows,1,allRows.length);
        int headersize= header.split(",").length;

        List<List<String >> result = new ArrayList<>();
        for (String row:rows){
            ArrayList<String> rowEntries = new ArrayList<>(); //create an arraylist
            String[] splitByComa = row.split(",");
            int rowNum=1;
            for (String entry:splitByComa) {
                if (entry.charAt(0)=='"' && entry.charAt(entry.length()-1)!='"'){
                    throw new UnmatchedQuotesException(filname, rowNum);
                }
                rowEntries.add(entry);
                if (rowEntries.size()>headersize){
                    throw new TooManyEntriesException(filname, rowNum);
                }
                rowNum++;

            }

        }
        return result;

    }

    public static void main(String[] args) {
        try
            {System.out.println(readCsv("test.csv"));
            } catch (IOException e){
            e.printStackTrace();
        }
    }
}