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.GenericDeclaration; |
| 29 | import java.lang.reflect.TypeVariable; |
| 30 | |
| 31 | |
| 32 | |
| 33 | /** |
| 34 | * Abstract superclass for lazy scope objects, used when building |
| 35 | * factories for generic information repositories. |
| 36 | * The type parameter <tt>D</tt> represents the type of reflective |
| 37 | * object whose scope this class is representing. |
| 38 | * <p> To subclass this, all one needs to do is implement |
| 39 | * <tt>computeEnclosingScope</tt> and the subclass' constructor. |
| 40 | */ |
| 41 | public abstract class AbstractScope<D extends GenericDeclaration> |
| 42 | implements Scope { |
| 43 | |
| 44 | private D recvr; // the declaration whose scope this instance represents |
| 45 | private Scope enclosingScope; // the enclosing scope of this scope |
| 46 | |
| 47 | /** |
| 48 | * Constructor. Takes a reflective object whose scope the newly |
| 49 | * constructed instance will represent. |
| 50 | * @param D - A generic declaration whose scope the newly |
| 51 | * constructed instance will represent |
| 52 | */ |
| 53 | protected AbstractScope(D decl){ recvr = decl;} |
| 54 | |
| 55 | /** |
| 56 | * Accessor for the receiver - the object whose scope this <tt>Scope</tt> |
| 57 | * object represents. |
| 58 | * @return The object whose scope this <tt>Scope</tt> object represents |
| 59 | */ |
| 60 | protected D getRecvr() {return recvr;} |
| 61 | |
| 62 | /** This method must be implemented by any concrete subclass. |
| 63 | * It must return the enclosing scope of this scope. If this scope |
| 64 | * is a top-level scope, an instance of DummyScope must be returned. |
| 65 | * @return The enclosing scope of this scope |
| 66 | */ |
| 67 | protected abstract Scope computeEnclosingScope(); |
| 68 | |
| 69 | /** |
| 70 | * Accessor for the enclosing scope, which is computed lazily and cached. |
| 71 | * @return the enclosing scope |
| 72 | */ |
| 73 | protected Scope getEnclosingScope(){ |
| 74 | if (enclosingScope == null) {enclosingScope = computeEnclosingScope();} |
| 75 | return enclosingScope; |
| 76 | } |
| 77 | |
| 78 | /** |
| 79 | * Lookup a type variable in the scope, using its name. Returns null if |
| 80 | * no type variable with this name is declared in this scope or any of its |
| 81 | * surrounding scopes. |
| 82 | * @param name - the name of the type variable being looked up |
| 83 | * @return the requested type variable, if found |
| 84 | */ |
| 85 | public TypeVariable<?> lookup(String name) { |
| 86 | TypeVariable[] tas = getRecvr().getTypeParameters(); |
| 87 | for (TypeVariable/*<?>*/ tv : tas) { |
| 88 | if (tv.getName().equals(name)) {return tv;} |
| 89 | } |
| 90 | return getEnclosingScope().lookup(name); |
| 91 | } |
| 92 | } |