public static  void indexDoc(String segment,
    String fileName) throws Exception 
{
    Directory directory = FSDirectory.getDirectory("test", false);
    Analyzer analyzer = new SimpleAnalyzer();
    DocumentWriter writer =
      new DocumentWriter(directory, analyzer, Similarity.getDefault(), 1000);
    File file = new File(fileName);
    Document doc = FileDocument.Document(file);
    writer.addDocument(segment, doc);
    directory.close();
}

 public static  void main(String[] args) 
{
    try {
      Directory directory = FSDirectory.getDirectory("test", true);
      directory.close();
      indexDoc("one", "test.txt");
      printSegment("one");
      indexDoc("two", "test2.txt");
      printSegment("two");
      merge("one", "two", "merge");
      printSegment("merge");
      merge("one", "two", "merge2");
      printSegment("merge2");
      merge("merge", "merge2", "merge3");
      printSegment("merge3");
    } catch (Exception e) {
      System.out.println(" caught a " + e.getClass() +
                         "\n with message: " + e.getMessage());
      e.printStackTrace();
    }
}

 static  void merge(String seg1,
    String seg2,
    String merged) throws Exception 
{
    Directory directory = FSDirectory.getDirectory("test", false);
    SegmentReader r1 = new SegmentReader(new SegmentInfo(seg1, 1, directory));
    SegmentReader r2 = new SegmentReader(new SegmentInfo(seg2, 1, directory));
    SegmentMerger merger = new SegmentMerger(directory, merged, false);
    merger.add(r1);
    merger.add(r2);
    merger.merge();
    merger.closeReaders();
    directory.close();
}

 static  void printSegment(String segment) throws Exception 
{
    Directory directory = FSDirectory.getDirectory("test", false);
    SegmentReader reader =
      new SegmentReader(new SegmentInfo(segment, 1, directory));
    for (int i = 0; i <  reader.numDocs(); i++)
      System.out.println(reader.document(i));
    TermEnum tis = reader.terms();
    while (tis.next()) {
      System.out.print(tis.term());
      System.out.println(" DF=" + tis.docFreq());
      TermPositions positions = reader.termPositions(tis.term());
      try {
        while (positions.next()) {
          System.out.print(" doc=" + positions.doc());
          System.out.print(" TF=" + positions.freq());
          System.out.print(" pos=");
          System.out.print(positions.nextPosition());
          for (int j = 1; j <  positions.freq(); j++)
            System.out.print("," + positions.nextPosition());
          System.out.println("");
        }
      } finally {
        positions.close();
      }
    }
    tis.close();
    reader.close();
    directory.close();
}