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Java > Open Source Codes > org > apache > xpath > functions > FuncSum


1 /*
2  * Copyright 1999-2004 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 /*
17  * $Id: FuncSum.java,v 1.10 2004/02/17 04:34:01 minchau Exp $
18  */
19 package org.apache.xpath.functions;
20
21 import org.apache.xml.dtm.DTM;
22 import org.apache.xml.dtm.DTMIterator;
23 import org.apache.xml.utils.XMLString;
24 import org.apache.xpath.XPathContext;
25 import org.apache.xpath.objects.XNumber;
26 import org.apache.xpath.objects.XObject;
27
28 /**
29  * Execute the Sum() function.
30  * @xsl.usage advanced
31  */
32 public class FuncSum extends FunctionOneArg
33 {
34
35   /**
36    * Execute the function. The function must return
37    * a valid object.
38    * @param xctxt The current execution context.
39    * @return A valid XObject.
40    *
41    * @throws javax.xml.transform.TransformerException
42    */
43   public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException JavaDoc
44   {
45
46     DTMIterator nodes = m_arg0.asIterator(xctxt, xctxt.getCurrentNode());
47     double sum = 0.0;
48     int pos;
49
50     while (DTM.NULL != (pos = nodes.nextNode()))
51     {
52       DTM dtm = nodes.getDTM(pos);
53       XMLString s = dtm.getStringValue(pos);
54
55       if (null != s)
56         sum += s.toDouble();
57     }
58     nodes.detach();
59
60     return new XNumber(sum);
61   }
62 }
63
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