Chapter 4 XML Processing

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benefit of avoiding the creation of an intermediate resource consuming represen 

tation. Finally, SAX is good for implementing stream processing where the busi 

ness logic is invoked in the midst of document processing. However, SAX can be

tedious to use for more complex documents that necessitate managing sophisti 

cated context, and in these cases, developers may find it better to use DOM or

JAXB.

In summary, consider using the SAX processing model when any of the fol 

lowing circumstances apply:

E

You are familiar with event based programming.

E

Your application only consumes documents without making structural modifi 

cations to them.

E

The document must only be processed one time.

E

You have to effectively extract and process only parts of the document.

E

Memory usage is an issue or documents may potentially be very large.

E

You want to implement performant stream processing, such as for dealing with 

very large documents.

E

The structure of a document and the order of its information map well to the 

domain specific objects or corresponds to the order in which discrete methods 

of the application's logic must be invoked. Otherwise, you may have to main 

tain rather complicated contexts. 

Note that the SAX model may not be the best candidate for application devel 

opers who are more concerned about implementing business logic. 

4.4.1.2

DOM Programming Model

With the DOM programming model, you write code to traverse a tree like data

structure created by the parser from the source document. Typically, processing the

XML input data is done in a minimum of two steps, as follows:

1. The DOM parser creates a tree like data structure that models the XML source 

document. This structure is called a DOM tree.

2. The application code walks the DOM tree, searching for relevant information 

that it extracts, consolidates, and processes further. Developers can use consol