| /* |
| * This file is part of the Jikes RVM project (http://jikesrvm.org). |
| * |
| * This file is licensed to You under the Common Public License (CPL); |
| * You may not use this file except in compliance with the License. You |
| * may obtain a copy of the License at |
| * |
| * http://www.opensource.org/licenses/cpl1.0.php |
| * |
| * See the COPYRIGHT.txt file distributed with this work for information |
| * regarding copyright ownership. |
| */ |
| package org.vmmagic.unboxed; |
| |
| import org.vmmagic.Unboxed; |
| |
| /** |
| * The object reference type is used by the runtime system and collector to |
| * represent a type that holds a reference to a single object. |
| * We use a separate type instead of the Java Object type for coding clarity, |
| * to make a clear distinction between objects the VM is written in, and |
| * objects that the VM is managing. No operations that can not be completed in |
| * pure Java should be allowed on Object. |
| */ |
| @Unboxed |
| public final class ObjectReference { |
| |
| /** |
| * The object field. |
| */ |
| @SuppressWarnings("unused") |
| private Object data; |
| |
| /** |
| * Convert from an object to a reference. |
| * @param obj The object |
| * @return The corresponding reference |
| */ |
| public static ObjectReference fromObject(Object obj) { |
| return null; |
| } |
| |
| /** |
| * Return a null reference |
| */ |
| public static ObjectReference nullReference() { |
| return null; |
| } |
| |
| /** |
| * Convert from an reference to an object. Note: this is a JikesRVM |
| * specific extension to vmmagic. |
| * @return The object |
| */ |
| public Object toObject() { |
| return null; |
| } |
| |
| /** |
| * Get a heap address for the object. |
| */ |
| public Address toAddress() { |
| return null; |
| } |
| |
| /** |
| * Is this a null reference? |
| */ |
| public boolean isNull() { |
| return false; |
| } |
| } |