Package org.apache.uima.flow

Class CasFlowController_ImplBase

java.lang.Object
org.apache.uima.flow.FlowController_ImplBase
org.apache.uima.flow.CasFlowController_ImplBase
All Implemented Interfaces:
FlowController
Direct Known Subclasses:
CapabilityLanguageFlowController, FixedFlowController
public abstract class CasFlowController_ImplBase extends FlowController_ImplBase
Base class to be extended by FlowControllers that use the CAS interface.

  • Constructor Details

    • CasFlowController_ImplBase

      public CasFlowController_ImplBase()

  • Method Details

    • getRequiredCasInterface

      public Class<CAS> getRequiredCasInterface()
      Description copied from interface: FlowController
      Returns the specific CAS interface that this FlowController requires the framework to pass to its FlowController.computeFlow(AbstractCas) method.
      Returns:
      the required CAS interface. This must specify a subtype of AbstractCas.

    • computeFlow

      public final Flow computeFlow(AbstractCas aCAS) throws AnalysisEngineProcessException
      Overriden to check that aCAS is an instanceof CAS. If it is, then computeFlow(CAS) is called. If not, an exception is thrown.
      Parameters:
      aCAS - A CAS that this FlowController should process. The framework will ensure that aCAS implements the specific CAS interface declared in the <casInterface> element of this FlowController's descriptor.
      Returns:
      a Flow object that has responsibility for routing aCAS through the Aggregate Analysis Engine.
      Throws:
      AnalysisEngineProcessException - if this FlowController encounters a problem computing the flow for the CAS
      See Also:

    • computeFlow

      public abstract Flow computeFlow(CAS aCAS) throws AnalysisEngineProcessException
      This method must be overriden by subclasses. It takes a CAS and returns a Flow object that is responsible for routing this particular CAS through the components of this Aggregate. The Flow object should be given a handle to the CAS, so that it can use information in the CAS to make routing decisions.

      FlowController implementations will typically define their own class that implements Flow by extending from the base class CasFlow_ImplBase. This method would then just instantiate the flow object, call its setCas method to provide a handle to the CAS, and return the flow object.

      Parameters:
      aCAS - the CAS to be routed
      Returns:
      a Flow object that will be used to route aCAS
      Throws:
      AnalysisEngineProcessException - if a problem occurs during processing
      See Also:

    • typeSystemInit

      public void typeSystemInit(TypeSystem aTypeSystem) throws AnalysisEngineProcessException
      This method may be overriden by subclasses. It is called whenever th TypeSystem of the CAS changes. This method will be called immediately prior to the first call to computeFlow(CAS), and will be called again whenever the CAS TypeSystem changes.

      In this method, the FlowController can use the TypeSystem to resolve the names of Type and Features to the actual Type and Feature objects, which can then be used to access information from the CAS during routing.

      Parameters:
      aTypeSystem - the typesystem
      Throws:
      AnalysisEngineProcessException - if a problem occurs during processing