public static File tokenizeFile(File file) throws IOException {
		  String tokenizedFileName = file.getAbsolutePath() + "_tokenized";
	      FileWriter tokenizedFileWriter = new FileWriter(tokenizedFileName);
	      DocumentPreprocessor dp = new DocumentPreprocessor(file.getAbsolutePath());
	      int CurrentSentIndex = 1;
	      int tokenizedSentCounter = 1;
	      for (List sentence : dp) {
	    	  for(int i = 0; i < sentence.size(); i++){
	    		  if(i == 0){
	    			  Pattern p = Pattern.compile("[0-9]+");  
					  if(p.matcher(sentence.get(i).toString()).matches()){
			    		  tokenizedFileWriter.append(tokenizedSentCounter + "\t" + sentence.get(i) + "\t");
			    		  CurrentSentIndex = Integer.valueOf(sentence.get(i).toString());
					  } else {
						  System.out.println(tokenizedSentCounter + "\t" + CurrentSentIndex +"\t" + sentence.get(i) + " ");
			    		  tokenizedFileWriter.append(tokenizedSentCounter + "\t" + CurrentSentIndex +"\t" + sentence.get(i) + " ");
					  }
	    		  } else {
	        		  tokenizedFileWriter.append(sentence.get(i) + " ");
	    		  } 
	    	 }
	    	tokenizedSentCounter++;
	        tokenizedFileWriter.append("\n");
	        tokenizedFileWriter.flush();
	      }
	      return new File(tokenizedFileName);
	  }