Chapter 5: XML Linking Language (XLink)

Summary

• A notation for creating linking elements, which specify link relationships between two ore more resources.
• Any element with an xlink:type attribute is an XLink.
• The xlink namespace must be declared.

• Simple XLinks are just like HTML links (with some extra features).
• Provides a link from a local resource to a remote resource. Example:

  <mylink xlink:type="simple" xlink:href="xml.htm"> XML Accelerated Technical Training </mylink>

• Attributes:
  • xlink:type="simple"
  • xlink:href - URL of the remote resource
  • xlink:title - Optional title (ToolTip).
  • xlink:show - (embed|replace|new)
  • xlink:actuate - (onLoad|onRequest)

• Connect any number of resources, local or remote. Example:

  <mylink xlink:type="extended"> <local xlink:type="resource" xlink:label="localResource"/> <remote xlink:type="locator" xlink:href="book1.xml" xlink:label="remote1" /> <remote xlink:type="locator" xlink:href="book2.xml" xlink:label="remote2" /> <go xlink:type="arc" xlink:from="localResource" xlink:to="remote1" /> <go xlink:type="arc" xlink:from="localResource" xlink:to="remote2" /> </mylink>

• Contains the following elements:
  • xlink:type="resource" - Local resource.
  • xlink:type="locator" - Remote resource.
  • xlink:type="arc" - Resource relationship.

• Notation for pointing to specific points within a document.
• Based on XPath. Example:

  <mylink xlink:type="simple" xlink:href="mydoc.xml#xpointer(//chapter[2]//id("xmltable")) />

  Creates a simple link to the element with an ID attribute equal to xmltable, within the second chapter of mydoc.xml.

• Some constructs:

  /	Child nodes.
  //	Descendant nodes.
  |	Used to specify multiple nodes.
  *	Wildcard.
  @	Attributes.
  [ ]	Tests.
  [n]	Position.

• Other constructs:

  id()	Identifies nodes with a particular id.
  descendant()	Like //
  ancestor()	Identifies ancestor nodes.
  preceding()	Identifies preceding nodes.
  following()	Identifies nodes after the current node.
  preceding-sibling()	Identifies sibling nodes that appear before the current node.
  following-sibling()	Identifies sibling nodes that appear after the current node.
  range-to()	Identifies a range.