/**************************************************************************************
* 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.pattern.observer;
import com.espertech.esper.client.EPException;
import com.espertech.esper.epl.expression.ExprNode;
import com.espertech.esper.epl.expression.ExprTimePeriod;
import com.espertech.esper.pattern.EvalStateNodeNumber;
import com.espertech.esper.pattern.MatchedEventConvertor;
import com.espertech.esper.pattern.MatchedEventMap;
import com.espertech.esper.pattern.PatternAgentInstanceContext;
import com.espertech.esper.util.JavaClassHelper;
import com.espertech.esper.util.MetaDefItem;
import java.io.Serializable;
import java.util.List;
/**
* Factory for making observer instances.
*/
public class TimerIntervalObserverFactory implements ObserverFactory, MetaDefItem, Serializable
{
private static final long serialVersionUID = -2808651894497586884L;
/**
* Parameters.
*/
protected ExprNode parameter;
/**
* Convertor to events-per-stream.
*/
protected transient MatchedEventConvertor convertor;
public void setObserverParameters(List<ExprNode> parameters, MatchedEventConvertor convertor) throws ObserverParameterException
{
String errorMessage = "Timer-interval observer requires a single numeric or time period parameter";
if (parameters.size() != 1) {
throw new ObserverParameterException(errorMessage);
}
if (!(parameters.get(0) instanceof ExprTimePeriod)) {
Class returnType = parameters.get(0).getExprEvaluator().getType();
if (!(JavaClassHelper.isNumeric(returnType))) {
throw new ObserverParameterException(errorMessage);
}
}
parameter = parameters.get(0);
this.convertor = convertor;
}
protected long computeMilliseconds(MatchedEventMap beginState, PatternAgentInstanceContext context) {
if (parameter instanceof ExprTimePeriod) {
ExprTimePeriod timePeriod = (ExprTimePeriod) parameter;
return timePeriod.nonconstEvaluator().deltaMillisecondsUseEngineTime(convertor.convert(beginState), context.getAgentInstanceContext());
}
else {
Object result = parameter.getExprEvaluator().evaluate(convertor.convert(beginState), true, context.getAgentInstanceContext());
if (result == null) {
throw new EPException("Null value returned for guard expression");
}
Number param = (Number) result;
if (JavaClassHelper.isFloatingPointNumber(param)) {
return Math.round(1000d * param.doubleValue());
}
else {
return 1000 * param.longValue();
}
}
}
public EventObserver makeObserver(PatternAgentInstanceContext context, MatchedEventMap beginState, ObserverEventEvaluator observerEventEvaluator, EvalStateNodeNumber stateNodeId, Object observerState)
{
return new TimerIntervalObserver(computeMilliseconds(beginState, context), beginState, observerEventEvaluator);
}
}