/**
  * This function is called prior to building and submitting the form
  */
 function preProcess()
 {
     // check contact_id
     $this->_contactId = CRM_Utils_Request::retrieve('cid', 'Positive', $this);
     if (empty($this->_contactId)) {
         CRM_Core_Error::statusBounce(ts('Could not get a contact id.'), NULL, ts('Lidmaatschap Wijziging - Contact'));
         // this also redirects to the default civicrm page
     }
     // check for permissions
     $session = CRM_Core_Session::singleton();
     if (!CRM_Contact_BAO_Contact_Permission::allow($this->_contactId, CRM_Core_Permission::EDIT)) {
         CRM_Core_Error::statusBounce(ts('You do not have the necessary permission to edit this contact.'), NULL, ts('Lidmaatschap Wijziging - Contact'));
         // this also redirects to the default civicrm page
     }
     // get session
     $session = CRM_Core_Session::singleton();
     // get values
     $this->_configGroup = CRM_Lidmaatschapwijziging_ConfigGroup::singleton($this->_contactId);
     $this->_values = $this->_configGroup->getContact();
     // set display name
     $this->_display_name = $this->_values['display_name'];
     // set title
     CRM_Utils_System::setTitle('LidmaatschapWijziging - Group - ' . $this->_values['display_name']);
     // set contact id
     $this->_values['contact_id'] = $this->_contactId;
 }
 /**
  * Function to return singleton object
  * 
  * @return object $_singleton
  * @access public
  * @static
  */
 public static function &singleton($contact_id)
 {
     if (self::$_singleton === NULL) {
         self::$_singleton = new CRM_Lidmaatschapwijziging_ConfigGroup($contact_id);
     }
     return self::$_singleton;
 }