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    1   /*
    2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/NameFunction.java,v 1.10 2005/06/28 13:44:45 elharo Exp $
    3    * $Revision: 1.10 $
    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: NameFunction.java,v 1.10 2005/06/28 13:44:45 elharo Exp $
    60   */
    61
    62
    63  package org.jaxen.function;
    64
    65  import java.util.List;
    66
    67  import org.jaxen.Context;
    68  import org.jaxen.Function;
    69  import org.jaxen.FunctionCallException;
    70  import org.jaxen.Navigator;
    71
    72  /***
    73   * <p><b>4.1</b> <code><i>string</i> name(<i>node-set?</i>)</code> </p>
    74   *
    75   *
    76   * <blockquote src="http://www.w3.org/TR/xpath">
    77   * The <b>name</b> function returns a string containing a QName representing
    78   * the expanded-name of the node in the argument node-set that is first in document order.
    79   * The QName must represent the expanded-name with respect to the namespace declarations
    80   * in effect on the node whose expanded-name is being represented. Typically, this will
    81   * be the QName that occurred in the XML source....If
    82   * the argument node-set is empty or the first node has
    83   * no expanded-name, an empty string is returned.
    84   * If the argument it omitted, it defaults to a node-set with the context node as its only member.
    85   * </blockquote>
    86   *
    87   * @author bob mcwhirter (bob @ werken.com)
    88   *
    89   * @see <a href="http://www.w3.org/TR/xpath#function-name" target="_top">Section 4.1 of the XPath Specification</a>
    90   */
    91  public class NameFunction implements Function
    92  {
    93
    94
    95      /***
    96       * Create a new <code>NameFunction</code> object.
    97       */
    98      public NameFunction() {}
    99
    100     /***
    101      * Returns the name of the specified node or the name of the context node if
    102      * no arguments are provided.
    103      *
    104      * @param context the context at the point in the
    105      *         expression where the function is called
    106      * @param args a <code>List</code> containing zero or one items
    107      *
    108      * @return a <code>String</code> containing the name
    109      *
    110      * @throws FunctionCallException if <code>args</code> has more than one item
    111      */
    112     public Object call(Context context,
    113                        List args) throws FunctionCallException
    114     {
    115         if ( args.size() == 0 )
    116         {
    117             return evaluate( context.getNodeSet(),
    118                              context.getNavigator() );
    119         }
    120
    121         if ( args.size() == 1 )
    122         {
    123             return evaluate( args,
    124                              context.getNavigator() );
    125         }
    126
    127         throw new FunctionCallException( "name() requires zero or one argument." );
    128     }
    129
    130     /***
    131      * Returns the name of <code>list.get(0)</code>
    132      *
    133      * @param list a list of nodes
    134      * @param nav the <code>Navigator</code> used to retrieve the name
    135      *
    136      * @return the name of <code>list.get(0)</code>
    137      *
    138      * @throws FunctionCallException if <code>list.get(0)</code> is not a node
    139      */
    140     public static String evaluate(List list,
    141                                   Navigator nav) throws FunctionCallException
    142     {
    143         if ( ! list.isEmpty() )
    144         {
    145             Object first = list.get(0);
    146
    147             if (first instanceof List)
    148             {
    149                 return evaluate( (List) first,
    150                                  nav );
    151             }
    152             else if ( nav.isElement( first ) )
    153             {
    154                 return nav.getElementQName( first );
    155             }
    156             else if ( nav.isAttribute( first ) )
    157             {
    158                 return nav.getAttributeQName( first );
    159             }
    160             else if ( nav.isProcessingInstruction( first ) )
    161             {
    162                 return nav.getProcessingInstructionTarget( first );
    163             }
    164             else if ( nav.isNamespace( first ) )
    165             {
    166                 return nav.getNamespacePrefix( first );
    167             }
    168             else if ( nav.isDocument( first ) )
    169             {
    170                 return "";
    171             }
    172             else if ( nav.isComment( first ) )
    173             {
    174                 return "";
    175             }
    176             else if ( nav.isText( first ) )
    177             {
    178                 return "";
    179             }
    180             else {
    181                 throw new FunctionCallException("The argument to the name function must be a node-set");
    182             }
    183         }
    184
    185         return "";
    186
    187     }
    188
    189 }