XSLT: How to find source and target Xpath for the edge?

Question

I want to write an xslt file to transfer an xmi file in a graphical file. But I meet the problem that the edge can not connect the right source node and target node. I have tried already two weeks. But I am still confused. Please help me. Thanks a million.

The original code is:

<?xml version="1.0" encoding="UTF-8"?>
<xml xmlns:xmi="#">
<element xmi:id="BasicElement-Line1" name="Line1" xmi:type="association"/>

<element xmi:id="BasicElement-Line2" name="Line2" xmi:type="association"/>

<element xmi:id="BasicElement-Object1" name="Object1" xmi:type="class">
    <ownedAttribute xmi:type="Property" name="input" type="BasicElement-Object2" association="BasicElement-Line1"/>
    <ownedAttribute xmi:type="Property" name="output" type="BasicElement-Object3" association="BasicElement-Line2"/>
</element>

<element xmi:id="BasicElement-Object2" name="Object2" xmi:type="class">
</element>

<element xmi:id="BasicElement-Object3" name="Object3" xmi:type="class">
</element>
</xml>

and my aim code is:

<?xml version="1.0" encoding="UTF-8"?>
<xmi xmlns:y="##">
   <edge target="N1002D" source="N1001B" id="N10005">
      <y:PolyLineEdge>
         <y:Arrows target="none" source="none" />
      </y:PolyLineEdge>
   </edge>
   <edge target="N1002D" source="N1001B" id="N10010">
      <y:PolyLineEdge>
         <y:Arrows target="none" source="none" />
      </y:PolyLineEdge>
   </edge>
   <node id="N1001B">
      <y:NodeLabel>BasicElement-Object1</y:NodeLabel>
   </node>
   <node id="N1002D">
      <y:NodeLabel>BasicElement-Object2</y:NodeLabel>
   </node>
   <node id="N10033">
      <y:NodeLabel>BasicElement-Object3</y:NodeLabel>
   </node>
</xmi>

Because there will be more "class" element in the future. So I used "{generate-id()}" to define the node IDs. But when I do that, I found the edge can not find the way of source node and target node. So I have already worked on it two weeks and have no idea on it. Please help me, I really appreciate.

Answer 1

I'm not really familiar with XMI and the target format, but here's something that should fit your description.

Source:

<?xml version="1.0" encoding="UTF-8"?>
<xml xmlns:xmi="#">
    <element xmi:id="BasicElement-Line1" name="Line1" xmi:type="association">
         <ownedEnd xmi:type="Property" type="BasicElement-Object1" association="BasicElement-Line1"/>
    </element>

    <element xmi:id="BasicElement-Line2" name="Line2" xmi:type="association">
        <ownedEnd xmi:type="Property" type="BasicElement-Object1" association="BasicElement-Line2"/>
    </element>

    <element xmi:id="BasicElement-Object1" name="Object1" xmi:type="class">
        <ownedAttribute xmi:type="Property" name="input" type="BasicElement-Object2" association="BasicElement-Line1"/>
        <ownedAttribute xmi:type="Property" name="output" type="BasicElement-Object3" association="BasicElement-Line2"/>
    </element>

    <element xmi:id="BasicElement-Object2" name="Object2" xmi:type="class">
    </element>

    <element xmi:id="BasicElement-Object3" name="Object3" xmi:type="class">
    </element>
</xml>

Transformed with (adjust the namespaces to the correct uris):

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:xmi="#" xmlns:y="##"
exclude-result-prefixes="xmi" version="1.0">
<xsl:output indent="yes"/>

<xsl:template match="xml">
    <xmi>
        <xsl:apply-templates select="element"/>
    </xmi>
</xsl:template>

<xsl:template match="element[@xmi:type='class']">
    <node id="{generate-id()}">
        <y:NodeLabel>
            <xsl:value-of select="@xmi:id"/>
        </y:NodeLabel>
        <y:UMLClassNode/>
    </node>
</xsl:template>

<xsl:template match="element[@xmi:type='association']">
    <!-- association name -->
    <xsl:variable name="association" select="ownedEnd/@association"/>
    <!-- id of source -->
    <xsl:variable name="ownedEnd-type" select="ownedEnd/@type"/>
    <!-- using association variable to select the correct id of target -->
    <xsl:variable name="ownedAttribute-type"
        select="//element[@xmi:id = $ownedEnd-type]/ownedAttribute[@association = $association]/@type"/>
    <edge id="{ generate-id() }" 
        source="{ generate-id( /xml/element[@xmi:id = $ownedEnd-type] ) }"
        target="{ generate-id( /xml/element[@xmi:id = $ownedAttribute-type] ) }">
        <y:PolyLineEdge>
            <y:Arrows source="none" target="none"/>
        </y:PolyLineEdge>
    </edge>
</xsl:template>

</xsl:stylesheet>

gives you:

<xmi xmlns:y="##">
   <edge id="d0e3" source="d0e13" target="d0e20">
      <y:PolyLineEdge>
         <y:Arrows source="none" target="none"/>
      </y:PolyLineEdge>
   </edge>
   <edge id="d0e8" source="d0e13" target="d0e23">
      <y:PolyLineEdge>
         <y:Arrows source="none" target="none"/>
      </y:PolyLineEdge>
   </edge>
   <node id="d0e13">
       <y:NodeLabel>BasicElement-Object1</y:NodeLabel>
       <y:UMLClassNode/>
   </node>
   <node id="d0e20">
       <y:NodeLabel>BasicElement-Object2</y:NodeLabel>
       <y:UMLClassNode/>
   </node>
   <node id="d0e23">
       <y:NodeLabel>BasicElement-Object3</y:NodeLabel>
       <y:UMLClassNode/>
   </node>
</xmi>