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Java > Open Source Codes > org > jaxen > expr > DefaultStep


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 JavaDoc;
64 import java.util.Iterator JavaDoc;
65 import java.util.List JavaDoc;
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 JavaDoc 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 JavaDoc getAxisName()
111     {
112         return Axis.lookup(getAxis());
113     }
114
115     public String JavaDoc getText()
116     {
117         return this.predicates.getText();
118     }
119
120     public String JavaDoc toString()
121     {
122         return getIterableAxis() + " " + super.toString();
123     }
124
125     public void simplify()
126     {
127         this.predicates.simplify();
128     }
129
130     public Iterator JavaDoc axisIterator(Object JavaDoc contextNode, ContextSupport support)
131         throws UnsupportedAxisException
132     {
133         return getIterableAxis().iterator(contextNode, support);
134     }
135
136     public List JavaDoc evaluate(final Context context) throws JaxenException
137     {
138         final List JavaDoc 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 JavaDoc interimSet = new ArrayList JavaDoc();
145         final ArrayList JavaDoc newNodeSet = new ArrayList JavaDoc();
146         final ContextSupport support = context.getContextSupport();
147             
148         // ???? use iterator instead
149
for ( int i = 0 ; i < contextSize ; ++i )
150         {
151             Object JavaDoc 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 JavaDoc axisNodeIter = axis.iterator(eachContextNode, support);
162             while ( axisNodeIter.hasNext() )
163             {
164                 Object JavaDoc 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 }
182
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