--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.dynalink/share/classes/jdk/dynalink/linker/support/TypeUtilities.java Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,349 @@
+/*
+ * 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
+
+ Licensed under both the Apache License, Version 2.0 (the "Apache License")
+ and the BSD License (the "BSD License"), with licensee being free to
+ choose either of the two at their discretion.
+
+ You may not use this file except in compliance with either the Apache
+ License or the BSD License.
+
+ If you choose to use this file in compliance with the Apache License, the
+ following notice applies to you:
+
+ You may obtain a copy of the Apache License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ implied. See the License for the specific language governing
+ permissions and limitations under the License.
+
+ If you choose to use this file in compliance with the BSD License, the
+ following notice applies to you:
+
+ 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);
+ }
+}