/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.xpath.functions;

import org.apache.xpath.XPathContext;
import org.apache.xpath.objects.XNumber;
import org.apache.xpath.objects.XObject;

/**
 * Implementation of an XPath 3.1 function fn:abs.
 * 
 * @author Mukul Gandhi <mukulg@apache.org>
 * 
 * @xsl.usage advanced
 */
public class FuncAbs extends FunctionDef1Arg
{

	private static final long serialVersionUID = 7292919650996994647L;
	
	/**
	 * Class constructor.
	 */
	public FuncAbs() {
		m_defined_arity = new Short[] { 1 };
	}

	/**
	 * Evaluate the function. The function must return a valid object.
	 * 
	 * @param xctxt The current execution context.
	 * @return A valid XObject.
	 *
	 * @throws javax.xml.transform.TransformerException
	 */
	public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
	{
		String strValueOfArg = (getArg0AsString(xctxt)).toString();

		return new XNumber(Math.abs(Double.valueOf(strValueOfArg)));
	}
}
