stoplightcolor.java

来自「java 完全探索的随书源码」· Java 代码 · 共 19 行

public class StopLightColor {

  // declare static instances to represent all allowed states
  public static final StopLightColor GREEN = new StopLightColor("Green");
  public static final StopLightColor YELLOW = new StopLightColor("Yellow");
  public static final StopLightColor RED = new StopLightColor("Red");

  private String color;

  // constructor is private to prevent any extraneous values
  private StopLightColor(String colorName) {
    color = colorName;
  }

  public String toString() {
    return color;
  }
}