title: Merging multiple sorted csv files with complex comparison
body: <p>I have list  of sorted,csv,files that I want to sort and merge into output file. </p>
  
  <p>I don't want to do a simple comparison of strings, but comparison accordingly to map of types that i have for every value, e.g:</p>
  
  <p>One of the lines:<br>
  <strong>1, 15/12/2011, David Raiven, New York</strong> </p>
  
  <p>In the type map I have this: first column - long, second- date, third-string,...</p>
  
  <p>So the comparator should compare values accordingly. </p>
  
  <p>How can i do it with highest efficiency?<br>
  PriorityQueue? TreeMap? </p>
  
  <p>I prefer not to use 3rd party libraries or sorters.<br>
  The input file is enormous.  </p>