com.espertech.esper.view.window
Class LengthBatchView

java.lang.Object
  com.espertech.esper.view.ViewSupport
      com.espertech.esper.view.window.LengthBatchView

All Implemented Interfaces:

CloneableView, DataWindowView, EventCollection, GroupableView, View, Viewable, ViewDataVisitable, java.lang.Iterable<EventBean>

public class LengthBatchView
extends ViewSupport
implements CloneableView, 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 Summary

protected AgentInstanceViewFactoryChainContext	agentInstanceViewFactoryContext
protected java.util.ArrayDeque<EventBean>	currentBatch
protected java.util.ArrayDeque<EventBean>	lastBatch

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

EMPTY_VIEW_ARRAY, parent

Constructor Summary

LengthBatchView(AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext, LengthBatchViewFactory lengthBatchViewFactory, int size, ViewUpdatedCollection viewUpdatedCollection)
Constructor.

Method Summary

View	cloneView() Duplicates the view.
EventType	getEventType() Provides metadata information about the type of object the event collection contains.
int	getSize() Returns the number of events to batch (data window size).
ViewFactory	getViewFactory()
boolean	isEmpty() Returns true if the window is empty, or false if not empty.
java.util.Iterator<EventBean>	iterator() Allows iteration through all elements in this event collection.
protected void	sendBatch() This method updates child views and clears the batch of events.
java.lang.String	toString()
void	update(EventBean[] newData, EventBean[] oldData) Notify that data has been added or removed from the Viewable parent.
void	visitView(ViewDataVisitor viewDataVisitor)

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, wait, wait, wait

Methods inherited from interface com.espertech.esper.view.View

getParent, setParent

Methods inherited from interface com.espertech.esper.view.Viewable

addView, getViews, hasViews, removeAllViews, removeView

Field Detail

agentInstanceViewFactoryContext

protected final AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext

lastBatch

protected java.util.ArrayDeque<EventBean> lastBatch

currentBatch

protected java.util.ArrayDeque<EventBean> currentBatch

Constructor Detail

LengthBatchView

public LengthBatchView(AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext,
                       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

Method Detail

cloneView

public View cloneView()

Description copied from interface: CloneableView

Duplicates the view.

Expected to return a same view in initialized state for grouping.

Specified by:

cloneView in interface CloneableView

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: EventCollection

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

Specified by:

getEventType in interface EventCollection

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 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.

Specified by:

iterator in interface EventCollection

Specified by:

iterator in interface java.lang.Iterable<EventBean>

Returns:

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

toString

public final java.lang.String toString()

Overrides:

toString in class java.lang.Object

visitView

public void visitView(ViewDataVisitor viewDataVisitor)

Specified by:

visitView in interface ViewDataVisitable

getViewFactory

public ViewFactory getViewFactory()

Specified by:

getViewFactory in interface GroupableView