001/* An entity that implements an explicit change context declares that it modifies variable values.
002
003 Copyright (c) 2003-2013 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
021 CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
022 ENHANCEMENTS, OR MODIFICATIONS.
023
024 PT_COPYRIGHT_VERSION_2
025 COPYRIGHTENDKEY
026
027 */
028package ptolemy.actor.util;
029
030import java.util.List;
031
032import ptolemy.kernel.Entity;
033import ptolemy.kernel.util.IllegalActionException;
034import ptolemy.kernel.util.Nameable;
035
036///////////////////////////////////////////////////////////////////
037//// ExplicitChangeContext
038
039/**
040 An entity that implements an explicit change context declares a
041 change context, in which parameters are modified.  If the
042 ExplicitChangeContext is an Entity, then the change context is
043 assumed to be the entity.  If the ExplicitChangeContext is not an
044 entity, but directly contained by an entity, then that entity is
045 considered to be the change context.  This capability allows
046 directors to easily declare change contexts.  The information
047 declared by this class is used by the ConstVariableModelAnalysis to
048 determine what parameters might be modified by a given entity.
049
050 @author Steve Neuendorffer
051 @version $Id$
052 @since Ptolemy II 4.0
053 @Pt.ProposedRating Red (neuendor)
054 @Pt.AcceptedRating Red (neuendor)
055 @see ptolemy.actor.util.ConstVariableModelAnalysis
056 */
057public interface ExplicitChangeContext extends Nameable {
058    ///////////////////////////////////////////////////////////////////
059    ////                         public methods                    ////
060
061    /** Return a list of variables that this entity modifies.  The
062     *  variables are assumed to have a change context of the given
063     *  entity.
064     *  @return A list of variables.
065     *  @exception IllegalActionException If the list of modified
066     *  variables cannot be returned.
067     */
068    public List getModifiedVariables() throws IllegalActionException;
069
070    /** Return the change context being made explicit.  In simple cases, this
071     *  will simply be the entity implementing this interface.  However, in
072     *  more complex cases, directors may implement this interface, or entities
073     *  may modify parameters according to a different change context (i.e. HDF)
074     *  @return The change context being made explicit.
075     *  @exception IllegalActionException If the context is not available.
076     */
077    public Entity getContext() throws IllegalActionException;
078}