| /******************************************************************************* |
| * Copyright (c) 2000, 2005 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.jdi.hcr; |
| |
| |
| /** |
| * Hot code replacement extension to <code>com.sun.jdi.ReferenceType</code>. |
| */ |
| public interface ReferenceType { |
| /** |
| * An HCR-eligible class file may now be loaded and reloaded at some later point(s). |
| * Methods on the stack may come from any of several versions of the same HCR-eligible class. |
| * The debugger can query any class file related object (class, method, or field) for |
| * information about the version of the class file from which it came. |
| * <p> |
| * Classes loaded by a cooperating class loader are flagged as HCR-eligible for hot code |
| * replacement. |
| * <p> |
| * Class file versions are identified by the CRC-32 of the entire class file contents. |
| * <p> |
| * The VM typically computes and remembers the CRC when it digests a class file. Note |
| * this behavior is optional; VM need not retain any CRCs. |
| * A debugger can query any class for its class CRC and eligibility: |
| * <ul> |
| * <li>The query can be made at at time. |
| * <li>This is not directed to any specific thread. |
| * <li>Threads may be running at the time; they are not stopped. |
| * <li>Other JDI-level operations may be in progress. |
| * <li>If a debugger knows only about a method or a field, it must first query its defining |
| * class first to find out what is the CRC for this method or field. |
| * </ul> |
| * All information returned does not change over the lifetime of the reference type object |
| * (replacing the class results in a new reference type object). This info can therefore be |
| * cached client-side with impunity. |
| * <p> |
| * This simple mechanism allows the IDE to detect that an object does not belong to the current |
| * class file base (debugger computes CRC of current class file and queries VM and compares to |
| * its CRC). It also allows the debugger to quickly detect whether two objects come from |
| * the same class file (debugger queries VM and compares CRCs). By checking the HCR-eligibility |
| * bit, the debugger can determine whether the class could be hot replaced in principle. |
| * <p> |
| * Returns the CRC-32 of the entire class file contents for this reference type. |
| * |
| * @see org.eclipse.jdi.hcr.VirtualMachine#classesHaveChanged |
| */ |
| public int getClassFileVersion(); |
| |
| /** |
| * Returns whether this reference type is eligible for hot code replacement. |
| * |
| * @see org.eclipse.jdi.hcr.ReferenceType#getClassFileVersion |
| */ |
| public boolean isHCREligible(); |
| |
| /** |
| * Returns whether this reference type knows its class file version. |
| * Returns false for <code>ArrayType</code>s. |
| */ |
| public boolean isVersionKnown(); |
| } |