PHP单例模式模拟Java Bean实现方法示例

/**
 * author Winter
 * 2016-11-22
 * PHP的单例模式
 * 模拟Java Bean
 * Class Php_bean
 */
class Php_bean{
  private static $_instance = null;
  private function __construct(){}
  private $hit = 0;//命中次数
  private $array = array();//缓存
  private $itratorCount = 0;//迭代次数
  public function add_itratorCount(){
    $this->itratorCount ++;
  }
  public function get_itratorCount(){
    return $this->itratorCount;
  }
  public function set_cache($row,$col,$value){
    $this->array[$row."_".$col] = $value;
  }
  public function get_cache($row,$col){
    if(isset($this->array[$row."_".$col])){
      return $this->array[$row."_".$col];
    }else{
      return false;
    }
  }
  public function add_hit(){
    $this->hit ++;
  }
  public function get_hit(){
    return $this->hit;
  }
  public static function instance(){
    if(self::$_instance instanceof self) return self::$_instance;
    self::$_instance = new self;
    return self::$_instance;
  }
}
/**
 * @param $row 行
 * @param $col 列
 * @return int
 */
function get_value($row,$col){
  $php_bean = Php_bean::instance();
  $php_bean->add_itratorCount();
  if($col > $row) return 0;
  if($row <=0) return 0;
  if($col == $row) return 1;
  if($row == 1) return 1;
  if($col == 1) return 1;
  $pre = $php_bean->get_cache($row-1,$col-1);
  $next = $php_bean->get_cache($row-1,$col-0);
  if($pre === false){
    $pre = get_value($row-1,$col-1);
    $php_bean->set_cache($row-1,$col-1,$pre);
  }else{
    $php_bean->add_hit();
  }
  if($next === false){
    $next = get_value($row-1,$col-0);
    $php_bean->set_cache($row-1,$col-0,$next);
  }else{
    $php_bean->add_hit();
  }
  $value = $pre + $next;
  return $value;
}
$v = get_value(6,6);
var_dump($v);
$php_bean_obj = Php_bean::instance();
echo "hit:".$php_bean_obj->get_hit()."<br/>";
echo "itratorCount:".$php_bean_obj->get_itratorCount()."<br/>";