SegmentMerger(Directory dir,
    String name) 
{
                               
    directory = dir;
    segment = name;
}

This ctor used only by test code.

Parameters:

dir - The Directory to merge the other segments into

name - The name of the new segment

 SegmentMerger(IndexWriter writer,
    String name,
    MergePolicy.OneMerge merge) 
{
    directory = writer.getDirectory();
    segment = name;
    if (merge != null)
      checkAbort = new CheckAbort(merge, directory);
    termIndexInterval = writer.getTermIndexInterval();
}

 final  void add(IndexReader reader) 
{
    readers.addElement(reader);
}

Add an IndexReader to the collection of readers that are to be merged

 final  void closeReaders() throws IOException 
{
    for (int i = 0; i <  readers.size(); i++) {  // close readers
      IndexReader reader = (IndexReader) readers.elementAt(i);
      reader.close();
    }
}

close all IndexReaders that have been added. Should not be called before merge().

 final Vector createCompoundFile(String fileName) throws IOException 
{
    CompoundFileWriter cfsWriter =
      new CompoundFileWriter(directory, fileName, checkAbort);
    Vector files =
      new Vector(IndexFileNames.COMPOUND_EXTENSIONS.length + 1);    
    // Basic files
    for (int i = 0; i <  IndexFileNames.COMPOUND_EXTENSIONS.length; i++) {
      String ext = IndexFileNames.COMPOUND_EXTENSIONS[i];
      if (mergeDocStores || (!ext.equals(IndexFileNames.FIELDS_EXTENSION) &&
                            !ext.equals(IndexFileNames.FIELDS_INDEX_EXTENSION)))
        files.add(segment + "." + ext);
    }
    // Fieldable norm files
    for (int i = 0; i <  fieldInfos.size(); i++) {
      FieldInfo fi = fieldInfos.fieldInfo(i);
      if (fi.isIndexed && !fi.omitNorms) {
        files.add(segment + "." + IndexFileNames.NORMS_EXTENSION);
        break;
      }
    }
    // Vector files
    if (fieldInfos.hasVectors() && mergeDocStores) {
      for (int i = 0; i <  IndexFileNames.VECTOR_EXTENSIONS.length; i++) {
        files.add(segment + "." + IndexFileNames.VECTOR_EXTENSIONS[i]);
      }
    }
    // Now merge all added files
    Iterator it = files.iterator();
    while (it.hasNext()) {
      cfsWriter.addFile((String) it.next());
    }
    // Perform the merge
    cfsWriter.close();
    return files;
}

 final int merge() throws IOException, CorruptIndexException 
{
    return merge(true);
}

Merges the readers specified by the #add method into the directory passed to the constructor

 final int merge(boolean mergeDocStores) throws IOException, CorruptIndexException 
{
    this.mergeDocStores = mergeDocStores;
    // NOTE: it's important to add calls to
    // checkAbort.work(...) if you make any changes to this
    // method that will spend alot of time.  The frequency
    // of this check impacts how long
    // IndexWriter.close(false) takes to actually stop the
    // threads.
    mergedDocs = mergeFields();
    mergeTerms();
    mergeNorms();
    if (mergeDocStores && fieldInfos.hasVectors())
      mergeVectors();
    return mergedDocs;
}

Merges the readers specified by the #add method into the directory passed to the constructor.

 final IndexReader segmentReader(int i) 
{
    return (IndexReader) readers.elementAt(i);
}