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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/Step.java,v 1.8 2004/04/08 09:49:51 cnentwich Exp $
3    * $Revision: 1.8 $
4    * $Date: 2004/04/08 09:49:51 $
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: Step.java,v 1.8 2004/04/08 09:49:51 cnentwich Exp $
60   */
61  
62  package org.jaxen.expr;
63  
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  
72  /***
73   * A Step represents a location step in a LocationPath. The node-set selected by 
74   * the location step is the node-set that results from generating an initial 
75   * node-set from the axis and node-test, and then filtering that node-set by 
76   * each of the predicates in turn.
77   * 
78   * The initial node-set consists of the nodes having the relationship to the 
79   * context node specified by the axis, and having the node type and expanded-name 
80   * specified by the node test.
81   */
82  public interface Step extends Predicated, Visitable
83  {
84  
85      /***
86       * Performs the node-test part of evaluating the step for the given node
87       * (which must be on the axis).
88       */    
89      boolean matches(Object node,
90                      ContextSupport contextSupport) throws JaxenException;
91  
92      String getText();
93  
94      void simplify();
95  
96      /***
97       * Get an identifier for the current axis.
98       * @see org.jaxen.saxpath.Axis
99       */
100     public int getAxis();
101 
102     /***
103      * Get an Iterator for the current axis starting in the given contextNode.
104      */    
105     Iterator axisIterator(Object contextNode,
106                           ContextSupport support) throws UnsupportedAxisException;
107 
108     /***
109      * For each node in the given context calls matches() for every node on the
110      * axis, then filters the result by each of the predicates.
111      */
112     List evaluate(Context context) throws JaxenException;
113 
114 }
115