Tracking item in solidity

tracking.sol

/* Cette solution simple de traçabilité repose sur un contrat principal (Traceability)
et un contrat ad hoc par objet à tracer (Tracking).
Le contrat principal se comporte comme une liste blanche associant les identifiants
des objets et les contrats de traçabilité.
Une version plus avancée intègrera le déploiement du contrat Tracking à l'intérieur
de Traceability

An Idea of Jerôme De Tychey, implemented in solc by Romain Lafforgue

"numéro de série: 0001; date de fabrication: 09082016;Lieu de fabrication: 75017PARIS"
sha3(00010908201675017PARIS)=
15905d14d04be568d5e263a664721065a484ffe9c94b474947d601468b2ea744
*/
contract Traceabilityv1 {

    // Used to log the transfert
    struct Transfert{
        address to;
        uint transfertDate;
    }
    
    struct Entry { // ucfirst for struct and Enums
        address     owner;             // Used to store the current owner wich is capable to act with its entry
        
        string      serial;             // dunno the type, optionnal
        uint        date;               // UNIX Time, optionnal
        // ...add other storage like city or coutry or storeit wherever you like
        
        uint32      nbTransferts;       // Increments transferts (beware to increment this when creating)
        mapping ( uint32 => Transfert) transferts; 
    }
    
    //You can provide a search by bytes32 now :)
    mapping ( bytes32 => Entry ) public entries;
    
    address public admin; // no camelcase nor capital letters for global vars
    
    modifier onlyAdmin() { 
        if (msg.sender != admin) throw;
        _
    }
    
    event addedTrack(address _trackAddress, bytes32 _identifier);
    event updatedTrack(address _trackAddress, bytes32 _identifier);

    function Traceabilityv1() {
        admin = msg.sender;
    }
    
    /* Add an entry - if don't already exists (ie in entries) - identified by bytes32 (sha3 checksum) */
    function addEntry(string _serial, uint _date, bytes32 _checksum) onlyAdmin {
        if (entries[_checksum].owner != 0) throw; // if the entry already exist, we throw; SFYL;

        Entry e = entries[_checksum]; // maybe a bad thing to checksum a sha3 of a sha3

        e.owner = msg.sender;
        e.serial = _serial;
        e.date = _date;
        e.nbTransferts = 0;
        e.transferts[0] = Transfert({to:msg.sender, transfertDate: now}); //First transfert
        
        addedTrack(msg.sender, _checksum);
    }
    
    /* Change the ownership of a bytes32 */
    function changeOwnership(bytes32 _checksum, address _to)
    {
        if (entries[_checksum].owner == 0) throw; // if the entry don't exists exist, we throw; SFYL;
        if (entries[_checksum].owner != msg.sender) throw; // If the entry doesn't exists, we throw; SFYL;
        
        uint32 _nb = entries[_checksum].nbTransferts++;
        entries[_checksum].transferts[_nb] = Transfert({to:msg.sender, transfertDate: now}); //Following transfert
        updatedTrack(_to, _checksum);
    }
    
    /* Admin can choose a new admin */
    function changeAdmin(address _newAdmin) onlyAdmin()
   {
       admin = _newAdmin;
   }

    /* Killcontract */
    function kill() onlyAdmin() { 
        selfdestruct(admin);
    }
    
    /* better than killcontract : you reimburse every eth sent, this can overhelm dictatorial behaviour */
    function(){
        if (msg.value >0) {
            msg.sender.send(msg.value);
        }
    }
}