code: protected void addStringValue(Document doc, String fieldName, Object internalValue, boolean tokenized,
        boolean includeInNodeIndex, float boost, boolean useInExcerpt)
     {
  
        // simple String
        String stringValue = (String)internalValue;
        doc.add(createFieldWithoutNorms(fieldName, stringValue, PropertyType.STRING));
        if (tokenized)
        {
           if (stringValue.length() == 0)
           {
              return;
           }
           // create fulltext index on property
           int idx = fieldName.indexOf(':');
           fieldName = fieldName.substring(0, idx + 1) + FieldNames.FULLTEXT_PREFIX + fieldName.substring(idx + 1);
           Field f = new Field(fieldName, stringValue, Field.Store.NO, Field.Index.ANALYZED, Field.TermVector.NO);
           f.setBoost(boost);
           doc.add(f);
  
           if (includeInNodeIndex)
           {
              // also create fulltext index of this value
              boolean store = supportHighlighting && useInExcerpt;
              f = createFulltextField(stringValue, store, supportHighlighting);
              if (useInExcerpt)
              {
                 doc.add(f);
              }
              else
              {
                 doNotUseInExcerpt.add(f);
              }
           }
        }
     }
docs: Adds the string value to the document both as the named field and
  optionally for full text indexing if <code>tokenized</code> is
  <code>true</code>.
  
  @param doc                The document to which to add the field
  @param fieldName          The name of the field to add
  @param internalValue      The value for the field to add to the
  document.
  @param tokenized          If <code>true</code> the string is also
  tokenized and fulltext indexed.
  @param includeInNodeIndex If <code>true</code> the string is also
  tokenized and added to the node scope fulltext
  index.
  @param boost              the boost value for this string field.
  @param useInExcerpt       If <code>true</code> the string may show up in
  an excerpt.