How to use org.apache.lucene.index

@Override
public void close()
{
  waitForAllTasks();
  super.close();
}

  private static boolean hasCommits( Directory directory ) throws IOException
  {
    return DirectoryReader.indexExists( directory ) && SegmentInfos.readLatestCommit( directory ) != null;
  }
}

private void disposeWriter() throws IOException
{
  if ( !writerIsClosed )
  {
    writer.close();
    writerIsClosed = true;
  }
}

@Override
public void addDocument( Document document ) throws IOException
{
  writer.addDocument( document );
}

private Object getFieldValue( IndexableField field )
{
  Number numericFieldValue = field.numericValue();
  return numericFieldValue != null ? numericFieldValue : field.stringValue();
}

@Override
public void deleteDocuments( Query query ) throws IOException
{
  writer.deleteDocuments( query );
}

@Override
public long maxCount()
{
  return reader.maxDoc();
}

PrefixMultiTermsQuery( Term term )
{
  super( term.field() );
  this.term = term;
}

@Override
public void updateDocument( Term term, Document document ) throws IOException
{
  writer.updateDocument( term, document );
}

@Override
protected void doSetNextReader( LeafReaderContext context )
{
  this.reader = context.reader();
}

@Override
public void addDocuments( int numDocs, Iterable<Document> document ) throws IOException
{
  writer.addDocuments( document );
}

WritableIndexSnapshotFileIterator( File indexDirectory, SnapshotDeletionPolicy snapshotDeletionPolicy )
    throws IOException
{
  super( indexDirectory, snapshotDeletionPolicy.snapshot() );
  this.snapshotDeletionPolicy = snapshotDeletionPolicy;
}

@Override
public SortedSetDocValues getSortedSetDocValues( String field )
{
  return DocValues.emptySortedSet();
}

@Override
public BinaryDocValues getBinaryDocValues( String field )
{
  return DocValues.emptyBinary();
}

@Override
public NumericDocValues getNormValues( String field )
{
  return DocValues.emptyNumeric();
}

@Override
public SortedNumericDocValues getSortedNumericDocValues( String field )
{
  return DocValues.emptySortedNumeric( elements.length );
}

@Override
protected synchronized MergeThread getMergeThread( IndexWriter writer, MergePolicy.OneMerge merge )
{
  return new BlockingMerge( writer, merge, executionLatch );
}

@Override
public void deleteDocuments( Term term ) throws IOException
{
  writer.deleteDocuments( term );
}

  @Override
  protected void onNextDoc( int localDocID, LeafReaderContext context )
  {
    updateCurrentDocument( localDocID, context.reader() );
  }
};

  @Override
  protected void doSetNextReader( LeafReaderContext context )
  {
    this.reader = context.reader();
  }
}