/**************************************************************************************
* 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.EventBean;
import java.util.Map;
/**
* Represents the RSTREAM() function in an expression tree.
*/
public class ExprIStreamNode extends ExprNodeBase implements ExprEvaluator
{
private static final long serialVersionUID = -6911351346095189882L;
/**
* Ctor.
*/
public ExprIStreamNode()
{
}
public ExprEvaluator getExprEvaluator()
{
return this;
}
public void validate(ExprValidationContext validationContext) throws ExprValidationException
{
if (this.getChildNodes().size() != 0)
{
throw new ExprValidationException("current_timestamp function node must have exactly 1 child node");
}
}
public boolean isConstantResult()
{
return false;
}
public Class getType()
{
return Boolean.class;
}
public Map<String, Object> getEventType() {
return null;
}
public Object evaluate(EventBean[] eventsPerStream, boolean isNewData, ExprEvaluatorContext exprEvaluatorContext)
{
return isNewData;
}
public String toExpressionString()
{
StringBuilder buffer = new StringBuilder();
buffer.append("istream()");
return buffer.toString();
}
public boolean equalsNode(ExprNode node)
{
if (!(node instanceof ExprIStreamNode))
{
return false;
}
return true;
}
}