1 /*
2 * Copyright (c) 2005, 2017, 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 * @since 1.6
81 */
82 @SupportedSourceVersion(RELEASE_6)
83 public class SimpleTypeVisitor6<R, P> extends AbstractTypeVisitor6<R, P> {
84 /**
85 * Default value to be returned; {@link #defaultAction
86 * defaultAction} returns this value unless the method is
87 * overridden.
88 */
89 protected final R DEFAULT_VALUE;
90
91 /**
92 * Constructor for concrete subclasses; uses {@code null} for the
93 * default value.
94 * @deprecated Release 6 is obsolete; update to a visitor for a newer
95 * release level.
96 */
97 @Deprecated(since="9")
98 protected SimpleTypeVisitor6(){
99 DEFAULT_VALUE = null;
100 }
101
102 /**
103 * Constructor for concrete subclasses; uses the argument for the
104 * default value.
105 *
106 * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
107 * @deprecated Release 6 is obsolete; update to a visitor for a newer
108 * release level.
109 */
110 @Deprecated(since="9")
111 protected SimpleTypeVisitor6(R defaultValue){
112 DEFAULT_VALUE = defaultValue;
113 }
114
115 /**
116 * The default action for visit methods.
117 *
118 * @implSpec The implementation in this class just returns {@link
119 * #DEFAULT_VALUE}; subclasses will commonly override this method.
120 *
121 * @param e the type to process
122 * @param p a visitor-specified parameter
123 * @return {@code DEFAULT_VALUE} unless overridden
124 */
125 protected R defaultAction(TypeMirror e, P p) {
126 return DEFAULT_VALUE;
127 }
128
129 /**
130 * {@inheritDoc}
131 *
132 * @implSpec This implementation calls {@code defaultAction}.
133 *
134 * @param t {@inheritDoc}
135 * @param p {@inheritDoc}
136 * @return the result of {@code defaultAction}
137 */
138 public R visitPrimitive(PrimitiveType t, P p) {
139 return defaultAction(t, p);
140 }
141
142 /**
143 * {@inheritDoc} This implementation calls {@code defaultAction}.
144 *
145 * @implSpec This implementation calls {@code defaultAction}.
146 *
147 * @param t {@inheritDoc}
148 * @param p {@inheritDoc}
149 * @return the result of {@code defaultAction}
150 */
151 public R visitNull(NullType t, P p){
152 return defaultAction(t, p);
153 }
154
155 /**
156 * {@inheritDoc}
157 *
158 * @implSpec This implementation calls {@code defaultAction}.
159 *
160 * @param t {@inheritDoc}
161 * @param p {@inheritDoc}
162 * @return the result of {@code defaultAction}
163 */
164 public R visitArray(ArrayType t, P p){
165 return defaultAction(t, p);
166 }
167
168 /**
169 * {@inheritDoc}
170 *
171 * @implSpec This implementation calls {@code defaultAction}.
172 *
173 * @param t {@inheritDoc}
174 * @param p {@inheritDoc}
175 * @return the result of {@code defaultAction}
176 */
177 public R visitDeclared(DeclaredType t, P p){
178 return defaultAction(t, p);
179 }
180
181 /**
182 * {@inheritDoc}
183 *
184 * @implSpec This implementation calls {@code defaultAction}.
185 *
186 * @param t {@inheritDoc}
187 * @param p {@inheritDoc}
188 * @return the result of {@code defaultAction}
189 */
190 public R visitError(ErrorType t, P p){
191 return defaultAction(t, p);
192 }
193
194 /**
195 * {@inheritDoc}
196 *
197 * @implSpec This implementation calls {@code defaultAction}.
198 *
199 * @param t {@inheritDoc}
200 * @param p {@inheritDoc}
201 * @return the result of {@code defaultAction}
202 */
203 public R visitTypeVariable(TypeVariable t, P p){
204 return defaultAction(t, p);
205 }
206
207 /**
208 * {@inheritDoc}
209 *
210 * @implSpec This implementation calls {@code defaultAction}.
211 *
212 * @param t {@inheritDoc}
213 * @param p {@inheritDoc}
214 * @return the result of {@code defaultAction}
215 */
216 public R visitWildcard(WildcardType t, P p){
217 return defaultAction(t, p);
218 }
219
220 /**
221 * {@inheritDoc}
222 *
223 * @implSpec This implementation calls {@code defaultAction}.
224 *
225 * @param t {@inheritDoc}
226 * @param p {@inheritDoc}
227 * @return the result of {@code defaultAction}
228 */
229 public R visitExecutable(ExecutableType t, P p) {
230 return defaultAction(t, p);
231 }
232
233 /**
234 * {@inheritDoc}
235 *
236 * @implSpec This implementation calls {@code defaultAction}.
237 *
238 * @param t {@inheritDoc}
239 * @param p {@inheritDoc}
240 * @return the result of {@code defaultAction}
241 */
242 public R visitNoType(NoType t, P p){
243 return defaultAction(t, p);
244 }
245 }