multiple values with same key tree set

Question

I have a text file with some data like this

A+,John,James,Henry
B+,Andrew,Chris,Andy
O,Grant,Celina,Claudia

I use buffered reader to load the text into a Treeset of string, and print the set. Next I want to separate the names followed by the key i.e.

John A+
James A+
Henry A+
Andrew B+ 
etc.

How can I assign the key to each of the names separately? I tried using split to separate the strings by commas, but I couldn't get it to work. I tried doing:

TreeSet<String> set1 = loadSetFromFile( infile2 ); 

and then making a new list and using split to separate the commas with this line

List<String> splitlist = Arrays.asList(set1.split(","));//dont work

Obviously not the correct thing to do. I was thinking that maybe I would have to do it in my set loading method

  static TreeSet<String> loadSet( BufferedReader infile ) throws Exception
     {TreeSet<String> set = new TreeSet<String>();
      while( infile.ready() )
        set.add(infile.readLine());//split(",") lol
      infile.close();
      return set;
     }

I would then have to somehow associate the first letter of the line with all of the following. Don't know how to do that either. Any help would be greatly appreciated.

Answer 1

I think you're over-complicating this.

Presuming you have a file in my/path named foo.txt containing the text in your example, here's a way to process your data, with a simple Map and String.split, Java 6 style:

BufferedReader br = null;
try {
     br = new BufferedReader(new InputStreamReader(new FileInputStream(
            new File("/my/path/foo.txt"))));
     String line = null;
     Map<String, String> input = new HashMap<String, String>();
     while ((line = br.readLine()) != null) {
         // splitting each line of the file by commas
         String[] splitted = line.split(",");
         // iterating over splitted Strings
         for (int i = 1; i < splitted.length; i++) {
             // putting each value into map as key (starting at 2nd value), 
             // with value as first element of the splitted String
             input.put(splitted[i], splitted[0]);
         }
     }
     // printing the map
     System.out.println(input);
     // printing the map "nicely"
     for (String key: input.keySet()) {
         System.out.println(key.concat(" ").concat(input.get(key)));
     }
}
// your typical exception "handling"
catch (FileNotFoundException fnfe) {
    fnfe.printStackTrace();
}
catch (IOException ioe) {
    ioe.printStackTrace();
}
// Java 6 style resource closing
finally {
    if (br != null) {
        try {
            br.close();
        }
        catch (IOException ioe) {
            ioe.printStackTrace();
        }
    }
}

Output

{Henry=A+, Celina=O, Grant=O, James=A+, Claudia=O, Andrew=B+, John=A+, Andy=B+, Chris=B+}

Henry A+
Celina O
Grant O
James A+
Claudia O
Andrew B+
John A+
Andy B+
Chris B+