Java程序，一个实现Enumeration的组合类

import java.util.Enumeration;
public class CipherTest implements Enumeration {
private int N;
private int c[], k;
private Object[] objs;
public CipherTest(Object[] items) {
N = items.length;
c = new int[N + 1];
for (int i = 0; i <= N; i++)
c[i] = i;
objs = items;
k = 1;
}
public boolean hasMoreElements() {
return (k < N);
}
public Object nextElement() {
int i = 0;
if ((k & 1) != 0)
i = c[k];
Object tmp = objs[k];
objs[k] = objs[i];
objs[i] = tmp;
k = 1;
while (c[k] == 0)
c[k] = k++;
c[k]--;
return objs;
}
public static void main(String[] args) {
// String[] strs = { "1", "2", "3", "4" };
Integer[] nums = new Integer[6];
for (int i = 0; i < nums.length; i++)
nums[i] = i + 1;
System.out.println("N=" + nums.length);
Enumeration e = new CipherTest(nums);
int count = 0;
while (e.hasMoreElements()) {
Object[] a = (Object[]) e.nextElement();
if (((Integer) a[0]).intValue() != 4)
continue;
boolean isContinue = false;
for (int i = 0; i < a.length - 1; i++) {
if ((((Integer) a[i]).intValue() == 2 && ((Integer) a[i + 1])
.intValue() == 3)
|| (((Integer) a[i]).intValue() == 3 && ((Integer) a[i + 1])
.intValue() == 2)) {
isContinue = true;
break;
}
}
if (isContinue)
continue;
System.out.print("{" + a[0]);
for (int i = 1; i < a.length; i++)
System.out.print(", " + a[i]);
System.out.println("}");
count++;
}
System.out.println("count=" + count);
}
}