Copy linkedset with object copier

Prerequisite: You must be familiar with the Syntax used in Tutorials and have already created an extension.

In this tutorial, we will see how we can enrich the extension User actions configurator, to copy relationships.
Example: When creating a Ticket from a FunctionalCI, we want to retrieve contacts linked to the Functional CI and link them automatically to the Ticket.

class:Ticket

public function CopyContactsFromFunctionalCI($oSource)
{
   // This method is supposed to be called from a FunctionalCI.
   $sSourceClass = get_class($oSource);
   if ($sSourceClass != 'FunctionalCI')
   {
        throw new Exception("Wrong source class '$sSourceClass' : 
        CopyContactsFromFunctionalCI method should be called by a user action on a FunctionalCI!");
   }
   // This method is called twice: 
   //   when creation form is displayed: '????'
   //   and when it is saved : 'apply_new' 
   // Copy the links only in one case, to avoid links duplication
   $sOperation= utils::ReadPostedParam('operation');
   if ($sOperation == 'apply_new')
   {
        return;
   }
   // Get the list of related objects - in this case, the OQL is not needed but it works
   $oSetSrc = new CMDBObjectSet(DBObjectSearch::FromOQL("
        SELECT Contact AS c
        JOIN lnkContactToFunctionalCI AS l1 ON l1.contact_id = c.id
        WHERE l.functionalci_id = :id"), array(), array('id'=>$oSource->GetKey()));
   // A simpler solution is to use: $oSetSrc = $oSource->Get('contacts_list');
 
   $oSetDst = $this->Get('contacts_list');
   while ($oSrc = $oSetSrc->Fetch())
   {
        $oLnkDst = MetaModel::NewObject('lnkContactToTicket');
        $oLnkDst->Set('contact_id', $oSrc->GetKey());
        $oSetDst->AddItem($oLnkDst);
    }
    $this->Set('contacts_list', $oSetDst);
}