Databases Reference
In-Depth Information
File communication is either inbound (this means that a file has been created by an
application and must be read) or outbound (this means that a file must be written
to provide input to an application). The files that are written and read by existing
applications may be in a variety of formats including XML, separator delimited files,
or fixed format files.
A payroll use case
Consider a company that has a payroll application that produces a file detailing
payments. This file must be transformed into a file format that is accepted by the
company's bank and then delivered to the bank via FTP. The company wants to
use SOA technologies to perform this transfer because it allows them to perform
additional validations or enrichment of the data before sending it to the bank. In
addition, they want to store the details of what was sent in a database for audit
purposes. In this scenario, a file adapter could be used to take the data from the file,
an FTP adapter to deliver it to the bank, and a database adapter could post it into the
tables required for audit purposes.
Reading a payroll file
Let's look at how we would read from a payroll file. Normally, we will poll to check
for the arrival of a file, although it is also possible to read a file without polling. The
key points to be considered beforehand are:
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How often should we poll for the file?
Do we need to read the contents of the file?
Do we need to move it to a different location?
What do we do with the file when we have read or moved it?
Should we delete it?
Should we move it to an archive directory?
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How large is the file and its records?
Does the file have one record or many?
We will consider all these factors as we interact with the File Adapter Wizard.
