1 /*
2 * Copyright (c) 2003, 2015, 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 java.lang.reflect;
27
28 /**
29 * TypeVariable is the common superinterface for type variables of kinds.
30 * A type variable is created the first time it is needed by a reflective
31 * method, as specified in this package. If a type variable t is referenced
32 * by a type (i.e, class, interface or annotation type) T, and T is declared
33 * by the nth enclosing class of T (see JLS 8.1.2), then the creation of t
34 * requires the resolution (see JVMS 5) of the ith enclosing class of T,
35 * for i = 0 to n, inclusive. Creating a type variable must not cause the
36 * creation of its bounds. Repeated creation of a type variable has no effect.
37 *
38 * <p>Multiple objects may be instantiated at run-time to
39 * represent a given type variable. Even though a type variable is
40 * created only once, this does not imply any requirement to cache
41 * instances representing the type variable. However, all instances
42 * representing a type variable must be equal() to each other.
43 * As a consequence, users of type variables must not rely on the identity
44 * of instances of classes implementing this interface.
45 *
46 * @param <D> the type of generic declaration that declared the
47 * underlying type variable.
48 *
49 * @since 1.5
50 */
51 public interface TypeVariable<D extends GenericDeclaration> extends Type, AnnotatedElement {
52 /**
53 * Returns an array of {@code Type} objects representing the
54 * upper bound(s) of this type variable. If no upper bound is
55 * explicitly declared, the upper bound is {@code Object}.
56 *
57 * <p>For each upper bound B: <ul> <li>if B is a parameterized
58 * type or a type variable, it is created, (see {@link
59 * java.lang.reflect.ParameterizedType ParameterizedType} for the
60 * details of the creation process for parameterized types).
61 * <li>Otherwise, B is resolved. </ul>
62 *
63 * @throws TypeNotPresentException if any of the
64 * bounds refers to a non-existent type declaration
65 * @throws MalformedParameterizedTypeException if any of the
66 * bounds refer to a parameterized type that cannot be instantiated
67 * for any reason
68 * @return an array of {@code Type}s representing the upper
69 * bound(s) of this type variable
70 */
71 Type[] getBounds();
72
73 /**
74 * Returns the {@code GenericDeclaration} object representing the
75 * generic declaration declared this type variable.
76 *
77 * @return the generic declaration declared for this type variable.
78 *
79 * @since 1.5
80 */
81 D getGenericDeclaration();
82
83 /**
84 * Returns the name of this type variable, as it occurs in the source code.
85 *
86 * @return the name of this type variable, as it appears in the source code
87 */
88 String getName();
89
90 /**
91 * Returns an array of AnnotatedType objects that represent the use of
92 * types to denote the upper bounds of the type parameter represented by
93 * this TypeVariable. The order of the objects in the array corresponds to
94 * the order of the bounds in the declaration of the type parameter. Note that
95 * if no upper bound is explicitly declared, the upper bound is unannotated
96 * {@code Object}.
97 *
98 * @return an array of objects representing the upper bound(s) of the type variable
99 * @since 1.8
100 */
101 AnnotatedType[] getAnnotatedBounds();
102 }
103