Reading XML using Groovy's DOMCategory

Information

Java has in-built support for DOM processing of XML using classes representing the various parts of XML documents, e.g. Document, Element, NodeList, Attr etc. For more information about these classes, refer to the respective JavaDocs. Some of the key classes are:

DOM class	JavaDocs
Element	1.4 5
NodeList	1.4 5

Groovy syntax benefits can be applied when using these classes resulting in code which is similar to but more compact than the Java equivalent. In addition, Groovy supports the following built-in helper method for these classes.

DOM class	Method	Description/Equivalent longhand
NodeList	.iterator()	same as for loop, enables closures, e.g. findAll, every, etc.

In addition, the DOMCategory class provides numerous additional helper methods and syntax shortcuts:

DOM class	Method	Description/Equivalent longhand
Element	.'child' or .child	.getElementsByTagName('child')
Element	.''*	special case of above which finds all (nested) children
Element	.'@attr'	.getAttribute('attr')
Element	.attributes()	equivalent to .attributes returns a NamedNodeMap
Element	.text()	.firstChild.nodeValue (or textContent if you are using Xerces)
Element	.name()	.nodeName
Element	.parent()	.parentNode
Element	.children()	.childNodes (potentially including whitespace textnodes etc.)
NodeList	.size()	.length
NodeList	.list()	converted to a list of nodes
NodeList	[n]	.item(n)
NodeList	.text()	.collect{ it.text() }
NodeList	.child	flattened version of .getElementsByTagName('child') for each node in the NodeList
NamedNodeMap	.size()	.length
NamedNodeMap	.'child' or .child	.getNamedItem(elementName).nodeValue

All these methods return standard Java classes (e.g. String and List) or standard DOM classes (e.g. Element, NodeList), so there are no new classes to learn, just some improved syntax.

Example

This example assumes the following class is already on your CLASSPATH:

XmlExamples.groovy

Here is an example of using Groovy's DOMCategory: