1 /*
2 * Copyright (c) 2005, 2012, 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
29 import javax.lang.model.element.*;
30
31 import static javax.lang.model.SourceVersion.*;
32 import javax.lang.model.SourceVersion;
33 import javax.annotation.processing.SupportedSourceVersion;
34
35 /**
36 * A skeletal visitor for annotation values with default behavior
37 * appropriate for the {@link SourceVersion#RELEASE_6 RELEASE_6}
38 * source version.
39 *
40 * <p> <b>WARNING:</b> The {@code AnnotationValueVisitor} interface
41 * implemented by this class may have methods added to it in the
42 * future to accommodate new, currently unknown, language structures
43 * added to future versions of the Java™ programming language.
44 * Therefore, methods whose names begin with {@code "visit"} may be
45 * added to this class in the future; to avoid incompatibilities,
46 * classes which extend this class should not declare any instance
47 * methods with names beginning with {@code "visit"}.
48 *
49 * <p>When such a new visit method is added, the default
50 * implementation in this class will be to call the {@link
51 * #visitUnknown visitUnknown} method. A new abstract annotation
52 * value visitor class will also be introduced to correspond to the
53 * new language level; this visitor will have different default
54 * behavior for the visit method in question. When the new visitor is
55 * introduced, all or portions of this visitor may be deprecated.
56 *
57 * <p>Note that adding a default implementation of a new visit method
58 * in a visitor class will occur instead of adding a <em>default
59 * method</em> directly in the visitor interface since a Java SE 8
60 * language feature cannot be used to this version of the API since
61 * this version is required to be runnable on Java SE 7
62 * implementations. Future versions of the API that are only required
63 * to run on Java SE 8 and later may take advantage of default methods
64 * in this situation.
65 *
66 * @param <R> the return type of this visitor's methods
67 * @param <P> the type of the additional parameter to this visitor's methods.
68 *
69 * @author Joseph D. Darcy
70 * @author Scott Seligman
71 * @author Peter von der Ahé
72 *
73 * @see AbstractAnnotationValueVisitor7
74 * @see AbstractAnnotationValueVisitor8
75 * @since 1.6
76 */
77 @SupportedSourceVersion(RELEASE_6)
78 public abstract class AbstractAnnotationValueVisitor6<R, P>
79 implements AnnotationValueVisitor<R, P> {
80
81 /**
82 * Constructor for concrete subclasses to call.
83 */
84 protected AbstractAnnotationValueVisitor6() {}
85
86 /**
87 * Visits an annotation value as if by passing itself to that
88 * value's {@link AnnotationValue#accept accept}. The invocation
89 * {@code v.visit(av)} is equivalent to {@code av.accept(v, p)}.
90 * @param av {@inheritDoc}
91 * @param p {@inheritDoc}
92 */
93 public final R visit(AnnotationValue av, P p) {
94 return av.accept(this, p);
95 }
96
97 /**
98 * Visits an annotation value as if by passing itself to that
99 * value's {@link AnnotationValue#accept accept} method passing
100 * {@code null} for the additional parameter. The invocation
101 * {@code v.visit(av)} is equivalent to {@code av.accept(v,
102 * null)}.
103 * @param av {@inheritDoc}
104 */
105 public final R visit(AnnotationValue av) {
106 return av.accept(this, null);
107 }
108
109 /**
110 * {@inheritDoc}
111 *
112 * <p>The default implementation of this method in {@code
113 * AbstractAnnotationValueVisitor6} will always throw {@code
114 * UnknownAnnotationValueException}. This behavior is not
115 * required of a subclass.
116 *
117 * @param av {@inheritDoc}
118 * @param p {@inheritDoc}
119 */
120 public R visitUnknown(AnnotationValue av, P p) {
121 throw new UnknownAnnotationValueException(av, p);
122 }
123 }