/*
Below is the copyright agreement for the Ptolemy II system.

Copyright (c) 1995-2014 The Regents of the University of California.
All rights reserved.

Permission is hereby granted, without written agreement and without
license or royalty fees, to use, copy, modify, and distribute this
software and its documentation for any purpose, provided that the above
copyright notice and the following two paragraphs appear in all copies
of this software.

IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.

THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
ENHANCEMENTS, OR MODIFICATIONS.

Ptolemy II includes the work of others, to see those copyrights, follow
the copyright link on the splash page or see copyright.htm.
 */
package ptolemy.domains.coroutine.lib;

import ptolemy.domains.coroutine.kernel.AtomicContinuationActor;
import ptolemy.domains.coroutine.kernel.ControlEntryToken;
import ptolemy.domains.coroutine.kernel.ControlEntryToken.EntryLocation;
import ptolemy.domains.coroutine.kernel.ControlExitToken;
import ptolemy.domains.coroutine.kernel.ControlExitToken.ExitLocation;
import ptolemy.kernel.CompositeEntity;
import ptolemy.kernel.util.IllegalActionException;
import ptolemy.kernel.util.NameDuplicationException;
import ptolemy.kernel.util.Workspace;

/**
 * Pause class.
 *
 * @author shaver
 * @version $Id: Pause.java 70402 2014-10-23 00:52:20Z cxh $
 * @since Ptolemy II 10.0
 * @Pt.ProposedRating Red (cxh)
 * @Pt.AcceptedRating Red (cxh)
 */
public class Pause extends AtomicContinuationActor {

    public Pause() {
        // TODO Auto-generated constructor stub
    }

    public Pause(Workspace workspace) {
        super(workspace);
        // TODO Auto-generated constructor stub
    }

    public Pause(CompositeEntity container, String name)
            throws IllegalActionException, NameDuplicationException {
        super(container, name);
        _init();
    }

    ///////////////////////////////////////////////////////////////////

    /* (non-Javadoc)
     * @see ptolemy.domains.coroutine.kernel.ContinuationActor#enter(ptolemy.domains.coroutine.kernel.ControlEntryToken)
     */
    @Override
    public ControlExitToken controlEnter(ControlEntryToken entry)
            throws IllegalActionException {

        ControlEntryToken.EntryLocation loc = null;
        ControlExitToken extk = null;

        /**/if (entry.isInit()) {
            loc = pauseEntry;
        } else if (entry.isResume()) {
            loc = _resumeLoc;
        } else if (entry.isEntry()) {
            loc = entry.getLocation();
        } else {
            super.controlEnter(entry);
        }

        while (true) {
            if (loc == pauseEntry) {
                _currentLoc = resumeEntry;
                extk = ControlExitToken.Suspend();
                break;
            }
            if (loc == resumeEntry) {
                _currentLoc = pauseEntry;
                extk = ControlExitToken.Exit(nextExit);
                break;
            }
            break;
        }

        if (extk != null) {
            return extk;
        } else {
            return super.controlEnter(entry);
        }
    }

    /* (non-Javadoc)
     * @see ptolemy.actor.AtomicActor#postfire()
     */
    @Override
    public boolean postfire() throws IllegalActionException {
        _resumeLoc = _currentLoc;
        return super.postfire();
    }

    ///////////////////////////////////////////////////////////////////

    protected void _init() throws IllegalActionException,
    NameDuplicationException {

        addEntryLocation(pauseEntry);
        addEntryLocation(resumeEntry);
        addExitLocation(nextExit);
    }

    final public EntryLocation pauseEntry = new EntryLocation("pause");
    final public EntryLocation resumeEntry = new EntryLocation("resume");
    final public ExitLocation nextExit = new ExitLocation("next");
    private EntryLocation _resumeLoc, _currentLoc;
}