You are developing a microservice that processes loan requests and performs a variety of calculations. In this particular scenario, you will receive a batch of loan requests which must be processed to obtain the monthly interest rate, monthly payment amount and the risk factor. These 3 values must be stored in a read efficient in-memory structure in order to serve as a cache for other systems to query.
The formula to calculate the monthly payment amount is as follows:
(LOAN_AMOUNT * MONTHLY_RATE) / (1 - (1 + MONTHLY_RATE ^ ((-1) * TERM_MONTHS))
The risk factor is a value from 0 to 1, where 0 means no risk and 1 is the highest possible risk. The bank follows these guidelines to estimate a borrower's credit quality (higher percentages mean better credit capabilities):
- No delinquent debt (+35%)
- Debt to Income ratio (Monthly Debt / Monthly Income) < 43% (+30%)
- Credit history (Good +25%)
- Type of credit used (Mortgage +10%)
Input:
JSON Array of loan submissions
[
{
loanId: 1,
amount: 100000,
termYears: 10,
termMonths: 0,
anualInterest: 6,
type: "mortgage",
borrower: {
name: "Jhon Smith",
anualIncome: "150000",
delinquentDebt: false,
amountOwed: 0
}
},
{
loanId: 2,
amount: 200000,
termYears: 15,
termMonths: 0,
anualInterest: 6.5,
type: "student",
borrower: {
name: "James Gosling",
anualIncome: "150000",
delinquentDebt: false,
amountOwed: 0
}
}
]
Output:
In-memory collections of instances of LoanAnalysis POJO containing:
- loanId,
- monthlyInterestRate
- monthlyPayment,
- riskFactor
public class Loan {
private int amount;
private int termYears;
private int termMonths;
private double anualInterest;
public Loan(int amount, int termYears, int termMonths, double anualInterest){
this.amount = amount;
this.termYears = termYears;
this.termMonths = termMonths;
this.anualInterest = anualInterest;
}
public double getMonthlyPayment(){
return this.amount*this.getMonthlyRate()/
(1-Math.pow(1+this.getMonthlyRate(), -this.getTermInMonths()));
}
public double getMonthlyRate(){
return this.anualInterest/100/12;
}
public int getTermInMonths(){
return this.termYears*12+this.termMonths;
}
public double riskFactor(int anualIncome){
return 0;
}
}import org.junit.Test;
import static org.junit.Assert.assertEquals;
import org.junit.runners.JUnit4;
// TODO: Replace examples and use TDD development by writing your own tests
public class SolutionTest {
@Test
public void testSomething() {
Loan loan = new Loan(100000, 10, 0, 6);
assertEquals(1110.21, loan.getMonthlyPayment(), 1);
}
}