com.ibm.streams.operator.window

Interface StreamWindowListener<T>

Type Parameters:

T - Type of the tuple being handled.

All Superinterfaces:

java.util.EventListener

All Known Subinterfaces:

CheckpointableWindowListener<O,T>

All Known Implementing Classes:

SortedTupleWindow, StatefulWindowListener, TumblingWindowSort

public interface StreamWindowListener<T>
extends java.util.EventListener

Handle StreamWindowEvents being generated by a StreamWindow.

If an implementation of this class also implements StateHandler then when it is registered as a window listener it is also registered as an operator's state handler

StatefulWindowListener provides a abstract implementation of this interface that correctly maintains window state including support for partitioned windows and per-partition state, and persistence of that state. Operators may extend StatefulWindowListener to implement their specific event handling without having to worry about per-partition state managment.

Correct ordering of calls tohandleEvent() is guaranteed by StreamWindow. Calls to handleEvent() are synchronous but may be invoked by different threads. Each previous handleEvent() happens-before any handleEvent() call to guarantee changes made in any previous handleEvent() are visible to the current call.

Method Summary

Methods

Modifier and Type	Method and Description
void	handleEvent(StreamWindowEvent<T> event) Handle a event from a StreamWindow.

Method Detail

handleEvent

void handleEvent(StreamWindowEvent<T> event)
                 throws java.lang.Exception

Handle a event from a StreamWindow.

Parameters:

event - Windowing event.

Throws:

java.lang.Exception - Exception processing an event.