//
// Copyright (C) 2010 United States Government as represented by the
// Administrator of the National Aeronautics and Space Administration
// (NASA). All Rights Reserved.
//
// This software is distributed under the NASA Open Source Agreement
// (NOSA), version 1.3. The NOSA has been approved by the Open Source
// Initiative. See the file NOSA-1.3-JPF at the top of the distribution
// directory tree for the complete NOSA document.
//
// THE SUBJECT SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY OF ANY
// KIND, EITHER EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT
// LIMITED TO, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL CONFORM TO
// SPECIFICATIONS, ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR
// A PARTICULAR PURPOSE, OR FREEDOM FROM INFRINGEMENT, ANY WARRANTY THAT
// THE SUBJECT SOFTWARE WILL BE ERROR FREE, OR ANY WARRANTY THAT
// DOCUMENTATION, IF PROVIDED, WILL CONFORM TO THE SUBJECT SOFTWARE.
//
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);
}