Chapter 4 XML Processing

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Generally, when using XML documents, follow these suggestions:

E

Rely on XML protocols, such as those implemented by JAX RPC and others, 

to interoperate with heterogeneous systems and to provide loosely coupled in 

tegration points.

E

Avoid using XML for unexposed interfaces or for exchanges between compo 

nents that should be otherwise tightly coupled.

Direct Java serialization of domain specific objects is usually faster than

XML serialization of an equivalent DOM tree or even the Java serialization of the

DOM tree itself (when the DOM implementation supports such a Java serializa 

tion). Also, direct Java serialization of the domain specific objects usually results

in a serialized object form that is smaller than the serialized forms of the other two

approaches. The Java serialization of the DOM tree is usually the most expensive

in processing time as well as in memory footprint; therefore it should be used with

extreme care (if ever), especially in an EJB context where serialization occurs

when accessing remote enterprise beans. When accessing local enterprise beans,

you can pass DOM tree or DOM tree fragments without incurring this processing

expense. Table 4.2 summarizes the guidelines for using XML for component

interactions.

To summarize, when implementing an application which spans multiple con 

tainers, keep the following points in mind (also see Table 4.2).

E

For remote component interaction, Java objects are efficient, serialized XML 

 although expensive may be used for interoperability. DOM is very expen 

sive, and Java serialization of DOM trees is not always supported.

E

For local component interaction, Java objects are the most efficient and DOM 

may be used when required by the application processing model. However, se 

rialized XML is to be avoided.

E

Bind to domain specific Java objects as soon as possible and process these ob 

jects rather than XML documents.