com.espertech.esper.view.internal
Class BufferView

java.lang.Object
  com.espertech.esper.view.ViewSupport
      com.espertech.esper.view.internal.BufferView

All Implemented Interfaces:

EventCollection, View, Viewable, java.lang.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.

Field Summary

Fields inherited from class com.espertech.esper.view.ViewSupport

EMPTY_VIEW_ARRAY, parent

Constructor Summary

BufferView(int streamId)
Ctor.

Method Summary

EventType	getEventType() Provides metadata information about the type of object the event collection contains.
FlushedEventBuffer	getNewDataBuffer() Returns the buffer for new data.
java.util.Iterator<EventBean>	iterator() Allows iteration through all elements in this event collection.
void	setObserver(BufferObserver observer) Set the observer for indicating new and old data.
void	update(EventBean[] newData, EventBean[] oldData) Notify that data has been added or removed from the Viewable parent.

Methods inherited from class com.espertech.esper.view.ViewSupport

addView, addView, dumpChildViews, dumpUpdateParams, dumpUpdateParams, findDescendent, findViewIndex, getParent, getViews, hasViews, removeAllViews, removeView, removeView, setParent, updateChildren, updateChildren

Methods inherited from class java.lang.Object

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

Constructor Detail

BufferView

public BufferView(int streamId)

Ctor.

Parameters:

streamId - - number of the stream for which the view buffers the generated events.

Method Detail

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: EventCollection

Provides metadata information about the type of object the event collection contains.

Returns:

metadata for the objects in the collection

iterator

public final java.util.Iterator<EventBean> iterator()

Description copied from interface: EventCollection

Allows iteration through all elements in this event collection. 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