Initial Add Multi-Currency Money

src/main/java/guru/springframework/Dollar.java

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+package guru.springframework;
+
+public class Dollar extends Money{
+
+    public Dollar(int amount, String currency) {
+        super(amount, currency);
+    }
+
+     public Money times(int multiplier) {
+        return Money.dollar(amount*multiplier);
+    }
+}

src/main/java/guru/springframework/Franc.java

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+package guru.springframework;
+
+public class Franc extends Money{
+
+    public Franc(int amount, String currency) {
+        super(amount, currency);
+    }
+
+    public Money times(int multiplier) {
+        return Money.franc(amount*multiplier);
+    }
+
+}

src/main/java/guru/springframework/Money.java

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+package guru.springframework;
+
+public abstract class Money {
+    private final String currency;
+    protected final int amount;
+
+    public Money(int amount, String currency) {
+        this.amount = amount;
+        this.currency = currency;
+    }
+
+    protected String currency() {
+        return currency;
+    }
+
+    public abstract Money times(int multiplier);
+
+    public static Money dollar(int amount) {
+        return new Dollar(amount, "USD");
+    }
+
+    public static Money franc(int amount) {
+        return new Franc(amount, "CHF");
+    }
+
+    public boolean equals(Object object) {
+        Money money  = (Money) object;
+        return amount == money.amount && this.getClass().equals(object.getClass());
+    }
+}

src/test/java/guru/springframework/MoneyTest.java

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+package guru.springframework;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+public class MoneyTest {
+
+    @Test
+    void testMultiplicationDollar() {
+        Money five = Money.dollar(5);
+        assertEquals(Money.dollar(10), five.times(2));
+        assertEquals(Money.dollar(15), five.times(3));
+    }
+
+    @Test
+    void testEqualityDollar() {
+        assertEquals(Money.dollar(5), Money.dollar(5));
+        assertNotEquals(Money.dollar(5), Money.dollar(10));
+        assertNotEquals(Money.dollar(5),Money.franc(5));
+    }
+
+
+    @Test
+    void testMultiplicationFranc() {
+        Money five = Money.franc(5);
+        assertEquals(Money.franc(10), five.times(2));
+        assertEquals(Money.franc(15), five.times(3));
+    }
+
+    @Test
+    void testEqualityFranc() {
+        assertEquals(Money.franc(5), Money.franc(5));
+        assertNotEquals(Money.franc(5), Money.franc(10));
+    }
+
+    @Test
+    void testCurrency() {
+        assertEquals("USD", Money.dollar(1).currency());
+        assertEquals("CHF", Money.franc(1).currency());
+    }
+}