XLink: Extended Links

• A simple link connects a local resource to a remote resource.

• Extended links connect any number of resources, local or remote.

• You specify the relationships between the resources, such as direction.

• For example, suppose your application has many drop-down menus such as:
  Select a publication... Revista Nexos Revista Proceso EZLN

• This example is not the usual one-to-one link ubiquitous on the web. Rather, it connects the local resource to several remote resources:

  

• It could be coded as follows:

  <publications xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="extended"> <dropdown xlink:type="resource" xlink:title="Select a Publication..." xlink:label="myLink"/> <website xlink:type="locator" xlink:href="http://www.nexos.com.mx/" xlink:title="Revista Nexos" xlink:label="Nexos"/> <website xlink:type="locator" xlink:href="http://www.proceso.com.mx/" xlink:title="Revista Proceso" xlink:label="Proceso"/> <website xlink:type="locator" xlink:href="http://www.ezln.org/" xlink:title="EZLN" xlink:label="EZLN"/> <go xlink:type="arc" xlink:from="myLink" xlink:to="Nexos"> <go xlink:type="arc" xlink:from="myLink" xlink:to="Proceso"> <go xlink:type="arc" xlink:from="myLink" xlink:to="EZLN"> </publications>

  (You could set defaults in the DTD to avoid having to repeat all attributes).

• Remember, XLink is a language, not an application.
  How links are actually implemented depends on the application.

• Extended links can contain three types of elements (defined by xlink:type):

  

  • resource: Specifies a local resource. Attributes:
    • xlink:label - Identifies the resource.
    • xlink:title - A human-readable title.

  • locator: Specifies a remote resource. Attributes:
    • xlink:href - Specifies the resource's location.
    • xlink:label - Identifies the resource.
    • xlink:title - A human-readable title.

  • arc: Specifies resource relationships. Attributes:
    • xlink:from - Identifies the starting resource.
      (A previously-defined label for a local or remote resource).
    • xlink:to - Identifies the ending resource.
      (A previously-defined label for a local or remote resource).
    • xlink:show - (new|replace|embed)
    • xlink:actuate - (onRequest|onLoad)
    • xlink:title - A human-readable title.

Lab 5C