Understanding Basic Structure of an XML DOM Based Module

DOM - (Document Object model) will allow the access to information that is stored in a XML document in the form of hierarchical object model. DOM actually creates something like a tree of nodes that is based on the structure and information in a XML document which inturn can access information by interacting with the tree of nodes. Later, the textual information in XML document gets turned into a bunch of tree nodes.

Irrespective of whether it is tabular data or documents or just list of items, the type of information in a XML document creates a tree of nodes. Since XML is hierarchical in nature, it forces to use a tree model to access the information even the information is tabular or listed.

When some kind of pure data is been contained in a XML document the it will be very appropriate to lump all the required data in just one string and then have the DOM return that particular string value of a given element node. The general lsequence of elements always play an mportant role in documents.

So, DOM always used to preserve the sequence of elements from XML documents as it accepts everything as a document, like a word or FrameMaker document. DOM is really not a very good object model to be used for storing information stored in xml document and can be used only when xml documents contain only document data.

An example is the DataChannel RIO product, which can index and organize information that comes from all kinds of data sources. DOM allows access to information stored in these documents.

The role of application during an event based parsing, the main focus of the activity in a DOM based application is post parsing.

The basic layout of an XML module using DOM is as follows:

DOM Parser

------------------1------------------

0
DOM Manipulator -------------- 0 DOM_Node
manipulates

Follow these 3 basic steps for creating a ML module :

· first create & then register handlers for the errors and other implementations dependent activity.

· then create a DOM manipulator which will take the responsibility (a) to issue parsing requests to the parser and (b) to manipulate results made by such requests.

· finally, include all the required manipulators for rest of the application interactions.