/*

  * $Header$

  * $Revision: 1128 $

  * $Date: 2006-02-05 13:49:04 -0800 (Sun, 05 Feb 2006) $

  *

  * ====================================================================

  *

  * Copyright 2000-2002 bob mcwhirter & James Strachan.

  * All rights reserved.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions are

  * met:

  * 

  *   * Redistributions of source code must retain the above copyright

  *     notice, this list of conditions and the following disclaimer.

  * 

  *   * Redistributions in binary form must reproduce the above copyright

  *     notice, this list of conditions and the following disclaimer in the

  *     documentation and/or other materials provided with the distribution.

  * 

  *   * Neither the name of the Jaxen Project nor the names of its

  *     contributors may be used to endorse or promote products derived 

  *     from this software without specific prior written permission.

  * 

  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED

  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A

  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER

  * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

  *

  * ====================================================================

  * This software consists of voluntary contributions made by many 

  * individuals on behalf of the Jaxen Project and was originally 

  * created by bob mcwhirter <bob@werken.com> and 

  * James Strachan <jstrachan@apache.org>.  For more information on the 

  * Jaxen Project, please see <http://www.jaxen.org/>.

  * 

  * $Id: ConcatFunction.java 1128 2006-02-05 21:49:04Z elharo $

  */

 package org.jaxen.function;

 import java.util.Iterator;

 import java.util.List;

 import org.jaxen.Context;

 import org.jaxen.Function;

 import org.jaxen.FunctionCallException;

 import org.jaxen.Navigator;

 /**

  * <b>4.2</b> <code><i>string</i> concat(<i>string</i>,<i>string</i>,<i>string*</i>)</code> 

  * <p>

  * Concatenates its arguments and returns the resulting string.

  * </p>

  *  

  *  @author bob mcwhirter (bob@werken.com)

  * 

  * @see <a href="http://www.w3.org/TR/xpath#function-concat">Section 4.2 of the XPath Specification</a>

  */

 public class ConcatFunction implements Function

 {

     /**

      * Create a new <code>ConcatFunction</code> object.

      */

     public ConcatFunction() {}

     /** 

      * Concatenates the arguments and returns the resulting string.

      * Non-string items are first converted to strings as if by the 

      * XPath <code>string()<code> function.

      *

      * @param context the context at the point in the

      *         expression when the function is called

      * @param args the list of strings to be concatenated

      * 

      * @return a <code>String</code> containing the concatenation of the items 

      *     of <code>args</code>

      * 

      * @throws FunctionCallException if <code>args</code> has less than two items

      */

     public Object call(Context context,

                        List args) throws FunctionCallException

     {

         if ( args.size() >= 2 )

         {

             return evaluate( args,

                              context.getNavigator() );

         }

         throw new FunctionCallException("concat() requires at least two arguments");

     }

     /** 

      * Converts each item in the list to a string and returns the 

      * concatenation of these strings.

      * If necessary, each item is first converted to a <code>String</code>

      * as if by the XPath <code>string()</code> function.

      * 

      * @param list the items to be concatenated

      * @param nav ignored

      * 

      * @return the concatenation of the arguments

      */

    public static String evaluate(List list,

                                   Navigator nav)

     {

         StringBuffer result = new StringBuffer();

         Iterator argIter = list.iterator();

         while ( argIter.hasNext() )

         {

             result.append( StringFunction.evaluate( argIter.next(),

                                                     nav ) );

         }

         return result.toString();

     }

 }