/**************************************************************************************
* Copyright (C) 2008 EsperTech, Inc. All rights reserved. *
* http://esper.codehaus.org *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
**************************************************************************************/
package com.espertech.esper.view.window;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.client.EventType;
import com.espertech.esper.collection.ViewUpdatedCollection;
import com.espertech.esper.core.context.util.AgentInstanceViewFactoryChainContext;
import com.espertech.esper.core.service.EPStatementHandleCallback;
import com.espertech.esper.core.service.ExtensionServicesContext;
import com.espertech.esper.epl.expression.ExprTimePeriodEvalDeltaConst;
import com.espertech.esper.metrics.instrumentation.InstrumentationHelper;
import com.espertech.esper.schedule.ScheduleHandleCallback;
import com.espertech.esper.schedule.ScheduleSlot;
import com.espertech.esper.util.StopCallback;
import com.espertech.esper.view.*;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.util.ArrayList;
import java.util.Iterator;
/**
* A data window view that holds events in a stream and only removes events from a stream (rstream) if
* no more events arrive for a given time interval.
* <p>
* No batch version of the view exists as the batch version is simply the remove stream of this view, which removes
* in batches.
* <p>
* The view is continuous, the insert stream consists of arriving events. The remove stream
* only posts current window contents when no more events arrive for a given timer interval.
*/
public class TimeAccumView extends ViewSupport implements CloneableView, DataWindowView, StoppableView, StopCallback
{
// View parameters
private final TimeAccumViewFactory factory;
protected final AgentInstanceViewFactoryChainContext agentInstanceContext;
protected final ExprTimePeriodEvalDeltaConst timeDeltaComputation;
protected final ViewUpdatedCollection viewUpdatedCollection;
protected final ScheduleSlot scheduleSlot;
// Current running parameters
protected ArrayList<EventBean> currentBatch = new ArrayList<EventBean>();
protected long callbackScheduledTime;
protected EPStatementHandleCallback handle;
/**
* Constructor.
* @param viewUpdatedCollection is a collection that the view must update when receiving events
* @param timeBatchViewFactory fr copying this view in a group-by
* @param agentInstanceContext is required view services
*/
public TimeAccumView(TimeAccumViewFactory timeBatchViewFactory,
AgentInstanceViewFactoryChainContext agentInstanceContext,
ExprTimePeriodEvalDeltaConst timeDeltaComputation,
ViewUpdatedCollection viewUpdatedCollection)
{
this.agentInstanceContext = agentInstanceContext;
this.factory = timeBatchViewFactory;
this.timeDeltaComputation = timeDeltaComputation;
this.viewUpdatedCollection = viewUpdatedCollection;
this.scheduleSlot = agentInstanceContext.getStatementContext().getScheduleBucket().allocateSlot();
ScheduleHandleCallback callback = new ScheduleHandleCallback() {
public void scheduledTrigger(ExtensionServicesContext extensionServicesContext)
{
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().qViewScheduledEval(TimeAccumView.this, TimeAccumView.this.factory.getViewName());}
TimeAccumView.this.sendRemoveStream();
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().aViewScheduledEval();}
}
};
handle = new EPStatementHandleCallback(agentInstanceContext.getEpStatementAgentInstanceHandle(), callback);
agentInstanceContext.addTerminationCallback(this);
}
public View cloneView()
{
return factory.makeView(agentInstanceContext);
}
public ExprTimePeriodEvalDeltaConst getTimeDeltaComputation() {
return timeDeltaComputation;
}
public final EventType getEventType()
{
return parent.getEventType();
}
public void update(EventBean[] newData, EventBean[] oldData)
{
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().qViewProcessIRStream(this, factory.getViewName(), newData, oldData);}
// we don't care about removed data from a prior view
if ((newData == null) || (newData.length == 0))
{
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().aViewProcessIRStream();}
return;
}
// If we have an empty window about to be filled for the first time, addSchedule a callback
boolean removeSchedule = false;
boolean addSchedule = false;
long timestamp = agentInstanceContext.getStatementContext().getSchedulingService().getTime();
if (!currentBatch.isEmpty())
{
// check if we need to reschedule
long callbackTime = timestamp + timeDeltaComputation.deltaMillisecondsAdd(timestamp);
if (callbackTime != callbackScheduledTime)
{
removeSchedule = true;
addSchedule = true;
}
}
else
{
addSchedule = true;
}
if (removeSchedule)
{
agentInstanceContext.getStatementContext().getSchedulingService().remove(handle, scheduleSlot);
}
if (addSchedule)
{
long msecIntervalSize = timeDeltaComputation.deltaMillisecondsAdd(timestamp);
agentInstanceContext.getStatementContext().getSchedulingService().add(msecIntervalSize, handle, scheduleSlot);
callbackScheduledTime = msecIntervalSize + timestamp;
}
// add data points to the window
for (EventBean newEvent : newData) {
currentBatch.add(newEvent);
}
// forward insert stream to child views
if (viewUpdatedCollection != null)
{
viewUpdatedCollection.update(newData, null);
}
// update child views
if (this.hasViews())
{
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().qViewIndicate(this, factory.getViewName(), newData, null);}
updateChildren(newData, null);
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().aViewIndicate();}
}
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().aViewProcessIRStream();}
}
/**
* This method sends the remove stream for all accumulated events.
*/
protected void sendRemoveStream()
{
callbackScheduledTime = -1;
// If there are child views and the batch was filled, fireStatementStopped update method
if (this.hasViews())
{
// Convert to object arrays
EventBean[] oldData = null;
if (!currentBatch.isEmpty())
{
oldData = currentBatch.toArray(new EventBean[currentBatch.size()]);
}
// Post old data
if (viewUpdatedCollection != null)
{
viewUpdatedCollection.update(null, oldData);
}
if (oldData != null)
{
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().qViewIndicate(this, factory.getViewName(), null, oldData);}
updateChildren(null, oldData);
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().aViewIndicate();}
}
}
currentBatch.clear();
}
/**
* Returns true if the window is empty, or false if not empty.
* @return true if empty
*/
public boolean isEmpty()
{
return currentBatch.isEmpty();
}
public final Iterator<EventBean> iterator()
{
return currentBatch.iterator();
}
public final String toString()
{
return this.getClass().getName();
}
public void stopView() {
stopSchedule();
agentInstanceContext.removeTerminationCallback(this);
}
public void stop() {
stopSchedule();
}
public void stopSchedule() {
if (handle != null) {
agentInstanceContext.getStatementContext().getSchedulingService().remove(handle, scheduleSlot);
}
}
public void visitView(ViewDataVisitor viewDataVisitor) {
viewDataVisitor.visitPrimary(currentBatch, true, factory.getViewName(), null);
}
private static final Log log = LogFactory.getLog(TimeAccumView.class);
}