fix: Double to BigDecimal

pom.xml

@@ -110,6 +110,7 @@
                 <configuration>
                     <sourceDirectory>${basedir}/src/main/resources/schema</sourceDirectory>
                     <targetPackage>eu.ztsh.wymiana.model</targetPackage>
+                    <useBigDecimals>true</useBigDecimals>
                 </configuration>
                 <executions>
                     <execution>

readme.md

@@ -37,7 +37,7 @@ Prosty mikroserwis stworzony na potrzeby rekrutacji
       "name",
       "surname",
       "pesel",
-      "pln"
+      "initial"
     ]
   }
   ```

src/main/java/eu/ztsh/wymiana/data/entity/CurrencyEntity.java

@@ -7,6 +7,8 @@ import lombok.AllArgsConstructor;
 import lombok.Data;
 import lombok.NoArgsConstructor;
 
+import java.math.BigDecimal;
+
 @Data
 @NoArgsConstructor
 @AllArgsConstructor
@@ -18,6 +20,6 @@ public class CurrencyEntity {
     String pesel;
     @Id
     String symbol;
-    Double amount;
+    BigDecimal amount;
 
 }

src/main/java/eu/ztsh/wymiana/model/Currency.java

@@ -1,5 +1,7 @@
 package eu.ztsh.wymiana.model;
 
-public record Currency(String symbol, double amount) {
+import java.math.BigDecimal;
+
+public record Currency(String symbol, BigDecimal amount) {
 
 }

src/main/java/eu/ztsh/wymiana/service/CurrencyService.java

@@ -45,8 +45,8 @@ public class CurrencyService {
                 }
                 var exchanged = performExchange(from,
                     Optional.ofNullable(user.currencies().get(request.to().toUpperCase())).orElse(create(request.to())),
-                    Optional.ofNullable(request.toSell()).orElse(0D),
+                    Optional.ofNullable(request.toSell()).orElse(BigDecimal.ZERO),
-                    Optional.ofNullable(request.toBuy()).orElse(0D));
+                    Optional.ofNullable(request.toBuy()).orElse(BigDecimal.ZERO));
                 user.currencies().putAll(exchanged);
                 return userService.update(user);
             })
@@ -55,32 +55,36 @@ public class CurrencyService {
 
     private Currency create(String symbol) {
         // TODO: check if supported - now limited to PLN <-> USD
-        return new Currency(symbol.toUpperCase(), 0D);
+        return new Currency(symbol.toUpperCase(), BigDecimal.ZERO);
     }
 
-    private Map<String, Currency> performExchange(Currency from, Currency to, double toSell, double toBuy) {
+    private Map<String, Currency> performExchange(Currency from, Currency to, BigDecimal toSell, BigDecimal toBuy) {
-        double exchangeRate;
+        BigDecimal exchangeRate;
-        double neededFromAmount;
+        BigDecimal neededFromAmount;
-        double requestedToAmount;
+        BigDecimal requestedToAmount;
         if (from.symbol().equalsIgnoreCase("PLN")) {
             exchangeRate = nbpService.getSellRate(to.symbol());
-            neededFromAmount = round(toBuy != 0 ? toBuy * exchangeRate : toSell);
+            neededFromAmount = round(toBuy.signum() != 0 ? toBuy.multiply(exchangeRate) : toSell);
-            requestedToAmount = round(toBuy != 0 ? toBuy : toSell / exchangeRate);
+            requestedToAmount = round(toBuy.signum() != 0 ? toBuy : divide(toSell, exchangeRate));
         } else {
             exchangeRate = nbpService.getBuyRate(from.symbol());
-            neededFromAmount = round(toBuy != 0 ? toBuy / exchangeRate : toSell);
+            neededFromAmount = round(toBuy.signum() != 0 ? divide(toBuy, exchangeRate) : toSell);
-            requestedToAmount = round(toBuy != 0 ? toBuy : toSell * exchangeRate);
+            requestedToAmount = round(toBuy.signum() != 0 ? toBuy : toSell.multiply(exchangeRate));
         }
-        if (neededFromAmount > from.amount()) {
+        if (neededFromAmount.compareTo(from.amount()) > 0) {
             throw new InsufficientFundsException();
         }
-        var newFrom = new Currency(from.symbol(), from.amount() - neededFromAmount);
+        var newFrom = new Currency(from.symbol(), from.amount().subtract(neededFromAmount));
-        var newTo = new Currency(to.symbol(), to.amount() + requestedToAmount);
+        var newTo = new Currency(to.symbol(), to.amount().add(requestedToAmount));
         return Stream.of(newFrom, newTo).collect(Collectors.toMap(Currency::symbol, currency -> currency));
     }
 
-    private double round(double input) {
+    private BigDecimal round(BigDecimal input) {
-        return BigDecimal.valueOf(input).setScale(2, RoundingMode.HALF_UP).doubleValue();
+        return input.setScale(2, RoundingMode.HALF_UP);
+    }
+
+    private BigDecimal divide(BigDecimal input, BigDecimal division) {
+        return input.setScale(2, RoundingMode.HALF_UP).divide(division, RoundingMode.HALF_UP);
     }
 
 }

src/main/java/eu/ztsh/wymiana/service/NbpService.java

@@ -8,6 +8,7 @@ import org.springframework.http.HttpStatusCode;
 import org.springframework.stereotype.Service;
 import org.springframework.web.client.RestClient;
 
+import java.math.BigDecimal;
 import java.time.Clock;
 import java.time.DayOfWeek;
 import java.time.LocalDate;
@@ -30,11 +31,11 @@ public class NbpService {
 
     private final ConcurrentMap<String, RatesCache> cache = new ConcurrentHashMap<>(1);
 
-    public double getSellRate(String currency) {
+    public BigDecimal getSellRate(String currency) {
         return getCurrency(currency.toUpperCase()).sell();
     }
 
-    public double getBuyRate(String currency) {
+    public BigDecimal getBuyRate(String currency) {
         return getCurrency(currency.toUpperCase()).buy();
     }
 
@@ -43,7 +44,7 @@ public class NbpService {
         var cacheObject = cache.get(currency);
         if (cacheObject == null || cacheObject.date().isBefore(today)) {
             var fresh = fetchData(currency, dtf.format(today));
-            var rate = fresh.getRates().get(0);
+            var rate = fresh.getRates().getFirst();
             cacheObject = new RatesCache(
                 LocalDate.parse(rate.getEffectiveDate(), dtf),
                 rate.getBid(),
@@ -82,7 +83,7 @@ public class NbpService {
             || today.getDayOfWeek() == DayOfWeek.SUNDAY;
     }
 
-    private record RatesCache(LocalDate date, double buy, double sell) {
+    private record RatesCache(LocalDate date, BigDecimal buy, BigDecimal sell) {
 
     }
 

src/main/java/eu/ztsh/wymiana/util/UserMapper.java

@@ -21,7 +21,7 @@ public class UserMapper {
 
     public static UserEntity requestToEntity(UserCreateRequest request) {
         return new UserEntity(request.pesel(), request.name(), request.surname(),
-            List.of(new CurrencyEntity(request.pesel(), "PLN", request.pln())));
+            List.of(new CurrencyEntity(request.pesel(), "PLN", request.initial())));
     }
 
     private UserMapper() {

src/main/java/eu/ztsh/wymiana/validation/ValidExchangeRequestValidator.java

@@ -18,8 +18,8 @@ public class ValidExchangeRequestValidator implements
         return (request.from() != null && !request.from().equals(request.to()))
             && !((request.toBuy() == null && request.toSell() == null)
                 || (request.toBuy() != null && request.toSell() != null))
-            && ((request.toBuy() != null && request.toBuy() >= 0)
+            && ((request.toBuy() != null && request.toBuy().signum() >= 0)
-                || (request.toSell() != null && request.toSell() >= 0));
+                || (request.toSell() != null && request.toSell().signum() >= 0));
     }
 
 }

src/main/java/eu/ztsh/wymiana/web/model/CurrencyExchangeRequest.java

@@ -5,14 +5,16 @@ import jakarta.validation.constraints.NotNull;
 import lombok.Builder;
 import org.hibernate.validator.constraints.pl.PESEL;
 
+import java.math.BigDecimal;
+
 @Builder
 @ValidExchangeRequest
 public record CurrencyExchangeRequest(
     @PESEL String pesel,
     @NotNull String from,
     @NotNull String to,
-    Double toBuy,
+    BigDecimal toBuy,
-    Double toSell
+    BigDecimal toSell
 ) {
 
 }

src/main/java/eu/ztsh/wymiana/web/model/UserCreateRequest.java

@@ -6,11 +6,13 @@ import jakarta.validation.constraints.NotNull;
 import lombok.Builder;
 import org.hibernate.validator.constraints.pl.PESEL;
 
+import java.math.BigDecimal;
+
 @Builder
 public record UserCreateRequest(
     @NotNull String name,
     @NotNull String surname,
     @PESEL @Adult String pesel,
-    @Min(0) double pln) {
+    @Min(0) BigDecimal initial) {
 
 }

src/test/java/eu/ztsh/wymiana/EntityCreator.java

@@ -9,6 +9,8 @@ import eu.ztsh.wymiana.model.User;
 import eu.ztsh.wymiana.web.model.CurrencyExchangeRequest;
 import eu.ztsh.wymiana.web.model.UserCreateRequest;
 
+import java.math.BigDecimal;
+import java.math.RoundingMode;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -24,13 +26,13 @@ public class EntityCreator {
         public static String ANOTHER_PESEL = "08280959342";
         public static String NAME = "Janina";
         public static String SURNAME = "Kowalska";
-        public static double PLN = 20.10;
+        public static BigDecimal PLN = createScaled(20.10, 2);
-        public static double USD_SELL = 5.18;
+        public static BigDecimal USD_SELL = createScaled(5.18, 2);
-        public static double USD_BUY = 5.08;
+        public static BigDecimal USD_BUY = createScaled(5.08, 2);
         public static String PLN_SYMBOL = "PLN";
         public static String USD_SYMBOL = "USD";
-        public static double BUY_RATE = 3.8804;
+        public static BigDecimal BUY_RATE = createScaled(3.8804, 4);
-        public static double SELL_RATE = 3.9572;
+        public static BigDecimal SELL_RATE = createScaled(3.9572, 4);
 
     }
 
@@ -39,25 +41,29 @@ public class EntityCreator {
     }
 
     public static User user() {
-        return user(Constants.PLN, 0);
+        return user(Constants.PLN, BigDecimal.ZERO);
     }
 
-    public static User user(double pln, double usd) {
+    public static User user(BigDecimal pln, BigDecimal usd) {
         Map<String, Currency> currencies = new HashMap<>();
-        if (pln > 0) {
+        if (pln.signum() > 0) {
             currencies.put("PLN", new Currency("PLN", pln));
         }
-        if (usd > 0) {
+        if (usd.signum() > 0) {
             currencies.put("USD", new Currency("USD", usd));
         }
         return new User(Constants.NAME, Constants.SURNAME, Constants.PESEL, currencies);
     }
 
     public static UserCreateRequest.UserCreateRequestBuilder userRequest() {
+        return userRequest(null);
+    }
+
+    public static UserCreateRequest.UserCreateRequestBuilder userRequest(Double initial) {
         return UserCreateRequest.builder().name(Constants.NAME)
             .surname(Constants.SURNAME)
             .pesel(Constants.PESEL)
-            .pln(Constants.PLN);
+            .initial(initial != null ? createScaled(initial, 2) : Constants.PLN);
     }
 
     public static CurrencyExchangeRequest.CurrencyExchangeRequestBuilder exchangeRequest() {
@@ -83,8 +89,8 @@ public class EntityCreator {
         String name;
         String surname;
         String pesel;
-        double pln = -1;
+        BigDecimal pln = BigDecimal.valueOf(-1);
-        double usd = -1;
+        BigDecimal usd = BigDecimal.valueOf(-1);
 
         public UserEntityBuilder name(String name) {
             this.name = name;
@@ -102,22 +108,30 @@ public class EntityCreator {
         }
 
         public UserEntityBuilder pln(double pln) {
-            this.pln = pln;
+            return this.pln(BigDecimal.valueOf(pln));
+        }
+
+        public UserEntityBuilder pln(BigDecimal pln) {
+            this.pln = pln.setScale(2, RoundingMode.HALF_UP);
             return this;
         }
 
         public UserEntityBuilder usd(double usd) {
-            this.usd = usd;
+            return this.usd(BigDecimal.valueOf(usd));
+        }
+
+        public UserEntityBuilder usd(BigDecimal usd) {
+            this.usd = usd.setScale(2, RoundingMode.HALF_UP);
             return this;
         }
 
         public UserEntity build() {
             var nonnulPesel = Optional.ofNullable(pesel).orElse(Constants.PESEL);
             List<CurrencyEntity> currencies = new ArrayList<>();
-            if (pln > -1) {
+            if (pln.signum() > -1) {
                 currencies.add(new CurrencyEntity(nonnulPesel, "PLN", pln));
             }
-            if (usd > -1) {
+            if (usd.signum() > -1) {
                 currencies.add(new CurrencyEntity(nonnulPesel, "USD", usd));
             }
             if (currencies.isEmpty()) {
@@ -133,4 +147,8 @@ public class EntityCreator {
 
     }
 
+    private static BigDecimal createScaled(double input, int scale) {
+        return BigDecimal.valueOf(input).setScale(scale, RoundingMode.HALF_UP);
+    }
+
 }

src/test/java/eu/ztsh/wymiana/service/CurrencyServiceTest.java

@@ -16,6 +16,8 @@ import org.junit.jupiter.params.provider.MethodSource;
 import org.mockito.Mockito;
 import org.springframework.beans.factory.annotation.Autowired;
 
+import java.math.BigDecimal;
+import java.util.Objects;
 import java.util.stream.Stream;
 
 import static eu.ztsh.wymiana.EntityCreator.Constants.*;
@@ -46,7 +48,7 @@ class CurrencyServiceTest extends RepositoryBasedTest {
             .toSell(PLN)
             .build());
         assertThat(result.currencies())
-            .matches(map -> map.get(PLN_SYMBOL).amount() == 0 && map.get(USD_SYMBOL).amount() == USD_BUY);
+            .matches(map -> map.get(PLN_SYMBOL).amount().signum() == 0 && Objects.equals(map.get(USD_SYMBOL).amount(), USD_BUY), "USD 5.08");
         var expected = EntityCreator.userEntity().pln(0).usd(USD_BUY).build();
         expect(expected);
     }
@@ -62,7 +64,7 @@ class CurrencyServiceTest extends RepositoryBasedTest {
             .toBuy(USD_BUY)
             .build());
         assertThat(result.currencies())
-            .matches(map -> map.get(PLN_SYMBOL).amount() == 0 && map.get(USD_SYMBOL).amount() == USD_BUY);
+            .matches(map -> map.get(PLN_SYMBOL).amount().signum() == 0 && Objects.equals(map.get(USD_SYMBOL).amount(), USD_BUY));
         var expected = EntityCreator.userEntity().pln(0).usd(USD_BUY).build();
         expect(expected);
     }
@@ -78,7 +80,7 @@ class CurrencyServiceTest extends RepositoryBasedTest {
             .toSell(USD_SELL)
             .build());
         assertThat(result.currencies())
-            .matches(map -> map.get(PLN_SYMBOL).amount() == PLN && map.get(USD_SYMBOL).amount() == 0);
+            .matches(map -> Objects.equals(map.get(PLN_SYMBOL).amount(), PLN) && map.get(USD_SYMBOL).amount().signum() == 0, "PLN 20.10");
         var expected = EntityCreator.userEntity().pln(PLN).usd(0).build();
         expect(expected);
     }
@@ -94,7 +96,7 @@ class CurrencyServiceTest extends RepositoryBasedTest {
             .toBuy(PLN)
             .build());
         assertThat(result.currencies())
-            .matches(map -> map.get(PLN_SYMBOL).amount() == PLN && map.get(USD_SYMBOL).amount() == 0);
+            .matches(map -> Objects.equals(map.get(PLN_SYMBOL).amount(), PLN) && map.get(USD_SYMBOL).amount().signum() == 0, "PLN 20.10");
         var expected = EntityCreator.userEntity().pln(PLN).usd(0).build();
         expect(expected);
     }
@@ -116,7 +118,7 @@ class CurrencyServiceTest extends RepositoryBasedTest {
     @Transactional
     @Test
     void doubleExchangeTest() {
-        var initialValue = 100;
+        var initialValue = BigDecimal.valueOf(100);
         var entity = EntityCreator.userEntity().pln(initialValue).build();
         userRepository.save(entity);
         var result1 = currencyService.exchange(EntityCreator.exchangeRequest()
@@ -136,7 +138,7 @@ class CurrencyServiceTest extends RepositoryBasedTest {
         assertThat(resultEntity.getCurrencies()
             .stream()
             .filter(c -> c.getSymbol().equalsIgnoreCase("PLN"))
-            .findFirst()).isNotEmpty().get().matches(currencyEntity -> currencyEntity.getAmount() < initialValue);
+            .findFirst()).isNotEmpty().get().matches(currencyEntity -> currencyEntity.getAmount().compareTo(initialValue) < 0);
     }
 
     @Transactional

src/test/java/eu/ztsh/wymiana/service/UserServiceTest.java

@@ -50,10 +50,9 @@ class UserServiceTest extends RepositoryBasedTest {
     @DisplayName("Try to create another user with same PESEL")
     void createDuplicatedPeselTest() {
         var first = EntityCreator.userRequest().build();
-        var second = EntityCreator.userRequest()
+        var second = EntityCreator.userRequest(30.30)
                 .name("Jan")
                 .surname("Kowalski")
-                .pln(30.30)
                 .build();
         userService.create(first);
         assertThatThrownBy(() -> userService.create(second))

src/test/java/eu/ztsh/wymiana/validation/ValidExchangeRequestValidatorTest.java

@@ -5,6 +5,8 @@ import eu.ztsh.wymiana.web.model.CurrencyExchangeRequest;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 
+import java.math.BigDecimal;
+
 import static eu.ztsh.wymiana.EntityCreator.Constants.PLN_SYMBOL;
 import static eu.ztsh.wymiana.EntityCreator.Constants.USD_BUY;
 import static eu.ztsh.wymiana.EntityCreator.Constants.USD_SELL;
@@ -72,7 +74,7 @@ class ValidExchangeRequestValidatorTest extends ValidatorTest<ValidExchangeReque
         assertThatValidation(EntityCreator.exchangeRequest()
             .from(PLN_SYMBOL)
             .to(USD_SYMBOL)
-            .toBuy(-1.0)
+            .toBuy(BigDecimal.valueOf(-1.0))
             .build()).isFalse();
     }
 
@@ -82,7 +84,7 @@ class ValidExchangeRequestValidatorTest extends ValidatorTest<ValidExchangeReque
         assertThatValidation(EntityCreator.exchangeRequest()
             .from(PLN_SYMBOL)
             .to(USD_SYMBOL)
-            .toSell(-1.0)
+            .toSell(BigDecimal.valueOf(-1.0))
             .build()).isFalse();
     }
 

src/test/java/eu/ztsh/wymiana/web/ApplicationIntegrationTests.java

@@ -18,6 +18,7 @@ import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.test.context.ActiveProfiles;
 import org.springframework.test.web.reactive.server.WebTestClient;
 
+import java.math.BigDecimal;
 import java.time.DayOfWeek;
 import java.time.LocalDate;
 import java.time.format.DateTimeFormatter;
@@ -80,7 +81,7 @@ class ApplicationIntegrationTests {
         void createUserTest() {
             webTestClient.post()
                 .uri(endpoint)
-                .bodyValue(EntityCreator.userRequest().pln(100).build())
+                .bodyValue(EntityCreator.userRequest(100D).build())
                 .exchange()
                 .expectStatus().isNoContent();
         }
@@ -169,7 +170,7 @@ class ApplicationIntegrationTests {
                 200,
                 asJson(EntityCreator.rates(date))
             );
-            var expected = asJson(EntityCreator.user(100 - PLN, USD_BUY));
+            var expected = asJson(EntityCreator.user(BigDecimal.valueOf(100).subtract(PLN), USD_BUY));
             webTestClient.post()
                 .uri(endpoint)
                 .bodyValue(EntityCreator.exchangeRequest()