1 /*
   2  * Copyright (c) 2003, 2005, 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 {
  52     /**
  53      * Returns an array of {@code Type} objects representing the
  54      * upper bound(s) of this type variable.  Note that 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 }