1 /*
2 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultStep.java,v 1.18 2005/06/01 11:18:27 elharo Exp $
3 * $Revision: 1.18 $
4 * $Date: 2005/06/01 11:18:27 $
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 1.18 2005/06/01 11:18:27 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 public abstract class DefaultStep implements Step
75 {
76 private IterableAxis axis;
77 private PredicateSet predicates;
78
79 public DefaultStep(IterableAxis axis, PredicateSet predicates)
80 {
81 this.axis = axis;
82 this.predicates = predicates;
83 }
84
85 public void addPredicate(Predicate predicate)
86 {
87 this.predicates.addPredicate(predicate);
88 }
89
90 public List getPredicates()
91 {
92 return this.predicates.getPredicates();
93 }
94
95 public PredicateSet getPredicateSet()
96 {
97 return this.predicates;
98 }
99
100 public int getAxis()
101 {
102 return this.axis.value();
103 }
104
105 public IterableAxis getIterableAxis()
106 {
107 return this.axis;
108 }
109
110 public String getAxisName()
111 {
112 return Axis.lookup(getAxis());
113 }
114
115 public String getText()
116 {
117 return this.predicates.getText();
118 }
119
120 public String toString()
121 {
122 return getIterableAxis() + " " + super.toString();
123 }
124
125 public void simplify()
126 {
127 this.predicates.simplify();
128 }
129
130 public Iterator axisIterator(Object contextNode, ContextSupport support)
131 throws UnsupportedAxisException
132 {
133 return getIterableAxis().iterator(contextNode, support);
134 }
135
136 public List evaluate(final Context context) throws JaxenException
137 {
138 final List contextNodeSet = context.getNodeSet();
139 final IdentitySet unique = new IdentitySet();
140 final int contextSize = contextNodeSet.size();
141
142 // ???? try linked lists instead?
143 // ???? initial size for these?
144 final ArrayList interimSet = new ArrayList();
145 final ArrayList newNodeSet = new ArrayList();
146 final ContextSupport support = context.getContextSupport();
147
148 // ???? use iterator instead
149 for ( int i = 0 ; i < contextSize ; ++i )
150 {
151 Object eachContextNode = contextNodeSet.get( i );
152
153
154 /* See jaxen-106. Might be able to optimize this by doing
155 * specific matching for individual axes. For instance on namespace axis
156 * we should only get namespace nodes and on attribute axes we only get
157 * attribute nodes. Self and parent axes have single members.
158 * Children, descendant, ancestor, and sibling axes never
159 * see any attributes or namespaces
160 */
161 Iterator axisNodeIter = axis.iterator(eachContextNode, support);
162 while ( axisNodeIter.hasNext() )
163 {
164 Object eachAxisNode = axisNodeIter.next();
165 if ( ! unique.contains( eachAxisNode ) )
166 {
167 if ( matches( eachAxisNode, support ) )
168 {
169 unique.add( eachAxisNode );
170 interimSet.add( eachAxisNode );
171 }
172 }
173 }
174 newNodeSet.addAll(getPredicateSet().evaluatePredicates(
175 interimSet, support ));
176 interimSet.clear();
177 }
178 return newNodeSet;
179 }
180
181 }