| /* |
| * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * This file is available under and governed by the GNU General Public |
| * License version 2 only, as published by the Free Software Foundation. |
| * However, the following notice accompanied the original version of this |
| * file, and Oracle licenses the original version of this file under the BSD |
| * license: |
| */ |
| /* |
| Copyright 2009-2013 Attila Szegedi |
| |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions are |
| met: |
| * Redistributions of source code must retain the above copyright |
| notice, this list of conditions and the following disclaimer. |
| * Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in the |
| documentation and/or other materials provided with the distribution. |
| * Neither the name of the copyright holder nor the names of |
| contributors may be used to endorse or promote products derived from |
| this software without specific prior written permission. |
| |
| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
| IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A |
| PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER |
| BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR |
| BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
| OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| package jdk.dynalink.linker.support; |
| |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.IdentityHashMap; |
| import java.util.Map; |
| import jdk.dynalink.DynamicLinkerFactory; |
| import jdk.dynalink.linker.MethodTypeConversionStrategy; |
| |
| /** |
| * Various static utility methods for working with Java types. |
| */ |
| public final class TypeUtilities { |
| static final Class<Object> OBJECT_CLASS = Object.class; |
| |
| private TypeUtilities() { |
| } |
| |
| private static final Map<Class<?>, Class<?>> WRAPPER_TYPES = createWrapperTypes(); |
| private static final Map<Class<?>, Class<?>> PRIMITIVE_TYPES = invertMap(WRAPPER_TYPES); |
| private static final Map<String, Class<?>> PRIMITIVE_TYPES_BY_NAME = createClassNameMapping(WRAPPER_TYPES.keySet()); |
| |
| private static Map<Class<?>, Class<?>> createWrapperTypes() { |
| final Map<Class<?>, Class<?>> wrapperTypes = new IdentityHashMap<>(8); |
| wrapperTypes.put(Void.TYPE, Void.class); |
| wrapperTypes.put(Boolean.TYPE, Boolean.class); |
| wrapperTypes.put(Byte.TYPE, Byte.class); |
| wrapperTypes.put(Character.TYPE, Character.class); |
| wrapperTypes.put(Short.TYPE, Short.class); |
| wrapperTypes.put(Integer.TYPE, Integer.class); |
| wrapperTypes.put(Long.TYPE, Long.class); |
| wrapperTypes.put(Float.TYPE, Float.class); |
| wrapperTypes.put(Double.TYPE, Double.class); |
| return Collections.unmodifiableMap(wrapperTypes); |
| } |
| |
| private static Map<String, Class<?>> createClassNameMapping(final Collection<Class<?>> classes) { |
| final Map<String, Class<?>> map = new HashMap<>(); |
| for(final Class<?> clazz: classes) { |
| map.put(clazz.getName(), clazz); |
| } |
| return map; |
| } |
| |
| private static <K, V> Map<V, K> invertMap(final Map<K, V> map) { |
| final Map<V, K> inverted = new IdentityHashMap<>(map.size()); |
| for(final Map.Entry<K, V> entry: map.entrySet()) { |
| inverted.put(entry.getValue(), entry.getKey()); |
| } |
| return Collections.unmodifiableMap(inverted); |
| } |
| |
| /** |
| * Determines whether one type can be converted to another type using a method invocation conversion, as per JLS 5.3 |
| * "Method Invocation Conversion". This is basically all conversions allowed by subtyping (see |
| * {@link #isSubtype(Class, Class)}) as well as boxing conversion (JLS 5.1.7) optionally followed by widening |
| * reference conversion, and unboxing conversion (JLS 5.1.8) optionally followed by widening primitive conversion. |
| * |
| * @param sourceType the type being converted from (call site type for parameter types, method type for return types) |
| * @param targetType the parameter type being converted to (method type for parameter types, call site type for return types) |
| * @return true if source type is method invocation convertible to target type. |
| */ |
| public static boolean isMethodInvocationConvertible(final Class<?> sourceType, final Class<?> targetType) { |
| if(targetType.isAssignableFrom(sourceType)) { |
| return true; |
| } |
| if(sourceType.isPrimitive()) { |
| if(targetType.isPrimitive()) { |
| return isProperPrimitiveSubtype(sourceType, targetType); |
| } |
| return isBoxingAndWideningReferenceConversion(sourceType, targetType); |
| } |
| if(targetType.isPrimitive()) { |
| final Class<?> unboxedCallSiteType = getPrimitiveType(sourceType); |
| return unboxedCallSiteType != null |
| && (unboxedCallSiteType == targetType || isProperPrimitiveSubtype(unboxedCallSiteType, targetType)); |
| } |
| return false; |
| } |
| |
| private static boolean isBoxingAndWideningReferenceConversion(final Class<?> sourceType, final Class<?> targetType) { |
| final Class<?> wrapperType = getWrapperType(sourceType); |
| assert wrapperType != null : sourceType.getName(); |
| return targetType.isAssignableFrom(wrapperType); |
| } |
| |
| /** |
| * Determines whether a type can be converted to another without losing any |
| * precision. As a special case, void is considered convertible only to void |
| * and {@link Object} (either as {@code null} or as a custom value set in |
| * {@link DynamicLinkerFactory#setAutoConversionStrategy(MethodTypeConversionStrategy)}). |
| * Somewhat unintuitively, we consider anything to be convertible to void |
| * even though converting to void causes the ultimate loss of data. On the |
| * other hand, conversion to void essentially means that the value is of no |
| * interest and should be discarded, thus there's no expectation of |
| * preserving any precision. |
| * |
| * @param sourceType the source type |
| * @param targetType the target type |
| * @return true if lossless conversion is possible |
| */ |
| public static boolean isConvertibleWithoutLoss(final Class<?> sourceType, final Class<?> targetType) { |
| if(targetType.isAssignableFrom(sourceType) || targetType == void.class) { |
| return true; |
| } |
| if(sourceType.isPrimitive()) { |
| if(sourceType == void.class) { |
| // Void should be losslessly representable by Object, either as null or as a custom value that |
| // can be set with DynamicLinkerFactory.setAutoConversionStrategy. |
| return targetType == Object.class; |
| } |
| if(targetType.isPrimitive()) { |
| return isProperPrimitiveLosslessSubtype(sourceType, targetType); |
| } |
| return isBoxingAndWideningReferenceConversion(sourceType, targetType); |
| } |
| // Can't convert from any non-primitive type to any primitive type without data loss because of null. |
| // Also, can't convert non-assignable reference types. |
| return false; |
| } |
| |
| /** |
| * Determines whether one type is a subtype of another type, as per JLS |
| * 4.10 "Subtyping". Note: this is not strict or proper subtype, therefore |
| * true is also returned for identical types; to be completely precise, it |
| * allows identity conversion (JLS 5.1.1), widening primitive conversion |
| * (JLS 5.1.2) and widening reference conversion (JLS 5.1.5). |
| * |
| * @param subType the supposed subtype |
| * @param superType the supposed supertype of the subtype |
| * @return true if subType can be converted by identity conversion, widening primitive conversion, or widening |
| * reference conversion to superType. |
| */ |
| public static boolean isSubtype(final Class<?> subType, final Class<?> superType) { |
| // Covers both JLS 4.10.2 "Subtyping among Class and Interface Types" |
| // and JLS 4.10.3 "Subtyping among Array Types", as well as primitive |
| // type identity. |
| if(superType.isAssignableFrom(subType)) { |
| return true; |
| } |
| // JLS 4.10.1 "Subtyping among Primitive Types". Note we don't test for |
| // identity, as identical types were taken care of in the |
| // isAssignableFrom test. As per 4.10.1, the supertype relation is as |
| // follows: |
| // double > float |
| // float > long |
| // long > int |
| // int > short |
| // int > char |
| // short > byte |
| if(superType.isPrimitive() && subType.isPrimitive()) { |
| return isProperPrimitiveSubtype(subType, superType); |
| } |
| return false; |
| } |
| |
| /** |
| * Returns true if a supposed primitive subtype is a proper subtype ( meaning, subtype and not identical) of the |
| * supposed primitive supertype |
| * |
| * @param subType the supposed subtype |
| * @param superType the supposed supertype |
| * @return true if subType is a proper (not identical to) primitive subtype of the superType |
| */ |
| private static boolean isProperPrimitiveSubtype(final Class<?> subType, final Class<?> superType) { |
| if(superType == boolean.class || subType == boolean.class) { |
| return false; |
| } |
| if(subType == byte.class) { |
| return superType != char.class; |
| } |
| if(subType == char.class) { |
| return superType != short.class && superType != byte.class; |
| } |
| if(subType == short.class) { |
| return superType != char.class && superType != byte.class; |
| } |
| if(subType == int.class) { |
| return superType == long.class || superType == float.class || superType == double.class; |
| } |
| if(subType == long.class) { |
| return superType == float.class || superType == double.class; |
| } |
| if(subType == float.class) { |
| return superType == double.class; |
| } |
| return false; |
| } |
| |
| /** |
| * Similar to {@link #isProperPrimitiveSubtype(Class, Class)}, except it disallows conversions from int and long to |
| * float, and from long to double, as those can lose precision. It also disallows conversion from and to char and |
| * anything else (similar to boolean) as char is not meant to be an arithmetic type. |
| * @param subType the supposed subtype |
| * @param superType the supposed supertype |
| * @return true if subType is a proper (not identical to) primitive subtype of the superType that can be represented |
| * by the supertype without no precision loss. |
| */ |
| private static boolean isProperPrimitiveLosslessSubtype(final Class<?> subType, final Class<?> superType) { |
| if(superType == boolean.class || subType == boolean.class) { |
| return false; |
| } |
| if(superType == char.class || subType == char.class) { |
| return false; |
| } |
| if(subType == byte.class) { |
| return true; |
| } |
| if(subType == short.class) { |
| return superType != byte.class; |
| } |
| if(subType == int.class) { |
| return superType == long.class || superType == double.class; |
| } |
| if(subType == float.class) { |
| return superType == double.class; |
| } |
| return false; |
| } |
| |
| /** |
| * Given a name of a primitive type returns the class representing it. I.e. |
| * when invoked with "int", returns {@link Integer#TYPE}. |
| * @param name the name of the primitive type |
| * @return the class representing the primitive type, or null if the name |
| * does not correspond to a primitive type. |
| */ |
| public static Class<?> getPrimitiveTypeByName(final String name) { |
| return PRIMITIVE_TYPES_BY_NAME.get(name); |
| } |
| |
| /** |
| * When passed a class representing a wrapper for a primitive type, returns |
| * the class representing the corresponding primitive type. I.e. calling it |
| * with {@code Integer.class} will return {@code Integer.TYPE}. If passed a |
| * class that is not a wrapper for primitive type, returns null. |
| * @param wrapperType the class object representing a wrapper for a |
| * primitive type. |
| * @return the class object representing the primitive type, or null if the |
| * passed class is not a primitive wrapper. |
| */ |
| public static Class<?> getPrimitiveType(final Class<?> wrapperType) { |
| return PRIMITIVE_TYPES.get(wrapperType); |
| } |
| |
| /** |
| * When passed a class representing a primitive type, returns the class representing the corresponding |
| * wrapper type. I.e. calling it with {@code int.class} will return {@code Integer.class}. If passed a class |
| * that is not a primitive type, returns null. |
| * @param primitiveType the class object representing a primitive type |
| * @return the class object representing the wrapper type, or null if the passed class is not a primitive. |
| */ |
| public static Class<?> getWrapperType(final Class<?> primitiveType) { |
| return WRAPPER_TYPES.get(primitiveType); |
| } |
| |
| /** |
| * Returns true if the passed type is a wrapper for a primitive type. |
| * @param type the examined type |
| * @return true if the passed type is a wrapper for a primitive type. |
| */ |
| public static boolean isWrapperType(final Class<?> type) { |
| return PRIMITIVE_TYPES.containsKey(type); |
| } |
| } |