1 /*
2 * $Header$
3 * $Revision$
4 * $Date$
5 *
6 * ====================================================================
7 *
8 * Copyright 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 are
13 * met:
14 *
15 * * Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 *
18 * * Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 *
22 * * Neither the name of the Jaxen Project nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
27 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
29 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
30 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
32 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
33 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37 *
38 * ====================================================================
39 * This software consists of voluntary contributions made by many
40 * individuals on behalf of the Jaxen Project and was originally
41 * created by bob mcwhirter <bob@werken.com> and
42 * James Strachan <jstrachan@apache.org>. For more information on the
43 * Jaxen Project, please see <http://www.jaxen.org/>.
44 *
45 * $Id$
46 */
47
48 package org.jaxen.expr;
49
50 import java.util.Iterator;
51 import java.util.List;
52
53 import org.jaxen.Context;
54 import org.jaxen.ContextSupport;
55 import org.jaxen.JaxenException;
56 import org.jaxen.UnsupportedAxisException;
57
58 /**
59 * <p>Represents a location step in a LocationPath. The node-set selected by
60 * the location step is the node-set that results from generating an initial
61 * node-set from the axis and node-test, and then filtering that node-set by
62 * each of the predicates in turn.</p>
63 *
64 * <p>
65 * The initial node-set consists of the nodes having the relationship to the
66 * context node specified by the axis, and having the node type and expanded-name
67 * specified by the node test.</p>
68 */
69 public interface Step extends Predicated
70 {
71
72 /**
73 * Performs the node-test part of evaluating the step for the given node
74 * (which must be on the axis).
75 *
76 * @param node the node to test
77 * @param contextSupport function, namespace, and variable contexts
78 * @return true if the node matches this step; false if it doesn't
79 */
80 boolean matches(Object node,
81 ContextSupport contextSupport) throws JaxenException;
82
83 /**
84 * Returns a <code>String</code> containing the XPath expression.
85 *
86 * @return the text form of this step
87 */
88 String getText();
89
90 /**
91 * Simplifies the XPath step. In practice, this is usually a noop.
92 * Jaxen does not currently perform any simplification.
93 */
94 void simplify();
95
96 /**
97 * Get an identifier for the current axis.
98 *
99 * @return the axis identifier
100 * @see org.jaxen.saxpath.Axis
101 */
102 public int getAxis();
103
104 /**
105 * Get an Iterator for the current axis starting in the given contextNode.
106 *
107 * @param contextNode the node from which to follow this step
108 * @param support the remaining context for the traversal
109 * @return an iterator over the nodes along the axis
110 * @throws UnsupportedAxisException if the navigator does not support this step's axis
111 */
112 Iterator axisIterator(Object contextNode,
113 ContextSupport support) throws UnsupportedAxisException;
114
115
116 /**
117 * For each node in the given context calls matches() for every node on the
118 * axis, then filters the result by each of the predicates.
119 *
120 * @param context the node in context of its position in the document
121 * @return a list of matching nodes
122 */
123 List evaluate(Context context) throws JaxenException;
124
125 }
126