/* Split a stream into two according to a boolean selector parameter.

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 All rights reserved.
 Permission is hereby granted, without written agreement and without
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 PT_COPYRIGHT_VERSION_2
 COPYRIGHTENDKEY

 This is similar to the BooleanSwitch actor.
 */
package ptolemy.actor.lib;

import ptolemy.actor.TypedAtomicActor;
import ptolemy.actor.TypedIOPort;
import ptolemy.actor.parameters.PortParameter;
import ptolemy.data.BooleanToken;
import ptolemy.data.IntToken;
import ptolemy.data.Token;
import ptolemy.data.expr.Parameter;
import ptolemy.data.type.BaseType;
import ptolemy.kernel.CompositeEntity;
import ptolemy.kernel.util.Attribute;
import ptolemy.kernel.util.IllegalActionException;
import ptolemy.kernel.util.NameDuplicationException;
import ptolemy.kernel.util.Settable;
import ptolemy.kernel.util.StringAttribute;
import ptolemy.kernel.util.Workspace;

///////////////////////////////////////////////////////////////////
//// ConfigurationSwitch

/**
 Split an input stream onto two output ports depending on a
 boolean selector parameter.  The value of the <i>selector</i> parameter specifies the
 output port that should be written to in this and subsequent iterations.
 In each iteration, at most one token on each channel of the <i>input</i> port
 is read and sent to the corresponding channel of the
 <i>trueOutput</i> port or the <i>falseOutput</i> port, depending on the
 most value of the <i>selector</i> parameter.
 If the input has width greater than an output port, then
 some input tokens will be discarded (those on input channels for which
 there is no corresponding output channel).
 Because tokens are
 immutable, the same Token is sent to the output, rather than a copy.
 The <i>input</i> port may receive Tokens of any type.

 <p>Note that the this actor may be used in Synchronous Dataflow (SDF)
 models, but only under certain circumstances. It specifies an output
 production rate of zero on the output port not used, so downstream
 actors will not be fired.

 @author Charles Shelton
 @version $Id: ConfigurationSwitch.java 70398 2014-10-22 23:44:32Z cxh $
 @since Ptolemy II 8.0
 @Pt.ProposedRating Green (cshelton)
 @Pt.AcceptedRating Red (cshelton)
 */
public class ConfigurationSwitch extends TypedAtomicActor {
    /** Construct an actor in the specified container with the specified
     *  name.
     *  @param container The container.
     *  @param name The name of this actor within the container.
     *  @exception IllegalActionException If the actor cannot be contained
     *   by the proposed container.
     *  @exception NameDuplicationException If the name coincides with
     *   an actor already in the container.
     */
    public ConfigurationSwitch(CompositeEntity container, String name)
            throws IllegalActionException, NameDuplicationException {
        super(container, name);

        input = new TypedIOPort(this, "input", true, false);
        input.setMultiport(true);

        // Default selector value to false
        selector = new PortParameter(this, "selector", new BooleanToken(false));
        selector.setTypeEquals(BaseType.BOOLEAN);

        // Put the selector input on the bottom of the actor.
        StringAttribute selectorCardinal = new StringAttribute(
                selector.getPort(), "_cardinal");
        selectorCardinal.setExpression("SOUTH");

        trueOutput = new TypedIOPort(this, "trueOutput", false, true);
        falseOutput = new TypedIOPort(this, "falseOutput", false, true);
        trueOutput.setTypeAtLeast(input);
        falseOutput.setTypeAtLeast(input);
        trueOutput.setMultiport(true);
        falseOutput.setMultiport(true);
        trueOutput.setWidthEquals(input, true);
        falseOutput.setWidthEquals(input, true);

        // For the benefit of the DDF and SDF director, this actor sets
        // consumption rate values.
        trueOutput_tokenProductionRate = new Parameter(trueOutput,
                "tokenProductionRate", _zero);
        trueOutput_tokenProductionRate.setVisibility(Settable.NOT_EDITABLE);
        trueOutput_tokenProductionRate.setTypeEquals(BaseType.INT);

        falseOutput_tokenProductionRate = new Parameter(falseOutput,
                "tokenProductionRate", _one);
        falseOutput_tokenProductionRate.setVisibility(Settable.NOT_EDITABLE);
        falseOutput_tokenProductionRate.setTypeEquals(BaseType.INT);

        /** Make the icon show T and F for trueOutput and falseOutput.
         */
        _attachText("_iconDescription", "<svg>\n"
                + "<rect x=\"-50\" y=\"-20\" " + "width=\"100\" height=\"40\" "
                + "style=\"fill:white\"/>\n" + "<text x=\"39\" y=\"-3\" "
                + "style=\"font-size:14\">\n" + "T \n" + "</text>\n"
                + "<text x=\"39\" y=\"15\" " + "style=\"font-size:14\">\n"
                + "F \n" + "</text>\n" + "</svg>\n");
    }

    ///////////////////////////////////////////////////////////////////
    ////                     ports and parameters                  ////

    /** PortParameter that selects one of the two input ports.  The type is
     *  BooleanToken that defaults to false.
     */
    public PortParameter selector;

    /** The input port.  The type can be anything. This is a multiport,
     *  and input tokens on all channels are routed to corresponding
     *  channels on the output port, if there are such channels.
     */
    public TypedIOPort input;

    /** Output for tokens on the true path.  The type is at least the
     *  type of the input.
     */
    public TypedIOPort trueOutput;

    /** Output for tokens on the false path.  The type is at least the
     *  type of the input.
     */
    public TypedIOPort falseOutput;

    /** This parameter provides token consumption rate for <i>trueOutput</i>.
     *  The type is int and it defaults to zero.
     */
    public Parameter trueOutput_tokenProductionRate;

    /** This parameter provides token consumption rate for <i>falseOutput</i>.
     *  The type is int and it defaults to one.
     */
    public Parameter falseOutput_tokenProductionRate;

    ///////////////////////////////////////////////////////////////////
    ////                         public methods                    ////

    /** React to a change in an attribute.  This method is called by
     *  a contained attribute when its value changes.  In this base class,
     *  the method does nothing.  In derived classes, this method may
     *  throw an exception, indicating that the new attribute value
     *  is invalid.  It is up to the caller to restore the attribute
     *  to a valid value if an exception is thrown.
     *  @param attribute The attribute that changed.
     *  @exception IllegalActionException If the change is not acceptable
     *   to this container (not thrown in this base class).
     */
    @Override
    public void attributeChanged(Attribute attribute)
            throws IllegalActionException {
        if (attribute == selector) {
            boolean previousSelector = _selector;
            _selector = ((BooleanToken) selector.getToken()).booleanValue();
            if (_selector != previousSelector) {
                if (_selector) {
                    trueOutput_tokenProductionRate.setToken(_one);
                    falseOutput_tokenProductionRate.setToken(_zero);
                } else {
                    trueOutput_tokenProductionRate.setToken(_zero);
                    falseOutput_tokenProductionRate.setToken(_one);
                }
                getDirector().invalidateSchedule();
            }
        }
    }

    /** Clone this actor into the specified workspace. The new actor is
     *  <i>not</i> added to the directory of that workspace (you must do this
     *  yourself if you want it there).
     *  The result is a new actor with the same ports as the original, but
     *  no connections and no container.  A container must be set before
     *  much can be done with this actor.
     *
     *  @param workspace The workspace for the cloned object.
     *  @exception CloneNotSupportedException If cloned ports cannot have
     *   as their container the cloned entity (this should not occur), or
     *   if one of the attributes cannot be cloned.
     *  @return A new ComponentEntity.
     */
    @Override
    public Object clone(Workspace workspace) throws CloneNotSupportedException {
        ConfigurationSwitch newObject = (ConfigurationSwitch) super
                .clone(workspace);

        newObject.trueOutput.setTypeAtLeast(newObject.input);
        newObject.falseOutput.setTypeAtLeast(newObject.input);
        newObject.trueOutput.setWidthEquals(newObject.input, true);
        newObject.falseOutput.setWidthEquals(newObject.input, true);

        return newObject;
    }

    /** Read a token from each input port.  If the
     *  <i>selector</i> parameter is true, then output the token consumed from the
     *  <i>input</i> port on the <i>trueOutput</i> port,
     *  otherwise output the token on the <i>falseOutput</i> port.
     *  @exception IllegalActionException If there is no director.
     */
    @Override
    public void fire() throws IllegalActionException {
        super.fire();
        for (int i = 0; i < input.getWidth(); i++) {
            if (input.hasToken(i)) {
                Token token = input.get(i);

                if (_selector) {
                    if (i < trueOutput.getWidth()) {
                        trueOutput.send(i, token);
                    }
                } else {
                    if (i < falseOutput.getWidth()) {
                        falseOutput.send(i, token);
                    }
                }
            }
        }
    }

    ///////////////////////////////////////////////////////////////////
    ////                         private variables                 ////

    /** Cached value of selector. */
    private boolean _selector = false;

    /** A final static IntToken with value 0. */
    private final static IntToken _zero = new IntToken(0);

    /** A final static IntToken with value 1. */
    private final static IntToken _one = new IntToken(1);
}