/************************************************************************************** * 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; } }