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1   /*
2    * Copyright (c) 2005, 2013, 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.type;
27  
28  
29  import javax.lang.model.element.Element;
30  import javax.lang.model.element.TypeParameterElement;
31  import javax.lang.model.util.Types;
32  
33  
34  /**
35   * Represents a type variable.
36   * A type variable may be explicitly declared by a
37   * {@linkplain TypeParameterElement type parameter} of a
38   * type, method, or constructor.
39   * A type variable may also be declared implicitly, as by
40   * the capture conversion of a wildcard type argument
41   * (see chapter 5 of
42   * <cite>The Java&trade; Language Specification</cite>).
43   *
44   * @author Joseph D. Darcy
45   * @author Scott Seligman
46   * @author Peter von der Ah&eacute;
47   * @see TypeParameterElement
48   * @since 1.6
49   */
50  public interface TypeVariable extends ReferenceType {
51  
52      /**
53       * Returns the element corresponding to this type variable.
54       *
55       * @return the element corresponding to this type variable
56       */
57      Element asElement();
58  
59      /**
60       * Returns the upper bound of this type variable.
61       *
62       * <p> If this type variable was declared with no explicit
63       * upper bounds, the result is {@code java.lang.Object}.
64       * If it was declared with multiple upper bounds,
65       * the result is an {@linkplain IntersectionType intersection type};
66       * individual bounds can be found by examining the result's
67       * {@linkplain IntersectionType#getBounds() bounds}.
68       *
69       * @return the upper bound of this type variable
70       */
71      TypeMirror getUpperBound();
72  
73      /**
74       * Returns the lower bound of this type variable.  While a type
75       * parameter cannot include an explicit lower bound declaration,
76       * capture conversion can produce a type variable with a
77       * non-trivial lower bound.  Type variables otherwise have a
78       * lower bound of {@link NullType}.
79       *
80       * @return the lower bound of this type variable
81       */
82      TypeMirror getLowerBound();
83  }