com.espertech.esper.view.window

Class TimeLengthBatchView

java.lang.Object

com.espertech.esper.view.ViewSupport

com.espertech.esper.view.window.TimeLengthBatchView

All Implemented Interfaces:

StopCallback, CloneableView, DataWindowView, EventCollection, GroupableView, StoppableView, View, Viewable, ViewDataVisitable, Iterable<EventBean>

public class TimeLengthBatchView
extends ViewSupport
implements CloneableView, StoppableView, StopCallback, DataWindowView

A data view that aggregates events in a stream and releases them in one batch if either one of these conditions is reached, whichever comes first: One, a time interval passes. Two, a given number of events collected.

The view releases the batched events after the interval or number of events as new data to child views. The prior batch if not empty is released as old data to child view. The view DOES release intervals with no old or new data. It does not collect old data published by a parent view. If there are no events in the current and prior batch, the view WILL invoke the update method of child views.

The view starts the first interval when the view is created.

Field Summary

Fields

Modifier and Type	Field and Description
protected AgentInstanceViewFactoryChainContext	agentInstanceContext
protected Long	callbackScheduledTime
protected ArrayList<EventBean>	currentBatch
protected EPStatementHandleCallback	handle
protected boolean	isForceOutput
protected boolean	isStartEager
protected ArrayList<EventBean>	lastBatch
protected long	numberOfEvents
protected long	scheduleSlot
protected ExprTimePeriodEvalDeltaConst	timeDeltaComputation
protected ViewUpdatedCollection	viewUpdatedCollection

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

EMPTY_VIEW_ARRAY, parent

Constructor Summary

Constructors

Constructor and Description
TimeLengthBatchView(TimeLengthBatchViewFactory timeBatchViewFactory, AgentInstanceViewFactoryChainContext agentInstanceContext, ExprTimePeriodEvalDeltaConst timeDeltaComputation, long numberOfEvents, boolean forceOutput, boolean isStartEager, ViewUpdatedCollection viewUpdatedCollection) Constructor.

Method Summary

Modifier and Type	Method and Description
View	cloneView() Duplicates the view.
EventType	getEventType() Provides metadata information about the type of object the event collection contains.
long	getNumberOfEvents() Returns the length of the batch.
ExprTimePeriodEvalDeltaConst	getTimeDeltaComputation()
ViewFactory	getViewFactory()
void	internalHandleAdded(EventBean newEvent)
void	internalHandleRemoved(EventBean eventBean)
boolean	isEmpty() Returns true if the window is empty, or false if not empty.
boolean	isForceOutput() True for force-output.
boolean	isStartEager() True for start-eager.
Iterator<EventBean>	iterator() Allows iteration through all elements in this event collection.
protected void	scheduleCallback(long delta)
protected void	sendBatch(boolean isFromSchedule) This method updates child views and clears the batch of events.
void	stop() Stops the underlying resources.
void	stopSchedule()
void	stopView()
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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

agentInstanceContext

protected final AgentInstanceViewFactoryChainContext agentInstanceContext

timeDeltaComputation

protected final ExprTimePeriodEvalDeltaConst timeDeltaComputation

numberOfEvents

protected final long numberOfEvents

isForceOutput

protected final boolean isForceOutput

isStartEager

protected final boolean isStartEager

viewUpdatedCollection

protected final ViewUpdatedCollection viewUpdatedCollection

scheduleSlot

protected final long scheduleSlot

lastBatch

protected ArrayList<EventBean> lastBatch

currentBatch

protected ArrayList<EventBean> currentBatch

callbackScheduledTime

protected Long callbackScheduledTime

handle

protected EPStatementHandleCallback handle

Constructor Detail

TimeLengthBatchView

public TimeLengthBatchView(TimeLengthBatchViewFactory timeBatchViewFactory,
                           AgentInstanceViewFactoryChainContext agentInstanceContext,
                           ExprTimePeriodEvalDeltaConst timeDeltaComputation,
                           long numberOfEvents,
                           boolean forceOutput,
                           boolean isStartEager,
                           ViewUpdatedCollection viewUpdatedCollection)

Constructor.

Parameters:

numberOfEvents - is the event count before the batch fires off

viewUpdatedCollection - is a collection that the view must update when receiving events

timeBatchViewFactory - for copying this view in a group-by

forceOutput - is true if the batch should produce empty output if there is no value to output following time intervals

isStartEager - is true for start-eager

agentInstanceContext - context

timeDeltaComputation - time delta eval

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

Returns:

cloned view

getTimeDeltaComputation

public ExprTimePeriodEvalDeltaConst getTimeDeltaComputation()

isForceOutput

public boolean isForceOutput()

True for force-output.

Returns:

indicates force-output

getNumberOfEvents

public long getNumberOfEvents()

Returns the length of the batch.

Returns:

maximum number of events allowed before window gets flushed

isStartEager

public boolean isStartEager()

True for start-eager.

Returns:

indicates start-eager

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

internalHandleAdded

public void internalHandleAdded(EventBean newEvent)

internalHandleRemoved

public void internalHandleRemoved(EventBean eventBean)

sendBatch

protected void sendBatch(boolean isFromSchedule)

This method updates child views and clears the batch of events. We cancel and old callback and schedule a new callback at this time if there were events in the batch.

Parameters:

isFromSchedule - true if invoked from a schedule, false if not

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: 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 Iterable<EventBean>

Returns:

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

toString

public final String toString()

Overrides:

toString in class Object

scheduleCallback

protected void scheduleCallback(long delta)

stopView

public void stopView()

stop

public void stop()

Description copied from interface: StopCallback

Stops the underlying resources.

Specified by:

stop in interface StopCallback

stopSchedule

public void stopSchedule()

visitView

public void visitView(ViewDataVisitor viewDataVisitor)

Specified by:

visitView in interface ViewDataVisitable

getViewFactory

public ViewFactory getViewFactory()

Specified by:

getViewFactory in interface GroupableView