immutablecircle.java

来自「Practical Java也是一本和J2ME手机游戏开发相关的书」· Java 代码 · 共 32 行

class MutableCircle
{
  private double radius;
  public MutableCircle(double r)
  {
    radius = r;
  }

  public void setRadius(double r)
  {
    radius = r;
  }

  public double radius()
  {
    return radius;
  }
}

final class ImmutableCircle
{
  private MutableCircle mCircle;
  public ImmutableCircle(double r)
  {
    mCircle = new MutableCircle(r);
  }

  public double radius()
  {
    return mCircle.radius();
  }
}