jdk/src/share/classes/java/lang/reflect/TypeVariable.java

/*
 * Copyright 2003-2005 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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 */

package java.lang.reflect;

/**
 * TypeVariable is the common superinterface for type variables of kinds.
 * A type variable is created the first time it is needed by a reflective
 * method, as specified in this package.  If a type variable t is referenced
 * by a type (i.e, class, interface or annotation type) T, and T is declared
 * by the nth enclosing class of T (see JLS 8.1.2), then the creation of t
 * requires the resolution (see JVMS 5) of the ith enclosing class of T,
 * for i = 0 to n, inclusive. Creating a type variable must not cause the
 * creation of its bounds. Repeated creation of a type variable has no effect.
 *
 * <p>Multiple objects may be instantiated at run-time to
 * represent a given type variable. Even though a type variable is
 * created only once, this does not imply any requirement to cache
 * instances representing the type variable. However, all instances
 * representing a type variable must be equal() to each other.
 * As a consequence, users of type variables must not rely on the identity
 * of instances of classes implementing this interface.
 *
 * @param <D> the type of generic declaration that declared the
 * underlying type variable.
 *
 * @since 1.5
 */
public interface TypeVariable<D extends GenericDeclaration> extends Type {
    /**
     * Returns an array of {@code Type} objects representing the
     * upper bound(s) of this type variable.  Note that if no upper bound is
     * explicitly declared, the upper bound is {@code Object}.
     *
     * <p>For each upper bound B: <ul> <li>if B is a parameterized
     * type or a type variable, it is created, (see {@link
     * java.lang.reflect.ParameterizedType ParameterizedType} for the
     * details of the creation process for parameterized types).
     * <li>Otherwise, B is resolved.  </ul>
     *
     * @throws TypeNotPresentException  if any of the
     *     bounds refers to a non-existent type declaration
     * @throws MalformedParameterizedTypeException if any of the
     *     bounds refer to a parameterized type that cannot be instantiated
     *     for any reason
     * @return an array of {@code Type}s representing the upper
     *     bound(s) of this type variable
    */
    Type[] getBounds();

    /**
     * Returns the {@code GenericDeclaration} object representing the
     * generic declaration declared this type variable.
     *
     * @return the generic declaration declared for this type variable.
     *
     * @since 1.5
     */
    D getGenericDeclaration();

    /**
     * Returns the name of this type variable, as it occurs in the source code.
     *
     * @return the name of this type variable, as it appears in the source code
     */
    String getName();
}