code: protected void init() {
          this.codePage = new RtfCodePage(this.document);
          this.colorList = new RtfColorList(this.document);
          this.fontList = new RtfFontList(this.document);
          this.listTable = new RtfListTable(this.document);
          this.stylesheetList = new RtfStylesheetList(this.document);
          this.infoGroup = new RtfInfoGroup(this.document);
          this.protectionSetting = new RtfProtectionSetting(this.document);
          this.pageSetting = new RtfPageSetting(this.document);
          this.header = new RtfHeaderFooterGroup(this.document, RtfHeaderFooter.TYPE_HEADER);
          this.footer = new RtfHeaderFooterGroup(this.document, RtfHeaderFooter.TYPE_FOOTER);
          this.generator = new RtfGenerator(this.document);
      }
docs: initializes the RtfDocumentHeader.