Java and XML, Second Edition

XPointer

XPointer is another XML linking technology, and in fact builds on XLink’s capabilities. XLink, while useful in and of itself, only allows you to refer to another document. However, there are many times when you may want to refer to a specific part of another document. This is a very common task, and is somewhat analogous to using named anchors in HTML. It is made possible by using XPointer on top of XLink; the specs build very naturally on each other, and are intended to work together. First, you want to take a look at the target document you are going to link to. If you can, ensure that this document uses id attributes in it. This will make the linking and pointing much easier. Example 16-2 shows the listing of some of the guitars that luthier Dana Bourgeois makes, and has IDs for each type.

Example 16-2. A listing of Bourgeois guitars

<?xml version="1.0"?> <guitarTypes xmlns="http://www.bourgeoisguitars.com"> <type model="OM" ID="OM"> <picture url="http://www.bourgeoisguitars.com/images/vvOM.jpg"/> <description>Small bodied orchestra model.</description> </type> <type model="D" ID="D"> <picture url="http://www.bourgeoisguitars.com/images/ricky%20skaggs%20model.jpg"/> <description>Bluegrass powerhouse in a standard dreadnought shape.</description> </type> <type model="slopeD" ID="slopeD"> <picture url="http://www.bourgeoisguitars.com/images/slope%20d,%20custom%20version.jpg"/> <description> Slope shouldered dreadnought, perfect for vocal accompaniment. </description> ...