Since the FSM (>= 1.3) now uses external schema files, it seems only logical to generate these from a visual editor instead of hand-typing them. And with OOo being the de facto standard for office work, OOo Draw seems a logical choice. In addition, while I'd gladly have used Dia or Inkscape as a drawing tools, both are significantly less easy to use for this type of diagramming (IMHO).

Now, how can one go about it ? Simply enough, with OpenDocument being an open standard, its layour is rather obvious.

The data in OpenDocument drawings is held in the office:document-content/office:body/office:drawing/draw:page element of the content.xml file in the zipped archive making up an OpenDocument document.

A FSM diagram source only needs two element types (rect: rectangles, and connector: transitions), so we can ignore all other elements.

• The rect elements are used for the states. We only use their ID and the content of their 'text:p' child as the state name
• The connector element has several attributes and a child element, but only a few are useful for this application
  • draw:start-shape defines the ID of the transition entry state
  • draw:end-shape defines the ID of the transition exit state
  • the child text:p element defines UML description of the transition, the content of which we can parse as an UML description
    • name
    • event guard (ignored in version 1.3)
    • output conditions
    • action

This following excerpt represents the useful part of a two-state transition diagram:

   [..snip..]
    <draw:page draw:name="page1" draw:style-name="dp1" draw:master-page-name="Standard">
      <office:forms form:automatic-focus="false" form:apply-design-mode="false"/>
      <draw:rect draw:style-name="gr1" draw:text-style-name="P1" draw:id="id1" 
        draw:layer="layout" 
	svg:width="4.5cm" svg:height="3.5cm" svg:x="2.5cm" svg:y="3.5cm">
        <text:p/>
	</draw:rect>
      <draw:connector draw:style-name="gr2" draw:text-style-name="P1" 
        draw:layer="layout" draw:type="curve" 
	svg:x1="4.75cm" svg:y1="7cm" svg:x2="11.75cm" svg:y2="15.5cm" 
	draw:start-shape="id1" draw:start-glue-point="2" 
	draw:end-shape="id2" draw:end-glue-point="0">
        <text:p text:style-name="P2">Square 1 to 2</text:p>
	</draw:connector>
      <draw:rect draw:style-name="gr1" draw:text-style-name="P1" draw:id="id2" 
        draw:layer="layout" 
	svg:width="6.5cm" svg:height="4.5cm" svg:x="8.5cm" svg:y="15.5cm">
        <text:p/>
	</draw:rect>
      </draw:page>
  [..snip..]

Supposing for now that the OOo document has already been unzipped to directory draw2, here is a possible piece of code to parse the FSM: <php> error_reporting(E_ALL|E_STRICT);

$doc = new DOMDocument(); $doc→preserveWhiteSpace = false; $doc→load('draw2/content.xml');

$xpath = new DOMXPath($doc); $xpath→registerNamespace('office', “urn:oasis:names:tc:opendocument:xmlns:office:1.0”); $xpath→registerNamespace('draw', “urn:oasis:names:tc:opendocument:xmlns:drawing:1.0”); $xpath→registerNamespace('text', “urn:oasis:names:tc:opendocument:xmlns:text:1.0”);

$qtext = 'text:p'; $qnodes = '('

. '//office:document-content/office:body/office:drawing/draw:page/draw:rect'
. '|'
. '//office:document-content/office:body/office:drawing/draw:page/draw:connector'
. ')';

$result = $xpath→query($qnodes, $doc);

foreach ($result as $node)

{
$name = $node->tagName;
switch ($name)
  {
  case 'draw:rect':
    $id = $node->getAttribute('id');
    $restext = $xpath->query($qtext, $node);
    $textnode = $restext->item(0);
    $state = $textnode->nodeValue;
    $states[$id] = $state;
    break;
  case 'draw:connector':
    $start = $node->getAttribute('start-shape');
    $end   = $node->getAttribute('end-shape');
    $restext = $xpath->query($qtext, $node);
    $textnode = $restext->item(0);
    $event = $textnode->nodeValue;
    $events[$start][$end] = $event;
    break;
  default:
    // nothing
  }
}

</php>