001/* Interface for directors that use a super-dense model of time.
002
003 Copyright (c) 2009-2011 The Regents of the University of California.
004 All rights reserved.
005 Permission is hereby granted, without written agreement and without
006 license or royalty fees, to use, copy, modify, and distribute this
007 software and its documentation for any purpose, provided that the above
008 copyright notice and the following two paragraphs appear in all copies
009 of this software.
010
011 IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
012 FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
013 ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
014 THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
015 SUCH DAMAGE.
016
017 THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
018 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
019 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
020 PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
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023
024 PT_COPYRIGHT_VERSION_2
025 COPYRIGHTENDKEY
026
027 */
028package ptolemy.actor;
029
030import ptolemy.kernel.util.IllegalActionException;
031
032//////////////////////////////////////////////////////////////////////////
033//// SuperdenseTimeDirector
034
035/**
036 This is an interface for directors that use a superdense model of time.
037 Actors can determine the index, also called the microstep,
038 of current time by calling getIndex().
039 <p>
040 Superdense time is defined by Haiyang Zheng as:
041 <blockquote>
042 <p>"The interactions between CT and DE subsystems and between DE
043 subsystems themselves are captured by discontinuities in
044 continuous-time signals and simultaneous discrete events in
045 discrete-event signals."</p>
046
047 <p>"In order to precisely represent them in compute execution
048 results, a two-dimension domain, called "superdense time," is used
049 as the domain for defining signals. This domain allows a signal to
050 have multiple values at the same time point while keeping the values
051 ordered."</p>
052 </blockquote>
053 <p>See: Haiyang Zheng.
054<a href="https://ptolemy.berkeley.edu/projects/chess/pubs/303.html#in_browser" target="_top"><i>Operational Semantics of Hybrid Systems</i></a>, PhD thesis,
055 University of California, Berkeley, May, 2007.</p>
056
057 @author Edward A. Lee
058 @version $Id$
059 @since Ptolemy II 8.0
060 @Pt.ProposedRating Yellow (eal)
061 @Pt.AcceptedRating Red (eal)
062 */
063public interface SuperdenseTimeDirector {
064    /** Return a superdense time index for the current time.
065     *  @return A superdense time object.
066     *  @see #setIndex(int)
067     */
068    public int getIndex();
069
070    /** Set the superdense time index. This should only be
071     *  called by an enclosing director.
072     *  @param index The index of the superdense time object.
073     *  Events that occur at the same time have different indicies.
074     *  @exception IllegalActionException If the specified index is invalid.
075     *  @see #getIndex()
076     */
077    public void setIndex(int index) throws IllegalActionException;
078}