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


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: FuncConcat.java,v 1.11 2004/02/17 04:34:01 minchau Exp $
18  */
19 package org.apache.xpath.functions;
20
21 import org.apache.xalan.res.XSLMessages;
22 import org.apache.xpath.XPathContext;
23 import org.apache.xpath.objects.XObject;
24 import org.apache.xpath.objects.XString;
25
26 /**
27  * Execute the Concat() function.
28  * @xsl.usage advanced
29  */
30 public class FuncConcat extends FunctionMultiArgs
31 {
32
33   /**
34    * Execute the function. The function must return
35    * a valid object.
36    * @param xctxt The current execution context.
37    * @return A valid XObject.
38    *
39    * @throws javax.xml.transform.TransformerException
40    */
41   public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException JavaDoc
42   {
43
44     StringBuffer JavaDoc sb = new StringBuffer JavaDoc();
45
46     // Compiler says we must have at least two arguments.
47 sb.append(m_arg0.execute(xctxt).str());
48     sb.append(m_arg1.execute(xctxt).str());
49
50     if (null != m_arg2)
51       sb.append(m_arg2.execute(xctxt).str());
52
53     if (null != m_args)
54     {
55       for (int i = 0; i < m_args.length; i++)
56       {
57         sb.append(m_args[i].execute(xctxt).str());
58       }
59     }
60
61     return new XString(sb.toString());
62   }
63
64   /**
65    * Check that the number of arguments passed to this function is correct.
66    *
67    *
68    * @param argNum The number of arguments that is being passed to the function.
69    *
70    * @throws WrongNumberArgsException
71    */
72   public void checkNumberArgs(int argNum) throws WrongNumberArgsException
73   {
74     if (argNum < 2)
75       reportWrongNumberArgs();
76   }
77
78   /**
79    * Constructs and throws a WrongNumberArgException with the appropriate
80    * message for this function object.
81    *
82    * @throws WrongNumberArgsException
83    */
84   protected void reportWrongNumberArgs() throws WrongNumberArgsException {
85       throw new WrongNumberArgsException(XSLMessages.createXPATHMessage("gtone", null));
86   }
87 }
88
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