DocumentWriter(Directory directory,
    Analyzer analyzer,
    Similarity similarity,
    int maxFieldLength) 
{
    this.directory = directory;
    this.analyzer = analyzer;
    this.similarity = similarity;
    this.maxFieldLength = maxFieldLength;
}

Parameters:

directory - The directory to write the document information to

analyzer - The analyzer to use for the document

similarity - The Similarity function

maxFieldLength - The maximum number of tokens a field may have

 final  void addDocument(String segment,
    Document doc) throws IOException 
{
    // write field names
    fieldInfos = new FieldInfos();
    fieldInfos.add(doc);
    fieldInfos.write(directory, segment + ".fnm");
    // write field values
    FieldsWriter fieldsWriter =
            new FieldsWriter(directory, segment, fieldInfos);
    try {
      fieldsWriter.addDocument(doc);
    } finally {
      fieldsWriter.close();
    }
    // invert doc into postingTable
    postingTable.clear();			  // clear postingTable
    fieldLengths = new int[fieldInfos.size()];    // init fieldLengths
    fieldPositions = new int[fieldInfos.size()];  // init fieldPositions
    fieldBoosts = new float[fieldInfos.size()];	  // init fieldBoosts
    Arrays.fill(fieldBoosts, doc.getBoost());
    invertDocument(doc);
    // sort postingTable into an array
    Posting[] postings = sortPostingTable();
    /*
    for (int i = 0; i <  postings.length; i++) {
      Posting posting = postings[i];
      System.out.print(posting.term);
      System.out.print(" freq=" + posting.freq);
      System.out.print(" pos=");
      System.out.print(posting.positions[0]);
      for (int j = 1; j <  posting.freq; j++)
	System.out.print("," + posting.positions[j]);
      System.out.println("");
    }
    */
    // write postings
    writePostings(postings, segment);
    // write norms of indexed fields
    writeNorms(doc, segment);
}