org.wso2.siddhi.core.query.processor.stream.window

Class FrequentWindowProcessor

java.lang.Object

org.wso2.siddhi.core.query.processor.stream.AbstractStreamProcessor

org.wso2.siddhi.core.query.processor.stream.window.WindowProcessor

org.wso2.siddhi.core.query.processor.stream.window.FrequentWindowProcessor

All Implemented Interfaces:

Processor, FindableProcessor, EternalReferencedHolder, Snapshotable

public class FrequentWindowProcessor
extends WindowProcessor
implements FindableProcessor

Implementation of WindowProcessor which represent a Window operating based on frequency of incoming events. Implementation uses a counting algorithm based on Misra-Gries counting algorithm

Field Summary

Fields inherited from class org.wso2.siddhi.core.query.processor.stream.AbstractStreamProcessor

additionalAttributes, attributeExpressionExecutors, attributeExpressionLength, complexEventPopulater, elementId, inputDefinition, nextProcessor, queryName, siddhiAppContext, streamEventCloner

Constructor Summary

Constructors

Constructor and Description
FrequentWindowProcessor()

Method Summary

Modifier and Type	Method and Description
CompiledCondition	compileCondition(org.wso2.siddhi.query.api.expression.Expression condition, MatchingMetaInfoHolder matchingMetaInfoHolder, SiddhiAppContext siddhiAppContext, List<VariableExpressionExecutor> variableExpressionExecutors, Map<String,Table> tableMap, String queryName) To construct a finder having the capability of finding events at the processor that corresponds to the incoming matchingEvent and the given matching expression logic.
Map<String,Object>	currentState() Used to collect the serializable state of the processing element, that need to be persisted for the reconstructing the element to the same state on a different point of time
StreamEvent	find(StateEvent matchingEvent, CompiledCondition compiledCondition) To find events from the processor event pool, that the matches the matchingEvent based on finder logic.
protected void	init(ExpressionExecutor[] attributeExpressionExecutors, ConfigReader configReader, boolean outputExpectsExpiredEvents, SiddhiAppContext siddhiAppContext) The init method of the WindowProcessor, this method will be called before other methods
protected void	process(ComplexEventChunk<StreamEvent> streamEventChunk, Processor nextProcessor, StreamEventCloner streamEventCloner) The main processing method that will be called upon event arrival
void	restoreState(Map<String,Object> state) Used to restore serialized state of the processing element, for reconstructing the element to the same state as if was on a previous point of time.
void	start() This will be called only once and this can be used to acquire required resources for the processing element.
void	stop() This will be called only once and this can be used to release the acquired resources for processing.

Methods inherited from class org.wso2.siddhi.core.query.processor.stream.window.WindowProcessor

init, processEventChunk

Methods inherited from class org.wso2.siddhi.core.query.processor.stream.AbstractStreamProcessor

cloneProcessor, constructStreamEventPopulater, getElementId, getNextProcessor, initProcessor, process, setNextProcessor, setStreamEventCloner, setToLast

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FrequentWindowProcessor

public FrequentWindowProcessor()

Method Detail

init

protected void init(ExpressionExecutor[] attributeExpressionExecutors,
                    ConfigReader configReader,
                    boolean outputExpectsExpiredEvents,
                    SiddhiAppContext siddhiAppContext)

Description copied from class: WindowProcessor

The init method of the WindowProcessor, this method will be called before other methods

Specified by:

init in class WindowProcessor

Parameters:

attributeExpressionExecutors - the executors of each function parameters

configReader - the config reader of window

outputExpectsExpiredEvents - is expired event out put or not

siddhiAppContext - the context of the siddhi app

process

protected void process(ComplexEventChunk<StreamEvent> streamEventChunk,
                       Processor nextProcessor,
                       StreamEventCloner streamEventCloner)

Description copied from class: WindowProcessor

The main processing method that will be called upon event arrival

Specified by:

process in class WindowProcessor

Parameters:

streamEventChunk - the stream event chunk that need to be processed

nextProcessor - the next processor to which the success events need to be passed

streamEventCloner - helps to clone the incoming event for local storage or modification

start

public void start()

Description copied from interface: EternalReferencedHolder

This will be called only once and this can be used to acquire required resources for the processing element. This will be called after initializing the system and before starting to process the events.

Specified by:

start in interface EternalReferencedHolder

stop

public void stop()

Description copied from interface: EternalReferencedHolder

This will be called only once and this can be used to release the acquired resources for processing. This will be called before shutting down the system.

Specified by:

stop in interface EternalReferencedHolder

currentState

public Map<String,Object> currentState()

Description copied from interface: Snapshotable

Used to collect the serializable state of the processing element, that need to be persisted for the reconstructing the element to the same state on a different point of time

Specified by:

currentState in interface Snapshotable

Returns:

stateful objects of the processing element as an array

restoreState

public void restoreState(Map<String,Object> state)

Description copied from interface: Snapshotable

Used to restore serialized state of the processing element, for reconstructing the element to the same state as if was on a previous point of time.

Specified by:

restoreState in interface Snapshotable

Parameters:

state - the stateful objects of the element as an array on the same order provided by currentState().

find

public StreamEvent find(StateEvent matchingEvent,
                        CompiledCondition compiledCondition)

Description copied from interface: FindableProcessor

To find events from the processor event pool, that the matches the matchingEvent based on finder logic.

Specified by:

find in interface FindableProcessor

Parameters:

matchingEvent - the event to be matched with the events at the processor

compiledCondition - the execution element responsible for matching the corresponding events that matches the matchingEvent based on pool of events at Processor

Returns:

the matched events

compileCondition

public CompiledCondition compileCondition(org.wso2.siddhi.query.api.expression.Expression condition,
                                          MatchingMetaInfoHolder matchingMetaInfoHolder,
                                          SiddhiAppContext siddhiAppContext,
                                          List<VariableExpressionExecutor> variableExpressionExecutors,
                                          Map<String,Table> tableMap,
                                          String queryName)

Description copied from interface: FindableProcessor

To construct a finder having the capability of finding events at the processor that corresponds to the incoming matchingEvent and the given matching expression logic.

Specified by:

compileCondition in interface FindableProcessor

Parameters:

condition - the matching condition

matchingMetaInfoHolder - the meta structure of the incoming matchingEvent

siddhiAppContext - current siddhi app context

variableExpressionExecutors - the list of variable ExpressionExecutors already created

tableMap - map of event tables

queryName - query name of findable processor belongs to.

Returns:

compiled Condition having the capability of matching events against the incoming matchingEvent