Taverna 1.5.1

Taverna is a collection of workflow enactment and description components, including a high level language for workflows called Scufl (Simple Conceptual Unified Flow Language), a pure Java object model, parser to populate the model, and a set of views and controllers (including some Swing components to drop into your workflow-enabled applications). In order to actually run workflows you also need the myGrid workflow enactment engine.

Taverna core data models include the object representations of the workflow itself, all entities within the workflow (processors, ports, data links etc) and the model for the data values flowing along data links during a workflow enactment.

Taverna task extensions sit within an enactment engine - in this case FreeFluo - and provide concrete implementations of the abstract tasks specified by Processor objects within the workflow object model. It is these tasks which contain the logic required to contact web services, run local java classes and perform the other actions associated with their Processor entities.

Instances of the task extensions are created when a workflow and associated input objects are submitted through the Workflow Submission Interface. This interface may be an in process java method call or may be invoked across some transport such as SOAP in the case of a remote service based enactment engine. FreeFluo is capable of acting in both modes, the Taverna workbench incorporates an instance of the FreeFluo enactor to provide basic enactment services to users without a central workflow engine server.

The graphical user interface classes sit on a client machine and allow interaction with the core data model classes as well as with running workflow instance objects within an enactment engine. This allows workflow construction, editing and visualisation as well as enactor management and data browsing across the results and intermediate values within a workflow instance.

The storage interface is a plugable framework that allows external data and metadata stores to observe events within the workflow enactment service and collection information about those events. This could include a provenance collection plugin which watches the workflow enactment and records metadata about it in RDF form, or a storage plugin which streams results back to a relation database, possibly a Life Science Identifier (LSID) authority, as the enactment runs.

The LSID authority interface is a read only access point to data stored within a data store, and can potentially be used by the Taverna graphical user interface components to fetch results of previous workflows and make use of them as inputs to successive ones.