OpenPonk / xml-dom-visitor

XML DOM Visitor

XML DOM Visitor

An extension for XMLParser's DOM.

Three functionalities:

• base class for DOM visitors by the element's types (Document, Element, CData, String, ...)
• delegating visitor with which you can visit the DOM by element's name
• typed retrieval of node values and attribute values
  • supported selectors

• Example
• Installation

Example

<people>
	<docId>cc254e89-569e-5b46-a6e9-4a06de4d9da0</docId>
	<person name="Sarah" age="32" />
	<person name="Carl" age="27" />
</people>

The XML above can be visited with a visitor such as the following one:

MyVisitor>>visitPeople: aPeopleElement
	"nothing to do"

MyVisitor>>visitDocId: aDocIdElement
	aDocIdElement uuidValue "an instace of UUID('cc254e89-569e-5b46-a6e9-4a06de4d9da0')"

MyVisitor>>visitPerson: aPersonElement
	aPersonElement stringAt: #name "returns string 'Sarah'"
	aPersonElement numberAt: #age "returns number '32'"

Usage - Creating generic DOM visitor

Subclass XMLDOMVisitor to create your own visitor.

Example: Look at in-image class XMLDOMTestVisitor.

Usage - Element delegating visitor

Use XMLDOMElementVisitor to delegate the visiting by the element's localName (without namespace) as the selector, e.g.

visitor := MyVisitor new.
XMLDOMElementVisitor new
	elementVisitor: visitor;
	visit: dom.

Then e.g. for an element <person>, the visitPerson: message will be sent to your MyVisitor.

Usage - Typed values

If you specify XMLDOMTypedElement as the parsing node, then you can retrieve values with a specific type.

dom := (XMLDOMParser on: aStream)
	nodeFactory: (XMLPluggableElementFactory new elementClass: XMLDOMTypedElement);
	parseDocument.

Example:

<myElement isRandom="true">12.7</myElement> will be parsed into XMLDOMTypedElement instance.

element booleanAt: #isRandom. "-> true"
element stringAt: #isRandom. "-> 'true'"

element numberValue. "-> 12.7"
element stringValue. "-> '12.7'"

Supported selectors

Look into the protocols typed attribute accessing and typed value accessing of XMLDOMTypedElement.

The following conversions are supported: boolean, date, number, string, symbol, and uuid.

Extras:

• booleanAt:/booleanValue will return true for strings 'true', '1', or 'yes'.
• XMLDOMTypedElement>>isEmptyValue will return boolean if the element has any content. (e.g. <el></el> versus <el>data</el>)

Installation

Metacello new
	baseline: 'XMLDOMVisitor';
	repository: 'github://OpenPonk/xml-dom-visitor/repository';
	load.