Thu, 10 Jun 2010 09:29:23 +0100
6945418: Project Coin: Simplified Varargs Method Invocation
Summary: Add new mandatory warning for unsafe vararg method declaration. Warning can be suppressed as usual (@SuppressWarnings("varargs")/-Xlint:-varargs)
Reviewed-by: jjg, darcy
duke@1 | 1 | /* |
ohair@554 | 2 | * Copyright (c) 2001, 2008, Oracle and/or its affiliates. All rights reserved. |
duke@1 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@1 | 4 | * |
duke@1 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@1 | 6 | * under the terms of the GNU General Public License version 2 only, as |
ohair@554 | 7 | * published by the Free Software Foundation. Oracle designates this |
duke@1 | 8 | * particular file as subject to the "Classpath" exception as provided |
ohair@554 | 9 | * by Oracle in the LICENSE file that accompanied this code. |
duke@1 | 10 | * |
duke@1 | 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@1 | 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@1 | 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@1 | 14 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@1 | 15 | * accompanied this code). |
duke@1 | 16 | * |
duke@1 | 17 | * You should have received a copy of the GNU General Public License version |
duke@1 | 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@1 | 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@1 | 20 | * |
ohair@554 | 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
ohair@554 | 22 | * or visit www.oracle.com if you need additional information or have any |
ohair@554 | 23 | * questions. |
duke@1 | 24 | */ |
duke@1 | 25 | |
duke@1 | 26 | package com.sun.tools.javac.util; |
duke@1 | 27 | |
duke@1 | 28 | import java.util.*; |
duke@1 | 29 | |
duke@1 | 30 | /** |
duke@1 | 31 | * Support for an abstract context, modelled loosely after ThreadLocal |
duke@1 | 32 | * but using a user-provided context instead of the current thread. |
duke@1 | 33 | * |
duke@1 | 34 | * <p>Within the compiler, a single Context is used for each |
duke@1 | 35 | * invocation of the compiler. The context is then used to ensure a |
duke@1 | 36 | * single copy of each compiler phase exists per compiler invocation. |
duke@1 | 37 | * |
duke@1 | 38 | * <p>The context can be used to assist in extending the compiler by |
duke@1 | 39 | * extending its components. To do that, the extended component must |
duke@1 | 40 | * be registered before the base component. We break initialization |
duke@1 | 41 | * cycles by (1) registering a factory for the component rather than |
duke@1 | 42 | * the component itself, and (2) a convention for a pattern of usage |
duke@1 | 43 | * in which each base component registers itself by calling an |
duke@1 | 44 | * instance method that is overridden in extended components. A base |
duke@1 | 45 | * phase supporting extension would look something like this: |
duke@1 | 46 | * |
duke@1 | 47 | * <p><pre> |
duke@1 | 48 | * public class Phase { |
duke@1 | 49 | * protected static final Context.Key<Phase> phaseKey = |
duke@1 | 50 | * new Context.Key<Phase>(); |
duke@1 | 51 | * |
duke@1 | 52 | * public static Phase instance(Context context) { |
duke@1 | 53 | * Phase instance = context.get(phaseKey); |
duke@1 | 54 | * if (instance == null) |
duke@1 | 55 | * // the phase has not been overridden |
duke@1 | 56 | * instance = new Phase(context); |
duke@1 | 57 | * return instance; |
duke@1 | 58 | * } |
duke@1 | 59 | * |
duke@1 | 60 | * protected Phase(Context context) { |
duke@1 | 61 | * context.put(phaseKey, this); |
duke@1 | 62 | * // other intitialization follows... |
duke@1 | 63 | * } |
duke@1 | 64 | * } |
duke@1 | 65 | * </pre> |
duke@1 | 66 | * |
duke@1 | 67 | * <p>In the compiler, we simply use Phase.instance(context) to get |
duke@1 | 68 | * the reference to the phase. But in extensions of the compiler, we |
duke@1 | 69 | * must register extensions of the phases to replace the base phase, |
duke@1 | 70 | * and this must be done before any reference to the phase is accessed |
duke@1 | 71 | * using Phase.instance(). An extended phase might be declared thus: |
duke@1 | 72 | * |
duke@1 | 73 | * <p><pre> |
duke@1 | 74 | * public class NewPhase extends Phase { |
duke@1 | 75 | * protected NewPhase(Context context) { |
duke@1 | 76 | * super(context); |
duke@1 | 77 | * } |
duke@1 | 78 | * public static void preRegister(final Context context) { |
duke@1 | 79 | * context.put(phaseKey, new Context.Factory<Phase>() { |
duke@1 | 80 | * public Phase make() { |
duke@1 | 81 | * return new NewPhase(context); |
duke@1 | 82 | * } |
duke@1 | 83 | * }); |
duke@1 | 84 | * } |
duke@1 | 85 | * } |
duke@1 | 86 | * </pre> |
duke@1 | 87 | * |
duke@1 | 88 | * <p>And is registered early in the extended compiler like this |
duke@1 | 89 | * |
duke@1 | 90 | * <p><pre> |
duke@1 | 91 | * NewPhase.preRegister(context); |
duke@1 | 92 | * </pre> |
duke@1 | 93 | * |
duke@1 | 94 | * <p><b>This is NOT part of any API supported by Sun Microsystems. If |
duke@1 | 95 | * you write code that depends on this, you do so at your own risk. |
duke@1 | 96 | * This code and its internal interfaces are subject to change or |
duke@1 | 97 | * deletion without notice.</b> |
duke@1 | 98 | */ |
duke@1 | 99 | public class Context { |
duke@1 | 100 | /** The client creates an instance of this class for each key. |
duke@1 | 101 | */ |
duke@1 | 102 | public static class Key<T> { |
duke@1 | 103 | // note: we inherit identity equality from Object. |
duke@1 | 104 | } |
duke@1 | 105 | |
duke@1 | 106 | /** |
duke@1 | 107 | * The client can register a factory for lazy creation of the |
duke@1 | 108 | * instance. |
duke@1 | 109 | */ |
duke@1 | 110 | public static interface Factory<T> { |
duke@1 | 111 | T make(); |
duke@1 | 112 | }; |
duke@1 | 113 | |
duke@1 | 114 | /** |
duke@1 | 115 | * The underlying map storing the data. |
duke@1 | 116 | * We maintain the invariant that this table contains only |
duke@1 | 117 | * mappings of the form |
duke@1 | 118 | * Key<T> -> T or Key<T> -> Factory<T> */ |
mcimadamore@184 | 119 | private Map<Key<?>,Object> ht = new HashMap<Key<?>,Object>(); |
duke@1 | 120 | |
duke@1 | 121 | /** Set the factory for the key in this context. */ |
duke@1 | 122 | public <T> void put(Key<T> key, Factory<T> fac) { |
duke@1 | 123 | checkState(ht); |
duke@1 | 124 | Object old = ht.put(key, fac); |
duke@1 | 125 | if (old != null) |
duke@1 | 126 | throw new AssertionError("duplicate context value"); |
duke@1 | 127 | } |
duke@1 | 128 | |
duke@1 | 129 | /** Set the value for the key in this context. */ |
duke@1 | 130 | public <T> void put(Key<T> key, T data) { |
mcimadamore@184 | 131 | if (data instanceof Factory<?>) |
duke@1 | 132 | throw new AssertionError("T extends Context.Factory"); |
duke@1 | 133 | checkState(ht); |
duke@1 | 134 | Object old = ht.put(key, data); |
mcimadamore@184 | 135 | if (old != null && !(old instanceof Factory<?>) && old != data && data != null) |
duke@1 | 136 | throw new AssertionError("duplicate context value"); |
duke@1 | 137 | } |
duke@1 | 138 | |
duke@1 | 139 | /** Get the value for the key in this context. */ |
duke@1 | 140 | public <T> T get(Key<T> key) { |
duke@1 | 141 | checkState(ht); |
duke@1 | 142 | Object o = ht.get(key); |
mcimadamore@184 | 143 | if (o instanceof Factory<?>) { |
mcimadamore@184 | 144 | Factory<?> fac = (Factory<?>)o; |
duke@1 | 145 | o = fac.make(); |
mcimadamore@184 | 146 | if (o instanceof Factory<?>) |
duke@1 | 147 | throw new AssertionError("T extends Context.Factory"); |
duke@1 | 148 | assert ht.get(key) == o; |
duke@1 | 149 | } |
duke@1 | 150 | |
duke@1 | 151 | /* The following cast can't fail unless there was |
duke@1 | 152 | * cheating elsewhere, because of the invariant on ht. |
duke@1 | 153 | * Since we found a key of type Key<T>, the value must |
duke@1 | 154 | * be of type T. |
duke@1 | 155 | */ |
duke@1 | 156 | return Context.<T>uncheckedCast(o); |
duke@1 | 157 | } |
duke@1 | 158 | |
duke@1 | 159 | public Context() {} |
duke@1 | 160 | |
duke@1 | 161 | private Map<Class<?>, Key<?>> kt = new HashMap<Class<?>, Key<?>>(); |
duke@1 | 162 | |
duke@1 | 163 | private <T> Key<T> key(Class<T> clss) { |
duke@1 | 164 | checkState(kt); |
duke@1 | 165 | Key<T> k = uncheckedCast(kt.get(clss)); |
duke@1 | 166 | if (k == null) { |
duke@1 | 167 | k = new Key<T>(); |
duke@1 | 168 | kt.put(clss, k); |
duke@1 | 169 | } |
duke@1 | 170 | return k; |
duke@1 | 171 | } |
duke@1 | 172 | |
duke@1 | 173 | public <T> T get(Class<T> clazz) { |
duke@1 | 174 | return get(key(clazz)); |
duke@1 | 175 | } |
duke@1 | 176 | |
duke@1 | 177 | public <T> void put(Class<T> clazz, T data) { |
duke@1 | 178 | put(key(clazz), data); |
duke@1 | 179 | } |
duke@1 | 180 | public <T> void put(Class<T> clazz, Factory<T> fac) { |
duke@1 | 181 | put(key(clazz), fac); |
duke@1 | 182 | } |
duke@1 | 183 | |
duke@1 | 184 | /** |
duke@1 | 185 | * TODO: This method should be removed and Context should be made type safe. |
duke@1 | 186 | * This can be accomplished by using class literals as type tokens. |
duke@1 | 187 | */ |
duke@1 | 188 | @SuppressWarnings("unchecked") |
duke@1 | 189 | private static <T> T uncheckedCast(Object o) { |
duke@1 | 190 | return (T)o; |
duke@1 | 191 | } |
duke@1 | 192 | |
duke@1 | 193 | public void dump() { |
duke@1 | 194 | for (Object value : ht.values()) |
duke@1 | 195 | System.err.println(value == null ? null : value.getClass()); |
duke@1 | 196 | } |
duke@1 | 197 | |
duke@1 | 198 | public void clear() { |
duke@1 | 199 | ht = null; |
duke@1 | 200 | kt = null; |
duke@1 | 201 | } |
duke@1 | 202 | |
duke@1 | 203 | private static void checkState(Map<?,?> t) { |
duke@1 | 204 | if (t == null) |
duke@1 | 205 | throw new IllegalStateException(); |
duke@1 | 206 | } |
duke@1 | 207 | } |