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<h2>Information</h2>

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:

<table class="confluenceTable"><tbody>
<tr>
<th class="confluenceTh">DOM class</th>
<th class="confluenceTh">JavaDocs</th>
</tr>
<tr>
<td class="confluenceTd">Element</td>
<td class="confluenceTd"><a href="http://download.oracle.com/javase/6/docs/api/org/w3c/dom/Element.html">6</a> <a href="http://download.oracle.com/javase/7/docs/api/org/w3c/dom/Element.html">7</a></td>
</tr>
<tr>
<td class="confluenceTd">NodeList</td>
<td class="confluenceTd"><a href="http://download.oracle.com/javase/6/docs/api/org/w3c/dom/NodeList.html">6</a> <a href="http://download.oracle.com/javase/7/docs/api/org/w3c/dom/NodeList.html">7</a></td>
</tr>
</tbody></table>

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.

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

<table class="confluenceTable"><tbody>
<tr>
<th class="confluenceTh">DOM class</th>
<th class="confluenceTh">Method</th>
<th class="confluenceTh">Description/Equivalent longhand</th>
</tr>
<tr>
<td class="confluenceTd">Element</td>
<td class="confluenceTd">.'child' or .child or ['child']</td>
<td class="confluenceTd">similar to .getElementsByTagName('child') but only gets direct children</td>
</tr>
<tr>
<td class="confluenceTd">Element</td>
<td class="confluenceTd">.children() or .'*' or ['*']</td>
<td class="confluenceTd">special case of above which finds all children regardless of tagname (plus text nodes)</td>
</tr>
<tr>
<td class="confluenceTd">Element</td>
<td class="confluenceTd">.'@attr' or ['@attr']</td>
<td class="confluenceTd">.getAttribute('attr')</td>
</tr>
<tr>
<td class="confluenceTd">Element</td>
<td class="confluenceTd">.attributes()</td>
<td class="confluenceTd">equivalent to .attributes returns a NamedNodeMap</td>
</tr>
<tr>
<td class="confluenceTd">Element</td>
<td class="confluenceTd">.text()</td>
<td class="confluenceTd">.firstChild.nodeValue (or textContent if you are using Xerces)</td>
</tr>
<tr>
<td class="confluenceTd">Element</td>
<td class="confluenceTd">.name()</td>
<td class="confluenceTd">.nodeName</td>
</tr>
<tr>
<td class="confluenceTd">Element</td>
<td class="confluenceTd">.parent() or .'..' or ['..']</td>
<td class="confluenceTd">.parentNode</td>
</tr>
<tr>
<td class="confluenceTd">Element</td>
<td class="confluenceTd">.depthFirst() or .'**'</td>
<td class="confluenceTd">depth-first traversal of nested children</td>
</tr>
<tr>
<td class="confluenceTd">Element</td>
<td class="confluenceTd">.breadthFirst()</td>
<td class="confluenceTd">breadth-first traversal of nested children</td>
</tr>
<tr>
<td class="confluenceTd">Node</td>
<td class="confluenceTd">.toString()</td>
<td class="confluenceTd">text node value as a String</td>
</tr>
<tr>
<td class="confluenceTd">NodeList</td>
<td class="confluenceTd">.size()</td>
<td class="confluenceTd">.length</td>
</tr>
<tr>
<td class="confluenceTd">NodeList</td>
<td class="confluenceTd">.list()</td>
<td class="confluenceTd">converted to a list of nodes</td>
</tr>
<tr>
<td class="confluenceTd">NodeList</td>
<td class="confluenceTd">[n]</td>
<td class="confluenceTd">.item(n)</td>
</tr>
<tr>
<td class="confluenceTd">NodeList</td>
<td class="confluenceTd">.text()</td>
<td class="confluenceTd">.collect{ it.text() }</td>
</tr>
<tr>
<td class="confluenceTd">NodeList</td>
<td class="confluenceTd">.child</td>
<td class="confluenceTd">flattened version of .child for each node in the NodeList</td>
</tr>
<tr>
<td class="confluenceTd">NamedNodeMap</td>
<td class="confluenceTd">.size()</td>
<td class="confluenceTd">.length</td>
</tr>
<tr>
<td class="confluenceTd">NamedNodeMap</td>
<td class="confluenceTd">.'child' or .child or ['child']</td>
<td class="confluenceTd">.getNamedItem(elementName).nodeValue</td>
</tr>
</tbody></table>

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.

<h2>Example</h2>

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

Here is an example of using Groovy's DOMCategory:

<table class="wysiwyg-macro" data-macro-name="code" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e2NvZGV9&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>
import groovy.xml.DOMBuilder
import groovy.xml.dom.DOMCategory

messages = []

def processCar(car) {
    assert car.name() == 'car'
    def make = car.'@make'
    def country = car.country[0].text()
    def type = car.record[0].'@type'
    messages &lt;&lt; make + ' of ' + country + ' has a ' + type + ' record'
}

def reader  = new StringReader(XmlExamples.CAR_RECORDS)
def doc     = DOMBuilder.parse(reader)
def records = doc.documentElement

use (DOMCategory) {
    assert 3 == records.'*'.size()
    def cars = records.'car'
    assert cars[0].parent() == records
    assert 3 == cars.size()
    assert 2 == cars.findAll{ it.'@year'.toInteger() > 1950 }.size()
    def carsByCentury = cars.list().groupBy{
        it.'@year'.toInteger() >= 2000 ? 'this century' : 'last century'
    }
    assert 1 == carsByCentury['this century'].size()
    assert 2 == carsByCentury['last century'].size()
    cars.each{ car -> processCar(car) }
}

assert messages == [
 'Holden of Australia has a speed record',
 'Peel of Isle of Man has a size record',
 'Bugatti of France has a price record'
]
</pre></td></tr></table>