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 | import javax.lang.model.element.*; |
29 | import javax.annotation.processing.SupportedSourceVersion; |
30 | import static javax.lang.model.element.ElementKind.*; |
31 | import javax.lang.model.SourceVersion; |
32 | import static javax.lang.model.SourceVersion.*; |
33 | |
34 | |
35 | /** |
36 | * A simple visitor of program elements with default behavior |
37 | * appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6} |
38 | * source version. |
39 | * |
40 | * Visit methods corresponding to {@code RELEASE_6} language |
41 | * constructs call {@link #defaultAction}, passing their arguments to |
42 | * {@code defaultAction}'s corresponding parameters. |
43 | * |
44 | * <p> Methods in this class may be overridden subject to their |
45 | * general contract. Note that annotating methods in concrete |
46 | * subclasses with {@link java.lang.Override @Override} will help |
47 | * ensure that methods are overridden as intended. |
48 | * |
49 | * <p> <b>WARNING:</b> The {@code ElementVisitor} interface |
50 | * implemented by this class may have methods added to it in the |
51 | * future to accommodate new, currently unknown, language structures |
52 | * added to future versions of the Java™ programming language. |
53 | * Therefore, methods whose names begin with {@code "visit"} may be |
54 | * added to this class in the future; to avoid incompatibilities, |
55 | * classes which extend this class should not declare any instance |
56 | * methods with names beginning with {@code "visit"}. |
57 | * |
58 | * <p>When such a new visit method is added, the default |
59 | * implementation in this class will be to call the {@link |
60 | * #visitUnknown visitUnknown} method. A new simple element visitor |
61 | * class will also be introduced to correspond to the new language |
62 | * level; this visitor will have different default behavior for the |
63 | * visit method in question. When the new visitor is introduced, all |
64 | * or portions of this visitor may be deprecated. |
65 | * |
66 | * @param <R> the return type of this visitor's methods. Use {@code Void} |
67 | * for visitors that do not need to return results. |
68 | * @param <P> the type of the additional parameter to this visitor's methods. Use {@code Void} |
69 | * for visitors that do not need an additional parameter. |
70 | * |
71 | * @author Joseph D. Darcy |
72 | * @author Scott Seligman |
73 | * @author Peter von der Ahé |
74 | * @since 1.6 |
75 | */ |
76 | @SupportedSourceVersion(RELEASE_6) |
77 | public class SimpleElementVisitor6<R, P> extends AbstractElementVisitor6<R, P> { |
78 | /** |
79 | * Default value to be returned; {@link #defaultAction |
80 | * defaultAction} returns this value unless the method is |
81 | * overridden. |
82 | */ |
83 | protected final R DEFAULT_VALUE; |
84 | |
85 | /** |
86 | * Constructor for concrete subclasses; uses {@code null} for the |
87 | * default value. |
88 | */ |
89 | protected SimpleElementVisitor6(){ |
90 | DEFAULT_VALUE = null; |
91 | } |
92 | |
93 | /** |
94 | * Constructor for concrete subclasses; uses the argument for the |
95 | * default value. |
96 | * |
97 | * @param defaultValue the value to assign to {@link #DEFAULT_VALUE} |
98 | */ |
99 | protected SimpleElementVisitor6(R defaultValue){ |
100 | DEFAULT_VALUE = defaultValue; |
101 | } |
102 | /** |
103 | * The default action for visit methods. The implementation in |
104 | * this class just returns {@link #DEFAULT_VALUE}; subclasses will |
105 | * commonly override this method. |
106 | * |
107 | * @param e the element to process |
108 | * @param p a visitor-specified parameter |
109 | * @return {@code DEFAULT_VALUE} unless overridden |
110 | */ |
111 | protected R defaultAction(Element e, P p) { |
112 | return DEFAULT_VALUE; |
113 | } |
114 | |
115 | /** |
116 | * {@inheritDoc} This implementation calls {@code defaultAction}. |
117 | * |
118 | * @param e {@inheritDoc} |
119 | * @param p {@inheritDoc} |
120 | * @return the result of {@code defaultAction} |
121 | */ |
122 | public R visitPackage(PackageElement e, P p) { |
123 | return defaultAction(e, p); |
124 | } |
125 | |
126 | /** |
127 | * {@inheritDoc} This implementation calls {@code defaultAction}. |
128 | * |
129 | * @param e {@inheritDoc} |
130 | * @param p {@inheritDoc} |
131 | * @return the result of {@code defaultAction} |
132 | */ |
133 | public R visitType(TypeElement e, P p) { |
134 | return defaultAction(e, p); |
135 | } |
136 | |
137 | /** |
138 | * {@inheritDoc} This implementation calls {@code defaultAction}. |
139 | * |
140 | * @param e {@inheritDoc} |
141 | * @param p {@inheritDoc} |
142 | * @return the result of {@code defaultAction} |
143 | */ |
144 | public R visitVariable(VariableElement e, P p) { |
145 | return defaultAction(e, p); |
146 | } |
147 | |
148 | /** |
149 | * {@inheritDoc} This implementation calls {@code defaultAction}. |
150 | * |
151 | * @param e {@inheritDoc} |
152 | * @param p {@inheritDoc} |
153 | * @return the result of {@code defaultAction} |
154 | */ |
155 | public R visitExecutable(ExecutableElement e, P p) { |
156 | return defaultAction(e, p); |
157 | } |
158 | |
159 | /** |
160 | * {@inheritDoc} This implementation calls {@code defaultAction}. |
161 | * |
162 | * @param e {@inheritDoc} |
163 | * @param p {@inheritDoc} |
164 | * @return the result of {@code defaultAction} |
165 | */ |
166 | public R visitTypeParameter(TypeParameterElement e, P p) { |
167 | return defaultAction(e, p); |
168 | } |
169 | } |