Processing XML with Java™: A Guide to SAX, DOM, JDOM, JAXP, and TrAX

Building Hierarchical Structures from Flat Data

Sometimes you want to convert only a subset of the available data. For example, you might want to store each year in a separate XML document. With a few tweaks to the basic code, this is not hard to do. Another possibility is to arrange the data hierarchically, with Agency elements containing Bureau elements, which contain Account elements, which contain Subfunction elements. This is a little more complex, but far from impossible. Or perhaps you want to massage the data while converting it, for example by changing the amounts of thousands of dollars to amounts of single dollars. Or you could do all three, in which case the hierarchy would be arranged something like in Example 4.5.

Example 4.5. A ...