一个用于产生全排列的java类源码

在写内容过程中，将写内容过程中常用的一些内容收藏起来，如下的资料是关于一个用于产生全排列的java类的内容，应该对码农们有一些帮助。

import java.util.Iterator;
import java.util.NoSuchElementException;
import java.lang.reflect.Array;

public class Permute implements Iterator {

private final int size;

private boolean next = true;

public Permute (Object [] e) {
size = e.length;
System.arraycopy (e, 0, elements, 0, size);
ar = Array.newInstance (e.getClass().getComponentType(), size);
System.arraycopy (e, 0, ar, 0, size);
permutation = new int [size+1];
for (int i=0; i<size+1; i++) {
permutation [i]=i;
}
}

private void formNextPermutation () {
for (int i=0; i<size; i++) {
Array.set (ar, i, elements[permutation[i+1]-1]);
}
}

public boolean hasNext() {
return next;
}

public void remove() throws UnsupportedOperationException {
throw new UnsupportedOperationException();
}

private void swap (final int i, final int j) {
final int x = permutation[i];
permutation[i] = permutation [j];
permutation[j] = x;
}

public Object next() throws NoSuchElementException {

int i = size-1;
while (permutation[i]>permutation[i+1]) i--;

if (i==0) {
next = false;
for (int j=0; j<size+1; j++) {
permutation [j]=j;
}
return ar;
}

int j = size;

while (permutation[i]>permutation[j]) j--;
swap (i,j);
int r = size;
int s = i+1;
while (r>s) { swap(r,s); r--; s++; }

return ar;
}

public String toString () {
final int n = Array.getLength(ar);
final StringBuffer sb = new StringBuffer ("[");
for (int j=0; j<n; j++) {
sb.append (Array.get(ar,j).toString());
if (j<n-1) sb.append (",");
}
sb.append("]");
return new String (sb);
}

public static void main (String [] args) {
for (Iterator i = new Permute(args); i.hasNext(); ) {
final String [] a = (String []) i.next();
System.out.println (i);
}
}
}