The Directory Scanner allows you to scan a certain directory on the file
system for files containing XML messages. Once the messages have been
read, they can be passed into the core message pipeline where the full
collection of message processing filters can act on them.
The Directory Scanner is typically used in cases where an external
application is dropping XML files (perhaps by FTP) on to the file system
so that they can be validated, modified, and potentially routed onwards
over HTTP, JMS, or simply stored back to another directory where the
application can pick them up again.
This sort of protocol mediation is very useful in cases where legacy
systems are involved. Instead of making drastic changes to the legacy
system by adding an HTTP engine to it, for example, the Enterprise Gateway can
be used to pull the files from the file system and then route them onwards
over HTTP to another back-end system. The added benefit here, of course,
is that messages are exposed to the full compliment of message processing
filters made available by the Enterprise Gateway. This ensures that only
properly validated messages will be routed on to the target system.
To add a new Directory Scanner, right-click the name of the Process
in the tree view of the Policy Studio (for example, "Oracle Enterprise Gateway"),
and select the Directory Scanner -> Add menu option.
The following sections describe how to configure the fields on the
Directory Scanner Settings dialog.
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