net.esper.view.window
Class LengthWindowView

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

public final class LengthWindowView
extends ViewSupport
implements DataWindowView, CloneableView

This view is a moving window extending the specified number of elements into the past.


Field Summary
 
Fields inherited from class net.esper.view.ViewSupport
parent
 
Constructor Summary
LengthWindowView(LengthWindowViewFactory lengthWindowViewFactory, int size, ViewUpdatedCollection viewUpdatedCollection)
          Constructor creates a moving window extending the specified number of elements into the past.
 
Method Summary
 View cloneView(StatementContext statementContext)
          Duplicates the view.
 EventType getEventType()
          Provides metadata information about the type of object the event collection contains.
 int getSize()
          Returns the size of the length window.
 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.
 Iterator<EventBean> iterator()
          Allows iteration through all elements in this event collection.
 String toString()
           
 void update(EventBean[] newData, EventBean[] oldData)
          Notify that data has been added or removed from the Viewable parent.
 
Methods inherited from class net.esper.view.ViewSupport
addView, dumpChildViews, 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 net.esper.view.View
getParent, setParent
 
Methods inherited from interface net.esper.view.Viewable
addView, getViews, hasViews, removeView
 

Constructor Detail

LengthWindowView

public LengthWindowView(LengthWindowViewFactory lengthWindowViewFactory,
                        int size,
                        ViewUpdatedCollection viewUpdatedCollection)
Constructor creates a moving window extending the specified number of elements into the past.

Parameters:
size - is the specified number of elements into the past
viewUpdatedCollection - is a collection that the view must update when receiving events
lengthWindowViewFactory - for copying this view in a group-by
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

isEmpty

public boolean isEmpty()
Returns true if the window is empty, or false if not empty.

Returns:
true if empty

getSize

public final int getSize()
Returns the size of the length window.

Returns:
size of length window

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

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 Iterable<EventBean>
Specified by:
iterator in interface EventCollection
Returns:
an iterator which will go through all current elements in the collection.

toString

public final String toString()
Overrides:
toString in class Object