/*
* *************************************************************************************
* 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.property;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.client.EventType;
import com.espertech.esper.client.FragmentEventType;
import com.espertech.esper.epl.expression.ExprEvaluator;
import com.espertech.esper.epl.expression.ExprEvaluatorContext;
import com.espertech.esper.epl.expression.ExprNodeUtility;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* Property evaluator that considers only level one and considers a where-clause,
* but does not consider a select clause or N-level.
*/
public class PropertyEvaluatorSimple implements PropertyEvaluator
{
private static final Log log = LogFactory.getLog(PropertyEvaluatorSimple.class);
private final ContainedEventEval containedEventEval;
private final FragmentEventType fragmentEventType;
private final ExprEvaluator filter;
private final String expressionText;
/**
* Ctor.
* @param containedEventEval property getter or other evaluator
* @param fragmentEventType property event type
* @param filter optional where-clause expression
* @param expressionText the property name
*/
public PropertyEvaluatorSimple(ContainedEventEval containedEventEval, FragmentEventType fragmentEventType, ExprEvaluator filter, String expressionText)
{
this.fragmentEventType = fragmentEventType;
this.containedEventEval = containedEventEval;
this.filter = filter;
this.expressionText = expressionText;
}
public EventBean[] getProperty(EventBean theEvent, ExprEvaluatorContext exprEvaluatorContext)
{
try
{
Object result = containedEventEval.getFragment(theEvent, new EventBean[] {theEvent}, exprEvaluatorContext);
EventBean[] rows;
if (fragmentEventType.isIndexed())
{
rows = (EventBean[]) result;
}
else
{
rows = new EventBean[] {(EventBean) result};
}
if (filter == null)
{
return rows;
}
return ExprNodeUtility.applyFilterExpression(filter, theEvent, (EventBean[]) result, exprEvaluatorContext);
}
catch (RuntimeException ex)
{
log.error("Unexpected error evaluating property expression for event of type '" +
theEvent.getEventType().getName() +
"' and property '" +
expressionText + "': " + ex.getMessage(), ex);
}
return null;
}
public EventType getFragmentEventType()
{
return fragmentEventType.getFragmentType();
}
/**
* Returns the property name.
* @return property name
*/
public String getExpressionText()
{
return expressionText;
}
/**
* Returns the filter.
* @return filter
*/
public ExprEvaluator getFilter()
{
return filter;
}
public boolean compareTo(PropertyEvaluator otherEval)
{
if (!(otherEval instanceof PropertyEvaluatorSimple))
{
return false;
}
PropertyEvaluatorSimple other = (PropertyEvaluatorSimple) otherEval;
if (!other.getExpressionText().equals(this.getExpressionText()))
{
return false;
}
if ((other.getFilter() == null) && (this.getFilter() == null))
{
return true;
}
return false;
}
}