Feat/#308 Moeny 도메인 추가

build.gradle

@@ -85,8 +85,8 @@ dependencies {
     testAnnotationProcessor 'org.projectlombok:lombok'
 
     // test container
-    testImplementation "org.testcontainers:junit-jupiter:1.16.3"
-    testImplementation 'org.testcontainers:mysql:1.16.3'
+    testImplementation 'org.testcontainers:junit-jupiter:1.19.7'
+    testImplementation 'org.testcontainers:mysql:1.19.7'
     implementation 'org.testcontainers:localstack:1.19.7'
 
     // Rest Docs

src/main/java/codesquad/fineants/domain/common/count/Count.java

@@ -3,6 +3,7 @@
 import java.math.BigInteger;
 import java.util.Objects;
 
+import codesquad.fineants.domain.common.money.Expression;
 import codesquad.fineants.domain.common.money.Money;
 import lombok.AccessLevel;
 import lombok.Getter;
@@ -41,15 +42,15 @@ public Count add(Count count) {
 		return new Count(value.add(count.value));
 	}
 
-	public Money multiply(Money money) {
-		return money.multiply(value);
+	public Expression multiply(Money money) {
+		return money.times(value.intValue());
 	}
 
 	public boolean isZero() {
 		return value.compareTo(BigInteger.ZERO) == 0;
 	}
 
-	public Money division(Money numerator) {
+	public Expression division(Money numerator) {
 		return numerator.divide(value);
 	}
 

src/main/java/codesquad/fineants/domain/common/money/AverageDivision.java

@@ -0,0 +1,63 @@
+package codesquad.fineants.domain.common.money;
+
+import static codesquad.fineants.domain.common.money.Currency.*;
+
+import org.jetbrains.annotations.NotNull;
+
+import codesquad.fineants.domain.common.count.Count;
+
+public class AverageDivision implements Expression {
+
+	private final Expression division;
+	private final Count divisor;
+
+	public AverageDivision(Expression division, Count divisor) {
+		this.division = division;
+		this.divisor = divisor;
+	}
+
+	@Override
+	public Money reduce(Bank bank, Currency to) {
+		Expression result = divisor.division(bank.reduce(division, to));
+		return bank.reduce(result, to);
+	}
+
+	@Override
+	public Expression plus(Expression addend) {
+		return new Sum(this, addend);
+	}
+
+	@Override
+	public Expression minus(Expression subtrahend) {
+		return new Subtraction(this, subtrahend);
+	}
+
+	@Override
+	public Expression times(int multiplier) {
+		return new AverageDivision(division.times(multiplier), divisor);
+	}
+
+	@Override
+	public Expression divide(Count divisor) {
+		return new AverageDivision(this, divisor);
+	}
+
+	@Override
+	public RateDivision divide(Expression divisor) {
+		return new RateDivision(this, divisor);
+	}
+
+	@Override
+	public Percentage toPercentage(Bank bank, Currency to) {
+		return Percentage.from(reduce(bank, to).amount);
+	}
+
+	@Override
+	public int compareTo(@NotNull Expression o) {
+		Bank bank = Bank.getInstance();
+		Currency to = KRW;
+		Money won = this.reduce(bank, to);
+		Money won2 = o.reduce(bank, to);
+		return won.compareTo(won2);
+	}
+}

src/main/java/codesquad/fineants/domain/common/money/Bank.java

@@ -0,0 +1,38 @@
+package codesquad.fineants.domain.common.money;
+
+import java.util.Hashtable;
+
+public final class Bank {
+
+	private static Bank instance;
+	private final Hashtable<Pair, Double> rates = new Hashtable<>();
+
+	Bank() {
+	}
+
+	public static Bank getInstance() {
+		if (instance == null) {
+			instance = new Bank();
+		}
+		return instance;
+	}
+
+	public Money reduce(Expression source, Currency to) {
+		return source.reduce(this, to);
+	}
+
+	public void addRate(Currency from, Currency to, double rate) {
+		rates.put(new Pair(from, to), rate);
+	}
+
+	double rate(Currency from, Currency to) {
+		if (from.equals(to)) {
+			return 1;
+		}
+		return rates.get(new Pair(from, to));
+	}
+
+	public Money toWon(Expression amount) {
+		return reduce(amount, Currency.KRW);
+	}
+}

src/main/java/codesquad/fineants/domain/common/money/Currency.java

@@ -0,0 +1,16 @@
+package codesquad.fineants.domain.common.money;
+
+import lombok.Getter;
+
+@Getter
+public enum Currency {
+	USD("$"),
+	CHF("FR"),
+	KRW("₩");
+
+	private final String symbol;
+
+	Currency(String symbol) {
+		this.symbol = symbol;
+	}
+}

src/main/java/codesquad/fineants/domain/common/money/Expression.java

@@ -0,0 +1,19 @@
+package codesquad.fineants.domain.common.money;
+
+import codesquad.fineants.domain.common.count.Count;
+
+public interface Expression extends Comparable<Expression> {
+	Money reduce(Bank bank, Currency to);
+
+	Expression plus(Expression addend);
+
+	Expression minus(Expression subtrahend);
+
+	Expression times(int multiplier);
+
+	Expression divide(Count divisor);
+
+	RateDivision divide(Expression divisor);
+
+	Percentage toPercentage(Bank bank, Currency to);
+}