Java example source code file (WildcardType.java)

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Java - Java tags/keywords

type, wildcardtype

The WildcardType.java Java example source code

/*
 * Copyright (c) 2003, 2004, Oracle and/or its affiliates. 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package java.lang.reflect;

/**
 * WildcardType represents a wildcard type expression, such as
 * {@code ?}, {@code ? extends Number}, or {@code ? super Integer}.
 *
 * @since 1.5
 */
public interface WildcardType 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>
     *
     * @return an array of Types representing the upper bound(s) of this
     *     type variable
     * @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
     */
    Type[] getUpperBounds();

    /**
     * Returns an array of {@code Type} objects representing the
     * lower bound(s) of this type variable.  Note that if no lower bound is
     * explicitly declared, the lower bound is the type of {@code null}.
     * In this case, a zero length array is returned.
     *
     * <p>For each lower 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>
     *
     * @return an array of Types representing the lower bound(s) of this
     *     type variable
     * @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
     */
    Type[] getLowerBounds();
    // one or many? Up to language spec; currently only one, but this API
    // allows for generalization.
}