| /* |
| * Copyright (c) 2012, 2015, 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. |
| * |
| * 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. |
| */ |
| package jdk.vm.ci.meta; |
| |
| import java.lang.invoke.MethodHandle; |
| |
| /** |
| * Reflection operations on values represented as {@linkplain JavaConstant constants}. All methods |
| * in this interface require the VM to access the actual object encapsulated in |
| * {@link JavaKind#Object object} constants. This access is not always possible, depending on kind |
| * of VM and the state that the VM is in. Therefore, all methods can return {@code null} at any |
| * time, to indicate that the result is not available at this point. The caller is responsible to |
| * check for {@code null} results and handle them properly, e.g., not perform an optimization. |
| */ |
| public interface ConstantReflectionProvider { |
| |
| /** |
| * Compares two constants for equality. The equality relationship is symmetric. Returns |
| * {@link Boolean#TRUE true} if the two constants represent the same run time value, |
| * {@link Boolean#FALSE false} if they are different. Returns {@code null} if the constants |
| * cannot be compared at this point. |
| */ |
| Boolean constantEquals(Constant x, Constant y); |
| |
| /** |
| * Returns the length of the array constant. Returns {@code null} if the constant is not an |
| * array, or if the array length is not available at this point. |
| */ |
| Integer readArrayLength(JavaConstant array); |
| |
| /** |
| * Reads a value from the given array at the given index. Returns {@code null} if the constant |
| * is not an array, if the index is out of bounds, or if the value is not available at this |
| * point. |
| */ |
| JavaConstant readArrayElement(JavaConstant array, int index); |
| |
| /** |
| * Gets the current value of this field for a given object, if available. |
| * |
| * There is no guarantee that the same value will be returned by this method for a field unless |
| * the field is considered to be constant by the runtime. |
| * |
| * @param receiver object from which this field's value is to be read. This value is ignored if |
| * this field is static. |
| * @return the value of this field or {@code null} if the value is not available (e.g., because |
| * the field holder is not yet initialized). |
| */ |
| JavaConstant readFieldValue(ResolvedJavaField field, JavaConstant receiver); |
| |
| /** |
| * Converts the given {@link JavaKind#isPrimitive() primitive} constant to a boxed |
| * {@link JavaKind#Object object} constant, according to the Java boxing rules. Returns |
| * {@code null} if the source is is not a primitive constant, or the boxed value is not |
| * available at this point. |
| */ |
| JavaConstant boxPrimitive(JavaConstant source); |
| |
| /** |
| * Converts the given {@link JavaKind#Object object} constant to a {@link JavaKind#isPrimitive() |
| * primitive} constant, according to the Java unboxing rules. Returns {@code null} if the source |
| * is is not an object constant that can be unboxed, or the unboxed value is not available at |
| * this point. |
| */ |
| JavaConstant unboxPrimitive(JavaConstant source); |
| |
| /** |
| * Gets a string as a {@link JavaConstant}. |
| */ |
| JavaConstant forString(String value); |
| |
| /** |
| * Returns the {@link ResolvedJavaType} for a {@link Class} object (or any other object regarded |
| * as a class by the VM) encapsulated in the given constant. Returns {@code null} if the |
| * constant does not encapsulate a class, or if the type is not available at this point. |
| */ |
| ResolvedJavaType asJavaType(Constant constant); |
| |
| /** |
| * Gets access to the internals of {@link MethodHandle}. |
| */ |
| MethodHandleAccessProvider getMethodHandleAccess(); |
| |
| /** |
| * Gets raw memory access. |
| */ |
| MemoryAccessProvider getMemoryAccessProvider(); |
| |
| /** |
| * Gets the runtime representation of the {@link Class} object of this type. |
| */ |
| JavaConstant asJavaClass(ResolvedJavaType type); |
| |
| /** |
| * Gets the runtime representation of the "hub" of this type--that is, the closest part of the |
| * type representation which is typically stored in the object header. |
| */ |
| Constant asObjectHub(ResolvedJavaType type); |
| } |