com.espertech.esper.view.window
Class TimeLengthBatchView

java.lang.Object
  extended by com.espertech.esper.view.ViewSupport
      extended by com.espertech.esper.view.window.TimeLengthBatchView
All Implemented Interfaces:
CloneableView, DataWindowView, EventCollection, View, Viewable, Iterable<EventBean>

public final class TimeLengthBatchView
extends ViewSupport
implements CloneableView, 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 inherited from class com.espertech.esper.view.ViewSupport
parent
 
Constructor Summary
TimeLengthBatchView(TimeLengthBatchViewFactory timeBatchViewFactory, StatementContext statementContext, long msecIntervalSize, long numberOfEvents, boolean forceOutput, boolean isStartEager, ViewUpdatedCollection viewUpdatedCollection)
          Constructor.
 
Method Summary
 View cloneView(StatementContext statementContext)
          Duplicates the view.
 EventType getEventType()
          Provides metadata information about the type of object the event collection contains.
 long getMsecIntervalSize()
          Returns the interval size in milliseconds.
 long getNumberOfEvents()
          Returns the length of the batch.
 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 sendBatch(boolean isFromSchedule)
          This method updates child views and clears the batch of events.
 String toString()
           
 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, dumpChildViews, dumpUpdateParams, dumpUpdateParams, findDescendent, getParent, getViews, hasViews, 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, removeView
 

Constructor Detail

TimeLengthBatchView

public TimeLengthBatchView(TimeLengthBatchViewFactory timeBatchViewFactory,
                           StatementContext statementContext,
                           long msecIntervalSize,
                           long numberOfEvents,
                           boolean forceOutput,
                           boolean isStartEager,
                           ViewUpdatedCollection viewUpdatedCollection)
Constructor.

Parameters:
msecIntervalSize - is the number of milliseconds to batch events for
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
statementContext - is required view services
isStartEager - is true for start-eager
Method Detail

cloneView

public View cloneView(StatementContext statementContext)
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
Parameters:
statementContext - is services for the view
Returns:
duplicated view

getMsecIntervalSize

public final long getMsecIntervalSize()
Returns the interval size in milliseconds.

Returns:
batch size

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 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

sendBatch

protected final 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

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