ElementKindVisitor7.java revision 2571:10fc81ac75b4 
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
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25
26package javax.lang.model.util;
27
28import javax.annotation.processing.SupportedSourceVersion;
29import javax.lang.model.SourceVersion;
30import javax.lang.model.element.*;
31import 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} <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 * <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)
90public 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}
122