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    1   /*
    2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/ConcatFunction.java,v 1.8 2005/06/28 13:44:45 elharo Exp $
    3    * $Revision: 1.8 $
    4    * $Date: 2005/06/28 13:44:45 $
    5    *
    6    * ====================================================================
    7    *
    8    * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
    9    * All rights reserved.
    10   *
    11   * Redistribution and use in source and binary forms, with or without
    12   * modification, are permitted provided that the following conditions
    13   * are met:
    14   *
    15   * 1. Redistributions of source code must retain the above copyright
    16   *    notice, this list of conditions, and the following disclaimer.
    17   *
    18   * 2. Redistributions in binary form must reproduce the above copyright
    19   *    notice, this list of conditions, and the disclaimer that follows
    20   *    these conditions in the documentation and/or other materials
    21   *    provided with the distribution.
    22   *
    23   * 3. The name "Jaxen" must not be used to endorse or promote products
    24   *    derived from this software without prior written permission.  For
    25   *    written permission, please contact license@jaxen.org.
    26   *
    27   * 4. Products derived from this software may not be called "Jaxen", nor
    28   *    may "Jaxen" appear in their name, without prior written permission
    29   *    from the Jaxen Project Management (pm@jaxen.org).
    30   *
    31   * In addition, we request (but do not require) that you include in the
    32   * end-user documentation provided with the redistribution and/or in the
    33   * software itself an acknowledgement equivalent to the following:
    34   *     "This product includes software developed by the
    35   *      Jaxen Project <http://www.jaxen.org/>."
    36   * Alternatively, the acknowledgment may be graphical using the logos
    37   * available at http://www.jaxen.org/
    38   *
    39   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
    40   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    41   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    42   * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
    43   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    44   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    45   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
    46   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
    47   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
    48   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
    49   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    50   * SUCH DAMAGE.
    51   *
    52   * ====================================================================
    53   * This software consists of voluntary contributions made by many
    54   * individuals on behalf of the Jaxen Project and was originally
    55   * created by bob mcwhirter <bob@werken.com> and
    56   * James Strachan <jstrachan@apache.org>.  For more information on the
    57   * Jaxen Project, please see <http://www.jaxen.org/>.
    58   *
    59   * $Id: ConcatFunction.java,v 1.8 2005/06/28 13:44:45 elharo Exp $
    60   */
    61
    62
    63  package org.jaxen.function;
    64
    65  import java.util.Iterator;
    66  import java.util.List;
    67
    68  import org.jaxen.Context;
    69  import org.jaxen.Function;
    70  import org.jaxen.FunctionCallException;
    71  import org.jaxen.Navigator;
    72
    73  /***
    74   * <b>4.2</b> <code><i>string</i> concat(<i>string</i>,<i>string</i>,<i>string*</i>)</code>
    75   * <p>
    76   * Concatenates its arguments and returns the resulting string.
    77   * </p>
    78   *
    79   *  @author bob mcwhirter (bob@werken.com)
    80   *
    81   * @see <a href="http://www.w3.org/TR/xpath#function-concat">Section 4.2 of the XPath Specification</a>
    82   */
    83  public class ConcatFunction implements Function
    84  {
    85
    86      /***
    87       * Create a new <code>ConcatFunction</code> object.
    88       */
    89      public ConcatFunction() {}
    90
    91      /***
    92       * Concatenates the arguments and returns the resulting string.
    93       * Non-string items are first converted to strings as if by the
    94       * XPath <code>string()<code> function.
    95       *
    96       * @param context the context at the point in the
    97       *         expression when the function is called
    98       * @param args the list of strings to be concatenated
    99       *
    100      * @return a <code>String</code> containing the concatenation of the items
    101      *     of <code>args</code>
    102      *
    103      * @throws FunctionCallException if <code>args</code> has less than two items
    104      */
    105     public Object call(Context context,
    106                        List args) throws FunctionCallException
    107     {
    108         if ( args.size() >= 2 )
    109         {
    110             return evaluate( args,
    111                              context.getNavigator() );
    112         }
    113
    114         throw new FunctionCallException("concat() requires at least two arguments");
    115     }
    116
    117     /***
    118      * Converts each item in the list to a string and returns the
    119      * concatenation of these strings.
    120      * If necessary, each item is first converted to a <code>String</code>
    121      * as if by the XPath <code>string()</code> function.
    122      *
    123      * @param list the items to be concatenated
    124      * @param nav ignored
    125      *
    126      * @return the concatenation of the arguments
    127      */
    128    public static String evaluate(List list,
    129                                   Navigator nav)
    130     {
    131         StringBuffer result = new StringBuffer();
    132         Iterator argIter = list.iterator();
    133         while ( argIter.hasNext() )
    134         {
    135             result.append( StringFunction.evaluate( argIter.next(),
    136                                                     nav ) );
    137         }
    138
    139         return result.toString();
    140     }
    141 }