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

Class BufferView

java.lang.Object
com.espertech.esper.common.internal.view.core.ViewSupport
com.espertech.esper.common.internal.view.util.BufferView
All Implemented Interfaces:
View, Viewable, Iterable<EventBean>
public final class BufferView extends ViewSupport
A view that acts as an adapter between views and update listeners. The view can be added to a parent view. When the parent view publishes data, the view will forward the data to the UpdateListener implementation that has been supplied. If no UpdateListener has been supplied, then the view will cache the last data published by the parent view.

  • Constructor Details

    • BufferView

      public BufferView(int streamId)
      Ctor.
      Parameters:
      streamId - - number of the stream for which the view buffers the generated events.

  • Method Details

    • setObserver

      public void setObserver(BufferObserver observer)
      Set the observer for indicating new and old data.
      Parameters:
      observer - to indicate new and old events

    • getEventType

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

    • 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.
      Returns:
      an iterator which will go through all current elements in the collection.

    • update

      public final 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.

      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

    • getNewDataBuffer

      public FlushedEventBuffer getNewDataBuffer()
      Returns the buffer for new data.
      Returns:
      new data buffer