address feedback comment: Consistent test file names

src/main/java/Finance.java

@@ -0,0 +1,62 @@
+import com.h2.BestLoanRates;
+import com.h2.MortgageCalculator;
+import com.h2.SavingsCalculator;
+
+import java.util.Arrays;
+import java.util.Map;
+
+public class Finance {
+    public static final String BEST_LOAN_RATES = "bestLoanRates";
+    public static final String SAVINGS_CALCULATOR = "savingsCalculator";
+    public static final String MORTGAGE_CALCULATOR = "mortgageCalculator";
+
+    public static final Map<String, String> commandsToUsage = Map.of(
+            BEST_LOAN_RATES, "usage: bestLoanRates",
+            SAVINGS_CALCULATOR, "usage: savingsCalculator <credits separated by ','> <debits separated by ','>",
+            MORTGAGE_CALCULATOR, "usage: mortgageCalculator <loanAmount> <termInYears> <annualRate>"
+    );
+
+    private static boolean validateCommandArguments(String[] args) {
+        switch (args[0]) {
+            case BEST_LOAN_RATES:
+                return args.length == 1;
+            case SAVINGS_CALCULATOR:
+                return args.length == 3;
+            case MORTGAGE_CALCULATOR:
+                return args.length == 4;
+        }
+        return false;
+    }
+
+    private static void executeCommand(String command, String[] arguments) {
+        switch (command) {
+            case BEST_LOAN_RATES:
+                System.out.println("Finding best loan rates ...");
+                BestLoanRates.main(arguments);
+                return;
+            case SAVINGS_CALCULATOR:
+                System.out.println("Finding your net savings ...");
+                SavingsCalculator.main(arguments);
+                return;
+            case MORTGAGE_CALCULATOR:
+                System.out.println("Finding your monthly payment ...");
+                MortgageCalculator.main(arguments);
+        }
+    }
+
+    public static void main(String[] args) {
+        final String command = args[0];
+        if (!commandsToUsage.containsKey(command)) {
+            System.out.println(command + ": command not found");
+            return;
+        }
+
+       final boolean isValidCommand = validateCommandArguments(args);
+        if (!isValidCommand) {
+            System.out.println(commandsToUsage.get(args[0]));
+            return;
+        }
+
+        executeCommand(command, Arrays.copyOfRange(args, 1, args.length));
+    }
+}

src/main/java/com/h2/BestLoanRates.java

@@ -0,0 +1,38 @@
+package com.h2;
+
+import java.util.Map;
+import java.util.Scanner;
+
+public class BestLoanRates {
+    public final static Map<Integer, Float> bestRates = Map.of(
+            1, 5.50f,
+            2, 3.45f,
+            3, 2.67f
+    );
+
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+
+        System.out.println("Enter your name");
+        String name = scanner.nextLine();
+        System.out.println("Hello " + name);
+
+        System.out.println("Enter the loan term (in years)");
+        int loanTermInYears = scanner.nextInt();
+        float bestRate = getRates(loanTermInYears);
+        if (bestRate == 0.0f) {
+            System.out.println("No available rates for term: " + loanTermInYears + " years");
+        } else {
+            System.out.println("Best Available Rate: " + getRates(loanTermInYears) + "%");
+        }
+
+        scanner.close();
+    }
+
+    public static float getRates(int loanTermInYears) {
+        if (bestRates.containsKey(loanTermInYears)) {
+            return bestRates.get(loanTermInYears);
+        }
+        return 0.0f;
+    }
+}

src/main/java/com/h2/MortgageCalculator.java

@@ -0,0 +1,51 @@
+package com.h2;
+
+import java.text.DecimalFormat;
+
+public class MortgageCalculator {
+    private long loanAmount;
+    private int termInYears;
+    private float annualRate;
+    private double monthlyPayment;
+
+    public MortgageCalculator(long loanAmount, int termInYears, float annualRate) {
+        this.loanAmount = loanAmount;
+        this.termInYears = termInYears;
+        this.annualRate = annualRate;
+    }
+
+    private int getNumberOfPayments() {
+        return termInYears * 12;
+    }
+
+    private float getMonthlyInterestRate() {
+        float interestRate = annualRate / 100;
+        return interestRate / 12;
+    }
+
+    public void calculateMonthlyPayment() {
+        long P = loanAmount;
+        float r = getMonthlyInterestRate();
+        int n = getNumberOfPayments();
+
+        double M = P * (((r * Math.pow(1 + r, n))) / ((Math.pow((1 + r), n)) - 1));
+
+        this.monthlyPayment = M;
+    }
+
+    public static void main(String[] args) {
+        final long loanAmount = Utilities.getLongValue(args[0]);
+        final int termInYears = Utilities.getIntValue(args[1]);
+        final float annualRate = Utilities.getFloatValue(args[2]);
+        final MortgageCalculator c = new MortgageCalculator(loanAmount, termInYears, annualRate);
+
+        c.calculateMonthlyPayment();
+
+        System.out.println(c.toString());
+    }
+
+    public String toString() {
+        DecimalFormat df = new DecimalFormat("####0.00");
+        return "monthlyPayment: " + df.format(monthlyPayment);
+    }
+}

src/main/java/com/h2/SavingsCalculator.java

@@ -0,0 +1,63 @@
+package com.h2;
+
+import java.time.LocalDate;
+import java.time.YearMonth;
+
+public class SavingsCalculator {
+    private float[] credits;
+    private float[] debits;
+
+    public SavingsCalculator(float[] credits, float[] debits) {
+        this.credits = credits;
+        this.debits = debits;
+    }
+
+    private float sumOfCredits() {
+        float sum = 0.0f;
+        for (float credit : credits) {
+            sum += credit;
+        }
+        return sum;
+    }
+
+    private float sumOfDebits() {
+        float sum = 0.0f;
+        for (float debit : debits) {
+            sum += debit;
+        }
+        return sum;
+    }
+
+    private static int remainingDaysInMonth(LocalDate date) {
+        YearMonth yearMonth = YearMonth.of(date.getYear(), date.getMonth());
+        int totalDaysInMonth = yearMonth.lengthOfMonth();
+        int remainingDays = totalDaysInMonth - date.getDayOfMonth();
+        return remainingDays;
+    }
+
+    public float calculate() {
+        return sumOfCredits() - sumOfDebits();
+    }
+
+    public static void main(String[] args) {
+        final String[] creditsAsString = args[0].split(",");
+        final String[] debitsAsString = args[1].split(",");
+
+        final float[] credits = new float[creditsAsString.length];
+        final float[] debits = new float[debitsAsString.length];
+
+        for (int i = 0; i < creditsAsString.length; i++) {
+            credits[i] = Float.parseFloat(creditsAsString[i]);
+        }
+
+        for (int i = 0; i < debitsAsString.length; i++) {
+            debits[i] = Float.parseFloat(debitsAsString[i]);
+        }
+
+        final SavingsCalculator calculator = new SavingsCalculator(credits, debits);
+
+        float netSavings = calculator.calculate();
+
+        System.out.println("Net Savings = " + netSavings + ", remaining days in month = " + remainingDaysInMonth(LocalDate.now()));
+    }
+}

src/main/java/com/h2/Utilities.java

@@ -0,0 +1,34 @@
+package com.h2;
+
+public class Utilities {
+
+    public static long getLongValue(String in) {
+        long out = Long.MIN_VALUE;
+        try {
+            out = Long.parseLong(in);
+        } catch (NumberFormatException e) {
+            throw new IllegalArgumentException(in + " cannot be converted into a 'long' value. Exiting program.");
+        }
+        return out;
+    }
+
+    public static int getIntValue(String in) {
+        int out = Integer.MIN_VALUE;
+        try {
+            out = Integer.parseInt(in);
+        } catch (NumberFormatException e) {
+            throw new IllegalArgumentException(in + " cannot be converted into a 'int' value. Exiting program.");
+        }
+        return out;
+    }
+
+    public static float getFloatValue(String in) {
+        float out = Float.MIN_VALUE;
+        try {
+            out = Float.parseFloat(in);
+        } catch (NumberFormatException e) {
+            throw new IllegalArgumentException(in + " cannot be converted into a 'float' value. Exiting program.");
+        }
+        return out;
+    }
+}

src/test/java/com/h2/Module04_Test.java → src/test/java/com/h2/Module4_Test.java

@@ -16,7 +16,7 @@
 import static org.junit.jupiter.api.Assertions.*;
 import static org.junit.platform.commons.util.ReflectionUtils.*;
 
-public class Module04_Test {
+public class Module4_Test {
     private static final String classToFind = "com.h2.MortgageCalculator";
     private final InputStream systemIn = System.in;
     private final PrintStream systemOut = System.out;

src/test/java/com/h2/Module05_Test.java → src/test/java/com/h2/Module5_Test.java

@@ -18,7 +18,7 @@
 import static org.junit.jupiter.api.Assertions.*;
 import static org.junit.platform.commons.util.ReflectionUtils.*;
 
-public class Module05_Test {
+public class Module5_Test {
     private final String classToFind = "Finance";
 
     private final InputStream systemIn = System.in;

src/test/java/com/h2/Module06_Test.java → src/test/java/com/h2/Module6_Test.java

@@ -13,7 +13,7 @@
 import static org.junit.jupiter.api.Assertions.*;
 import static org.junit.platform.commons.util.ReflectionUtils.*;
 
-public class Module06_Test {
+public class Module6_Test {
     private final String classToFind = "com.h2.Utilities";
 
 
@@ -139,7 +139,7 @@ public void m6_05_testGetFloatValueExistenceAndCorrectness() throws IllegalAcces
     public void m6_06_testMainMethodPrintsCorrectMortgageAmount() throws NoSuchMethodException {
         final String methodName = "main";
 
-        final Optional<Class<?>> maybeMortgageCalculator = Module04_Test.getMortgageClass();
+        final Optional<Class<?>> maybeMortgageCalculator = Module4_Test.getMortgageClass();
         assertTrue(maybeMortgageCalculator.isPresent(), classToFind + " must exist");
         final Class<?> mortgageCalculator = maybeMortgageCalculator.get();