package com.espertech.esper.epl.expression;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.util.JavaClassHelper;
import com.espertech.esper.type.FrequencyParameter;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.util.Map;
/**
* Expression for use within crontab to specify a frequency.
*/
public class ExprNumberSetFrequency extends ExprNodeBase implements ExprEvaluator
{
private static final Log log = LogFactory.getLog(ExprNumberSetFrequency.class);
private transient ExprEvaluator evaluator;
private static final long serialVersionUID = -5389069399403078192L;
@Override
public ExprEvaluator getExprEvaluator() {
return this;
}
public String toExpressionString()
{
return "*/" + this.getChildNodes().get(0);
}
public boolean isConstantResult()
{
return this.getChildNodes().get(0).isConstantResult();
}
public boolean equalsNode(ExprNode node)
{
if (!(node instanceof ExprNumberSetFrequency))
{
return false;
}
return true;
}
public void validate(ExprValidationContext validationContext) throws ExprValidationException
{
evaluator = this.getChildNodes().get(0).getExprEvaluator();
Class type = evaluator.getType();
if (!(JavaClassHelper.isNumericNonFP(type)))
{
throw new ExprValidationException("Frequency operator requires an integer-type parameter");
}
}
public Class getType()
{
return FrequencyParameter.class;
}
public Map<String, Object> getEventType() {
return null;
}
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);
}
}
}