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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultLocationPath.java,v 1.26 2005/05/16 10:46:43 elharo Exp $
3    * $Revision: 1.26 $
4    * $Date: 2005/05/16 10:46:43 $
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: DefaultLocationPath.java,v 1.26 2005/05/16 10:46:43 elharo Exp $
60   */
61  package org.jaxen.expr;
62  
63  import java.util.ArrayList;
64  import java.util.Collections;
65  import java.util.Iterator;
66  import java.util.LinkedList;
67  import java.util.List;
68  
69  import org.jaxen.Context;
70  import org.jaxen.ContextSupport;
71  import org.jaxen.JaxenException;
72  
73  abstract class DefaultLocationPath extends DefaultExpr implements LocationPath
74  {
75      private List steps;
76      
77      /***
78       * Create a new empty location path.
79       */
80      DefaultLocationPath()
81      {
82          this.steps = new LinkedList();
83      }
84  
85      public void addStep(Step step)
86      {
87          getSteps().add(step);
88      }
89  
90      public List getSteps()
91      {
92          return this.steps;
93      }
94  
95      public Expr simplify()
96      {
97          Iterator stepIter = getSteps().iterator();
98          Step eachStep = null;
99          while (stepIter.hasNext())
100         {
101             eachStep = (Step) stepIter.next();
102             eachStep.simplify();
103         }
104         return this;
105     }
106 
107     public String getText()
108     {
109         StringBuffer buf = new StringBuffer();
110         Iterator stepIter = getSteps().iterator();
111         while (stepIter.hasNext())
112         {
113             buf.append(((Step) stepIter.next()).getText());
114             if (stepIter.hasNext())
115             {
116                 buf.append("/");
117             }
118         }
119         return buf.toString();
120     }
121 
122     public String toString()
123     {
124         StringBuffer buf = new StringBuffer();
125         Iterator stepIter = getSteps().iterator();
126         while (stepIter.hasNext())
127         {
128             buf.append(stepIter.next().toString());
129             if (stepIter.hasNext())
130             {
131                 buf.append("/");
132             }
133         }
134         return buf.toString();
135     }
136 
137     public boolean isAbsolute()
138     {
139         return false;
140     }
141 
142     public Object evaluate(Context context) throws JaxenException
143     {
144         List nodeSet = context.getNodeSet();
145         List contextNodeSet = new ArrayList(nodeSet.size());
146         contextNodeSet.addAll(nodeSet);
147         ContextSupport support = context.getContextSupport();
148         Context stepContext = new Context(support);
149         Iterator stepIter = getSteps().iterator();
150         while ( stepIter.hasNext() )
151         {
152             Step eachStep = (Step) stepIter.next();
153             stepContext.setNodeSet(contextNodeSet);
154             contextNodeSet = eachStep.evaluate(stepContext);
155             // now we need to reverse the list if this is a reverse axis
156             if (isReverseAxis(eachStep)) {
157                 Collections.reverse(contextNodeSet);
158             }
159         }
160         
161         if (getSteps().size() > 1) {
162             Collections.sort(contextNodeSet, new NodeComparator(support.getNavigator()));
163         }
164         
165         return contextNodeSet;
166     }
167 
168     private boolean isReverseAxis(Step step) {
169 
170         int axis = step.getAxis();
171         return axis == org.jaxen.saxpath.Axis.PRECEDING
172           || axis == org.jaxen.saxpath.Axis.PRECEDING_SIBLING
173           || axis == org.jaxen.saxpath.Axis.ANCESTOR
174           || axis == org.jaxen.saxpath.Axis.ANCESTOR_OR_SELF;
175     }
176 
177 }
178