Mon, 03 Nov 2014 09:49:52 +0100
8059443: NPE when unboxing return values
Reviewed-by: lagergren, sundar
attila@90 | 1 | /* |
attila@90 | 2 | * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. |
attila@90 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
attila@90 | 4 | * |
attila@90 | 5 | * This code is free software; you can redistribute it and/or modify it |
attila@90 | 6 | * under the terms of the GNU General Public License version 2 only, as |
attila@90 | 7 | * published by the Free Software Foundation. Oracle designates this |
attila@90 | 8 | * particular file as subject to the "Classpath" exception as provided |
attila@90 | 9 | * by Oracle in the LICENSE file that accompanied this code. |
attila@90 | 10 | * |
attila@90 | 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
attila@90 | 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
attila@90 | 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
attila@90 | 14 | * version 2 for more details (a copy is included in the LICENSE file that |
attila@90 | 15 | * accompanied this code). |
attila@90 | 16 | * |
attila@90 | 17 | * You should have received a copy of the GNU General Public License version |
attila@90 | 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
attila@90 | 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
attila@90 | 20 | * |
attila@90 | 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
attila@90 | 22 | * or visit www.oracle.com if you need additional information or have any |
attila@90 | 23 | * questions. |
attila@90 | 24 | */ |
attila@90 | 25 | |
attila@90 | 26 | /* |
attila@90 | 27 | * This file is available under and governed by the GNU General Public |
attila@90 | 28 | * License version 2 only, as published by the Free Software Foundation. |
attila@90 | 29 | * However, the following notice accompanied the original version of this |
attila@90 | 30 | * file, and Oracle licenses the original version of this file under the BSD |
attila@90 | 31 | * license: |
attila@90 | 32 | */ |
attila@90 | 33 | /* |
attila@90 | 34 | Copyright 2009-2013 Attila Szegedi |
attila@90 | 35 | |
attila@90 | 36 | Licensed under both the Apache License, Version 2.0 (the "Apache License") |
attila@90 | 37 | and the BSD License (the "BSD License"), with licensee being free to |
attila@90 | 38 | choose either of the two at their discretion. |
attila@90 | 39 | |
attila@90 | 40 | You may not use this file except in compliance with either the Apache |
attila@90 | 41 | License or the BSD License. |
attila@90 | 42 | |
attila@90 | 43 | If you choose to use this file in compliance with the Apache License, the |
attila@90 | 44 | following notice applies to you: |
attila@90 | 45 | |
attila@90 | 46 | You may obtain a copy of the Apache License at |
attila@90 | 47 | |
attila@90 | 48 | http://www.apache.org/licenses/LICENSE-2.0 |
attila@90 | 49 | |
attila@90 | 50 | Unless required by applicable law or agreed to in writing, software |
attila@90 | 51 | distributed under the License is distributed on an "AS IS" BASIS, |
attila@90 | 52 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or |
attila@90 | 53 | implied. See the License for the specific language governing |
attila@90 | 54 | permissions and limitations under the License. |
attila@90 | 55 | |
attila@90 | 56 | If you choose to use this file in compliance with the BSD License, the |
attila@90 | 57 | following notice applies to you: |
attila@90 | 58 | |
attila@90 | 59 | Redistribution and use in source and binary forms, with or without |
attila@90 | 60 | modification, are permitted provided that the following conditions are |
attila@90 | 61 | met: |
attila@90 | 62 | * Redistributions of source code must retain the above copyright |
attila@90 | 63 | notice, this list of conditions and the following disclaimer. |
attila@90 | 64 | * Redistributions in binary form must reproduce the above copyright |
attila@90 | 65 | notice, this list of conditions and the following disclaimer in the |
attila@90 | 66 | documentation and/or other materials provided with the distribution. |
attila@90 | 67 | * Neither the name of the copyright holder nor the names of |
attila@90 | 68 | contributors may be used to endorse or promote products derived from |
attila@90 | 69 | this software without specific prior written permission. |
attila@90 | 70 | |
attila@90 | 71 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
attila@90 | 72 | IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
attila@90 | 73 | TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A |
attila@90 | 74 | PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER |
attila@90 | 75 | BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
attila@90 | 76 | CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
attila@90 | 77 | SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR |
attila@90 | 78 | BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
attila@90 | 79 | WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
attila@90 | 80 | OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
attila@90 | 81 | ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
attila@90 | 82 | */ |
attila@90 | 83 | |
attila@90 | 84 | package jdk.internal.dynalink.support; |
attila@90 | 85 | |
attila@90 | 86 | import java.util.ArrayList; |
attila@90 | 87 | import java.util.Collection; |
attila@90 | 88 | import java.util.Collections; |
attila@90 | 89 | import java.util.HashMap; |
attila@90 | 90 | import java.util.HashSet; |
attila@90 | 91 | import java.util.IdentityHashMap; |
attila@90 | 92 | import java.util.Iterator; |
attila@90 | 93 | import java.util.List; |
attila@90 | 94 | import java.util.Map; |
attila@90 | 95 | import java.util.Set; |
attila@90 | 96 | |
attila@90 | 97 | /** |
attila@90 | 98 | * Various static utility methods for testing type relationships. |
attila@90 | 99 | * |
attila@90 | 100 | * @author Attila Szegedi |
attila@90 | 101 | */ |
attila@90 | 102 | public class TypeUtilities { |
attila@90 | 103 | static final Class<Object> OBJECT_CLASS = Object.class; |
attila@90 | 104 | |
attila@90 | 105 | private TypeUtilities() { |
attila@90 | 106 | } |
attila@90 | 107 | |
attila@90 | 108 | /** |
attila@963 | 109 | * Given two types represented by c1 and c2, returns a type that is their most specific common supertype for |
attila@963 | 110 | * purposes of lossless conversions. |
attila@90 | 111 | * |
attila@90 | 112 | * @param c1 one type |
attila@90 | 113 | * @param c2 another type |
attila@963 | 114 | * @return their most common superclass or superinterface for purposes of lossless conversions. If they have several |
attila@963 | 115 | * unrelated superinterfaces as their most specific common type, or the types themselves are completely |
attila@963 | 116 | * unrelated interfaces, {@link java.lang.Object} is returned. |
attila@90 | 117 | */ |
attila@963 | 118 | public static Class<?> getCommonLosslessConversionType(final Class<?> c1, final Class<?> c2) { |
attila@90 | 119 | if(c1 == c2) { |
attila@90 | 120 | return c1; |
attila@963 | 121 | } else if(isConvertibleWithoutLoss(c2, c1)) { |
attila@963 | 122 | return c1; |
attila@963 | 123 | } else if(isConvertibleWithoutLoss(c1, c2)) { |
attila@963 | 124 | return c2; |
attila@90 | 125 | } |
attila@963 | 126 | if(c1 == void.class) { |
attila@963 | 127 | return c2; |
attila@963 | 128 | } else if(c2 == void.class) { |
attila@963 | 129 | return c1; |
attila@90 | 130 | } |
attila@963 | 131 | if(c1.isPrimitive() && c2.isPrimitive()) { |
attila@963 | 132 | if((c1 == byte.class && c2 == char.class) || (c1 == char.class && c2 == byte.class)) { |
attila@963 | 133 | // byte + char = int |
attila@963 | 134 | return int.class; |
attila@963 | 135 | } else if((c1 == short.class && c2 == char.class) || (c1 == char.class && c2 == short.class)) { |
attila@963 | 136 | // short + char = int |
attila@963 | 137 | return int.class; |
attila@963 | 138 | } else if((c1 == int.class && c2 == float.class) || (c1 == float.class && c2 == int.class)) { |
attila@963 | 139 | // int + float = double |
attila@963 | 140 | return double.class; |
attila@963 | 141 | } |
attila@963 | 142 | } |
attila@963 | 143 | // For all other cases. This will handle long + (float|double) = Number case as well as boolean + anything = Object case too. |
attila@963 | 144 | return getMostSpecificCommonTypeUnequalNonprimitives(c1, c2); |
attila@963 | 145 | } |
attila@963 | 146 | |
attila@963 | 147 | private static Class<?> getMostSpecificCommonTypeUnequalNonprimitives(final Class<?> c1, final Class<?> c2) { |
attila@963 | 148 | final Class<?> npc1 = c1.isPrimitive() ? getWrapperType(c1) : c1; |
attila@963 | 149 | final Class<?> npc2 = c2.isPrimitive() ? getWrapperType(c2) : c2; |
attila@963 | 150 | final Set<Class<?>> a1 = getAssignables(npc1, npc2); |
attila@963 | 151 | final Set<Class<?>> a2 = getAssignables(npc2, npc1); |
attila@90 | 152 | a1.retainAll(a2); |
attila@90 | 153 | if(a1.isEmpty()) { |
attila@90 | 154 | // Can happen when at least one of the arguments is an interface, |
attila@90 | 155 | // as they don't have Object at the root of their hierarchy. |
attila@90 | 156 | return Object.class; |
attila@90 | 157 | } |
attila@90 | 158 | // Gather maximally specific elements. Yes, there can be more than one |
attila@90 | 159 | // thank to interfaces. I.e., if you call this method for String.class |
attila@90 | 160 | // and Number.class, you'll have Comparable, Serializable, and Object |
attila@90 | 161 | // as maximal elements. |
attila@962 | 162 | final List<Class<?>> max = new ArrayList<>(); |
attila@962 | 163 | outer: for(final Class<?> clazz: a1) { |
attila@962 | 164 | for(final Iterator<Class<?>> maxiter = max.iterator(); maxiter.hasNext();) { |
attila@962 | 165 | final Class<?> maxClazz = maxiter.next(); |
attila@90 | 166 | if(isSubtype(maxClazz, clazz)) { |
attila@90 | 167 | // It can't be maximal, if there's already a more specific |
attila@90 | 168 | // maximal than it. |
attila@90 | 169 | continue outer; |
attila@90 | 170 | } |
attila@90 | 171 | if(isSubtype(clazz, maxClazz)) { |
attila@90 | 172 | // If it's more specific than a currently maximal element, |
attila@90 | 173 | // that currently maximal is no longer a maximal. |
attila@90 | 174 | maxiter.remove(); |
attila@90 | 175 | } |
attila@90 | 176 | } |
attila@90 | 177 | // If we get here, no current maximal is more specific than the |
attila@90 | 178 | // current class, so it is considered maximal as well |
attila@90 | 179 | max.add(clazz); |
attila@90 | 180 | } |
attila@90 | 181 | if(max.size() > 1) { |
attila@963 | 182 | return Object.class; |
attila@90 | 183 | } |
attila@90 | 184 | return max.get(0); |
attila@90 | 185 | } |
attila@90 | 186 | |
attila@962 | 187 | private static Set<Class<?>> getAssignables(final Class<?> c1, final Class<?> c2) { |
attila@962 | 188 | final Set<Class<?>> s = new HashSet<>(); |
attila@90 | 189 | collectAssignables(c1, c2, s); |
attila@90 | 190 | return s; |
attila@90 | 191 | } |
attila@90 | 192 | |
attila@962 | 193 | private static void collectAssignables(final Class<?> c1, final Class<?> c2, final Set<Class<?>> s) { |
attila@90 | 194 | if(c1.isAssignableFrom(c2)) { |
attila@90 | 195 | s.add(c1); |
attila@90 | 196 | } |
attila@962 | 197 | final Class<?> sc = c1.getSuperclass(); |
attila@90 | 198 | if(sc != null) { |
attila@90 | 199 | collectAssignables(sc, c2, s); |
attila@90 | 200 | } |
attila@962 | 201 | final Class<?>[] itf = c1.getInterfaces(); |
attila@90 | 202 | for(int i = 0; i < itf.length; ++i) { |
attila@90 | 203 | collectAssignables(itf[i], c2, s); |
attila@90 | 204 | } |
attila@90 | 205 | } |
attila@90 | 206 | |
attila@90 | 207 | private static final Map<Class<?>, Class<?>> WRAPPER_TYPES = createWrapperTypes(); |
attila@90 | 208 | private static final Map<Class<?>, Class<?>> PRIMITIVE_TYPES = invertMap(WRAPPER_TYPES); |
attila@90 | 209 | private static final Map<String, Class<?>> PRIMITIVE_TYPES_BY_NAME = createClassNameMapping(WRAPPER_TYPES.keySet()); |
attila@90 | 210 | |
attila@90 | 211 | private static Map<Class<?>, Class<?>> createWrapperTypes() { |
attila@90 | 212 | final Map<Class<?>, Class<?>> wrapperTypes = new IdentityHashMap<>(8); |
attila@90 | 213 | wrapperTypes.put(Boolean.TYPE, Boolean.class); |
attila@90 | 214 | wrapperTypes.put(Byte.TYPE, Byte.class); |
attila@90 | 215 | wrapperTypes.put(Character.TYPE, Character.class); |
attila@90 | 216 | wrapperTypes.put(Short.TYPE, Short.class); |
attila@90 | 217 | wrapperTypes.put(Integer.TYPE, Integer.class); |
attila@90 | 218 | wrapperTypes.put(Long.TYPE, Long.class); |
attila@90 | 219 | wrapperTypes.put(Float.TYPE, Float.class); |
attila@90 | 220 | wrapperTypes.put(Double.TYPE, Double.class); |
attila@90 | 221 | return Collections.unmodifiableMap(wrapperTypes); |
attila@90 | 222 | } |
attila@90 | 223 | |
attila@962 | 224 | private static Map<String, Class<?>> createClassNameMapping(final Collection<Class<?>> classes) { |
attila@90 | 225 | final Map<String, Class<?>> map = new HashMap<>(); |
attila@962 | 226 | for(final Class<?> clazz: classes) { |
attila@90 | 227 | map.put(clazz.getName(), clazz); |
attila@90 | 228 | } |
attila@90 | 229 | return map; |
attila@90 | 230 | } |
attila@90 | 231 | |
attila@962 | 232 | private static <K, V> Map<V, K> invertMap(final Map<K, V> map) { |
attila@90 | 233 | final Map<V, K> inverted = new IdentityHashMap<>(map.size()); |
attila@962 | 234 | for(final Map.Entry<K, V> entry: map.entrySet()) { |
attila@90 | 235 | inverted.put(entry.getValue(), entry.getKey()); |
attila@90 | 236 | } |
attila@90 | 237 | return Collections.unmodifiableMap(inverted); |
attila@90 | 238 | } |
attila@90 | 239 | |
attila@90 | 240 | /** |
attila@90 | 241 | * Determines whether one type can be converted to another type using a method invocation conversion, as per JLS 5.3 |
attila@90 | 242 | * "Method Invocation Conversion". This is basically all conversions allowed by subtyping (see |
attila@90 | 243 | * {@link #isSubtype(Class, Class)}) as well as boxing conversion (JLS 5.1.7) optionally followed by widening |
attila@90 | 244 | * reference conversion and unboxing conversion (JLS 5.1.8) optionally followed by widening primitive conversion. |
attila@90 | 245 | * |
attila@963 | 246 | * @param sourceType the type being converted from (call site type for parameter types, method type for return types) |
attila@963 | 247 | * @param targetType the parameter type being converted to (method type for parameter types, call site type for return types) |
attila@963 | 248 | * @return true if source type is method invocation convertible to target type. |
attila@90 | 249 | */ |
attila@963 | 250 | public static boolean isMethodInvocationConvertible(final Class<?> sourceType, final Class<?> targetType) { |
attila@963 | 251 | if(targetType.isAssignableFrom(sourceType)) { |
attila@90 | 252 | return true; |
attila@90 | 253 | } |
attila@963 | 254 | if(sourceType.isPrimitive()) { |
attila@963 | 255 | if(targetType.isPrimitive()) { |
attila@963 | 256 | return isProperPrimitiveSubtype(sourceType, targetType); |
attila@90 | 257 | } |
attila@90 | 258 | // Boxing + widening reference conversion |
attila@963 | 259 | assert WRAPPER_TYPES.get(sourceType) != null : sourceType.getName(); |
attila@963 | 260 | return targetType.isAssignableFrom(WRAPPER_TYPES.get(sourceType)); |
attila@90 | 261 | } |
attila@963 | 262 | if(targetType.isPrimitive()) { |
attila@963 | 263 | final Class<?> unboxedCallSiteType = PRIMITIVE_TYPES.get(sourceType); |
attila@90 | 264 | return unboxedCallSiteType != null |
attila@963 | 265 | && (unboxedCallSiteType == targetType || isProperPrimitiveSubtype(unboxedCallSiteType, targetType)); |
attila@90 | 266 | } |
attila@90 | 267 | return false; |
attila@90 | 268 | } |
attila@90 | 269 | |
attila@90 | 270 | /** |
attila@963 | 271 | * Determines whether a type can be converted to another without losing any |
attila@963 | 272 | * precision. |
attila@963 | 273 | * |
attila@963 | 274 | * @param sourceType the source type |
attila@963 | 275 | * @param targetType the target type |
attila@963 | 276 | * @return true if lossless conversion is possible |
attila@963 | 277 | */ |
attila@963 | 278 | public static boolean isConvertibleWithoutLoss(final Class<?> sourceType, final Class<?> targetType) { |
attila@963 | 279 | if(targetType.isAssignableFrom(sourceType)) { |
attila@963 | 280 | return true; |
attila@963 | 281 | } |
attila@963 | 282 | if(sourceType.isPrimitive()) { |
attila@963 | 283 | if(sourceType == void.class) { |
attila@963 | 284 | return false; // Void can't be losslessly represented by any type |
attila@963 | 285 | } |
attila@963 | 286 | if(targetType.isPrimitive()) { |
attila@963 | 287 | return isProperPrimitiveLosslessSubtype(sourceType, targetType); |
attila@963 | 288 | } |
attila@963 | 289 | // Boxing + widening reference conversion |
attila@963 | 290 | assert WRAPPER_TYPES.get(sourceType) != null : sourceType.getName(); |
attila@963 | 291 | return targetType.isAssignableFrom(WRAPPER_TYPES.get(sourceType)); |
attila@963 | 292 | } |
attila@963 | 293 | // Can't convert from any non-primitive type to any primitive type without data loss because of null. |
attila@963 | 294 | // Also, can't convert non-assignable reference types. |
attila@963 | 295 | return false; |
attila@963 | 296 | } |
attila@963 | 297 | |
attila@963 | 298 | /** |
attila@90 | 299 | * Determines whether one type can be potentially converted to another type at runtime. Allows a conversion between |
attila@90 | 300 | * any subtype and supertype in either direction, and also allows a conversion between any two primitive types, as |
attila@90 | 301 | * well as between any primitive type and any reference type that can hold a boxed primitive. |
attila@90 | 302 | * |
attila@90 | 303 | * @param callSiteType the parameter type at the call site |
attila@90 | 304 | * @param methodType the parameter type in the method declaration |
attila@90 | 305 | * @return true if callSiteType is potentially convertible to the methodType. |
attila@90 | 306 | */ |
attila@962 | 307 | public static boolean isPotentiallyConvertible(final Class<?> callSiteType, final Class<?> methodType) { |
attila@90 | 308 | // Widening or narrowing reference conversion |
attila@963 | 309 | if(areAssignable(callSiteType, methodType)) { |
attila@90 | 310 | return true; |
attila@90 | 311 | } |
attila@90 | 312 | if(callSiteType.isPrimitive()) { |
attila@90 | 313 | // Allow any conversion among primitives, as well as from any |
attila@90 | 314 | // primitive to any type that can receive a boxed primitive. |
attila@90 | 315 | // TODO: narrow this a bit, i.e. allow, say, boolean to Character? |
attila@90 | 316 | // MethodHandles.convertArguments() allows it, so we might need to |
attila@90 | 317 | // too. |
attila@90 | 318 | return methodType.isPrimitive() || isAssignableFromBoxedPrimitive(methodType); |
attila@90 | 319 | } |
attila@90 | 320 | if(methodType.isPrimitive()) { |
attila@90 | 321 | // Allow conversion from any reference type that can contain a |
attila@90 | 322 | // boxed primitive to any primitive. |
attila@90 | 323 | // TODO: narrow this a bit too? |
attila@90 | 324 | return isAssignableFromBoxedPrimitive(callSiteType); |
attila@90 | 325 | } |
attila@90 | 326 | return false; |
attila@90 | 327 | } |
attila@90 | 328 | |
attila@90 | 329 | /** |
attila@963 | 330 | * Returns true if either of the types is assignable from the other. |
attila@963 | 331 | * @param c1 one of the types |
attila@963 | 332 | * @param c2 another one of the types |
attila@963 | 333 | * @return true if either c1 is assignable from c2 or c2 is assignable from c1. |
attila@963 | 334 | */ |
attila@963 | 335 | public static boolean areAssignable(final Class<?> c1, final Class<?> c2) { |
attila@963 | 336 | return c1.isAssignableFrom(c2) || c2.isAssignableFrom(c1); |
attila@963 | 337 | } |
attila@963 | 338 | |
attila@963 | 339 | /** |
attila@90 | 340 | * Determines whether one type is a subtype of another type, as per JLS 4.10 "Subtyping". Note: this is not strict |
attila@90 | 341 | * or proper subtype, therefore true is also returned for identical types; to be completely precise, it allows |
attila@90 | 342 | * identity conversion (JLS 5.1.1), widening primitive conversion (JLS 5.1.2) and widening reference conversion (JLS |
attila@90 | 343 | * 5.1.5). |
attila@90 | 344 | * |
attila@90 | 345 | * @param subType the supposed subtype |
attila@90 | 346 | * @param superType the supposed supertype of the subtype |
attila@90 | 347 | * @return true if subType can be converted by identity conversion, widening primitive conversion, or widening |
attila@90 | 348 | * reference conversion to superType. |
attila@90 | 349 | */ |
attila@962 | 350 | public static boolean isSubtype(final Class<?> subType, final Class<?> superType) { |
attila@90 | 351 | // Covers both JLS 4.10.2 "Subtyping among Class and Interface Types" |
attila@90 | 352 | // and JLS 4.10.3 "Subtyping among Array Types", as well as primitive |
attila@90 | 353 | // type identity. |
attila@90 | 354 | if(superType.isAssignableFrom(subType)) { |
attila@90 | 355 | return true; |
attila@90 | 356 | } |
attila@90 | 357 | // JLS 4.10.1 "Subtyping among Primitive Types". Note we don't test for |
attila@90 | 358 | // identity, as identical types were taken care of in the |
attila@90 | 359 | // isAssignableFrom test. As per 4.10.1, the supertype relation is as |
attila@90 | 360 | // follows: |
attila@90 | 361 | // double > float |
attila@90 | 362 | // float > long |
attila@90 | 363 | // long > int |
attila@90 | 364 | // int > short |
attila@90 | 365 | // int > char |
attila@90 | 366 | // short > byte |
attila@90 | 367 | if(superType.isPrimitive() && subType.isPrimitive()) { |
attila@90 | 368 | return isProperPrimitiveSubtype(subType, superType); |
attila@90 | 369 | } |
attila@90 | 370 | return false; |
attila@90 | 371 | } |
attila@90 | 372 | |
attila@90 | 373 | /** |
attila@90 | 374 | * Returns true if a supposed primitive subtype is a proper subtype ( meaning, subtype and not identical) of the |
attila@90 | 375 | * supposed primitive supertype |
attila@90 | 376 | * |
attila@90 | 377 | * @param subType the supposed subtype |
attila@90 | 378 | * @param superType the supposed supertype |
attila@90 | 379 | * @return true if subType is a proper (not identical to) primitive subtype of the superType |
attila@90 | 380 | */ |
attila@962 | 381 | private static boolean isProperPrimitiveSubtype(final Class<?> subType, final Class<?> superType) { |
attila@90 | 382 | if(superType == boolean.class || subType == boolean.class) { |
attila@90 | 383 | return false; |
attila@90 | 384 | } |
attila@90 | 385 | if(subType == byte.class) { |
attila@90 | 386 | return superType != char.class; |
attila@90 | 387 | } |
attila@90 | 388 | if(subType == char.class) { |
attila@90 | 389 | return superType != short.class && superType != byte.class; |
attila@90 | 390 | } |
attila@90 | 391 | if(subType == short.class) { |
attila@90 | 392 | return superType != char.class && superType != byte.class; |
attila@90 | 393 | } |
attila@90 | 394 | if(subType == int.class) { |
attila@90 | 395 | return superType == long.class || superType == float.class || superType == double.class; |
attila@90 | 396 | } |
attila@90 | 397 | if(subType == long.class) { |
attila@90 | 398 | return superType == float.class || superType == double.class; |
attila@90 | 399 | } |
attila@90 | 400 | if(subType == float.class) { |
attila@90 | 401 | return superType == double.class; |
attila@90 | 402 | } |
attila@90 | 403 | return false; |
attila@90 | 404 | } |
attila@90 | 405 | |
attila@963 | 406 | /** |
attila@963 | 407 | * Similar to {@link #isProperPrimitiveSubtype(Class, Class)}, except it disallows conversions from int and long to |
attila@963 | 408 | * float, and from long to double, as those can lose precision. It also disallows conversion from and to char and |
attila@963 | 409 | * anything else (similar to boolean) as char is not meant to be an arithmetic type. |
attila@963 | 410 | * @param subType the supposed subtype |
attila@963 | 411 | * @param superType the supposed supertype |
attila@963 | 412 | * @return true if subType is a proper (not identical to) primitive subtype of the superType that can be represented |
attila@963 | 413 | * by the supertype without no precision loss. |
attila@963 | 414 | */ |
attila@963 | 415 | private static boolean isProperPrimitiveLosslessSubtype(final Class<?> subType, final Class<?> superType) { |
attila@963 | 416 | if(superType == boolean.class || subType == boolean.class) { |
attila@963 | 417 | return false; |
attila@963 | 418 | } |
attila@963 | 419 | if(superType == char.class || subType == char.class) { |
attila@963 | 420 | return false; |
attila@963 | 421 | } |
attila@963 | 422 | if(subType == byte.class) { |
attila@963 | 423 | return true; |
attila@963 | 424 | } |
attila@963 | 425 | if(subType == short.class) { |
attila@963 | 426 | return superType != byte.class; |
attila@963 | 427 | } |
attila@963 | 428 | if(subType == int.class) { |
attila@963 | 429 | return superType == long.class || superType == double.class; |
attila@963 | 430 | } |
attila@963 | 431 | if(subType == float.class) { |
attila@963 | 432 | return superType == double.class; |
attila@963 | 433 | } |
attila@963 | 434 | return false; |
attila@963 | 435 | } |
attila@963 | 436 | |
attila@90 | 437 | private static final Map<Class<?>, Class<?>> WRAPPER_TO_PRIMITIVE_TYPES = createWrapperToPrimitiveTypes(); |
attila@90 | 438 | |
attila@90 | 439 | private static Map<Class<?>, Class<?>> createWrapperToPrimitiveTypes() { |
attila@90 | 440 | final Map<Class<?>, Class<?>> classes = new IdentityHashMap<>(); |
attila@90 | 441 | classes.put(Void.class, Void.TYPE); |
attila@90 | 442 | classes.put(Boolean.class, Boolean.TYPE); |
attila@90 | 443 | classes.put(Byte.class, Byte.TYPE); |
attila@90 | 444 | classes.put(Character.class, Character.TYPE); |
attila@90 | 445 | classes.put(Short.class, Short.TYPE); |
attila@90 | 446 | classes.put(Integer.class, Integer.TYPE); |
attila@90 | 447 | classes.put(Long.class, Long.TYPE); |
attila@90 | 448 | classes.put(Float.class, Float.TYPE); |
attila@90 | 449 | classes.put(Double.class, Double.TYPE); |
attila@90 | 450 | return classes; |
attila@90 | 451 | } |
attila@90 | 452 | |
attila@90 | 453 | private static final Set<Class<?>> PRIMITIVE_WRAPPER_TYPES = createPrimitiveWrapperTypes(); |
attila@90 | 454 | |
attila@90 | 455 | private static Set<Class<?>> createPrimitiveWrapperTypes() { |
attila@90 | 456 | final Map<Class<?>, Class<?>> classes = new IdentityHashMap<>(); |
attila@90 | 457 | addClassHierarchy(classes, Boolean.class); |
attila@90 | 458 | addClassHierarchy(classes, Byte.class); |
attila@90 | 459 | addClassHierarchy(classes, Character.class); |
attila@90 | 460 | addClassHierarchy(classes, Short.class); |
attila@90 | 461 | addClassHierarchy(classes, Integer.class); |
attila@90 | 462 | addClassHierarchy(classes, Long.class); |
attila@90 | 463 | addClassHierarchy(classes, Float.class); |
attila@90 | 464 | addClassHierarchy(classes, Double.class); |
attila@90 | 465 | return classes.keySet(); |
attila@90 | 466 | } |
attila@90 | 467 | |
attila@962 | 468 | private static void addClassHierarchy(final Map<Class<?>, Class<?>> map, final Class<?> clazz) { |
attila@90 | 469 | if(clazz == null) { |
attila@90 | 470 | return; |
attila@90 | 471 | } |
attila@90 | 472 | map.put(clazz, clazz); |
attila@90 | 473 | addClassHierarchy(map, clazz.getSuperclass()); |
attila@962 | 474 | for(final Class<?> itf: clazz.getInterfaces()) { |
attila@90 | 475 | addClassHierarchy(map, itf); |
attila@90 | 476 | } |
attila@90 | 477 | } |
attila@90 | 478 | |
attila@90 | 479 | /** |
attila@90 | 480 | * Returns true if the class can be assigned from any boxed primitive. |
attila@90 | 481 | * |
attila@90 | 482 | * @param clazz the class |
attila@90 | 483 | * @return true if the class can be assigned from any boxed primitive. Basically, it is true if the class is any |
attila@90 | 484 | * primitive wrapper class, or a superclass or superinterface of any primitive wrapper class. |
attila@90 | 485 | */ |
attila@962 | 486 | private static boolean isAssignableFromBoxedPrimitive(final Class<?> clazz) { |
attila@90 | 487 | return PRIMITIVE_WRAPPER_TYPES.contains(clazz); |
attila@90 | 488 | } |
attila@90 | 489 | |
attila@90 | 490 | /** |
attila@90 | 491 | * Given a name of a primitive type (except "void"), returns the class representing it. I.e. when invoked with |
attila@90 | 492 | * "int", returns {@link Integer#TYPE}. |
attila@90 | 493 | * @param name the name of the primitive type |
attila@90 | 494 | * @return the class representing the primitive type, or null if the name does not correspond to a primitive type |
attila@90 | 495 | * or is "void". |
attila@90 | 496 | */ |
attila@962 | 497 | public static Class<?> getPrimitiveTypeByName(final String name) { |
attila@90 | 498 | return PRIMITIVE_TYPES_BY_NAME.get(name); |
attila@90 | 499 | } |
attila@90 | 500 | |
attila@90 | 501 | /** |
attila@90 | 502 | * When passed a class representing a wrapper for a primitive type, returns the class representing the corresponding |
attila@90 | 503 | * primitive type. I.e. calling it with {@code Integer.class} will return {@code Integer.TYPE}. If passed a class |
attila@90 | 504 | * that is not a wrapper for primitive type, returns null. |
attila@90 | 505 | * @param wrapperType the class object representing a wrapper for a primitive type |
attila@90 | 506 | * @return the class object representing the primitive type, or null if the passed class is not a primitive wrapper. |
attila@90 | 507 | */ |
attila@962 | 508 | public static Class<?> getPrimitiveType(final Class<?> wrapperType) { |
attila@90 | 509 | return WRAPPER_TO_PRIMITIVE_TYPES.get(wrapperType); |
attila@90 | 510 | } |
attila@90 | 511 | |
attila@90 | 512 | |
attila@90 | 513 | /** |
attila@90 | 514 | * When passed a class representing a primitive type, returns the class representing the corresponding |
attila@90 | 515 | * wrapper type. I.e. calling it with {@code int.class} will return {@code Integer.class}. If passed a class |
attila@90 | 516 | * that is not a primitive type, returns null. |
attila@90 | 517 | * @param primitiveType the class object representing a primitive type |
attila@90 | 518 | * @return the class object representing the wrapper type, or null if the passed class is not a primitive. |
attila@90 | 519 | */ |
attila@962 | 520 | public static Class<?> getWrapperType(final Class<?> primitiveType) { |
attila@90 | 521 | return WRAPPER_TYPES.get(primitiveType); |
attila@90 | 522 | } |
attila@1090 | 523 | |
attila@1090 | 524 | /** |
attila@1090 | 525 | * Returns true if the passed type is a wrapper for a primitive type. |
attila@1090 | 526 | * @param type the examined type |
attila@1090 | 527 | * @return true if the passed type is a wrapper for a primitive type. |
attila@1090 | 528 | */ |
attila@1090 | 529 | public static boolean isWrapperType(final Class<?> type) { |
attila@1090 | 530 | return PRIMITIVE_TYPES.containsKey(type); |
attila@1090 | 531 | } |
attila@101 | 532 | } |