1 /*
2 * Copyright (c) 2005, 2019, Oracle and/or its affiliates. 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package javax.lang.model.util;
27
28 import javax.lang.model.type.*;
29 import javax.annotation.processing.SupportedSourceVersion;
30 import javax.lang.model.SourceVersion;
31 import static javax.lang.model.SourceVersion.*;
32
33
34 /**
35 * A simple visitor of types with default behavior appropriate for the
36 * {@link SourceVersion#RELEASE_6 RELEASE_6} source version.
37 *
38 * Visit methods corresponding to {@code RELEASE_6} language
39 * constructs call {@link #defaultAction defaultAction}, passing their
40 * arguments to {@code defaultAction}'s corresponding parameters.
41 *
42 * For constructs introduced in {@code RELEASE_7} and later, {@code
43 * visitUnknown} is called instead.
44 *
45 * <p> Methods in this class may be overridden subject to their
46 * general contract. Note that annotating methods in concrete
47 * subclasses with {@link java.lang.Override @Override} will help
48 * ensure that methods are overridden as intended.
49 *
50 * <p> <b>WARNING:</b> The {@code TypeVisitor} interface implemented
51 * by this class may have methods added to it in the future to
52 * accommodate new, currently unknown, language structures added to
53 * future versions of the Java™ programming language.
54 * Therefore, methods whose names begin with {@code "visit"} may be
55 * added to this class in the future; to avoid incompatibilities,
56 * classes which extend this class should not declare any instance
57 * methods with names beginning with {@code "visit"}.
58 *
59 * <p>When such a new visit method is added, the default
60 * implementation in this class will be to call the {@link
61 * #visitUnknown visitUnknown} method. A new simple type visitor
62 * class will also be introduced to correspond to the new language
63 * level; this visitor will have different default behavior for the
64 * visit method in question. When the new visitor is introduced, all
65 * or portions of this visitor may be deprecated.
66 *
67 * @param <R> the return type of this visitor's methods. Use {@link
68 * Void} for visitors that do not need to return results.
69 * @param <P> the type of the additional parameter to this visitor's
70 * methods. Use {@code Void} for visitors that do not need an
71 * additional parameter.
72 *
73 * @author Joseph D. Darcy
74 * @author Scott Seligman
75 * @author Peter von der Ahé
76 *
77 * @see SimpleTypeVisitor7
78 * @see SimpleTypeVisitor8
79 * @see SimpleTypeVisitor9
80 * @see SimpleTypeVisitor14
81 * @since 1.6
82 */
83 @SupportedSourceVersion(RELEASE_6)
84 public class SimpleTypeVisitor6<R, P> extends AbstractTypeVisitor6<R, P> {
85 /**
86 * Default value to be returned; {@link #defaultAction
87 * defaultAction} returns this value unless the method is
88 * overridden.
89 */
90 protected final R DEFAULT_VALUE;
91
92 /**
93 * Constructor for concrete subclasses; uses {@code null} for the
94 * default value.
95 * @deprecated Release 6 is obsolete; update to a visitor for a newer
96 * release level.
97 */
98 @Deprecated(since="9")
99 protected SimpleTypeVisitor6(){
100 DEFAULT_VALUE = null;
101 }
102
103 /**
104 * Constructor for concrete subclasses; uses the argument for the
105 * default value.
106 *
107 * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
108 * @deprecated Release 6 is obsolete; update to a visitor for a newer
109 * release level.
110 */
111 @Deprecated(since="9")
112 protected SimpleTypeVisitor6(R defaultValue){
113 DEFAULT_VALUE = defaultValue;
114 }
115
116 /**
117 * The default action for visit methods.
118 *
119 * @implSpec The implementation in this class just returns {@link
120 * #DEFAULT_VALUE}; subclasses will commonly override this method.
121 *
122 * @param e the type to process
123 * @param p a visitor-specified parameter
124 * @return {@code DEFAULT_VALUE} unless overridden
125 */
126 protected R defaultAction(TypeMirror e, P p) {
127 return DEFAULT_VALUE;
128 }
129
130 /**
131 * {@inheritDoc}
132 *
133 * @implSpec This implementation calls {@code defaultAction}.
134 *
135 * @param t {@inheritDoc}
136 * @param p {@inheritDoc}
137 * @return the result of {@code defaultAction}
138 */
139 public R visitPrimitive(PrimitiveType t, P p) {
140 return defaultAction(t, p);
141 }
142
143 /**
144 * {@inheritDoc} This implementation calls {@code defaultAction}.
145 *
146 * @implSpec This implementation calls {@code defaultAction}.
147 *
148 * @param t {@inheritDoc}
149 * @param p {@inheritDoc}
150 * @return the result of {@code defaultAction}
151 */
152 public R visitNull(NullType t, P p){
153 return defaultAction(t, p);
154 }
155
156 /**
157 * {@inheritDoc}
158 *
159 * @implSpec This implementation calls {@code defaultAction}.
160 *
161 * @param t {@inheritDoc}
162 * @param p {@inheritDoc}
163 * @return the result of {@code defaultAction}
164 */
165 public R visitArray(ArrayType t, P p){
166 return defaultAction(t, p);
167 }
168
169 /**
170 * {@inheritDoc}
171 *
172 * @implSpec This implementation calls {@code defaultAction}.
173 *
174 * @param t {@inheritDoc}
175 * @param p {@inheritDoc}
176 * @return the result of {@code defaultAction}
177 */
178 public R visitDeclared(DeclaredType t, P p){
179 return defaultAction(t, p);
180 }
181
182 /**
183 * {@inheritDoc}
184 *
185 * @implSpec This implementation calls {@code defaultAction}.
186 *
187 * @param t {@inheritDoc}
188 * @param p {@inheritDoc}
189 * @return the result of {@code defaultAction}
190 */
191 public R visitError(ErrorType t, P p){
192 return defaultAction(t, p);
193 }
194
195 /**
196 * {@inheritDoc}
197 *
198 * @implSpec This implementation calls {@code defaultAction}.
199 *
200 * @param t {@inheritDoc}
201 * @param p {@inheritDoc}
202 * @return the result of {@code defaultAction}
203 */
204 public R visitTypeVariable(TypeVariable t, P p){
205 return defaultAction(t, p);
206 }
207
208 /**
209 * {@inheritDoc}
210 *
211 * @implSpec This implementation calls {@code defaultAction}.
212 *
213 * @param t {@inheritDoc}
214 * @param p {@inheritDoc}
215 * @return the result of {@code defaultAction}
216 */
217 public R visitWildcard(WildcardType t, P p){
218 return defaultAction(t, p);
219 }
220
221 /**
222 * {@inheritDoc}
223 *
224 * @implSpec This implementation calls {@code defaultAction}.
225 *
226 * @param t {@inheritDoc}
227 * @param p {@inheritDoc}
228 * @return the result of {@code defaultAction}
229 */
230 public R visitExecutable(ExecutableType t, P p) {
231 return defaultAction(t, p);
232 }
233
234 /**
235 * {@inheritDoc}
236 *
237 * @implSpec This implementation calls {@code defaultAction}.
238 *
239 * @param t {@inheritDoc}
240 * @param p {@inheritDoc}
241 * @return the result of {@code defaultAction}
242 */
243 public R visitNoType(NoType t, P p){
244 return defaultAction(t, p);
245 }
246 }