Glossary of Terms: XML and Java for Scientists/Engineers
Document Object Model (DOM).
The document object model (DOM) is the mechanism specified by the W3C for
access and manipulation of XML documents. DOM works by reading the entire
document into memory and constructing a tree from its contents.
Then, contents of the tree can be manipulated (e.g., creation, elimination,
or modification of tree elements) by an application program.
DOM is memory intensive.
For the handling of large documents that only need to be read
and parsed, SAX is probably a much better method.
Simple API for XML (SAX).
The Simple API for XML (otherwise known as SAX)
is the XML community's response to DOM.
Like DOM, SAX parses XML documents. But it is event-driven; that is,
it streams the documents through the parse window and issues events
to the caller when parts of the documents are found (i.e., an
element starts; an element ends; a processing instruction is found).
Compared to DOM, the memory requirements for SAX are minimal.
However, if the XML document has a complex structure (perhaps through
cross referencing with XML's ID and IDREF relationships),
using SAX can necessitate multiple parses of a document or use of
sophisticated buffering to retrieve needed information that has
already passed through the parse window.
XLink is a linking mechanism that is somewhat similar to HTML links.
However, unlike HTML links, XLink permits permits bidirectional
links and/or one link to connect many documents together.
XML schemas define XML vocabularies, and are intended as a replacement for DTDs.
This language allows specific nodes or values to be selected from a source document
for manipulation and presentation (perhaps via XSLT).
XPointer works somewhat like anchors in HTML, but allows much greater flexibility,
allowing specific nodes to sets of nodes to be selected from a target
document using XPath.
XSLT is a styling language for XML.
XSLT allows XML in one form to be transformed into another form of XML.
The latter can include HTML, and text-based formats like a comma-separated file.
As XML matures, it is likely that XSLT will be the method of choice for
transforming data-centric XML documents into a format suitable for presentation.
Developed in January 2002 by Mark Austin
Copyright © 2002, Mark Austin, University of Maryland