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Data Integration Guidelines

The adventure builder application applies the style sheet when an invoice is

sent to a supplier. See  Reuse and Pool Parsers and Style Sheets  on page 188 for

more information about pooling style sheets. 

Transition facades, which can apply to any object representation of data, are a

more general solution for transformations. You can use transition facades to hide

extra information or to provide simple mappings. To use a facade, you write a

Java class within which you do manual data transformation and mappings. 

You should also consider using one of the many tools available for data trans 

formations. These tools simplify the data transformation task and make it easier to

maintain.

E

When data is in an XML document, it is easier to write XSL style sheets that 

do the required transformations.

E

When you access data using EJB container managed persistence, you can ei 

ther directly modify the container managed persistent classes or write facades 

to do the required transformations. 

6.4.3 Data Filtering

When you do not have access to an application's code, such as for off the shelf

packaged applications or for applications that cannot be modified because they are

critical to a working business system, you might consider using filtering. That is,

you construct a filter that sits in front of the application and does all necessary

data translations. 

Generally, data filtering goes hand in hand with data transformations. The

canonical data model, because it must support all use cases within an enterprise, is

often a good candidate for filtering. Since many applications do not need access to

all data fields, you can filter data and simplify application development and

improve performance by reducing the amount of data that is exchanged. 

There are two types of filtering, and each has its own use cases: 

1. Filtering that hides information but saves it for later use

2. Filtering that outputs only needed information 

For example, in the adventure builder enterprise, a workflow manager

receives the invoices sent by the different suppliers. Since it needs only an identi 

fier to identify the workflow associated with the invoice, the workflow manager