class NewMongodb {  
  private $mongo;  //NewMongodb連接
  private $curr_db_name;
  private $curr_table_name;
  private $error;
  public $config;
  public function getInstance($mongo_server, $flag=array())
  {
    static $NewMongodb_arr;
    if (empty($flag['tag']))
    {
      $flag['tag'] = 'default';     }
    if (isset($flag['force']) && $flag['force'] == true)
    {
      $mongo = new NewMongodb($mongo_server);
      if (empty($NewMongodb_arr[$flag['tag']]))
      {
        $NewMongodb_arr[$flag['tag']] = $mongo;
      }
      return $mongo;
    }
    else if (isset($NewMongodb_arr[$flag['tag']]) && is_resource($NewMongodb_arr[$flag['tag']]))
    {
      return $NewMongodb_arr[$flag['tag']];
    }
    else
    {
      $mongo = new NewMongodb($mongo_server);
      $NewMongodb_arr[$flag['tag']] = $mongo;
      return $mongo;
    }
  }
  /**
   * 構(gòu)造函數(shù)
   * 支持傳入多個mongo_server(1.一個出問題時連接其它的server 2.自動將查詢均勻分發(fā)到不同server)
   *
   * 參數(shù)：
   * $mongo_server:數(shù)組或字符串-array("127.0.0.1:1111", "127.0.0.1:2222")-"127.0.0.1:1111"
   * $connect:初始化mongo對象時是否連接，默認連接
   * $auto_balance:是否自動做負載均衡，默認是
   *
   * 返回值：
   * 成功：mongo object
   * 失敗：false
   */
  public function __construct($mongo_server, $connect=true, $auto_balance=true)
  {
   if (is_array($mongo_server))
   {
   $mongo_server_num = count($mongo_server);
   if ($mongo_server_num > 1 && $auto_balance)
   {
    $prior_server_num = rand(1, $mongo_server_num);
    $rand_keys = array_rand($mongo_server,$mongo_server_num);
    $mongo_server_str = $mongo_server[$prior_server_num-1];
    foreach ($rand_keys as $key)
    {
    if ($key != $prior_server_num - 1)
    {
     $mongo_server_str .= ',' . $mongo_server[$key];
    }
    }
   }
   else
   {
    $mongo_server_str = implode(',', $mongo_server);
   }         }
   else
   {
    $mongo_server_str = $mongo_server;
   }
   try {
    $this->mongo = new MongoClient($mongo_server, array('connect'=>$connect));
   }
   catch (MongoConnectionException $e)
   {
    $this->error = $e->getMessage();
    return false;
   }
  }
  
  /**
  * 連接NewMongodb server
  *
  * 參數(shù)：無
  *
  * 返回值：
  * 成功：true
  * 失?。篺alse
  */
  public function connect()
  {
    try {
      $this->mongo->connect();
      return true;
    }
    catch (MongoConnectionException $e)
    {
      $this->error = $e->getMessage();
      return false;
    }
  }  
  /**
  * select db
  *
  * 參數(shù)：$dbname
  *
  * 返回值：無
  */
  public function selectDb($dbname)
  {
    $this->curr_db_name = $dbname;
  }  
  /**
  * 創(chuàng)建索引：如索引已存在，則返回。
  *
  * 參數(shù)：
  * $table_name:表名
  * $index:索引-array("id"=>1)-在id字段建立升序索引
  * $index_param:其它條件-是否唯一索引等
  *
  * 返回值：
  * 成功：true
  * 失?。篺alse
  */
  public function ensureIndex($table_name, $index, $index_param=array())
  {
    $dbname = $this->curr_db_name;
    $index_param['safe'] = 1;
    try {
      $this->mongo->$dbname->$table_name->ensureIndex($index, $index_param);
      return true;
    }
    catch (MongoCursorException $e)
    {
      $this->error = $e->getMessage();
      return false;
    }
  }
  /**
  * 插入記錄
  *
  * 參數(shù)：
  * $table_name:表名
  * $record:記錄
  *
  * 返回值：
  * 成功：true
  * 失敗：false
  */
  public function insert($table_name, $record)
  {
    $dbname = $this->curr_db_name;
    try {
      $this->mongo->$dbname->$table_name->insert($record, array('safe'=>true));
      return true;
    }
    catch (MongoCursorException $e)
    {
      $this->error = $e->getMessage();
      return false;
    }
  }  
  /**
  * 查詢表的記錄數(shù)
  *
  * 參數(shù)：
  * $table_name:表名
  *
  * 返回值：表的記錄數(shù)
  */
  public function count($table_name)
  {
    $dbname = $this->curr_db_name;
    return $this->mongo->$dbname->$table_name->count();
  }  
  /**
  * 更新記錄
  *
  * 參數(shù)：
  * $table_name:表名
  * $condition:更新條件
  * $newdata:新的數(shù)據(jù)記錄
  * $options:更新選擇-upsert/multiple
  *
  * 返回值：
  * 成功：true
  * 失?。篺alse
  */
  public function update($table_name, $condition, $newdata, $options=array())
  {
    $dbname = $this->curr_db_name;
    $options['safe'] = 1;
    if (!isset($options['multiple']))
    {
      $options['multiple'] = 0;     }
    try {
      $this->mongo->$dbname->$table_name->update($condition, $newdata, $options);
      return true;
    }
    catch (MongoCursorException $e)
    {
      $this->error = $e->getMessage();
      return false;
    }
  }  
  /**
  * 刪除記錄
  *
  * 參數(shù)：
  * $table_name:表名
  * $condition:刪除條件
  * $options:刪除選擇-justOne
  *
  * 返回值：
  * 成功：true
  * 失敗：false
  */
  public function remove($table_name, $condition, $options=array())
  {
    $dbname = $this->curr_db_name;
    $options['safe'] = 1;
    try {
      $this->mongo->$dbname->$table_name->remove($condition, $options);
      return true;
    }
    catch (MongoCursorException $e)
    {
      $this->error = $e->getMessage();
      return false;
  }  }  
  /**
  * 查找記錄
  *
  * 參數(shù)：
  * $table_name:表名
  * $query_condition:字段查找條件
  * $result_condition:查詢結(jié)果限制條件-limit/sort等
  * $fields:獲取字段
  *
  * 返回值：
  * 成功：記錄集
  * 失?。篺alse
  */
  public function find($table_name, $query_condition, $result_condition=array(), $fields=array())
  {
    $dbname = $this->curr_db_name;
    $cursor = $this->mongo->$dbname->$table_name->find($query_condition, $fields);
    if (!empty($result_condition['start']))
    {
      $cursor->skip($result_condition['start']);
    }
    if (!empty($result_condition['limit']))
    {
      $cursor->limit($result_condition['limit']);
    }
    if (!empty($result_condition['sort']))
    {
      $cursor->sort($result_condition['sort']);
    }
    $result = array();
    try {
      while ($cursor->hasNext())
      {
        $result[] = $cursor->getNext();
      }
    }
    catch (MongoConnectionException $e)
    {
      $this->error = $e->getMessage();
      return false;
    }
    catch (MongoCursorTimeoutException $e)
    {
      $this->error = $e->getMessage();
      return false;
    }
    return $result;
  }  
  /**
  * 查找一條記錄
  *
  * 參數(shù)：
  * $table_name:表名
  * $condition:查找條件
  * $fields:獲取字段
  *
  * 返回值：
  * 成功：一條記錄
  * 失?。篺alse
  */
  public function findOne($table_name, $condition, $fields=array())
  {
    $dbname = $this->curr_db_name;
    return $this->mongo->$dbname->$table_name->findOne($condition, $fields);
  }  
  /**
  * 獲取當前錯誤信息
  *
  * 參數(shù)：無
  *
  * 返回值：當前錯誤信息
  */
  public function getError()
  {
    return $this->error;
  }
  /*** NewMongodb類** examples:
   * $mongo = new NewMongodb("127.0.0.1:11223");
  * $mongo->selectDb("test_db");
  * 創(chuàng)建索引
  * $mongo->ensureIndex("test_table", array("id"=>1), array('unique'=>true));
  * 獲取表的記錄
  * $mongo->count("test_table");
  * 插入記錄
  * $mongo->insert("test_table", array("id"=>2, "title"=>"asdqw"));
  * 更新記錄
  * $mongo->update("test_table", array("id"=>1),array("id"=>1,"title"=>"bbb"));
  * 更新記錄-存在時更新，不存在時添加-相當于set
  * $mongo->update("test_table", array("id"=>1),array("id"=>1,"title"=>"bbb"),array("upsert"=>1));
  * 查找記錄
  * $mongo->find("c", array("title"=>"asdqw"), array("start"=>2,"limit"=>2,"sort"=>array("id"=>1)))
  * 查找一條記錄
  * $mongo->findOne("$mongo->findOne("ttt", array("id"=>1))", array("id"=>1));
  * 刪除記錄
  * $mongo->remove("ttt", array("title"=>"bbb"));
  * 僅刪除一條記錄
  * $mongo->remove("ttt", array("title"=>"bbb"), array("justOne"=>1));
  * 獲取Mongo操作的錯誤信息
  * $mongo->getError();
  */
}