org.apache.uima.flow.impl
Class FixedFlowController

java.lang.Object
  org.apache.uima.flow.FlowController_ImplBase
      org.apache.uima.flow.CasFlowController_ImplBase
          org.apache.uima.flow.impl.FixedFlowController

All Implemented Interfaces:

FlowController

public class FixedFlowController
extends CasFlowController_ImplBase

Simple FlowController that invokes components in a fixed sequence.

Field Summary

static java.lang.String

PARAM_ACTION_AFTER_CAS_MULTIPLIER Key for the configuration parameter that determines what should happen to a CAS after it has been input to a CAS Multiplier.

Constructor Summary

FixedFlowController()

Method Summary

void	addAnalysisEngines(java.util.Collection<java.lang.String> aKeys) Does nothing by default.
Flow	computeFlow(CAS aCAS) This method must be overriden by subclasses.
static FlowControllerDescription	getDescription()
void	initialize(FlowControllerContext aContext) Performs any startup tasks required by this component.
void	removeAnalysisEngines(java.util.Collection<java.lang.String> aKeys) Throws an AnalysisEngineProcessException by default.

Methods inherited from class org.apache.uima.flow.CasFlowController_ImplBase

computeFlow, getRequiredCasInterface, typeSystemInit

Methods inherited from class org.apache.uima.flow.FlowController_ImplBase

batchProcessComplete, collectionProcessComplete, destroy, getContext, reconfigure

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PARAM_ACTION_AFTER_CAS_MULTIPLIER

public static final java.lang.String PARAM_ACTION_AFTER_CAS_MULTIPLIER

Key for the configuration parameter that determines what should happen to a CAS after it has been input to a CAS Multiplier. Possible values are: continue: the CAS continues on to the next element in the flow stop: the CAS will no longer continue in the flow, and will be returned from the aggregate if possible. drop: the CAS will no longer continue in the flow, and will be dropped (not returned from the aggregate) if possible. dropIfNewCasProduced (the default): if the CAS multiplier produced a new CAS as a result of processing this CAS, then this CAS will be dropped. If not, then this CAS will continue.

See Also:

Constant Field Values

Constructor Detail

FixedFlowController

public FixedFlowController()

Method Detail

initialize

public void initialize(FlowControllerContext aContext)
                throws ResourceInitializationException

Description copied from interface: FlowController

Performs any startup tasks required by this component. The framework calls this method only once, just after the FlowController has been instantiated.

The framework supplies this FlowController with a reference to the FlowControllerContext that it will use, for example to access configuration settings or resources. This FlowController should store a reference to this Context for later use.

Specified by:

initialize in interface FlowController

Overrides:

initialize in class FlowController_ImplBase

Parameters:

aContext - Provides access to services and resources managed by the framework. This includes configuration parameters, logging, and access to external resources. Also provides the FlowController with the metadata of all of the AnalysisEngines that are possible targets for routing CASes.

Throws:

ResourceInitializationException - if the FlowController cannot initialize successfully.

computeFlow

public Flow computeFlow(CAS aCAS)
                 throws AnalysisEngineProcessException

Description copied from class: CasFlowController_ImplBase

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.

Specified by:

computeFlow in class CasFlowController_ImplBase

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:

FlowController.computeFlow(AbstractCas)

addAnalysisEngines

public void addAnalysisEngines(java.util.Collection<java.lang.String> aKeys)

Description copied from class: FlowController_ImplBase

Does nothing by default. Subclasses may override this to support adding new AnalysisEngines to the flow.

Specified by:

addAnalysisEngines in interface FlowController

Overrides:

addAnalysisEngines in class FlowController_ImplBase

Parameters:

aKeys - a Collection of Strings, each of which is the key of an Analysis Engine to which CASes can be routed. These are the same keys as used in FlowControllerContext.getAnalysisEngineMetaDataMap().

See Also:

FlowController.addAnalysisEngines(java.util.Collection)

removeAnalysisEngines

public void removeAnalysisEngines(java.util.Collection<java.lang.String> aKeys)
                           throws AnalysisEngineProcessException

Description copied from class: FlowController_ImplBase

Throws an AnalysisEngineProcessException by default. Subclasses may override this to support removing AnalysisEngines from the flow.

Specified by:

removeAnalysisEngines in interface FlowController

Overrides:

removeAnalysisEngines in class FlowController_ImplBase

Parameters:

aKeys - a Collection of Strings, each of which is the key of an Analysis Engine to which CASes may no longer be routed.

Throws:

AnalysisEngineProcessException - if the FlowController cannot continue with these Analysis Engines removed, or doesn't support removing Analysis Engines at all.

See Also:

FlowController.removeAnalysisEngines(java.util.Collection)

getDescription

public static FlowControllerDescription getDescription()