com.espertech.esper.view.window
Class TimeWindowView

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

All Implemented Interfaces:

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

public class TimeWindowView
extends ViewSupport
implements CloneableView, DataWindowView, ScheduleAdjustmentCallback, StoppableView, StopCallback

This view is a moving timeWindow extending the specified amount of milliseconds into the past. The view bases the timeWindow on the time obtained from the scheduling service. All incoming events receive a timestamp and are placed in a sorted map by timestamp. The view does not care about old data published by the parent view to this view. Events leave or expire from the time timeWindow by means of a scheduled callback registered with the scheduling service. Thus child views receive updates containing old data only asynchronously as the system-time-based timeWindow moves on. However child views receive updates containing new data as soon as the new data arrives.

Field Summary

protected AgentInstanceViewFactoryChainContext	agentInstanceContext
protected TimeWindow	timeWindow

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

EMPTY_VIEW_ARRAY, parent

Constructor Summary

TimeWindowView(AgentInstanceViewFactoryChainContext agentInstanceContext, TimeWindowViewFactory timeWindowViewFactory, ExprTimePeriodEvalDeltaConst timeDeltaComputation, ViewUpdatedCollection viewUpdatedCollection)
Constructor.

Method Summary

void	adjust(long delta) Adjust expiration date.
View	cloneView() Duplicates the view.
protected void	expire() This method removes (expires) objects from the window and schedules a new callback for the time when the next oldest message would expire from the window.
EventType	getEventType() Provides metadata information about the type of object the event collection contains.
ExprTimePeriodEvalDeltaConst	getTimeDeltaComputation()
ViewFactory	getViewFactory()
ViewUpdatedCollection	getViewUpdatedCollection() Returns the (optional) collection handling random access to window contents for prior or previous events.
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	scheduleExpiryCallback()
void	stop() Stops the underlying resources.
void	stopSchedule()
void	stopView()
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

timeWindow

protected final TimeWindow timeWindow

agentInstanceContext

protected final AgentInstanceViewFactoryChainContext agentInstanceContext

Constructor Detail

TimeWindowView

public TimeWindowView(AgentInstanceViewFactoryChainContext agentInstanceContext,
                      TimeWindowViewFactory timeWindowViewFactory,
                      ExprTimePeriodEvalDeltaConst timeDeltaComputation,
                      ViewUpdatedCollection viewUpdatedCollection)

Constructor.

Parameters:

timeDeltaComputation - is the computation for the number of milliseconds before events gets pushed out of the timeWindow as oldData in the update method.

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

timeWindowViewFactory - for copying the view in a group-by

Method Detail

adjust

public void adjust(long delta)

Description copied from interface: ScheduleAdjustmentCallback

Adjust expiration date.

Specified by:

adjust in interface ScheduleAdjustmentCallback

Parameters:

delta - to adjust

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

getViewUpdatedCollection

public ViewUpdatedCollection getViewUpdatedCollection()

Returns the (optional) collection handling random access to window contents for prior or previous events.

Returns:

buffer for events

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 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.

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

expire

protected final void expire()

This method removes (expires) objects from the window and schedules a new callback for the time when the next oldest message would expire from the window.

scheduleExpiryCallback

protected void scheduleExpiryCallback()

getTimeDeltaComputation

public ExprTimePeriodEvalDeltaConst getTimeDeltaComputation()

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

isEmpty

public boolean isEmpty()

Returns true if the window is empty, or false if not empty.

Returns:

true if empty

stopView

public void stopView()

Specified by:

stopView in interface StoppableView

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