What kind of data structure should I use?

Question

I have a user input dialog basically like following which need user input the sample number to specifiy each file belongs to which sample:
user input the sample number in the following dialog:
file name             sample
test 1                  1
test2                   2
test3                   1
test4                   2In another words, each sample could include multiple files, each file has a column of data. I tried to get
a data structure which specifies the sample and file relationship, to get an idea of what kind of files are in
one sample. I tried to use hashmap or hashtable, but they ask the key must be unique. What I need is to get the sample data structure for the later data processing.
thanks in advance!

Answer 1

You could make a Sample object, which creates a List of file names. Then put SampleNumber and SampleObject into a Map...
  class Sample {
    java.util.List fileNames;
    Sample()
    {  fileNames = java.util.ArrayList(5); }
    addFile(String fName)
    { fileNames.add(fName); }
    String[] getFileNames()
      String[] names = new String[fileNames.size()];
      for (int a = 0; a < names.length; a++)
      { names[a] = fileNames.get(a).toString(); }
      return names;
  Map samples = new HashMap();
  Sample samp1 = new Sample();
  samp1.addFile("Test1"); samp1.addFile("Test3");
  Sample samp2 = new Sample();
  samp2.addFile("Test2"); samp2.addFile("Test4");
  samples.add("1", samp1);
  samples.add("2", samp2);
  String selected = //String user selects...
  Sample sampNeeded = (Sample)samples.get(selected);
  String[] files = sampNeeded.getFileNames();