/* The interface of rollbackable objects.

@Copyright (c) 2005-2009 The Regents of the University of California.
All rights reserved.

Permission is hereby granted, without written agreement and without
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copies of this software.

IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
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                                                PT_COPYRIGHT_VERSION_2
                                                COPYRIGHTENDKEY



 */
package ptolemy.backtrack;

//////////////////////////////////////////////////////////////////////////
//// Rollbackable

/**
 The interface of rollbackable objects.

 @author Thomas Feng
 @version $Id: Rollbackable.java 53095 2009-04-12 19:12:45Z cxh $
 @since Ptolemy II 5.1
 @Pt.ProposedRating Red (tfeng)
 @Pt.AcceptedRating Red (tfeng)
 */
public interface Rollbackable {
    /** Commit changes up to the given timestamp, but not including changes
     *  made at timestamp and afterward.
     *
     *  @param timestamp The timestamp.
     */
    public void $COMMIT(long timestamp);

    /** Get the checkpoint object that monitors this rollbackable object.
     *
     *  @return The checkpoint object.
     */
    public Checkpoint $GET$CHECKPOINT();

    /** Restore a previous state to all the private fields of this rollbackable
     *  object.
     *
     *  @param timestamp The timestamp taken at the time when the previous
     *   state was recorded.
     *  @param trim Whether to delete the records used for the rollback.
     *  @see Checkpoint#rollback(long, boolean)
     */
    public void $RESTORE(long timestamp, boolean trim);

    /** Set the checkpoint object of this rollbackable object. A merge
     *  operation is performed on the current checkpoint object and the new
     *  checkpoint object, so that the two checkpoint objects monitor the same
     *  set of objects when this function returns.
     *
     *  @param checkpoint The new checkpoint object.
     *  @return This rollbackable object itself.
     *  @see Checkpoint#setCheckpoint(Checkpoint)
     */
    public Object $SET$CHECKPOINT(Checkpoint checkpoint);
}