Class Pre

  • All Implemented Interfaces:
    java.lang.Cloneable, Actor, Executable, FiringsRecordable, Initializable, TypedActor, Changeable, Debuggable, DebugListener, Derivable, Instantiable, ModelErrorHandler, MoMLExportable, Moveable, Nameable

    public class Pre
    extends Transformer
    When the input is present, the output is the previously received input. When the input is absent, the output is absent. The first time the input is present, the output is given by initialValue , or if initialValue is not given, then the output is absent. The output data type is greater than or equal to the input and the initialValue parameter, if it is given. Note that in contrast to the NonStrictDelay actor, this actor is strict. It cannot fire until the input is known. While NonStrictDelay delays by one clock tick, regardless of whether the input is present, this actor delays only present values, and produces an output only when the input is present.
    Since:
    Ptolemy II 4.1
    Version:
    $Id$
    Author:
    Edward A. Lee
    See Also:
    NonStrictDelay
    Pt.AcceptedRating:
    Red (cxh)
    Pt.ProposedRating:
    Yellow (eal)