Package com.espertech.esper.common.internal.view.lengthbatch

Class LengthBatchView

java.lang.Object
com.espertech.esper.common.internal.view.core.ViewSupport
com.espertech.esper.common.internal.view.lengthbatch.LengthBatchView
All Implemented Interfaces:
DataWindowView, View, Viewable, ViewDataVisitable, Iterable<EventBean>
public class LengthBatchView extends ViewSupport implements DataWindowView
A data view that aggregates events in a stream and releases them in one batch when a maximum number of events has been collected.

The view works similar to a length_window but is not continuous, and similar to a time_batch however is not time-based but reacts to the number of events.

The view releases the batched events, when a certain number of batched events has been reached or exceeded, as new data to child views. The prior batch if not empty is released as old data to any child views. The view doesn't release intervals with no old or new data. It also does not collect old data published by a parent view.

If there are no events in the current and prior batch, the view will not invoke the update method of child views.

  • Field Details

  • Constructor Details

    • LengthBatchView

      public LengthBatchView(AgentInstanceViewFactoryChainContext agentInstanceContext, LengthBatchViewFactory lengthBatchViewFactory, int size, ViewUpdatedCollection viewUpdatedCollection)
      Constructor.
      Parameters:
      size - is the number of events to batch
      viewUpdatedCollection - is a collection that the view must update when receiving events
      lengthBatchViewFactory - for copying this view in a group-by
      agentInstanceContext - context

  • Method Details

    • getSize

      public final int getSize()
      Returns the number of events to batch (data window size).
      Returns:
      batch size

    • getEventType

      public final EventType getEventType()
      Description copied from interface: Viewable
      Provides metadata information about the type of object the event collection contains.
      Specified by:
      getEventType in interface Viewable
      Returns:
      metadata for the objects in the collection

    • update

      public void update(EventBean[] newData, EventBean[] oldData)
      Description copied from interface: View
      Notify that data has been added or removed from the Viewable parent. The last object in the newData array of objects would be the newest object added to the parent view. The first object of the oldData array of objects would be the oldest object removed from the parent view.

      If the call to update contains new (inserted) data, then the first argument will be a non-empty list and the second will be empty. Similarly, if the call is a notification of deleted data, then the first argument will be empty and the second will be non-empty. Either the newData or oldData will be non-null. This method won't be called with both arguments being null, but either one could be null. The same is true for zero-length arrays. Either newData or oldData will be non-empty. If both are non-empty, then the update is a modification notification.

      When update() is called on a view by the parent object, the data in newData will be in the collection of the parent, and its data structures will be arranged to reflect that. The data in oldData will not be in the parent's data structures, and any access to the parent will indicate that that data is no longer there.

      Specified by:
      update in interface View
      Parameters:
      newData - is the new data that has been added to the parent view
      oldData - is the old data that has been removed from the parent view

    • sendBatch

      protected void sendBatch()
      This method updates child views and clears the batch of events.

    • isEmpty

      public boolean isEmpty()
      Returns true if the window is empty, or false if not empty.
      Returns:
      true if empty

    • iterator

      public final Iterator<EventBean> iterator()
      Description copied from interface: Viewable
      Allows iteration through all elements in this viewable. The iterator will return the elements in the collection in their natural order, or, if there is no natural ordering, in some unpredictable order.
      Specified by:
      iterator in interface Iterable<EventBean>
      Specified by:
      iterator in interface Viewable
      Returns:
      an iterator which will go through all current elements in the collection.

    • toString

      public final String toString()
      Overrides:
      toString in class Object

    • visitView

      public void visitView(ViewDataVisitor viewDataVisitor)
      Specified by:
      visitView in interface ViewDataVisitable

    • getViewFactory

      public ViewFactory getViewFactory()