Chapter 4 XML Processing

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To sum up, consider using DOM when any of these circumstances apply:

E

You want to consume or produce documents.

E

You want to manipulate documents and need fine grained control over the doc 

ument structure that you want to create or edit.

E

You want to process the document more than once.

E

You want random access to parts of the document. For example, you may want 

to traverse back and forth within the document.

E

Memory usage is not a big issue.

E

You want to implement data binding but you cannot use JAXB technology be 

cause the document either has no schema or it conforms to a DTD schema def 

inition rather than to an XSD schema definition. The document may also be too 

complex to use SAX to implement data binding. (See  SAX Programming 

Model  on page 165.)

E

You want to benefit from the flexibility of Xpath and apply Xpath expressions 

on DOM trees.

4.4.1.3

XML Data Binding Programming Model

The XML data binding programming model, contrary to the SAX and DOM

models, allows the developer to program the processing of the content of an XML

document without being concerned with XML document representations (infosets). 

Using a binding compiler, the XML data binding programming model, as

implemented by JAXB, binds components of a source XSD schema to schema 

derived Java content classes. JAXB binds an XML namespace to a Java package.

XSD schema instance documents can be unmarshalled into a tree of Java objects

(called a content tree), which are instances of the Java content classes generated

by compiling the schema. Applications can access the content of the source docu 

ments using JavaBeans style get and set accessor methods. In addition, you can

create or edit an in memory content tree, then marshal it to an XML document

instance of the source schema. Whether marshalling or unmarshalling, the devel 

oper can apply validation to ensure that either the source document or the docu 

ment about to be generated satisfy the constraints expressed in the source schema. 

The steps for using JAXB technology schema derived classes to process an

incoming XML document are very simple, and they are as follows: