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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/pattern/Pattern.java,v 1.8 2005/04/15 20:19:47 elharo Exp $
3    * $Revision: 1.8 $
4    * $Date: 2005/04/15 20:19:47 $
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: Pattern.java,v 1.8 2005/04/15 20:19:47 elharo Exp $
60   */
61  
62  package org.jaxen.pattern;
63  
64  import org.jaxen.Context;
65  import org.jaxen.JaxenException;
66  
67  /*** <p><code>Pattern</code> defines the behaviour for pattern in
68    * the XSLT processing model.</p>
69    *
70    * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
71    * @version $Revision: 1.8 $
72    */
73  public abstract class Pattern {
74  
75      // These node numbers are compatible with both DOM and dom4j's node types
76      /*** Matches Element nodes */
77      public static final short ELEMENT_NODE = 1;
78      /*** Matches attribute nodes */
79      public static final short ATTRIBUTE_NODE = 2;
80      /*** Matches text nodes */
81      public static final short TEXT_NODE = 3;
82      /*** Matches CDATA section nodes */
83      public static final short CDATA_SECTION_NODE = 4;
84      /*** Matches entity reference nodes */
85      public static final short ENTITY_REFERENCE_NODE = 5;
86      /*** Matches entity nodes */
87      //public static final short ENTITY_NODE = 6;
88      /*** Matches ProcessingInstruction */
89      public static final short PROCESSING_INSTRUCTION_NODE = 7;
90      /*** Matches comment nodes */
91      public static final short COMMENT_NODE = 8;
92      /*** Matches document nodes */
93      public static final short DOCUMENT_NODE = 9;
94      /*** Matches DocumentType nodes */
95      public static final short DOCUMENT_TYPE_NODE = 10;
96      //public static final short DOCUMENT_FRAGMENT_NODE = 11;
97      //public static final short NOTATION_NODE = 12;
98      
99      /*** Matches a Namespace Node - NOTE this differs from DOM */
100     // XXXX: ????
101     public static final short NAMESPACE_NODE = 13;
102     
103     /*** Does not match any valid node */
104     public static final short UNKNOWN_NODE = 14;
105     
106     /*** The maximum number of node types for sizing purposes */
107     public static final short MAX_NODE_TYPE = 14;
108 
109     /*** Matches any node */
110     public static final short ANY_NODE = 0;
111     
112     /*** Matches no nodes */
113     public static final short NO_NODE = 14;
114     
115     
116     /*** @return true if the pattern matches the given node
117       */
118     public abstract boolean matches( Object node, Context context ) throws JaxenException;
119     
120     /*** Returns the default resolution policy of the pattern according to the
121       * <a href="http://www.w3.org/TR/xslt11/#conflict">
122       * XSLT conflict resolution rules</a>. 
123       * 
124       */
125     public double getPriority() 
126     {
127         return 0.5;
128     }
129     
130     /*** If this pattern is a union pattern then this
131       * method should return an array of patterns which
132       * describe the union pattern, which should contain more than one pattern.
133       * Otherwise this method should return null.
134       *
135       * @return an array of the patterns which make up this union pattern
136       * or null if this pattern is not a union pattern
137       */
138     public Pattern[] getUnionPatterns() 
139     {
140         return null;
141     }
142 
143     
144     /*** @return the type of node the pattern matches;
145       * ANY_NODE unless overridden
146       */
147     public short getMatchType() 
148     {
149         return ANY_NODE;
150     }
151 
152 
153     /*** For patterns which only match an ATTRIBUTE_NODE or an 
154       * ELEMENT_NODE then this pattern may return the name of the
155       * element or attribute it matches. This allows a more efficient
156       * rule matching algorithm to be performed, rather than a brute 
157       * force approach of evaluating every pattern for a given Node.
158       *
159       * @return the name of the element or attribute this pattern matches
160       * or null if this pattern matches any or more than one name
161       */
162     public String getMatchesNodeName() 
163     {
164         return null;
165     }
166     
167     
168     public Pattern simplify() 
169     {
170         return this;
171     }
172     
173     /*** Returns a textual representation of this pattern
174      */
175     public abstract String getText();
176 
177 }