2.2 Text to XML conversion

This is the easiest conversion. An XML header (<?xml .... ?>) is first created. Then, one text record is read, item data is extracted from the current text record and the XML elements and their content are written one by one. The conversion process continues until the end of the text file. The XML elements can be classified in 3 categories :

• Root : this element must be unique in the whole XML file. That's why, DATA, a COBOL reserved word, was chosen as root element name. It has no equivalent in the COBOL copybook.
• First child : it appears each time a text record is read. It corresponds to the level of the first COBOL item in the copybook. As this first child element will include all the other XML elements, this COBOL item needs to be a grouping item,with the lowest level and ideally with a unique occurrence.
• Other child elements: The other XML elements.

All of them are built using the following rules :

• The name of the XML element is the capitalized COBOL item name with dashes (''-'') translated to underscore (''_''). For example : COBOL-ITEM-01 will become <cobol_item_01>,
• Content of the XML element is extracted from the current text record (using the starting position and the length computed in section ). Characters are escaped if necessary^2.4,
• FILLER clauses are skipped.
• Opened XML tags are closed :
  • immediately after the content of an XML element,
  • at the end of each COBOL grouping item,
  • at then end of the text record,
  • at the end of the text file.

If requested, TXT2XML can create a DTD (Document Type Definition), based on the COBOL copybook, which describes the XML structure. This DTD can be internal :

Figure: Internal DTD

or external :

Figure: XML file with an external DTD reference