/*
***************************************************************************************
* Copyright (C) 2006 EsperTech, Inc. All rights reserved. *
* http://www.espertech.com/esper *
* 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.core;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.type.FrequencyParameter;
import com.espertech.esper.util.JavaClassHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.StringWriter;
/**
* Expression for use within crontab to specify a frequency.
*/
public class ExprNumberSetFrequency extends ExprNodeBase implements ExprEvaluator {
private static final Logger log = LoggerFactory.getLogger(ExprNumberSetFrequency.class);
private transient ExprEvaluator evaluator;
private static final long serialVersionUID = -5389069399403078192L;
@Override
public ExprEvaluator getExprEvaluator() {
return this;
}
public void toPrecedenceFreeEPL(StringWriter writer) {
writer.append("*/");
this.getChildNodes()[0].toEPL(writer, ExprPrecedenceEnum.MINIMUM);
}
public ExprPrecedenceEnum getPrecedence() {
return ExprPrecedenceEnum.MINIMUM;
}
public boolean isConstantResult() {
return this.getChildNodes()[0].isConstantResult();
}
public boolean equalsNode(ExprNode node, boolean ignoreStreamPrefix) {
if (!(node instanceof ExprNumberSetFrequency)) {
return false;
}
return true;
}
public ExprNode validate(ExprValidationContext validationContext) throws ExprValidationException {
evaluator = this.getChildNodes()[0].getExprEvaluator();
Class type = evaluator.getType();
if (!(JavaClassHelper.isNumericNonFP(type))) {
throw new ExprValidationException("Frequency operator requires an integer-type parameter");
}
return null;
}
public Class getType() {
return FrequencyParameter.class;
}
public Object evaluate(EventBean[] eventsPerStream, boolean isNewData, ExprEvaluatorContext exprEvaluatorContext) {
Object value = evaluator.evaluate(eventsPerStream, isNewData, exprEvaluatorContext);
if (value == null) {
log.warn("Null value returned for frequency parameter");
return new FrequencyParameter(Integer.MAX_VALUE);
} else {
int intValue = ((Number) value).intValue();
return new FrequencyParameter(intValue);
}
}
}