IBM Version 5 manual Example 2-3 a simple link

￿Locator: Pointer to a external source. A locator can have a title as its child element type.

￿Arc: A rule between resources. An arc element can have a title as its child element type.

The simple and extended attributes are considered as linking elements. The other attributes describe the link. A resource is any available information or service that can be located by one means or another. The links, therefore, can link any two resources: files, documents, images, query results, and programs. A resource can refer to a portion of a resource, and may not have to refer to the whole file or document. A local resource is specified by value and a remote resource is specified by reference.

A transversal is a path from one resource to another. An arc describes the traversal and application behavior between two resources. A link is multi-directional if is coded such that the resources switch places at the starting and ending resources. This is not the same as going back on the link. An arc is out-boundif the starting resources is local and the ending resource is remote. An example would be the HTML A element. Conversely, if the ending resource is local, but the starting resource was remote, the arc is said to be in-bound. A remote resource is one, which we do not have write access to or one we cannot embed linking constructs.

The arc is said to be third-partyif both the starting and ending resource are remote. Typically, at any one time, the arc is in-bound, out-bound, or third-party.

Files or documents that contain a collection of in-bound and third-party links are called linkups or link databases.

An example of a simple link is found in Example 2-3.

Example 2-3 A simple link

<passengers:FlightReference

xlink:href="passengerList.xml"

xlink:role="http://www.airline.com/linkproperties/passengerlist" xlink:title="Passenger List">

xlink:show="replace"

xlink:actuate="onRequest">

List of Students for the Flight </passengers:FlightReference>

A simple link in its simplest form provides an outbound link for two resources. This would be very similar to the HTML-style A and IMG links. A click (for the

26 The XML Files: Development of XML/XSL Applications Using WebSphere Studio