A flow registrar that populates a flow registry from flow definitions defined within externalized resources. Encapsulates registration behaivior common to all externalized registrars and is not tied to a specific flow definition format (e.g. xml).

Concrete subclasses are expected to derive from this class to provide knowledge about a particular kind of definition format by implementing the abstract template methods in this class.

By default, when configuring the flowLocations property, flow definition registered by this registrar will be assigned a registry identifier equal to the filename of the underlying definition resource, minus the filename extension. For example, a XML-based flow definition defined in the file "flow1.xml" will be identified as "flow1" when registered in a registry.

For full control over the assignment of flow identifiers and flow properties, configure formal ExternalizedFlowDefinition instances using the flowDefinitions property.