ElementKindVisitor9.java revision 3189:70ac078df098 
1/*
2 * Copyright (c) 2011, 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
26package javax.lang.model.util;
27
28import javax.lang.model.element.*;
29import javax.annotation.processing.SupportedSourceVersion;
30import static javax.lang.model.SourceVersion.*;
31import 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_9 RELEASE_9} source version.  For {@linkplain
37 * Element elements} <tt><i>XYZ</i></tt> that may have more than one
38 * kind, the <tt>visit<i>XYZ</i></tt> methods in this class delegate
39 * to the <tt>visit<i>XYZKind</i></tt> method corresponding to the
40 * first argument's kind.  The <tt>visit<i>XYZKind</i></tt> 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&trade; 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 * @param <R> the return type of this visitor's methods.  Use {@link
69 *            Void} for visitors that do not need to return results.
70 * @param <P> the type of the additional parameter to this visitor's
71 *            methods.  Use {@code Void} for visitors that do not need an
72 *            additional parameter.
73 *
74 * @see ElementKindVisitor6
75 * @see ElementKindVisitor7
76 * @see ElementKindVisitor8
77 * @since 9
78 */
79@SupportedSourceVersion(RELEASE_9)
80public class ElementKindVisitor9<R, P> extends ElementKindVisitor8<R, P> {
81    /**
82     * Constructor for concrete subclasses; uses {@code null} for the
83     * default value.
84     */
85    protected ElementKindVisitor9() {
86        super(null);
87    }
88
89    /**
90     * Constructor for concrete subclasses; uses the argument for the
91     * default value.
92     *
93     * @param defaultValue the value to assign to {@link #DEFAULT_VALUE}
94     */
95    protected ElementKindVisitor9(R defaultValue) {
96        super(defaultValue);
97    }
98}
99