Package de.aristaflow.adept2.core.eventmanager.common

Class AbstractSharedEventDispatcher<T extends Event>

java.lang.Object
de.aristaflow.adept2.core.eventmanager.common.AbstractSharedEventDispatcher<T>
Type Parameters:
T - The type of the (sharing) event, that is the one created for the handling by the sharing event sources. This is not the type of the shared event (provided by the shared event source).
All Implemented Interfaces:
Callable<Boolean>
public abstract class AbstractSharedEventDispatcher<T extends Event> extends Object implements Callable<Boolean>
This class provides the basic means for handling of shared events. These events are created by a shared event source which combines several event sources that share a common configuration and wait for a similar event. This avoids polling overhead. For instance several event sources need to poll with the same SQL statement for results. The statement is regularly executed by the shared event source while the event handling will be forwarded to the corresponding sharing event sources (which are event handlers for the shared event source).
Instances of this class are responsible for dispatching a shared event created by a shared event source. It supports a windowing mechanism so that the event data may be reduced and the sharing event sources only get a partial result. This includes removal of consumed results.
All sharing event sources handle the event exclusively, that is, one event source after the other. for each event source a new (sharing) event will be created containing only the relevant results and only the maximum amount of results specified by the sharing event source. If a sharing event source (or rather the corresponding handlers) consume the event, the current results count as consumed. If there are more results in the original (shared) event, new results will be used for the event provided to the following event sources.

For logging purpose a sharedEventString will be used. This should identify the shared event source, for instance the SQL statement executed by the shared event source.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected final URI[]
    emUris
    The URIs of the event manager used for the sharing event.
    protected final String
    eventType
    The event type used for the corresponding sharing event.
    protected final String
    hierSrcName
    The hierarchical name of the event source used for logging.
    protected final Logger
    logger
    The logger for logging internal problems and behaviour.
    protected final Map<String,Integer>
    maxResults
    The maximum amount of results each sharing event source awaits, null if there is no restriction.
    protected final String
    sharedEventString
    The string identifying the shared event (source).
    protected final String
    sourceId
    The event source ID used for the corresponding sharing event.
    protected final List<Serializable>
    sourceKeys
    The keys identifying the sharing event sources, that is, the data of the sharing event sources.
    protected final Collection<SharingSource<T>>
    sources
    All sharing event sources waiting for the same data/keys.
    protected final String
    sourceType
    The event source type used for the corresponding sharing event.

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    AbstractSharedEventDispatcher(List<Serializable> sourceKeys, Collection<SharingSource<T>> sources, Map<String,Integer> maxResults, URI[] emUris, String eventType, String sourceType, String sourceId, String hierSrcName, String sharedEventString, Logger logger)
    Creates a new Callable for creating and forwarding shared events to a collection of sharing event sources interested in an event based on the very same event.

  • Method Summary

    Modifier and Type
    Method
    Description
    Boolean
    call()
     
    protected abstract T
    createNextEvent(Integer maxResult, int consumedRes)
    Creates the event for the next sharing event source with the designated amount of result entries and the designated amount of already consumed results.
    protected abstract int
    getConsumedResults(int consumedRes, T event)
    Gets the amount of consumed results after the designated amount of results have been consumed together with the results in the designated sharing event.

    Methods inherited from class java.lang.Object

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

  • Field Details

    • sourceKeys

      protected final List<Serializable> sourceKeys
      The keys identifying the sharing event sources, that is, the data of the sharing event sources.

    • sources

      protected final Collection<SharingSource<T extends Event>> sources
      All sharing event sources waiting for the same data/keys.

    • maxResults

      protected final Map<String,Integer> maxResults
      The maximum amount of results each sharing event source awaits, null if there is no restriction.

    • emUris

      protected final URI[] emUris
      The URIs of the event manager used for the sharing event.

    • eventType

      protected final String eventType
      The event type used for the corresponding sharing event.

    • sourceType

      protected final String sourceType
      The event source type used for the corresponding sharing event.

    • sourceId

      protected final String sourceId
      The event source ID used for the corresponding sharing event.

    • hierSrcName

      protected final String hierSrcName
      The hierarchical name of the event source used for logging.

    • sharedEventString

      protected final String sharedEventString
      The string identifying the shared event (source). This is used for logging.

    • logger

      protected final Logger logger
      The logger for logging internal problems and behaviour.

  • Constructor Details

    • AbstractSharedEventDispatcher

      protected AbstractSharedEventDispatcher(List<Serializable> sourceKeys, Collection<SharingSource<T>> sources, Map<String,Integer> maxResults, URI[] emUris, String eventType, String sourceType, String sourceId, String hierSrcName, String sharedEventString, Logger logger)
      Creates a new Callable for creating and forwarding shared events to a collection of sharing event sources interested in an event based on the very same event.
      Parameters:
      sourceKeys - The keys identifying the sharing event sources, that is, the data of the sharing event sources.
      sources - All sharing event sources waiting for the same data/keys.
      maxResults - The maximum amount of results each sharing event source awaits. If a sharing event source has no limit, it may map to null or be not in the map at all.
      emUris - The URIs of the event manager used for the corresponding sharing event.
      eventType - The event type used for the corresponding sharing event.
      sourceType - The event source type used for the corresponding sharing set event.
      sourceId - The event source ID used for the corresponding sharing event.
      hierSrcName - The hierarchical name of the event source used for logging.
      sharedEventString - The string identifying the shared event (source). This is used for logging.
      logger - The logger for logging internal problems and behaviour.

  • Method Details

    • call

      public Boolean call() throws Exception
      Specified by:
      call in interface Callable<T extends Event>
      Throws:
      Exception

    • createNextEvent

      protected abstract T createNextEvent(Integer maxResult, int consumedRes)
      Creates the event for the next sharing event source with the designated amount of result entries and the designated amount of already consumed results.
      This will be called before EventHandler.handleEvent(Event, boolean).
      Parameters:
      maxResult - The maximum amount of result entries the next handled sharing event source expects. This may be null or a non-positive value for no limit.
      consumedRes - The amount of already consumed results. If all results are consumed, implementations may decide on whether to notify all result entries or to finish handling the completely consumed event. Integer.MAX_VALUE indicates the complete consumption of the result entries.
      Returns:
      The event to be handled by the next sharing event source or null to skip handling this event.

    • getConsumedResults

      protected abstract int getConsumedResults(int consumedRes, T event)
      Gets the amount of consumed results after the designated amount of results have been consumed together with the results in the designated sharing event. This is called after a sharing event source has handled the event and signalled its consumption. In this case the window of available result entries usually has to be moved to the next result entries.
      Integer.MAX_VALUE indicates the complete consumption of the result entries.
      Parameters:
      consumedRes - The amount of consumed results before the handling of the designated sharing event.
      event - The sharing event that has been handled and consumed by the last sharing event source.
      Returns:
      Whether all result entries have been consumed yet and how many of them. Integer.MAX_VALUE indicates that all result entries have been consumed.