public class YourClass
{
    InventTransOrigin               inventTransOrigin;
    InventTrans                     inventTrans;
    InventDim                       inventDim;
    InventSerial                    inventSerial;

    int64                           recId;
    str                             transId;

    List                            recIds;
    List                            dimIds;
    List                            inventSerialIds;

    ListEnumerator                  enumerator;
}

public void getInventSerials()
{
    this.getRecId_InventTransId("DON1-000034", InventTransType::Production);
    this.getInventDimIds();
    this.getInventSerialIds();
}

public void getRecId_InventTransId(InventRefId _inventRefId, InventTransType _inventTransType)
{
    recIds = new List(Types::String);

    try
    {
        while select RecId, InventTransId
        from inventTransOrigin
        where inventTransOrigin.ReferenceId == _inventRefId &&
              inventTransOrigin.ReferenceCategory == _inventTransType
        {
            recId = inventTransOrigin.RecId;
            transId = inventTransOrigin.InventTransId;

            info(strFmt("RecId: %1, InventTransId: %2", int642str(inventTransOrigin.RecId), inventTransOrigin.InventTransId));
        }
    }
    catch(Exception::error)
    {
        error("There was an error getting the record.");
    }
}

public List getInventDimIds()
{
    dimIds = new List(Types::String);

    try
    {
        while select InventDimId
        from inventTrans
        where inventTrans.InventTransOrigin == recId
        {
            dimIds.addEnd(inventTrans.inventDimId);

            info(strFmt("InventDimId: %1", inventTrans.inventDimId));
        }
    }
    catch(Exception::error)
    {
        error("There was an error getting the record.");
    }

    return dimIds;
}

public List getInventSerialIds()
{
    enumerator = dimIds.getEnumerator();

    inventSerialIds = new List(Types::String);

    while(enumerator.moveNext())
    {
        try
        {
            while select InventSerialId
            from inventDim
            where inventDim.inventDimId == enumerator.current()
            {
                inventSerialIds.addEnd(inventDim.inventSerialId);

                info(strFmt("InventSerialId: %1", inventDim.inventSerialId));
            }
        }
        catch(Exception::error)
        {
            error("There was an error getting the record.");
        }
    }

    return inventSerialIds;
}

public static void main (Args _args)
{
    YourClass yourClass = new YourClass();

    YourClass.getInventSerials(); 
}