1 /*
2 * Copyright (c) 2010, 2014, 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.SourceVersion;
30 import javax.lang.model.element.*;
31 import static javax.lang.model.SourceVersion.*;
32
33 /**
34 * A visitor of program elements based on their {@linkplain
35 * ElementKind kind} with default behavior appropriate for the {@link
36 * SourceVersion#RELEASE_7 RELEASE_7} source version. For {@linkplain
37 * Element elements} <code><i>XYZ</i></code> that may have more than one
38 * kind, the <code>visit<i>XYZ</i></code> methods in this class delegate
39 * to the <code>visit<i>XYZKind</i></code> method corresponding to the
40 * first argument's kind. The <code>visit<i>XYZKind</i></code> methods
41 * call {@link #defaultAction defaultAction}, passing their arguments
42 * to {@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 or the
51 * {@code ElementKind} {@code enum} used in this case may have
52 * constants added to it in the future to accommodate new, currently
53 * unknown, language structures added to future versions of the
54 * Java™ programming language. Therefore, methods whose names
55 * begin with {@code "visit"} may be added to this class in the
56 * future; to avoid incompatibilities, classes which extend this class
57 * should not declare any instance methods with names beginning with
58 * {@code "visit"}.
59 *
60 * <p>When such a new visit method is added, the default
61 * implementation in this class will be to call the {@link
62 * #visitUnknown visitUnknown} method. A new abstract element kind
63 * visitor class will also be introduced to correspond to the new
64 * language level; this visitor will have different default behavior
65 * for the visit method in question. When the new visitor is
66 * introduced, all or portions of this visitor may be deprecated.
67 *
68 * <p>Note that adding a default implementation of a new visit method
69 * in a visitor class will occur instead of adding a <em>default
70 * method</em> directly in the visitor interface since a Java SE 8
71 * language feature cannot be used to this version of the API since
72 * this version is required to be runnable on Java SE 7
73 * implementations. Future versions of the API that are only required
74 * to run on Java SE 8 and later may take advantage of default methods
75 * in this situation.
76 *
77 * @param <R> the return type of this visitor's methods. Use {@link
78 * Void} for visitors that do not need to return results.
79 * @param <P> the type of the additional parameter to this visitor's
80 * methods. Use {@code Void} for visitors that do not need an
81 * additional parameter.
82 *
83 * @see ElementKindVisitor6
84 * @see ElementKindVisitor8
85 * @see ElementKindVisitor9
86 * @since 1.7
87 */
88 @SuppressWarnings("deprecation") // Superclass deprecated
89 @SupportedSourceVersion(RELEASE_7)
90 public class ElementKindVisitor7<R, P> extends ElementKindVisitor6<R, P> {
91 /**
92 * Constructor for concrete subclasses; uses {@code null} for the
93 * default value.
94 */
95 protected ElementKindVisitor7() {
96 super(null);
97 }
98
99 /**
100 * Constructor for concrete subclasses; uses the argument for the
101 * default value.
102 *
103 * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
104 */
105 protected ElementKindVisitor7(R defaultValue) {
106 super(defaultValue);
107 }
108
109 /**
110 * Visits a {@code RESOURCE_VARIABLE} variable element by calling
111 * {@code defaultAction}.
112 *
113 * @param e {@inheritDoc}
114 * @param p {@inheritDoc}
115 * @return the result of {@code defaultAction}
116 */
117 @Override
118 public R visitVariableAsResourceVariable(VariableElement e, P p) {
119 return defaultAction(e, p);
120 }
121 }