1 /*
2 * $Header$
3 * $Revision$
4 * $Date$
5 *
6 * ====================================================================
7 *
8 * Copyright 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 are
13 * met:
14 *
15 * * Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 *
18 * * Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 *
22 * * Neither the name of the Jaxen Project nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
27 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
29 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
30 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
32 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
33 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37 *
38 * ====================================================================
39 * This software consists of voluntary contributions made by many
40 * individuals on behalf of the Jaxen Project and was originally
41 * created by bob mcwhirter <bob@werken.com> and
42 * James Strachan <jstrachan@apache.org>. For more information on the
43 * Jaxen Project, please see <http://www.jaxen.org/>.
44 *
45 * $Id$
46 */
47
48
49
50 package org.jaxen.expr;
51
52 import org.jaxen.Context;
53 import org.jaxen.JaxenException;
54
55 /**
56 * Represents an XPath filter expression. This is
57 * <a href='http://www.w3.org/TR/xpath#NT-FilterExpr'>production 20</a> in the
58 * <a href="https://www.w3.org/TR/xpath">XPath 1.0 specification</a>:
59 *
60 * <table><tr valign="baseline">
61 * <td><a name="NT-FilterExpr"></a>[20] </td><td>FilterExpr</td><td> ::= </td><td><a href="https://www.w3.org/TR/xpath#NT-PrimaryExpr">PrimaryExpr</a></td><td></td>
62 * </tr>
63 * <tr valign="baseline">
64 * <td></td><td></td><td></td><td>| <a href="https://www.w3.org/TR/xpath#NT-FilterExpr">FilterExpr</a> <a href="https://www.w3.org/TR/xpath#NT-Predicate">Predicate</a></td><td></td>
65 * </tr>
66 * </table>
67 *
68 */
69 public interface FilterExpr extends Expr, Predicated
70 {
71
72 /**
73 * Evaluates the filter expression on the current context
74 * and returns true if at least one node matches.
75 *
76 * @return true if a node matches; false if no node matches
77 */
78 public boolean asBoolean(Context context) throws JaxenException;
79
80 /**
81 * @return the underlying filter expression
82 */
83 public Expr getExpr();
84 }