org.apache.uima.flow

## Class FlowController_ImplBase

- java.lang.Object
- - org.apache.uima.flow.FlowController_ImplBase

- All Implemented Interfaces:
    FlowController
  Direct Known Subclasses:
    CasFlowController_ImplBase, JCasFlowController_ImplBase

      public abstract class FlowController_ImplBase
      extends Object
      implements FlowController

  Implementation base class for FlowControllers. Normally developers do not extend this class directly. Instead use `JCasFlowController_ImplBase` or `CasFlowController_ImplBase`, depending on which CAS interface you would like to use.

  This class implements the `initialize(FlowControllerContext)` method and stores the `FlowControllerContext` in a private field where it can be accessed via the `getContext()` method.

  This class also provides a "dumb" implementation of the `reconfigure()` method, which simply calls `destroy()` followed by `initialize(FlowControllerContext)`. Developers of FlowControllers with expensive initialization logic should override this method and provide a more intelligent implementation.

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `FlowController_ImplBase()`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `addAnalysisEngines(Collection<String> aKeys)` Does nothing by default.
    `void` | `batchProcessComplete()` Completes the processing of a batch of CASes.
    `void` | `collectionProcessComplete()` Notifies this component that processing of an entire collection has been completed.
    `void` | `destroy()` Frees all resources held by this FlowController.
    `protected FlowControllerContext` | `getContext()` Gets the FlowControllerContext for this FlowController.
    `void` | `initialize(FlowControllerContext aContext)` Performs any startup tasks required by this component.
    `void` | `reconfigure()` Alerts this FlowController that the values of its configuration parameters or external resources have changed.
    `void` | `removeAnalysisEngines(Collection<String> aKeys)` Throws an AnalysisEngineProcessException by default.

    - ### Methods inherited from class java.lang.Object

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

    - ### Methods inherited from interface org.apache.uima.flow.FlowController

      `computeFlow, getRequiredCasInterface`

- - ### Constructor Detail

    - #### FlowController_ImplBase

          public FlowController_ImplBase()

  - ### 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`
      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.

    - #### reconfigure

          public void reconfigure()
                           throws ResourceInitializationException,
                                  ResourceConfigurationException

      Description copied from interface: `FlowController`
      Alerts this FlowController that the values of its configuration parameters or external resources have changed. This FlowController should re-read its configuration from the `UimaContext` and take appropriate action to reconfigure itself.

      In the abstract base classes provided by the framework, this is generally implemented by calling `destroy` followed by `initialize`. If a more efficient implementation is needed, you can override that implementation.

      Specified by:
        `reconfigure` in interface `FlowController`
      Throws:
        `ResourceInitializationException` - if this component encounters a problem in reinitializing itself from the new configuration
        `ResourceConfigurationException` - if the new configuration is invalid

    - #### batchProcessComplete

          public void batchProcessComplete()
                                    throws AnalysisEngineProcessException

      Description copied from interface: `FlowController`
      Completes the processing of a batch of CASes. The size of a batch is determined based on configuration provided by the application that is using this component. The purpose of `batchProcessComplete` is to give this component the change to flush information from memory to persistent storage. In the event of an error, this allows the processing to be restarted from the end of the last completed batch.

      If this component's descriptor declares that it is `recoverable`, then this component is required to be restartable from the end of the last completed batch.

      Specified by:
        `batchProcessComplete` in interface `FlowController`
      Throws:
        `AnalysisEngineProcessException` - if this component encounters a problem in flushing its state to persistent storage

    - #### collectionProcessComplete

          public void collectionProcessComplete()
                                         throws AnalysisEngineProcessException

      Description copied from interface: `FlowController`
      Notifies this component that processing of an entire collection has been completed. In this method, this component should finish writing any output relating to the current collection.
      Specified by:
        `collectionProcessComplete` in interface `FlowController`
      Throws:
        `AnalysisEngineProcessException` - if this component encounters a problem in its end-of-collection processing

    - #### destroy

          public void destroy()

      Description copied from interface: `FlowController`
      Frees all resources held by this FlowController. The framework calls this method only once, when it is finished using this component.
      Specified by:
        `destroy` in interface `FlowController`

    - #### addAnalysisEngines

          public void addAnalysisEngines(Collection<String> aKeys)

      Does nothing by default. Subclasses may override this to support adding new AnalysisEngines to the flow.
      Specified by:
        `addAnalysisEngines` in interface `FlowController`
      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(Collection<String> aKeys)
                                     throws AnalysisEngineProcessException

      Throws an AnalysisEngineProcessException by default. Subclasses may override this to support removing AnalysisEngines from the flow.
      Specified by:
        `removeAnalysisEngines` in interface `FlowController`
      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)`

    - #### getContext

          protected FlowControllerContext getContext()

      Gets the FlowControllerContext for this FlowController. This provides access to configuration parameters, resources, and also to metadata for each AnalysisEngine that is available for this FlowController to route CASes to.
      Returns:
        the FlowControllerContext for this FlowController

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