code: protected void addLength(Document doc, String propertyName, ValueData value, int propType)
     {
        long length = Util.getLength(value, propType);
        if (length != -1)
        {
           doc.add(new Field(FieldNames.PROPERTY_LENGTHS, FieldNames.createNamedLength(propertyName, length),
              Field.Store.NO, Field.Index.NOT_ANALYZED_NO_NORMS));
        }
     }
docs: Adds a {@link FieldNames#PROPERTY_LENGTHS} field to <code>document</code>
  with a named length value.
  
  @param doc          the lucene document.
  @param propertyName the property name.
  @param value        the internal value.
  @param propType