public function setContext(__Context &$context)
 {
     $this->_context_id = $context->getContextId();
 }
 protected function _addContext(__Context &$context)
 {
     $context_id = $context->getContextId();
     $this->_contexts[$context_id] =& $context;
     //Switch to the new context
     $this->switchContext($context_id);
 }