[Rcml-group2] some pseudo code for design

[<jx...@ga...>]

# Design for read() and write() methods of the Archive class.


Class: XMLInteracter  # purpose is to perform all interaction with Xerces
Members: (all private)
 DOM_Document doc;
Methods:
 get_doc
 set_doc(private)
 write_to_file(filename: string)
 read_from_file(filename: string)

read()
 create a new XMLInteracter, xml
 xml->read_from_file(filename)
 doc = xml->get_doc
 root = doc->getDocumentElement
 root is a tag of type "ARCHIVE"
 currev_list = root->getElementsByTagName("CURRENTREVISION")
 currev_list contains 1 element (no more, no less)
 currev = currev_list->item(0)
 currev is an element of type "CURRENTREVISION"
 create a new RevisionNumber, head_revno
 head_revno = currev->getAttribute("HEAD")
 create a new Text object, head_text
 head_text = currev->getFirstChild->getData

 diffelem_list = root->getElementsByTagName("DIFF")
 for each diff in diffelem_list
  create RevisionNumber revno(diff->getAttribute("REVISION"))
  patchelem_list = diff->getElementsByTagName("DIFFCMD")
  foreach patchelem in patchelem_list
   cmd = patchelem->getAttribute("CMD")
   lineno = patchelem->getAttribute("LINENO")
   numdeletedlines = patchelem->getAttribute("NUMDELETED")
   content = patchelem->getFirstChild->getData
   create a Patch, curpatch(cmd, lineno, numdeletedlines, content)
   push curpatch onto patch_list
  endfor
  create a Differences, curdiff(patch_list)
  create a Revision, rev(curdiff, revno)
  push rev onto rev_list
 endfor

 create a RevisionTree, tree(head_text, rev_list)
 create an Archive(head_revno, tree)

 return the Archive
done

write()
 create a new XMLInteracter, xml
 doc = xml->getdoc
 create a new DOM_Element, root("ARCHIVE")
 root->setAttribute("HEAD", Archive->headID)  # redundant?

 create a new DOM_DocumentType, dtd --
   with the DOM_Implementation::createDOM_DocumentType;
   with the address of the DTD
 That should be used in creating the DOM_Document in the XMLInteracter

 revtree = Archive->gettree
 create a new DOM_Element, currev("CURRENTREVISION")
 append it to root
 currev->setAttribute("HEAD", Archive->headID)
 create a new DOM_Text, head_text
 append it to currev

 rev_list = tree->getCollectionOfRevisions
 foreach revision in rev_list
  create a new DOM_Element, diff("DIFF")
  append it to root
  diff->setAttribute("REVISION", revision->getRevisionID)
  patch_list = revision->getDifferFromNext
  foreach patch in patch_list
   create a new DOM_Element, diffcmd("DIFFCMD")
   append it to diff
   diffcmd->setAttribute("CMD", patch->getcmd)
   diffcmd->setAttribute("LINENO", patch->getlineNumber)
   if (patch->getcmd is D or C)
    diffcmd->setAttribute("NUMDELETEDLINES", patch->getNumberOfLines)
   endif
   if (patch->getPatchData->length > 0)
    create a new DOM_Text, patch_contents(patch->getPatchData)
    append it to diffcmd
   endif
  endfor
 endfor

 xml->write_to_file(filename)
done



XMLInteracter::read_from_file()
 create a DOMParser, parser
 parser->parse(filename)
 doc = parser->getDocument()
 XMLInteracter->setdoc(doc)
done


XMLInteracter::write_to_file()
 open filename as an ofstream
 doc = XMLInteractor->getdoc()
 file << doc   # uses operator<<() from DOMPrint.cpp
done