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    1   /*
    2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/DefaultNavigator.java,v 1.17 2005/06/28 13:44:44 elharo Exp $
    3    * $Revision: 1.17 $
    4    * $Date: 2005/06/28 13:44:44 $
    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: DefaultNavigator.java,v 1.17 2005/06/28 13:44:44 elharo Exp $
    60   */
    61
    62
    63
    64  package org.jaxen;
    65
    66  import java.util.Iterator;
    67
    68  import org.jaxen.pattern.Pattern;
    69  import org.jaxen.util.AncestorAxisIterator;
    70  import org.jaxen.util.AncestorOrSelfAxisIterator;
    71  import org.jaxen.util.DescendantAxisIterator;
    72  import org.jaxen.util.DescendantOrSelfAxisIterator;
    73  import org.jaxen.util.FollowingAxisIterator;
    74  import org.jaxen.util.FollowingSiblingAxisIterator;
    75  import org.jaxen.util.PrecedingAxisIterator;
    76  import org.jaxen.util.PrecedingSiblingAxisIterator;
    77  import org.jaxen.util.SelfAxisIterator;
    78
    79  /*** Default implementation of {@link Navigator}.
    80   *
    81   *  <p>
    82   *  This implementation is an abstract class, since
    83   *  some required operations cannot be implemented without
    84   *  additional knowledge of the object model.
    85   *  </p>
    86   *
    87   *  <p>
    88   *  When possible, default method implementations build
    89   *  upon each other, to reduce the number of methods required
    90   *  to be implemented for each object model.  All methods,
    91   *  of course, may be overridden, to provide more-efficient
    92   *  implementations.
    93   *  </p>
    94   *
    95   *  @author bob mcwhirter (bob@werken.com)
    96   *  @author Erwin Bolwidt (ejb@klomp.org)
    97   */
    98  public abstract class DefaultNavigator implements Navigator
    99  {
    100
    101     /*** Throws <code>UnsupportedAxisException</code>
    102      *
    103      * @param contextNode
    104      * @return never returns
    105      * @throws UnsupportedAxisException always
    106      */
    107     public Iterator getChildAxisIterator(Object contextNode) throws UnsupportedAxisException
    108     {
    109         throw new UnsupportedAxisException("child");
    110     }
    111
    112     /* (non-Javadoc)
    113      * @see org.jaxen.Navigator#getDescendantAxisIterator(java.lang.Object)
    114      */
    115     public Iterator getDescendantAxisIterator(Object contextNode) throws UnsupportedAxisException
    116     {
    117         return new DescendantAxisIterator( contextNode,
    118                                            this );
    119     }
    120
    121     /*** Throws <code>UnsupportedAxisException</code>
    122      *
    123      * @param  contextNode
    124      * @return never returns
    125      * @throws UnsupportedAxisException
    126      */
    127     public Iterator getParentAxisIterator(Object contextNode) throws UnsupportedAxisException
    128     {
    129         throw new UnsupportedAxisException("parent");
    130     }
    131
    132     public Iterator getAncestorAxisIterator(Object contextNode) throws UnsupportedAxisException
    133     {
    134         return new AncestorAxisIterator( contextNode,
    135                                          this );
    136     }
    137
    138
    139     public Iterator getFollowingSiblingAxisIterator(Object contextNode) throws UnsupportedAxisException
    140     {
    141         return new FollowingSiblingAxisIterator( contextNode,
    142                                                  this );
    143     }
    144
    145
    146     public Iterator getPrecedingSiblingAxisIterator(Object contextNode) throws UnsupportedAxisException
    147     {
    148         return new PrecedingSiblingAxisIterator( contextNode,
    149                                                  this );
    150     }
    151
    152     public Iterator getFollowingAxisIterator(Object contextNode) throws UnsupportedAxisException
    153     {
    154         return new FollowingAxisIterator( contextNode,
    155                                           this );
    156
    157         // throw new UnsupportedAxisException("following");
    158     }
    159
    160
    161     public Iterator getPrecedingAxisIterator(Object contextNode) throws UnsupportedAxisException
    162     {
    163         return new PrecedingAxisIterator( contextNode,
    164                                          this );
    165
    166         // throw new UnsupportedAxisException("preceding");
    167     }
    168
    169     /*** Throws <code>UnsupportedAxisException</code>. Subclasses that
    170      * support the attribute axis must override this method.
    171      *
    172      * @param contextNode
    173      * @return never returns
    174      * @throws UnsupportedAxisException
    175      */
    176     public Iterator getAttributeAxisIterator(Object contextNode) throws UnsupportedAxisException
    177     {
    178         throw new UnsupportedAxisException("attribute");
    179     }
    180
    181     /*** Throws <code>UnsupportedAxisException</code>. Subclasses that
    182      * support the namespace axis must override this method.
    183      *
    184      * @param contextNode
    185      * @return never returns
    186      * @throws UnsupportedAxisException
    187      */
    188     public Iterator getNamespaceAxisIterator(Object contextNode) throws UnsupportedAxisException
    189     {
    190         throw new UnsupportedAxisException("namespace");
    191     }
    192
    193     public Iterator getSelfAxisIterator(Object contextNode) throws UnsupportedAxisException
    194     {
    195         return new SelfAxisIterator( contextNode );
    196     }
    197
    198     public Iterator getDescendantOrSelfAxisIterator(Object contextNode) throws UnsupportedAxisException
    199     {
    200         return new DescendantOrSelfAxisIterator( contextNode,
    201                                                  this );
    202     }
    203
    204     public Iterator getAncestorOrSelfAxisIterator(Object contextNode) throws UnsupportedAxisException
    205     {
    206         return new AncestorOrSelfAxisIterator( contextNode,
    207                                                this );
    208     }
    209
    210     public Object getDocumentNode(Object contextNode)
    211     {
    212         return null;
    213     }
    214
    215     public String translateNamespacePrefixToUri(String prefix, Object element)
    216     {
    217         return null;
    218     }
    219
    220     public String getProcessingInstructionTarget(Object obj)
    221     {
    222         return null;
    223     }
    224
    225     public String getProcessingInstructionData(Object obj)
    226     {
    227         return null;
    228     }
    229
    230     public short getNodeType(Object node)
    231     {
    232         if ( isElement(node) )
    233         {
    234             return Pattern.ELEMENT_NODE;
    235         }
    236         else if ( isAttribute(node) )
    237         {
    238             return Pattern.ATTRIBUTE_NODE;
    239         }
    240         else if ( isText(node) )
    241         {
    242             return Pattern.TEXT_NODE;
    243         }
    244         else if ( isComment(node) )
    245         {
    246             return Pattern.COMMENT_NODE;
    247         }
    248         else if ( isDocument(node) )
    249         {
    250             return Pattern.DOCUMENT_NODE;
    251         }
    252         else if ( isProcessingInstruction(node) )
    253         {
    254             return Pattern.PROCESSING_INSTRUCTION_NODE;
    255         }
    256         else if ( isNamespace(node) )
    257         {
    258             return Pattern.NAMESPACE_NODE;
    259         }
    260         else {
    261             return Pattern.UNKNOWN_NODE;
    262         }
    263     }
    264
    265     /***
    266      *  Default implementation that cannot find parent. Subclasses for
    267      *  models with parent should override this method.
    268      *
    269      * @param contextNode   the node whose parent to return
    270      * @return null
    271      * @throws UnsupportedAxisException if the parent axis is not supported
    272      */
    273     public Object getParentNode(Object contextNode) throws UnsupportedAxisException
    274     {
    275         Iterator iter = getParentAxisIterator( contextNode );
    276         if ( iter != null && iter.hasNext() )
    277         {
    278             return iter.next();
    279         }
    280         return null;
    281     }
    282
    283     /***
    284      *  Default implementation that always returns null. Override in subclass
    285      *  if the subclass can load documents.
    286      *
    287      * @param url the URL of the document to load
    288      *
    289      * @return null
    290      * @throws FunctionCallException if an error occurs while loading the
    291      *    URL; e.g. an I/O error or the document is malformed
    292      */
    293     public Object getDocument(String url) throws FunctionCallException
    294     {
    295         return null;
    296     }
    297
    298     /***
    299      *  Default implementation that cannot find elements. Override in subclass
    300      *  if subclass does know about attribute types.
    301      *
    302      *  @param contextNode   a node from the document in which to look for the
    303      *                       id
    304      *  @param elementId   id to look for
    305      *
    306      *  @return   null
    307      */
    308     public Object getElementById(Object contextNode, String elementId)
    309     {
    310         return null;
    311     }
    312
    313 }