选择排序算法的JAVA实现

package Utils.Sort;

/**

*@author Linyco

*利用选择排序法对数组排序，数组中元素必须实现了Comparable接口。

*/

public class ChooseSort implements SortStrategy

{    /**

       *对数组obj中的元素以选择排序算法进行排序

       */

       public void sort(Comparable[] obj)

       {  if (obj == null)

              {    throw new NullPointerException("The argument can not be null!");

              }

              Comparable tmp = null;

              int index = 0;

              for (int i = 0 ;i < obj.length - 1 ;i++ )

              {    index = i;

                     tmp = obj[i];

                     for (int j = i + 1 ;j < obj.length ;j++ )

                     {  //对邻接的元素进行比较，如果后面的小，就记下它的位置

                            if (tmp.compareTo(obj[j]) > 0)

                            {    tmp = obj[j];   //要每次比较都记录下当前小的这个值!

                                   index = j;

                            }

                     }

                     //将最小的元素交换到前面

                     tmp = obj[i];

                     obj[i] = obj[index];

                     obj[index] = tmp;

              }        } }