Error : Variable tab financial dimensions has not been declared.

Hello Everyone,

I'm new to AX 2012 R3 CU12, i'm also new to programming. Please guide me, i just created form, with data source Table= RetailTransactionSalesTrans. Now i need to override init method :

public void init()
{
    super();
    dimDefaultingController=DimensionDefaultingController::constructInTabWithValues(
            true,
            true,
            true,
            0,
            this,
            tabFinancialDimensions,
            "@SYS138487");

    dimDefaultingController.parmAttributeValueSetDataSource(RetailTransactionSalesTrans_ds,
        fieldstr(RetailTransactionSalesTrans, DefaultDimension));
}

Now, i'm getting this error :

Variable tab financial dimensions has not been declared