/**
  * @return boolean
  */
 public function isReadOnly()
 {
     if (null === $this->m_isReadOnly) {
         $this->m_isReadOnly = $this->m_uri->hasQueryParam('writable') && Boolean::valueIsFalse($this->m_uri->getQueryParam('writable'));
     }
     return $this->m_isReadOnly;
 }