Calculate Tax by the Tax Slab

I tried in the Internet to see the Tier based tax calculation , Though it looks simple i didnt get any correct solution.
Then I started wrote that logic and thought of publishing it here.


Lets assume , The give amount is Rs. 640 and we need to calculate Tax for that.

Tax Slabs are given below

Tier Range	Percentage
1-300	10
301-600	20
601-1000	30
1001 and above	40

The Tax Calculation for the given Amount Rs. 640 should be like this

           for the first 300 Rs                                            Tax    :                  30

           Second Tier   up to 600 Rs                               Tax    :                   60
          Last /  Third Tier    up to 40 Rs                          Tax   :                   12


Total Tax Amount :  102

The method to do this operation given below



private static void calculate( double salary) {

    TierRange[] tierRanges = new TierRange[] {

            new TierRange(1, 300, 1.25), new TierRange(301, 600, 1.75), new TierRange(601, 1000, 2.25),
            new TierRange(1001, 999999, 2.75),

    };
    double  given = salary;

    double amount = 0.0;

    if (given == 0) {
        amount = 0;
    } else {

        for (TierRange tierRange : tierRanges) {

            int calcValue = 0;
            if (given >= tierRange.low && given <= tierRange.high) {
                calcValue = (given - tierRange.low) + 1;
                amount += (calcValue * tierRange.value);
                System.out.println(given+"  "+calcValue+"  "+amount+" "+(calcValue * tierRange.value));
                break;
            } else {
                calcValue = (tierRange.high - tierRange.low) + 1;
                amount += (calcValue * tierRange.value);
                System.out.println(given+"  "+calcValue+"  "+amount+" "+(calcValue * tierRange.value));
            }

        }
    }


TierRange is a class which contains 3 fields low , high and percentage .



The same can be done using a Stored Procedure also

       

Assume Tier Ranges comes from a Table called

BILL_ADMIN.TIER_TEMPLATE

The query to fetch the Tier Range given below

SELECT TIER_START , TIER_END , RATE_PU FROM BILL_ADMIN.TIER_TEMPLATE;


TIER_START   --- Low Range
 TIER_END      ----  High Range
 RATE_PU       --- Rate Percentage


create or replace PROCEDURE BILLINGCALCPROC
IS

T_GIVEN NUMBER;
T_TIER_START NUMBER ;
T_TIER_END NUMBER;
T_RATE_PU NUMBER;
T_CALCVAL NUMBER;
T_BILL_ID VARCHAR2(30);
T_AMOUNT NUMBER;

CURSOR BILL_CALC
IS
SELECT TOTAL_UNIT, BILL_ID FROM BILL_ADMIN.MONTHLY_INVOICE ;
CURSOR TIER_RANGE
IS
SELECT TIER_START , TIER_END , RATE_PU FROM BILL_ADMIN.TIER_TEMPLATE;


BEGIN

OPEN BILL_CALC;
LOOP
FETCH BILL_CALC INTO T_GIVEN ,T_BILL_ID;
EXIT
WHEN BILL_CALC%NOTFOUND;
T_AMOUNT := 0;
IF (T_GIVEN=0) THEN
UPDATE BILL_ADMIN.MONTHLY_INVOICE SET AMOUNT = 0 WHERE BILL_ID = T_BILL_ID;
ELSE
OPEN TIER_RANGE;
LOOP
FETCH TIER_RANGE INTO T_TIER_START ,T_TIER_END, T_RATE_PU;
EXIT
WHEN TIER_RANGE%NOTFOUND;
T_CALCVAL := 0;
IF(T_GIVEN >= T_TIER_START AND T_GIVEN <= T_TIER_END) THEN
T_CALCVAL := (T_GIVEN - T_TIER_START ) +1;
T_AMOUNT := T_AMOUNT + (T_CALCVALT_RATE_PU);
UPDATE BILL_ADMIN.MONTHLY_INVOICE
SET AMOUNT = T_AMOUNT
WHERE BILL_ID = T_BILL_ID;
GOTO LOOP_END;
ELSE
T_CALCVAL := (T_TIER_END - T_TIER_START ) +1;
T_AMOUNT := T_AMOUNT + (T_CALCVALT_RATE_PU);
END IF;
END LOOP;
<>
CLOSE TIER_RANGE;
END IF;
END LOOP;
CLOSE BILL_CALC;
COMMIT;
END;


This is for the Refernce .