1 | /* |
2 | * Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved. |
3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 | * |
5 | * This code is free software; you can redistribute it and/or modify it |
6 | * under the terms of the GNU General Public License version 2 only, as |
7 | * published by the Free Software Foundation. Sun designates this |
8 | * particular file as subject to the "Classpath" exception as provided |
9 | * by Sun in the LICENSE file that accompanied this code. |
10 | * |
11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
14 | * version 2 for more details (a copy is included in the LICENSE file that |
15 | * accompanied this code). |
16 | * |
17 | * You should have received a copy of the GNU General Public License version |
18 | * 2 along with this work; if not, write to the Free Software Foundation, |
19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
20 | * |
21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
23 | * have any questions. |
24 | */ |
25 | |
26 | package javax.lang.model.util; |
27 | |
28 | |
29 | import javax.lang.model.element.*; |
30 | import javax.annotation.processing.SupportedSourceVersion; |
31 | import javax.lang.model.element.*; |
32 | import static javax.lang.model.element.ElementKind.*; |
33 | import static javax.lang.model.SourceVersion.*; |
34 | import javax.lang.model.SourceVersion; |
35 | |
36 | |
37 | /** |
38 | * A skeletal visitor of program elements with default behavior |
39 | * appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6} |
40 | * source version. |
41 | * |
42 | * <p> <b>WARNING:</b> The {@code ElementVisitor} interface |
43 | * implemented by this class may have methods added to it in the |
44 | * future to accommodate new, currently unknown, language structures |
45 | * added to future versions of the Java™ programming language. |
46 | * Therefore, methods whose names begin with {@code "visit"} may be |
47 | * added to this class in the future; to avoid incompatibilities, |
48 | * classes which extend this class should not declare any instance |
49 | * methods with names beginning with {@code "visit"}. |
50 | * |
51 | * <p>When such a new visit method is added, the default |
52 | * implementation in this class will be to call the {@link |
53 | * #visitUnknown visitUnknown} method. A new abstract element visitor |
54 | * class will also be introduced to correspond to the new language |
55 | * level; this visitor will have different default behavior for the |
56 | * visit method in question. When the new visitor is introduced, all |
57 | * or portions of this visitor may be deprecated. |
58 | * |
59 | * @param <R> the return type of this visitor's methods. Use {@link |
60 | * Void} for visitors that do not need to return results. |
61 | * @param <P> the type of the additional parameter to this visitor's |
62 | * methods. Use {@code Void} for visitors that do not need an |
63 | * additional parameter. |
64 | * |
65 | * @author Joseph D. Darcy |
66 | * @author Scott Seligman |
67 | * @author Peter von der Ahé |
68 | * @since 1.6 |
69 | */ |
70 | @SupportedSourceVersion(RELEASE_6) |
71 | public abstract class AbstractElementVisitor6<R, P> implements ElementVisitor<R, P> { |
72 | /** |
73 | * Constructor for concrete subclasses to call. |
74 | */ |
75 | protected AbstractElementVisitor6(){} |
76 | |
77 | /** |
78 | * Visits any program element as if by passing itself to that |
79 | * element's {@link Element#accept accept} method. The invocation |
80 | * {@code v.visit(elem)} is equivalent to {@code elem.accept(v, |
81 | * p)}. |
82 | * |
83 | * @param e the element to visit |
84 | * @param p a visitor-specified parameter |
85 | * @return a visitor-specified result |
86 | */ |
87 | public final R visit(Element e, P p) { |
88 | return e.accept(this, p); |
89 | } |
90 | |
91 | /** |
92 | * Visits any program element as if by passing itself to that |
93 | * element's {@link Element#accept accept} method and passing |
94 | * {@code null} for the additional parameter. The invocation |
95 | * {@code v.visit(elem)} is equivalent to {@code elem.accept(v, |
96 | * null)}. |
97 | * |
98 | * @param e the element to visit |
99 | * @return a visitor-specified result |
100 | */ |
101 | public final R visit(Element e) { |
102 | return e.accept(this, null); |
103 | } |
104 | |
105 | /** |
106 | * {@inheritDoc} |
107 | * |
108 | * <p> The default implementation of this method in |
109 | * {@code AbstractElementVisitor6} will always throw |
110 | * {@code UnknownElementException}. |
111 | * This behavior is not required of a subclass. |
112 | * |
113 | * @param e the element to visit |
114 | * @param p a visitor-specified parameter |
115 | * @return a visitor-specified result |
116 | * @throws UnknownElementException |
117 | * a visitor implementation may optionally throw this exception |
118 | */ |
119 | public R visitUnknown(Element e, P p) { |
120 | throw new UnknownElementException(e, p); |
121 | } |
122 | } |