package finalizerdemo;

public class B
{
    private int index;
    private B other;

    public B(int index)
    {
        this.index = index;
    }

    public void setOther(B other)
    {
        this.other = other;
    }

    @Override
    protected void finalize() throws Throwable
    {
        System.out.print("B(" + index + ")#finalize");
        finalizerAssert(other != null); // the other object must be still available
        finalizerAssert(index + 1 == other.index || index - 1 == other.index);  // the two indexes must be exactly 1 from each other
        System.out.print(" other(" + other.index + ")");
        if(index > other.index)
        {
            System.out.println(" calling other#finalize");
            System.out.print("\t");
            other.finalize();
        }
        other = null;   // just to make sure if we did something wrong, we would get an assertion error
        System.out.println(" finalizer finished");
    }

    private static void finalizerAssert(boolean success)
    {
        if(!success)
        {
            new AssertionError().printStackTrace();
            System.exit(1);
        }
    }

    public static void main(String[] args)
    {
        for(int i = 0; true; i += 2)
        {
            B a = new B(i);
            B b = new B(i + 1);
            a.setOther(b);
            b.setOther(a);
            System.out.print('.');  // this is just an indicator that GC doesn't run after every iteration
        }
    }
}