| J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2003 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.reflect.generics.scope; |
| 27 | |
| 28 | import java.lang.reflect.TypeVariable; |
| 29 | |
| 30 | /** |
| 31 | * This class is used to provide enclosing scopes for top level classes. |
| 32 | * We cannot use <tt>null</tt> to represent such a scope, since the |
| 33 | * enclosing scope is computed lazily, and so the field storing it is |
| 34 | * null until it has been computed. Therefore, <tt>null</tt> is reserved |
| 35 | * to represent an as-yet-uncomputed scope, and cannot be used for any |
| 36 | * other kind of scope. |
| 37 | */ |
| 38 | public class DummyScope implements Scope { |
| 39 | // Caches the unique instance of this class; instances contain no data |
| 40 | // so we can use the singleton pattern |
| 41 | private static DummyScope singleton = new DummyScope(); |
| 42 | |
| 43 | // constructor is private to enforce use of factory method |
| 44 | private DummyScope(){} |
| 45 | |
| 46 | /** |
| 47 | * Factory method. Enforces the singleton pattern - only one |
| 48 | * instance of this class ever exists. |
| 49 | */ |
| 50 | public static DummyScope make() { |
| 51 | return singleton; |
| 52 | } |
| 53 | |
| 54 | /** |
| 55 | * Lookup a type variable in the scope, using its name. Always returns |
| 56 | * <tt>null</tt>. |
| 57 | * @param name - the name of the type variable being looked up |
| 58 | * @return null |
| 59 | */ |
| 60 | public TypeVariable<?> lookup(String name) {return null;} |
| 61 | } |