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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultFilterExpr.java,v 1.14 2005/03/21 22:39:16 elharo Exp $
3    * $Revision: 1.14 $
4    * $Date: 2005/03/21 22:39:16 $
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: DefaultFilterExpr.java,v 1.14 2005/03/21 22:39:16 elharo Exp $
60   */
61  
62  
63  
64  package org.jaxen.expr;
65  
66  import java.util.ArrayList;
67  import java.util.List;
68  import org.jaxen.Context;
69  import org.jaxen.JaxenException;
70  
71  public class DefaultFilterExpr extends DefaultExpr implements FilterExpr, Predicated
72  {
73      private Expr expr;
74      private PredicateSet predicates;
75  
76      public DefaultFilterExpr(PredicateSet predicateSet)
77      {
78          this.predicates = predicateSet;
79      }
80  
81      public DefaultFilterExpr(Expr expr, PredicateSet predicateSet)
82      {
83          this.expr       = expr;
84          this.predicates = predicateSet;
85      }
86  
87      public void addPredicate(Predicate predicate)
88      {
89          this.predicates.addPredicate( predicate );
90      }
91  
92      public List getPredicates()
93      {
94          return this.predicates.getPredicates();
95      }
96  
97      public PredicateSet getPredicateSet()
98      {
99          return this.predicates;
100     }
101 
102     public Expr getExpr()
103     {
104         return this.expr;
105     }
106 
107     public String toString()
108     {
109         return "[(DefaultFilterExpr): expr: " + expr + " predicates: " + predicates + " ]";
110     }
111 
112     public String getText()
113     {
114         String text = "";
115         if ( this.expr != null )
116         {
117             text = this.expr.getText();
118         }
119         text += predicates.getText();
120         return text;
121     }
122 
123     public Expr simplify()
124     {
125         this.predicates.simplify();
126 
127         if ( this.expr != null ) 
128         {
129             this.expr = this.expr.simplify();
130         }
131 
132         if ( this.predicates.getPredicates().size() == 0 )
133         {
134             return getExpr();
135         }
136 
137         return this;
138     }
139 
140     /*** Returns true if the current filter matches at least one of the context nodes
141      */
142     public boolean asBoolean(Context context) throws JaxenException 
143     {
144         Object results = null;
145         if ( expr != null ) 
146         {
147             results = expr.evaluate( context );
148         }
149         else
150         {
151             List nodeSet = context.getNodeSet();
152             ArrayList list = new ArrayList(nodeSet.size());
153             list.addAll( nodeSet );
154             results = list;
155         }
156         
157         if ( results instanceof Boolean ) 
158         {
159             Boolean b = (Boolean) results;
160             return b.booleanValue();
161         }
162         if ( results instanceof List )
163         {
164             return getPredicateSet().evaluateAsBoolean( 
165                 (List) results, context.getContextSupport() 
166             );
167         }
168         
169         return false;
170     }
171     
172     public Object evaluate(Context context) throws JaxenException
173     {
174         Object results = getExpr().evaluate( context );
175         
176         if ( results instanceof List )
177         {
178             List newresults = getPredicateSet().evaluatePredicates( (List) results,
179                                     context.getContextSupport() );
180         results = newresults;
181         }
182 
183         return results;
184     }
185     public void accept(Visitor visitor)
186     {
187         visitor.visit(this);
188     }
189 }