AbstractTypeVisitor6.java revision 3892:444b89786af3 
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
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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).
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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24 */
25
26package javax.lang.model.util;
27
28import javax.annotation.processing.SupportedSourceVersion;
29import javax.lang.model.type.*;
30
31import 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&trade; 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 Ah&eacute;
64 *
65 * @see AbstractTypeVisitor7
66 * @see AbstractTypeVisitor8
67 * @see AbstractTypeVisitor9
68 * @since 1.6
69 */
70@SupportedSourceVersion(RELEASE_6)
71public abstract class AbstractTypeVisitor6<R, P> implements TypeVisitor<R, P> {
72    /**
73     * Constructor for concrete subclasses to call.
74     * @deprecated Release 6 is obsolete; update to a visitor for a newer
75     * release level.
76     */
77    @Deprecated
78    protected AbstractTypeVisitor6() {}
79
80    /**
81     * Visits any type mirror as if by passing itself to that type
82     * mirror's {@link TypeMirror#accept accept} method.  The
83     * invocation {@code v.visit(t, p)} is equivalent to {@code
84     * t.accept(v, p)}.
85     *
86     * @param t  the type to visit
87     * @param p  a visitor-specified parameter
88     * @return a visitor-specified result
89     */
90    public final R visit(TypeMirror t, P p) {
91        return t.accept(this, p);
92    }
93
94    /**
95     * Visits any type mirror as if by passing itself to that type
96     * mirror's {@link TypeMirror#accept accept} method and passing
97     * {@code null} for the additional parameter.  The invocation
98     * {@code v.visit(t)} is equivalent to {@code t.accept(v, null)}.
99     *
100     * @param t  the type to visit
101     * @return a visitor-specified result
102     */
103    public final R visit(TypeMirror t) {
104        return t.accept(this, null);
105    }
106
107    /**
108     * {@inheritDoc}
109     *
110     * @implSpec Visits a {@code UnionType} element by calling {@code
111     * visitUnknown}.
112     *
113     * @param t  {@inheritDoc}
114     * @param p  {@inheritDoc}
115     * @return the result of {@code visitUnknown}
116     *
117     * @since 1.7
118     */
119    public R visitUnion(UnionType t, P p) {
120        return visitUnknown(t, p);
121    }
122
123    /**
124     * {@inheritDoc}
125     *
126     * @implSpec Visits an {@code IntersectionType} element by calling {@code
127     * visitUnknown}.
128     *
129     * @param t  {@inheritDoc}
130     * @param p  {@inheritDoc}
131     * @return the result of {@code visitUnknown}
132     *
133     * @since 1.8
134     */
135    @Override
136    public R visitIntersection(IntersectionType t, P p) {
137        return visitUnknown(t, p);
138    }
139
140    /**
141     * {@inheritDoc}
142     *
143     * @implSpec The default implementation of this method in {@code
144     * AbstractTypeVisitor6} will always throw {@code
145     * UnknownTypeException}.  This behavior is not required of a
146     * subclass.
147     *
148     * @param t  {@inheritDoc}
149     * @param p  {@inheritDoc}
150     * @return a visitor-specified result
151     * @throws UnknownTypeException
152     *  a visitor implementation may optionally throw this exception
153     */
154    @Override
155    public R visitUnknown(TypeMirror t, P p) {
156        throw new UnknownTypeException(t, p);
157    }
158}
159