图形描述语言GraphML（5）:扩展 GraphML

GraphML的扩展是基于xml的扩展方式，通过增加namespace的引用就可以容易地扩展GraphML，包括xml属性的扩展和Complex Type的扩展。

 

属性扩展
xsd定义：

graphml+xlink.xsd

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema 
   targetNamespace="http://graphml.graphdrawing.org/xmlns"
   xmlns="http://graphml.graphdrawing.org/xmlns"  
   xmlns:xlink="http://www.w3.org/1999/xlink"
   xmlns:xs="http://www.w3.org/2001/XMLSchema"
   elementFormDefault="qualified"
   attributeFormDefault="unqualified"
>

<xs:import namespace="http://www.w3.org/1999/xlink"
           schemaLocation="xlink.xsd"/>

<xs:redefine 
    schemaLocation="http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd">
  <xs:attributeGroup name="node.extra.attrib">
    <xs:attributeGroup ref="node.extra.attrib"/>
    <xs:attribute ref="xlink:href" use="optional"/>
  </xs:attributeGroup>
</xs:redefine>

</xs:schema>

例子

<?xml version="1.0" encoding="UTF-8"?>
<graphml xmlns="http://graphml.graphdrawing.org/xmlns"  
            xmlns:xlink="http://www.w3.org/1999/xlink"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns 
                                graphml+xlink.xsd">
  <graph edgedefault="directed">
    <node id="n0" xlink:href="http://graphml.graphdrawing.org"/>
    <node id="n1" />
    <edge source="n0" target="n1"/>
  </graph>
</graphml>

Complex Type扩展
xsd定义：

graphml+svg.xsd

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema 
   targetNamespace="http://graphml.graphdrawing.org/xmlns"
   xmlns="http://graphml.graphdrawing.org/xmlns"  
   xmlns:svg="http://www.w3.org/2000/svg"
   xmlns:xs="http://www.w3.org/2001/XMLSchema"
   elementFormDefault="qualified"
   attributeFormDefault="unqualified"
>

<xs:import namespace="http://www.w3.org/2000/svg"
           schemaLocation="svg.xsd"/>

<xs:redefine 
    schemaLocation="http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd">
  <xs:complexType name="data-extension.type">
    <xs:complexContent>
      <xs:extension base="data-extension.type">
        <xs:sequence>
          <xs:element ref="svg:svg"/>
        </xs:sequence>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:redefine>

</xs:schema>

例子：

<?xml version="1.0" encoding="UTF-8"?>
<graphml xmlns="http://graphml.graphdrawing.org/xmlns"  
            xmlns:svg="http://www.w3.org/2000/svg"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns 
                                graphml+svg.xsd">
  <key id="k0" for="node">
    <default>
      <svg:svg width="5cm" height="4cm" version="1.1">
        <svg:desc>Default graphical representation for nodes
        </svg:desc>
        <svg:rect x="0.5cm" y="0.5cm" width="2cm" height="1cm"/>
      </svg:svg>
    </default>
  </key>  
  <key id="k1" for="edge">
    <desc>Graphical representation for edges
    </desc>
  </key>  
  <graph edgedefault="directed">
    <node id="n0">
      <data key="k0">
        <svg:svg width="4cm" height="8cm" version="1.1">
          <svg:ellipse cx="2cm" cy="4cm" rx="2cm" ry="1cm" />
        </svg:svg>  
      </data>
    </node>
    <node id="n1" />
    <edge source="n0" target="n1">
      <data key="k1">
        <svg:svg width="12cm" height="4cm" viewBox="0 0 1200 400">
          <svg:line x1="100" y1="300" x2="300" y2="100"
           stroke-width="5"  />
        </svg:svg>
      </data>
    </edge>
  </graph>
</graphml>