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view src/main/gov/nasa/jpf/vm/Memento.java @ 23:db918c531e6d

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streamlined class init, which was a mixed case of registerClass()/initializeClass() and pushRequiredClinits(). Now it is a single initializeClass(ti) method which combines the previous initializeClass(), pushRequiredClinits() and pushClinit() methods. The reason for combining these is the forthcoming replacement of separately locked clinits from different DirectCallStackFrames with a single synthetic frame that calls clinits from nested synchronized blocks. This is required to model hotspot, which does cause deadlocks with concurrent init of classes that cause subclass init during their clinit executions.
author Peter Mehlitz <Peter.C.Mehlitz@nasa.gov>
date Wed, 15 Apr 2015 22:40:21 -0700
parents 61d41facf527
children
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/*
 * Copyright (C) 2014, United States Government, as represented by the
 * Administrator of the National Aeronautics and Space Administration.
 * All rights reserved.
 *
 * The Java Pathfinder core (jpf-core) platform is licensed under the
 * Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the 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.
 */


package gov.nasa.jpf.vm;

/**
 * generic interface for objects that are used to restore previous states from
 * within a context that holds the references to the objects to restore (e.g. a
 * container), i.e. the caller knows where to restore the objects in question.
 * The caller can provide a cached object the memento can update. However, its
 * up to the memento if it uses this (optional) argument object to restore
 * in-situ, the only guarantee it makes is that it returns a restored object
 */
public interface Memento<T> {

  /**
   * note that there is no guarantee the restored object will be the same that
   * is (optionally) passed in.
   * 
   * Implementations are free to restore in-situ or create a new object if a
   * non-null reference is provided. Callers are responsible for identity
   * integrity if they do provide in-situ objects
   * 
   * The caller does not guarantee the provided in-situ object was the one the
   * Memento was created from
   */
  T restore(T inSitu);
}