/**
* Copyright (C) 2009 Orbeon, Inc.
*
* This program is free software; you can redistribute it and/or modify it under the terms of the
* GNU Lesser General Public License as published by the Free Software Foundation; either version
* 2.1 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Lesser General Public License for more details.
*
* The full text of the license is available at http://www.gnu.org/copyleft/lesser.html
*/
package org.orbeon.oxf.xforms.function;
import org.orbeon.saxon.expr.Expression;
import org.orbeon.saxon.expr.XPathContext;
import org.orbeon.saxon.om.Item;
import org.orbeon.saxon.trans.XPathException;
import org.orbeon.saxon.value.DoubleValue;
import org.orbeon.saxon.value.NumericValue;
/**
* XForms power() function (XForms 1.1).
*/
public class Power extends XFormsFunction {
public Item evaluateItem(XPathContext xpathContext) throws XPathException {
final Expression baseExpression = argument[0];
final Expression exponentExpression = argument[1];
try {
final double base = ((NumericValue)baseExpression.evaluateItem(xpathContext)).getDoubleValue();
final double exponent = ((NumericValue)exponentExpression.evaluateItem(xpathContext)).getDoubleValue();
return new DoubleValue(Math.pow(base, exponent));
} catch(NumberFormatException e) {
return DoubleValue.NaN;
}
}
}