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61 lines
2.4 KiB
Java
61 lines
2.4 KiB
Java
/*
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* Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package sun.reflect.generics.scope;
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import java.lang.reflect.TypeVariable;
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/**
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* This class is used to provide enclosing scopes for top level classes.
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* We cannot use {@code null} to represent such a scope, since the
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* enclosing scope is computed lazily, and so the field storing it is
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* null until it has been computed. Therefore, {@code null} is reserved
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* to represent an as-yet-uncomputed scope, and cannot be used for any
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* other kind of scope.
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*/
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public class DummyScope implements Scope {
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// Caches the unique instance of this class; instances contain no data
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// so we can use the singleton pattern
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private static final DummyScope singleton = new DummyScope();
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// constructor is private to enforce use of factory method
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private DummyScope(){}
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/**
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* Factory method. Enforces the singleton pattern - only one
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* instance of this class ever exists.
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*/
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public static DummyScope make() {
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return singleton;
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}
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/**
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* Lookup a type variable in the scope, using its name. Always returns
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* {@code null}.
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* @param name - the name of the type variable being looked up
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* @return null
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*/
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public TypeVariable<?> lookup(String name) {return null;}
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}
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