001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements. See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership. The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the  "License");
007     * you may not use this file except in compliance with the License.
008     * You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    /*
019     * $Id: FuncSum.java 468655 2006-10-28 07:12:06Z minchau $
020     */
021    package org.apache.xpath.functions;
022    
023    import org.apache.xml.dtm.DTM;
024    import org.apache.xml.dtm.DTMIterator;
025    import org.apache.xml.utils.XMLString;
026    import org.apache.xpath.XPathContext;
027    import org.apache.xpath.objects.XNumber;
028    import org.apache.xpath.objects.XObject;
029    
030    /**
031     * Execute the Sum() function.
032     * @xsl.usage advanced
033     */
034    public class FuncSum extends FunctionOneArg
035    {
036        static final long serialVersionUID = -2719049259574677519L;
037    
038      /**
039       * Execute the function.  The function must return
040       * a valid object.
041       * @param xctxt The current execution context.
042       * @return A valid XObject.
043       *
044       * @throws javax.xml.transform.TransformerException
045       */
046      public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
047      {
048    
049        DTMIterator nodes = m_arg0.asIterator(xctxt, xctxt.getCurrentNode());
050        double sum = 0.0;
051        int pos;
052    
053        while (DTM.NULL != (pos = nodes.nextNode()))
054        {
055          DTM dtm = nodes.getDTM(pos);
056          XMLString s = dtm.getStringValue(pos);
057    
058          if (null != s)
059            sum += s.toDouble();
060        }
061        nodes.detach();
062    
063        return new XNumber(sum);
064      }
065    }