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: FuncConcat.java 468655 2006-10-28 07:12:06Z minchau $
020     */
021    package org.apache.xpath.functions;
022    
023    import org.apache.xalan.res.XSLMessages;
024    import org.apache.xpath.XPathContext;
025    import org.apache.xpath.objects.XObject;
026    import org.apache.xpath.objects.XString;
027    
028    /**
029     * Execute the Concat() function.
030     * @xsl.usage advanced
031     */
032    public class FuncConcat extends FunctionMultiArgs
033    {
034        static final long serialVersionUID = 1737228885202314413L;
035    
036      /**
037       * Execute the function.  The function must return
038       * a valid object.
039       * @param xctxt The current execution context.
040       * @return A valid XObject.
041       *
042       * @throws javax.xml.transform.TransformerException
043       */
044      public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
045      {
046    
047        StringBuffer sb = new StringBuffer();
048    
049        // Compiler says we must have at least two arguments.
050        sb.append(m_arg0.execute(xctxt).str());
051        sb.append(m_arg1.execute(xctxt).str());
052    
053        if (null != m_arg2)
054          sb.append(m_arg2.execute(xctxt).str());
055    
056        if (null != m_args)
057        {
058          for (int i = 0; i < m_args.length; i++)
059          {
060            sb.append(m_args[i].execute(xctxt).str());
061          }
062        }
063    
064        return new XString(sb.toString());
065      }
066    
067      /**
068       * Check that the number of arguments passed to this function is correct.
069       *
070       *
071       * @param argNum The number of arguments that is being passed to the function.
072       *
073       * @throws WrongNumberArgsException
074       */
075      public void checkNumberArgs(int argNum) throws WrongNumberArgsException
076      {
077        if (argNum < 2)
078          reportWrongNumberArgs();
079      }
080    
081      /**
082       * Constructs and throws a WrongNumberArgException with the appropriate
083       * message for this function object.
084       *
085       * @throws WrongNumberArgsException
086       */
087      protected void reportWrongNumberArgs() throws WrongNumberArgsException {
088          throw new WrongNumberArgsException(XSLMessages.createXPATHMessage("gtone", null));
089      }
090    }