001/* An actor that synchronizes tokens.
002
003 Copyright (c) 1997-2014 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.lib;
029
030import ptolemy.kernel.CompositeEntity;
031import ptolemy.kernel.util.IllegalActionException;
032import ptolemy.kernel.util.NameDuplicationException;
033
034///////////////////////////////////////////////////////////////////
035//// Synchronizer
036
037/**
038 This actor implements a token synchronizer.  It has one input port and
039 one output port, both of which are multiports.  When at least one token
040 exists on every input channel, exactly one token is consumed from each
041 input channel, and the tokens are output on the corresponding output
042 channels. If any input channel is missing a token, then no output is
043 produced.
044 <p>
045 Note that the ordering of channels of a multiport is determined by the
046 order of connection.  Thus the n<sup>th</sup> input channel connected
047 corresponds to the n<sup>th</sup> output channel connected.
048
049 @author Paul Whitaker
050 @version $Id$
051 @since Ptolemy II 1.0
052 @Pt.ProposedRating Yellow (pwhitake)
053 @Pt.AcceptedRating Yellow (pwhitake)
054 */
055public class Synchronizer extends Transformer {
056    /** Construct an actor in the specified container with the specified
057     *  name.
058     *  @param container The container.
059     *  @param name The name of this actor within the container.
060     *  @exception IllegalActionException If the actor cannot be contained
061     *   by the proposed container.
062     *  @exception NameDuplicationException If the name coincides with
063     *   an actor already in the container.
064     */
065    public Synchronizer(CompositeEntity container, String name)
066            throws IllegalActionException, NameDuplicationException {
067        super(container, name);
068        input.setMultiport(true);
069        output.setMultiport(true);
070
071        input.setWidthEquals(output, true);
072
073        _attachText("_iconDescription",
074                "<svg>\n" + "<polygon points=\"-10,20 10,10 10,-10, -10,-20\" "
075                        + "style=\"fill:yellow\"/>\n" + "</svg>\n");
076    }
077
078    ///////////////////////////////////////////////////////////////////
079    ////                         public methods                    ////
080
081    /** Consume exactly one token from each input channel and output
082     *  the tokens on the corresponding output channels.
083     *  @exception IllegalActionException If there is no director or
084     *   if the number of input channels does not equal the number of
085     *   output channels.
086     */
087    @Override
088    public void fire() throws IllegalActionException {
089        super.fire();
090        int outWidth = output.getWidth();
091        int inWidth = input.getWidth();
092
093        if (inWidth != outWidth) {
094            throw new IllegalActionException(this,
095                    "Unequal synchronizer channels: " + inWidth + " inputs and "
096                            + outWidth + " outputs.");
097        } else {
098            for (int i = 0; i < inWidth; i++) {
099                output.send(i, input.get(i));
100            }
101        }
102    }
103
104    /** If all of the input channels have at least one token, return
105     *  what the superclass returns (presumably true).  Otherwise return
106     *  false.
107     *  @exception IllegalActionException If there is no director.
108     */
109    @Override
110    public boolean prefire() throws IllegalActionException {
111        for (int i = 0; i < input.getWidth(); i++) {
112            if (!input.hasToken(i)) {
113                return false;
114            }
115        }
116
117        return super.prefire();
118    }
119}