/*************************************************************************
 *  Compilation:  javac Wire.java
 *
 *  ADT for circuit wire.
 *
 *************************************************************************/

public class Wire {
    private Wire to;           // next wire in chain
    private Ternary signal;    // value of the wire
    private Circuit circuit;   // circuit in which this wire lives

    public Wire(Circuit circuit) {
        this.circuit = circuit;
        this.signal  = Ternary.UNKNOWN;
        this.to      = null;
    }

    public void solderTo(Wire x) { to = x;        }   // connect this Wire to x

    public Ternary isOn()        { return signal; }   // return the value of this Wire

    // set the value of this Wire, and propage its value recursively to
    // neighboring wire or enclosing circuit
    public void turnOn()  { setSignal(Ternary.TRUE);  }
    public void turnOff() { setSignal(Ternary.FALSE); }
    public void setSignal(Ternary s) {
        if (s != signal) {
            signal = s;
            if (to != null) to.setSignal(signal);
            if (circuit != null) circuit.propagate();
        }
    }


}