1 /*
2 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/PredicateSet.java,v 1.19 2005/06/28 13:44:44 elharo Exp $
3 * $Revision: 1.19 $
4 * $Date: 2005/06/28 13:44:44 $
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: PredicateSet.java,v 1.19 2005/06/28 13:44:44 elharo Exp $
60 */
61
62
63
64 package org.jaxen.expr;
65
66 import java.io.Serializable;
67 import java.util.ArrayList;
68 import java.util.Collections;
69 import java.util.Iterator;
70 import java.util.List;
71 import org.jaxen.Context;
72 import org.jaxen.ContextSupport;
73 import org.jaxen.JaxenException;
74 import org.jaxen.function.BooleanFunction;
75
76 public class PredicateSet implements Serializable
77 {
78 private List predicates;
79
80 public PredicateSet()
81 {
82 this.predicates = Collections.EMPTY_LIST;
83 }
84
85 public void addPredicate(Predicate predicate)
86 {
87 if ( this.predicates == Collections.EMPTY_LIST )
88 {
89 this.predicates = new ArrayList();
90 }
91
92 this.predicates.add( predicate );
93 }
94
95 public List getPredicates()
96 {
97 return this.predicates;
98 }
99
100 public void simplify()
101 {
102 Iterator predIter = this.predicates.iterator();
103 Predicate eachPred = null;
104
105 while ( predIter.hasNext() )
106 {
107 eachPred = (Predicate) predIter.next();
108 eachPred.simplify();
109 }
110 }
111
112 public String getText()
113 {
114 StringBuffer buf = new StringBuffer();
115
116 Iterator predIter = this.predicates.iterator();
117 Predicate eachPred = null;
118
119 while ( predIter.hasNext() )
120 {
121 eachPred = (Predicate) predIter.next();
122 buf.append( eachPred.getText() );
123 }
124
125 return buf.toString();
126 }
127
128 // FIXME: Note - this could be *MUCH* more efficient
129 // currently this creates many redundant collections and should halt
130 // evaluation on the first matching item.
131 protected boolean evaluateAsBoolean(List contextNodeSet,
132 ContextSupport support) throws JaxenException
133 {
134 List result = evaluatePredicates( contextNodeSet, support );
135
136 return ! result.isEmpty();
137 }
138
139 protected List evaluatePredicates(List contextNodeSet, ContextSupport support)
140 throws JaxenException {
141 // Easy way out (necessary)
142 if (predicates.size() == 0) {
143 return contextNodeSet;
144 }
145 Iterator predIter = predicates.iterator();
146
147 // initial list to filter
148 List nodes2Filter = contextNodeSet;
149 // apply all predicates
150 while(predIter.hasNext()) {
151 nodes2Filter =
152 applyPredicate((Predicate)predIter.next(), nodes2Filter, support);
153 }
154
155 return nodes2Filter;
156 }
157
158 public List applyPredicate(Predicate predicate, List nodes2Filter, ContextSupport support)
159 throws JaxenException {
160 final int nodes2FilterSize = nodes2Filter.size();
161 List filteredNodes = new ArrayList(nodes2FilterSize);
162 // Set up a dummy context with a list to hold each node
163 Context predContext = new Context(support);
164 List tempList = new ArrayList(1);
165 predContext.setNodeSet(tempList);
166 // loop through the current nodes to filter and add to the
167 // filtered nodes list if the predicate succeeds
168 for (int i = 0; i < nodes2FilterSize; ++i) {
169 Object contextNode = nodes2Filter.get(i);
170 tempList.clear();
171 tempList.add(contextNode);
172 predContext.setNodeSet(tempList);
173 // ????
174 predContext.setPosition(i + 1);
175 predContext.setSize(nodes2FilterSize);
176 Object predResult = predicate.evaluate(predContext);
177 if (predResult instanceof Number) {
178 // Here we assume nodes are in forward or reverse order
179 // as appropriate for axis
180 int proximity = ((Number) predResult).intValue();
181 if (proximity == (i + 1)) {
182 filteredNodes.add(contextNode);
183 }
184 }
185 else {
186 Boolean includes =
187 BooleanFunction.evaluate(predResult,
188 predContext.getNavigator());
189 if (includes.booleanValue()) {
190 filteredNodes.add(contextNode);
191 }
192 }
193 }
194 return filteredNodes;
195 }
196 }