/**************************************************************************************
* 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.stat;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.client.EventType;
import com.espertech.esper.collection.SingleEventIterator;
import com.espertech.esper.core.StatementContext;
import com.espertech.esper.epl.expression.ExprEvaluator;
import com.espertech.esper.epl.expression.ExprNode;
import com.espertech.esper.event.EventAdapterService;
import com.espertech.esper.view.CloneableView;
import com.espertech.esper.view.View;
import com.espertech.esper.view.ViewFieldEnum;
import com.espertech.esper.view.ViewSupport;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
/**
* View for computing statistics, which the view exposes via fields representing the sum, count, standard deviation
* for sample and for population and variance.
*/
public final class UnivariateStatisticsView extends ViewSupport implements CloneableView
{
private final StatementContext statementContext;
private final EventType eventType;
private final ExprNode fieldExpression;
private final ExprEvaluator fieldExpressionEvaluator;
private final BaseStatisticsBean baseStatisticsBean = new BaseStatisticsBean();
private final StatViewAdditionalProps additionalProps;
private EventBean lastNewEvent;
private EventBean[] eventsPerStream = new EventBean[1];
private Object[] lastValuesEventNew;
/**
* Constructor requires the name of the field to use in the parent view to compute the statistics.
* @param fieldExpression is the expression to use to get numeric data points for this view to
* compute the statistics on.
* @param statementContext contains required view services
*/
public UnivariateStatisticsView(StatementContext statementContext, ExprNode fieldExpression, EventType eventType, StatViewAdditionalProps additionalProps)
{
this.statementContext = statementContext;
this.fieldExpression = fieldExpression;
this.fieldExpressionEvaluator = fieldExpression.getExprEvaluator();
this.eventType = eventType;
this.additionalProps = additionalProps;
}
public View cloneView(StatementContext statementContext)
{
return new UnivariateStatisticsView(statementContext, fieldExpression, eventType, additionalProps);
}
/**
* Returns field name of the field to report statistics on.
* @return field name
*/
public final ExprNode getFieldExpression()
{
return fieldExpression;
}
public final void update(EventBean[] newData, EventBean[] oldData)
{
// If we have child views, keep a reference to the old values, so we can update them as old data event.
EventBean oldDataMap = null;
if (lastNewEvent == null)
{
if (this.hasViews())
{
oldDataMap = populateMap(baseStatisticsBean, statementContext.getEventAdapterService(), eventType, additionalProps, lastValuesEventNew);
}
}
// add data points to the bean
if (newData != null)
{
for (int i = 0; i < newData.length; i++)
{
eventsPerStream[0] = newData[i];
Number pointnum = (Number) fieldExpressionEvaluator.evaluate(eventsPerStream, true, statementContext);
if (pointnum != null) {
double point = pointnum.doubleValue();
baseStatisticsBean.addPoint(point, 0);
}
}
if ((additionalProps != null) && (newData.length != 0)) {
if (lastValuesEventNew == null) {
lastValuesEventNew = new Object[additionalProps.getAdditionalExpr().length];
}
for (int val = 0; val < additionalProps.getAdditionalExpr().length; val++) {
lastValuesEventNew[val] = additionalProps.getAdditionalExpr()[val].evaluate(eventsPerStream, true, statementContext);
}
}
}
// remove data points from the bean
if (oldData != null)
{
for (int i = 0; i < oldData.length; i++)
{
eventsPerStream[0] = oldData[i];
Number pointnum = (Number) fieldExpressionEvaluator.evaluate(eventsPerStream, true, statementContext);
if (pointnum != null) {
double point = pointnum.doubleValue();
baseStatisticsBean.removePoint(point, 0);
}
}
}
// If there are child view, call update method
if (this.hasViews())
{
EventBean newDataMap = populateMap(baseStatisticsBean, statementContext.getEventAdapterService(), eventType, additionalProps, lastValuesEventNew);
if (lastNewEvent == null)
{
updateChildren(new EventBean[] {newDataMap}, new EventBean[] {oldDataMap});
}
else
{
updateChildren(new EventBean[] {newDataMap}, new EventBean[] {lastNewEvent});
}
lastNewEvent = newDataMap;
}
}
public final EventType getEventType()
{
return eventType;
}
public final Iterator<EventBean> iterator()
{
return new SingleEventIterator(populateMap(baseStatisticsBean,
statementContext.getEventAdapterService(),
eventType,
additionalProps, lastValuesEventNew));
}
public final String toString()
{
return this.getClass().getName() + " fieldExpression=" + fieldExpression;
}
public static EventBean populateMap(BaseStatisticsBean baseStatisticsBean,
EventAdapterService eventAdapterService,
EventType eventType,
StatViewAdditionalProps additionalProps,
Object[] lastNewValues)
{
Map<String, Object> result = new HashMap<String, Object>();
result.put(ViewFieldEnum.UNIVARIATE_STATISTICS__DATAPOINTS.getName(), baseStatisticsBean.getN());
result.put(ViewFieldEnum.UNIVARIATE_STATISTICS__TOTAL.getName(), baseStatisticsBean.getXSum());
result.put(ViewFieldEnum.UNIVARIATE_STATISTICS__STDDEV.getName(), baseStatisticsBean.getXStandardDeviationSample());
result.put(ViewFieldEnum.UNIVARIATE_STATISTICS__STDDEVPA.getName(), baseStatisticsBean.getXStandardDeviationPop());
result.put(ViewFieldEnum.UNIVARIATE_STATISTICS__VARIANCE.getName(), baseStatisticsBean.getXVariance());
result.put(ViewFieldEnum.UNIVARIATE_STATISTICS__AVERAGE.getName(), baseStatisticsBean.getXAverage());
if (additionalProps != null) {
additionalProps.addProperties(result, lastNewValues);
}
return eventAdapterService.adaptorForTypedMap(result, eventType);
}
/**
* Creates the event type for this view.
* @param statementContext is the event adapter service
* @return event type of view
*/
public static EventType createEventType(StatementContext statementContext, StatViewAdditionalProps additionalProps)
{
Map<String, Object> eventTypeMap = new HashMap<String, Object>();
eventTypeMap.put(ViewFieldEnum.UNIVARIATE_STATISTICS__DATAPOINTS.getName(), Long.class);
eventTypeMap.put(ViewFieldEnum.UNIVARIATE_STATISTICS__TOTAL.getName(), Double.class);
eventTypeMap.put(ViewFieldEnum.UNIVARIATE_STATISTICS__STDDEV.getName(), Double.class);
eventTypeMap.put(ViewFieldEnum.UNIVARIATE_STATISTICS__STDDEVPA.getName(), Double.class);
eventTypeMap.put(ViewFieldEnum.UNIVARIATE_STATISTICS__VARIANCE.getName(), Double.class);
eventTypeMap.put(ViewFieldEnum.UNIVARIATE_STATISTICS__AVERAGE.getName(), Double.class);
StatViewAdditionalProps.addCheckDupProperties(eventTypeMap, additionalProps,
ViewFieldEnum.UNIVARIATE_STATISTICS__DATAPOINTS,
ViewFieldEnum.UNIVARIATE_STATISTICS__TOTAL,
ViewFieldEnum.UNIVARIATE_STATISTICS__STDDEV,
ViewFieldEnum.UNIVARIATE_STATISTICS__STDDEVPA,
ViewFieldEnum.UNIVARIATE_STATISTICS__VARIANCE,
ViewFieldEnum.UNIVARIATE_STATISTICS__AVERAGE
);
return statementContext.getEventAdapterService().createAnonymousMapType(eventTypeMap);
}
}