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    1   /*
    2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultStep.java,v 1.20 2005/09/06 13:41:01 elharo Exp $
    3    * $Revision: 1.20 $
    4    * $Date: 2005/09/06 13:41:01 $
    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: DefaultStep.java,v 1.20 2005/09/06 13:41:01 elharo Exp $
    60   */
    61  package org.jaxen.expr;
    62
    63  import java.util.ArrayList;
    64  import java.util.Iterator;
    65  import java.util.List;
    66
    67  import org.jaxen.Context;
    68  import org.jaxen.ContextSupport;
    69  import org.jaxen.JaxenException;
    70  import org.jaxen.UnsupportedAxisException;
    71  import org.jaxen.expr.iter.IterableAxis;
    72  import org.jaxen.saxpath.Axis;
    73
    74  /***
    75   * @deprecated this class will become non-public in the future;
    76   *     use the interface instead
    77   */
    78  public abstract class DefaultStep implements Step
    79  {
    80      private IterableAxis axis;
    81      private PredicateSet predicates;
    82
    83      public DefaultStep(IterableAxis axis, PredicateSet predicates)
    84      {
    85          this.axis = axis;
    86          this.predicates = predicates;
    87      }
    88
    89      public void addPredicate(Predicate predicate)
    90      {
    91          this.predicates.addPredicate(predicate);
    92      }
    93
    94      public List getPredicates()
    95      {
    96          return this.predicates.getPredicates();
    97      }
    98
    99      public PredicateSet getPredicateSet()
    100     {
    101         return this.predicates;
    102     }
    103
    104     public int getAxis()
    105     {
    106         return this.axis.value();
    107     }
    108
    109     public IterableAxis getIterableAxis()
    110     {
    111         return this.axis;
    112     }
    113
    114     public String getAxisName()
    115     {
    116         return Axis.lookup(getAxis());
    117     }
    118
    119     public String getText()
    120     {
    121         return this.predicates.getText();
    122     }
    123
    124     public String toString()
    125     {
    126         return getIterableAxis() + " " + super.toString();
    127     }
    128
    129     public void simplify()
    130     {
    131         this.predicates.simplify();
    132     }
    133
    134     public Iterator axisIterator(Object contextNode, ContextSupport support)
    135         throws UnsupportedAxisException
    136     {
    137         return getIterableAxis().iterator(contextNode, support);
    138     }
    139
    140     public List evaluate(final Context context) throws JaxenException
    141     {
    142         final List contextNodeSet  = context.getNodeSet();
    143         final IdentitySet unique = new IdentitySet();
    144         final int contextSize = contextNodeSet.size();
    145
    146         // ???? try linked lists instead?
    147         // ???? initial size for these?
    148         final ArrayList interimSet = new ArrayList();
    149         final ArrayList newNodeSet = new ArrayList();
    150         final ContextSupport support = context.getContextSupport();
    151
    152         // ???? use iterator instead
    153         for ( int i = 0 ; i < contextSize ; ++i )
    154         {
    155             Object eachContextNode = contextNodeSet.get( i );
    156
    157
    158                 /* See jaxen-106. Might be able to optimize this by doing
    159                  * specific matching for individual axes. For instance on namespace axis
    160                  * we should only get namespace nodes and on attribute axes we only get
    161                  * attribute nodes. Self and parent axes have single members.
    162                  * Children, descendant, ancestor, and sibling axes never
    163                  * see any attributes or namespaces
    164                  */
    165             Iterator axisNodeIter = axis.iterator(eachContextNode, support);
    166             while ( axisNodeIter.hasNext() )
    167             {
    168                 Object eachAxisNode = axisNodeIter.next();
    169                 if ( ! unique.contains( eachAxisNode ) )
    170                 {
    171                     if ( matches( eachAxisNode, support ) )
    172                     {
    173                         unique.add( eachAxisNode );
    174                         interimSet.add( eachAxisNode );
    175                     }
    176                 }
    177             }
    178             newNodeSet.addAll(getPredicateSet().evaluatePredicates(
    179                               interimSet, support ));
    180             interimSet.clear();
    181         }
    182         return newNodeSet;
    183     }
    184
    185 }