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.annotation.processing.SupportedSourceVersion;
29 import javax.lang.model.type.*;
30
31 import static javax.lang.model.SourceVersion.*;
32
33 /**
34 * A skeletal visitor of types with default behavior appropriate for
35 * the {@link javax.lang.model.SourceVersion#RELEASE_6 RELEASE_6}
36 * source version.
37 *
38 * <p> <b>WARNING:</b> The {@code TypeVisitor} interface implemented
39 * by this class may have methods added to it in the future to
40 * accommodate new, currently unknown, language structures added to
41 * future versions of the Java™ programming language.
42 * Therefore, methods whose names begin with {@code "visit"} may be
43 * added to this class in the future; to avoid incompatibilities,
44 * classes which extend this class should not declare any instance
45 * methods with names beginning with {@code "visit"}.
46 *
47 * <p>When such a new visit method is added, the default
48 * implementation in this class will be to call the {@link
49 * #visitUnknown visitUnknown} method. A new abstract type visitor
50 * class will also be introduced to correspond to the new language
51 * level; this visitor will have different default behavior for the
52 * visit method in question. When the new visitor is introduced, all
53 * or portions of this visitor may be deprecated.
54 *
55 * @param <R> the return type of this visitor's methods. Use {@link
56 * Void} for visitors that do not need to return results.
57 * @param <P> the type of the additional parameter to this visitor's
58 * methods. Use {@code Void} for visitors that do not need an
59 * additional parameter.
60 *
61 * @author Joseph D. Darcy
62 * @author Scott Seligman
63 * @author Peter von der Ahé
64 *
65 * @see AbstractTypeVisitor7
66 * @see AbstractTypeVisitor8
67 * @see AbstractTypeVisitor9
68 * @see AbstractTypeVisitor14
69 * @since 1.6
70 */
71 @SupportedSourceVersion(RELEASE_6)
72 public abstract class AbstractTypeVisitor6<R, P> implements TypeVisitor<R, P> {
73 /**
74 * Constructor for concrete subclasses to call.
75 * @deprecated Release 6 is obsolete; update to a visitor for a newer
76 * release level.
77 */
78 @Deprecated(since="9")
79 protected AbstractTypeVisitor6() {}
80
81 /**
82 * Visits any type mirror as if by passing itself to that type
83 * mirror's {@link TypeMirror#accept accept} method. The
84 * invocation {@code v.visit(t, p)} is equivalent to {@code
85 * t.accept(v, p)}.
86 *
87 * @param t the type to visit
88 * @param p a visitor-specified parameter
89 * @return a visitor-specified result
90 */
91 public final R visit(TypeMirror t, P p) {
92 return t.accept(this, p);
93 }
94
95 /**
96 * Visits any type mirror as if by passing itself to that type
97 * mirror's {@link TypeMirror#accept accept} method and passing
98 * {@code null} for the additional parameter. The invocation
99 * {@code v.visit(t)} is equivalent to {@code t.accept(v, null)}.
100 *
101 * @param t the type to visit
102 * @return a visitor-specified result
103 */
104 public final R visit(TypeMirror t) {
105 return t.accept(this, null);
106 }
107
108 /**
109 * {@inheritDoc}
110 *
111 * @implSpec Visits a {@code UnionType} element by calling {@code
112 * visitUnknown}.
113 *
114 * @param t {@inheritDoc}
115 * @param p {@inheritDoc}
116 * @return the result of {@code visitUnknown}
117 *
118 * @since 1.7
119 */
120 public R visitUnion(UnionType t, P p) {
121 return visitUnknown(t, p);
122 }
123
124 /**
125 * {@inheritDoc}
126 *
127 * @implSpec Visits an {@code IntersectionType} element by calling {@code
128 * visitUnknown}.
129 *
130 * @param t {@inheritDoc}
131 * @param p {@inheritDoc}
132 * @return the result of {@code visitUnknown}
133 *
134 * @since 1.8
135 */
136 @Override
137 public R visitIntersection(IntersectionType t, P p) {
138 return visitUnknown(t, p);
139 }
140
141 /**
142 * {@inheritDoc}
143 *
144 * @implSpec The default implementation of this method in {@code
145 * AbstractTypeVisitor6} will always throw {@code
146 * new UnknownTypeException(t, p)}. This behavior is not required of a
147 * subclass.
148 *
149 * @param t {@inheritDoc}
150 * @param p {@inheritDoc}
151 * @return a visitor-specified result
152 * @throws UnknownTypeException
153 * a visitor implementation may optionally throw this exception
154 */
155 @Override
156 public R visitUnknown(TypeMirror t, P p) {
157 throw new UnknownTypeException(t, p);
158 }
159 }