com.espertech.esper.view.window
Class ExpressionWindowView

java.lang.Object
  com.espertech.esper.view.ViewSupport
      com.espertech.esper.view.window.ExpressionViewBase
          com.espertech.esper.view.window.ExpressionWindowView

All Implemented Interfaces:

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

public class ExpressionWindowView
extends ExpressionViewBase

This view is a moving window extending the into the past until the expression passed to it returns false.

Field Summary

protected java.util.ArrayDeque<ExpressionWindowTimestampEventPair>

window

Fields inherited from class com.espertech.esper.view.window.ExpressionViewBase

agentInstanceContext, aggregateNodes, aggregationService, builtinEventProps, eventsPerStream, expiryExpression, scheduleHandle, scheduleSlot, variableNames, viewUpdatedCollection

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

EMPTY_VIEW_ARRAY, parent

Constructor Summary

ExpressionWindowView(ExpressionWindowViewFactory dataWindowViewFactory, ViewUpdatedCollection viewUpdatedCollection, ExprEvaluator expiryExpression, AggregationServiceFactoryDesc aggregationServiceFactoryDesc, ObjectArrayEventBean builtinEventProps, java.util.Set<java.lang.String> variableNames, AgentInstanceViewFactoryChainContext agentInstanceContext)
Constructor creates a moving window extending the specified number of elements into the past.

Method Summary

View	cloneView() Duplicates the view.
ViewFactory	getViewFactory()
java.lang.String	getViewName()
java.util.ArrayDeque<ExpressionWindowTimestampEventPair>	getWindow()
void	internalHandleAdd(ExpressionWindowTimestampEventPair pair)
void	internalHandleExpired(ExpressionWindowTimestampEventPair pair)
void	internalHandleRemoved(ExpressionWindowTimestampEventPair pair)
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.
void	scheduleCallback() Implemented to check the expiry expression.
void	update(EventBean[] newData, EventBean[] oldData) Notify that data has been added or removed from the Viewable parent.
void	update(java.lang.Object newValue, java.lang.Object oldValue) Indicate a change in variable value.
void	visitView(ViewDataVisitor viewDataVisitor)

Methods inherited from class com.espertech.esper.view.window.ExpressionViewBase

getAggregationService, getEventType, getViewUpdatedCollection, stop, stopScheduleAndVar, stopView, toString

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

window

protected final java.util.ArrayDeque<ExpressionWindowTimestampEventPair> window

Constructor Detail

ExpressionWindowView

public ExpressionWindowView(ExpressionWindowViewFactory dataWindowViewFactory,
                            ViewUpdatedCollection viewUpdatedCollection,
                            ExprEvaluator expiryExpression,
                            AggregationServiceFactoryDesc aggregationServiceFactoryDesc,
                            ObjectArrayEventBean builtinEventProps,
                            java.util.Set<java.lang.String> variableNames,
                            AgentInstanceViewFactoryChainContext agentInstanceContext)

Constructor creates a moving window extending the specified number of elements into the past.

Parameters:

dataWindowViewFactory - for copying this view in a group-by

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

variableNames - variable names

Method Detail

getViewName

public java.lang.String getViewName()

Specified by:

getViewName in class ExpressionViewBase

cloneView

public View cloneView()

Description copied from interface: CloneableView

Duplicates the view.

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

isEmpty

public boolean isEmpty()

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

Returns:

true if empty

scheduleCallback

public void scheduleCallback()

Description copied from class: ExpressionViewBase

Implemented to check the expiry expression.

Specified by:

scheduleCallback in class ExpressionViewBase

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

internalHandleRemoved

public void internalHandleRemoved(ExpressionWindowTimestampEventPair pair)

internalHandleExpired

public void internalHandleExpired(ExpressionWindowTimestampEventPair pair)

internalHandleAdd

public void internalHandleAdd(ExpressionWindowTimestampEventPair pair)

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 void update(java.lang.Object newValue,
                   java.lang.Object oldValue)

Description copied from interface: VariableChangeCallback

Indicate a change in variable value.

Specified by:

update in interface VariableChangeCallback

Overrides:

update in class ExpressionViewBase

Parameters:

newValue - new value

oldValue - old value

getWindow

public java.util.ArrayDeque<ExpressionWindowTimestampEventPair> getWindow()

visitView

public void visitView(ViewDataVisitor viewDataVisitor)

getViewFactory

public ViewFactory getViewFactory()