original_string: public function cache($key, $expires = null) {
          if ($this->getType() !== self::SELECT) {
              return $this;
          }
  
          $this->_cacheKey = $key;
          $this->_cacheLength = $expires;
  
          return $this;
      }
code: public function cache($key, $expires = null) {
          if ($this->getType() !== self::SELECT) {
              return $this;
          }
  
          $this->_cacheKey = $key;
          $this->_cacheLength = $expires;
  
          return $this;
      }
code_tokens: public function cache ( $ key , $ expires = null ) { if ( $ this -> getType ( ) !== self :: SELECT ) { return $ this ; } $ this -> _cacheKey = $ key ; $ this -> _cacheLength = $ expires ; return $ this ; }
docstring: Set the cache key and duration length.
  
  @param mixed $key
  @param mixed $expires
  @return $this
docstring_tokens: Set the cache key and duration length .