com.espertech.esper.epl.named
Class NamedWindowTailView

java.lang.Object
  extended by com.espertech.esper.view.ViewSupport
      extended by com.espertech.esper.epl.named.NamedWindowTailView
All Implemented Interfaces:
EventCollection, View, Viewable, Iterable<EventBean>

public class NamedWindowTailView
extends ViewSupport
implements Iterable<EventBean>

This view is hooked into a named window's view chain as the last view and handles dispatching of named window insert and remove stream results via NamedWindowService to consuming statements.


Field Summary
 
Fields inherited from class com.espertech.esper.view.ViewSupport
parent
 
Constructor Summary
NamedWindowTailView(EventType eventType, NamedWindowService namedWindowService, NamedWindowRootView namedWindowRootView, EPStatementHandle createWindowStmtHandle, StatementResultService statementResultService, ValueAddEventProcessor revisionProcessor)
          Ctor.
 
Method Summary
 NamedWindowConsumerView addConsumer(List<ExprNode> filterList, EPStatementHandle statementHandle, StatementStopService statementStopService)
          Adds a consumer view keeping the consuming statement's handle and lock to coordinate dispatches.
 void destroy()
          Destroy the view.
 EventType getEventType()
          Provides metadata information about the type of object the event collection contains.
 boolean isParentBatchWindow()
          Returns true to indicate that the data window view is a batch view.
 Iterator<EventBean> iterator()
          Allows iteration through all elements in this event collection.
 void removeConsumer(NamedWindowConsumerView namedWindowConsumerView)
          Called by the consumer view to indicate it was stopped or destroyed, such that the consumer can be deregistered and further dispatches disregard this consumer.
 Collection<EventBean> snapshot()
          Returns a snapshot of window contents, thread-safely
 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, toString, wait, wait, wait
 

Constructor Detail

NamedWindowTailView

public NamedWindowTailView(EventType eventType,
                           NamedWindowService namedWindowService,
                           NamedWindowRootView namedWindowRootView,
                           EPStatementHandle createWindowStmtHandle,
                           StatementResultService statementResultService,
                           ValueAddEventProcessor revisionProcessor)
Ctor.

Parameters:
eventType - the event type of the named window
namedWindowService - the service for dispatches to consumers for hooking into the dispatch loop
namedWindowRootView - the root data window view for indicating remove stream events to be removed from possible on-delete indexes
createWindowStmtHandle - statement handle for the statement that created the named window, for safe iteration
statementResultService - for coordinating on whether insert and remove stream events should be posted
revisionProcessor - handles update events
Method Detail

isParentBatchWindow

public boolean isParentBatchWindow()
Returns true to indicate that the data window view is a batch view.

Returns:
true if batch view

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

addConsumer

public NamedWindowConsumerView addConsumer(List<ExprNode> filterList,
                                           EPStatementHandle statementHandle,
                                           StatementStopService statementStopService)
Adds a consumer view keeping the consuming statement's handle and lock to coordinate dispatches.

Parameters:
statementHandle - the statement handle
statementStopService - for when the consumer stops, to unregister the consumer
filterList - is a list of filter expressions
Returns:
consumer representative view

removeConsumer

public void removeConsumer(NamedWindowConsumerView namedWindowConsumerView)
Called by the consumer view to indicate it was stopped or destroyed, such that the consumer can be deregistered and further dispatches disregard this consumer.

Parameters:
namedWindowConsumerView - is the consumer representative view

getEventType

public 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

iterator

public 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.

snapshot

public Collection<EventBean> snapshot()
Returns a snapshot of window contents, thread-safely

Returns:
window contents

destroy

public void destroy()
Destroy the view.


© 2007 EsperTech Inc.
All rights reserved.
Visit us at espertech.com