/*
* *************************************************************************************
* 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.epl.expression;
import com.espertech.esper.client.EPException;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.schedule.TimeProvider;
import com.espertech.esper.type.CronOperatorEnum;
import com.espertech.esper.type.CronParameter;
import com.espertech.esper.util.JavaClassHelper;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.util.Map;
/**
* Expression for a parameter within a crontab.
* <p>
* May have one subnode depending on the cron parameter type.
*/
public class ExprNumberSetCronParam extends ExprNodeBase implements ExprEvaluator
{
private static final Log log = LogFactory.getLog(ExprNumberSetCronParam.class);
private final CronOperatorEnum cronOperator;
private transient TimeProvider timeProvider;
private transient ExprEvaluator evaluator;
private static final long serialVersionUID = -1315999998249935318L;
/**
* Ctor.
* @param cronOperator type of cron parameter
*/
public ExprNumberSetCronParam(CronOperatorEnum cronOperator)
{
this.cronOperator = cronOperator;
}
public ExprEvaluator getExprEvaluator()
{
return this;
}
/**
* Returns the cron parameter type.
* @return type of cron parameter
*/
public CronOperatorEnum getCronOperator()
{
return cronOperator;
}
public String toExpressionString()
{
if (this.getChildNodes().length == 0)
{
return cronOperator.getSyntax();
}
return this.getChildNodes()[0].toExpressionString() + " " + cronOperator.getSyntax();
}
public boolean isConstantResult()
{
if (this.getChildNodes().length == 0)
{
return true;
}
return this.getChildNodes()[0].isConstantResult();
}
public Map<String, Object> getEventType() {
return null;
}
public boolean equalsNode(ExprNode node)
{
if (!(node instanceof ExprNumberSetCronParam))
{
return false;
}
ExprNumberSetCronParam other = (ExprNumberSetCronParam) node;
return other.cronOperator.equals(this.cronOperator);
}
public void validate(ExprValidationContext validationContext) throws ExprValidationException
{
this.timeProvider = validationContext.getTimeProvider();
if (this.getChildNodes().length == 0)
{
return;
}
evaluator = this.getChildNodes()[0].getExprEvaluator();
Class type = evaluator.getType();
if (!(JavaClassHelper.isNumericNonFP(type)))
{
throw new ExprValidationException("Frequency operator requires an integer-type parameter");
}
}
public Class getType()
{
return CronParameter.class;
}
public Object evaluate(EventBean[] eventsPerStream, boolean isNewData, ExprEvaluatorContext exprEvaluatorContext)
{
if (timeProvider == null)
{
throw new EPException("Expression node has not been validated");
}
if (this.getChildNodes().length == 0)
{
return new CronParameter(cronOperator, null, timeProvider.getTime());
}
Object value = evaluator.evaluate(eventsPerStream, isNewData, exprEvaluatorContext);
if (value == null)
{
log.warn("Null value returned for cron parameter");
return new CronParameter(cronOperator, null, timeProvider.getTime());
}
else
{
int intValue = ((Number) value).intValue();
return new CronParameter(cronOperator, intValue, timeProvider.getTime());
}
}
}