public class TrafficLight
extends java.lang.Object
TrafficLight object simulates a simple traffic light.
 Java Source Code for this class:
   
   http://www.cs.colorado.edu/~main/edu/colorado/simulations/TrafficLight.java
   | Constructor and Description | 
|---|
| TrafficLight(int r,
            int g)Construct a  TrafficLightwith a specified lengths of time
 that the light stays red and green. | 
| Modifier and Type | Method and Description | 
|---|---|
| boolean | isGreen()Check whether this  TrafficLightis green. | 
| boolean | isRed()Check whether this  TrafficLightis red. | 
| void | simulateTime(int t)Simulate the passage of a certain amount of time for this
  TrafficLight. | 
public TrafficLight(int r,
                    int g)
TrafficLight with a specified lengths of time
 that the light stays red and green.r - the number of seconds that this light stays redg - the number of seconds that this light stays green
 Precondition:
   Both r and g are positive.
 Postcondition:
   This TrafficLight has been initialized. It starts
   red and stays red for r seconds; then it switches to green for
   g seconds, back to red for r seconds, back to green for g
   seconds, and so on.java.lang.IllegalArgumentException - Indicates that one of the parameters is zero or negative.public void simulateTime(int t)
TrafficLight.t - the number of seconds to simulate during the call to this method
 Precondition:
   t >= 0
 Postcondition:
   This TrafficLight has simulated the passage of
   t more seconds of time.java.lang.IllegalArgumentException - Indicates that t is negative.public boolean isRed()
TrafficLight is red.TrafficLight is red, then the return
   value is true; otherwise the return value is false.public boolean isGreen()
TrafficLight is green.TrafficLight is green, then the return
   value is true; otherwise the return value is false.