/*
 * Copyright (c) 2003, 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 sun.reflect.generics.scope;

import java.lang.reflect.TypeVariable;

This class is used to provide enclosing scopes for top level classes. We cannot use null to represent such a scope, since the enclosing scope is computed lazily, and so the field storing it is null until it has been computed. Therefore, null is reserved to represent an as-yet-uncomputed scope, and cannot be used for any other kind of scope.
/** * This class is used to provide enclosing scopes for top level classes. * We cannot use {@code null} to represent such a scope, since the * enclosing scope is computed lazily, and so the field storing it is * null until it has been computed. Therefore, {@code null} is reserved * to represent an as-yet-uncomputed scope, and cannot be used for any * other kind of scope. */
public class DummyScope implements Scope { // Caches the unique instance of this class; instances contain no data // so we can use the singleton pattern private static final DummyScope singleton = new DummyScope(); // constructor is private to enforce use of factory method private DummyScope(){}
Factory method. Enforces the singleton pattern - only one instance of this class ever exists.
/** * Factory method. Enforces the singleton pattern - only one * instance of this class ever exists. */
public static DummyScope make() { return singleton; }
Lookup a type variable in the scope, using its name. Always returns null.
Params:
  • name – - the name of the type variable being looked up
Returns: null
/** * Lookup a type variable in the scope, using its name. Always returns * {@code null}. * @param name - the name of the type variable being looked up * @return null */
public TypeVariable<?> lookup(String name) {return null;} }