PBDOM objects

PBDOM_OBJECT, the base class for PBDOM objects that represent XML nodes, inherits from the PowerBuilder NonVisualObject class. PBDOM represents node types by the following classes:

You use methods from these classes to access objects in a PBDOM node tree.

The PBDOM_BUILDER class does not represent DOM nodes but can be used to build a PBDOM object tree from XML. It inherits from the PowerBuilder NonVisualObject class.

The PBDOM_EXCEPTION class inherits from the PowerBuilder Exception class and provides a method that obtains error codes.

Each of these classes and their methods are described in the chapters that follow.

Comparing PBDOM objects with W3C DOM and JDOM objects

The following table shows the W3C DOM and JDOM objects that correspond to each PBDOM object that represents a node in the DOM tree. Note that although these W3C DOM and JDOM objects correspond to PBDOM objects, they are not equivalent to the PBDOM objects.

**Table 4-1: W3C DOM and JDOM objects that correspond to PBDOM objects**
PBDOM	W3C DOM	JDOM
PBDOM_ATTRIBUTE	ATTRIBUTE_NODE	Attribute
PBDOM_BUILDER	None	DOMBuilder
PBDOM_CDATA	CDATA_SECTION_NODE	CDATA
PBDOM_CHARACTERDATA	CHARACTER_DATA_NODE	None
PBDOM_COMMENT	COMMENT_NODE	Comment
PBDOM_DOCUMENT	DOCUMENT_NODE	Document
PBDOM_DOCTYPE	DOCUMENT_TYPE_NODE	DocType
PBDOM_ELEMENT	ELEMENT_NODE	Element
PBDOM_ENTITYREFERENCE	ENTITY_REFERENCE_NODE	EntityRef
PBDOM_OBJECT	NODE	None
PBDOM_PROCESSINGINSTURCTION	PROCESSING_INSTRUCTION_NODE	Processinginstruction
PBDOM_TEXT	TEXT_NODE	Text

Object hierarchy

The W3C DOM and JDOM object hierarchies also differ from the PBDOM object hierarchy, which is shown in the following illustration.

Figure 4-1: The PBDOM object hierarchy

the P B DOM object hierarchy is represented by linked rectangles with P B DOM _ Object as the base class. The node types branching from it are P B DOM _ Attirbute, character data, doctype, document, element, entity reference, and processing instruction. Descendants of p b dom _ character data are P B DOM _ COMMENT and P B DOM _ TEXT, which in turn has its descendant P B DOM _ C DATA. Also shown are unlinked rectangles for P B DOM _ BUILDER and P B DOM _ EXCEPTION.

For more information about working with PBDOM, see the chapter on PowerBuilder XML services in Application Techniques.