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Merge pull request 'CurrencyService implementation' from currency-service into master

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Piotr Dec 2024-05-24 17:53:42 +02:00
commit 56162ad895
12 changed files with 367 additions and 58 deletions
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13
src/main/java/eu/ztsh/wymiana/exception/ExchangeFailedException.java Normal file
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@ -0,0 +1,13 @@
package eu.ztsh.wymiana.exception;
public class ExchangeFailedException extends RuntimeException {
public ExchangeFailedException() {
this("An exchange error has occurred");
}
public ExchangeFailedException(String message) {
super(message);
}
}

9
src/main/java/eu/ztsh/wymiana/exception/InsufficientFundsException.java Normal file
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@ -0,0 +1,9 @@
package eu.ztsh.wymiana.exception;
public class InsufficientFundsException extends RuntimeException {
public InsufficientFundsException() {
super("Insufficient funds");
}
}

85
src/main/java/eu/ztsh/wymiana/service/CurrencyService.java Normal file
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@ -0,0 +1,85 @@
package eu.ztsh.wymiana.service;
import eu.ztsh.wymiana.exception.ExchangeFailedException;
import eu.ztsh.wymiana.exception.InsufficientFundsException;
import eu.ztsh.wymiana.model.Currency;
import eu.ztsh.wymiana.model.User;
import eu.ztsh.wymiana.validation.InstanceValidator;
import eu.ztsh.wymiana.web.model.CurrencyExchangeRequest;
import lombok.RequiredArgsConstructor;
import org.springframework.stereotype.Service;
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Map;
import java.util.Optional;
import java.util.stream.Collectors;
import java.util.stream.Stream;
@RequiredArgsConstructor
@Service
public class CurrencyService {
private final UserService userService;
private final NbpService nbpService;
private final InstanceValidator validator;
public User exchange(CurrencyExchangeRequest request) {
validator.validate(request);
return userService.get(request.pesel()).map(user -> {
if (!request.from().equalsIgnoreCase("PLN") && !request.to().equalsIgnoreCase("PLN")) {
throw new ExchangeFailedException("Either 'from' or 'to' has to be PLN");
}
// As we support only USD now, we need to limit second parameter too
// Begin: unlock other currencies
if (!request.from().equalsIgnoreCase("USD") && !request.to().equalsIgnoreCase("USD")) {
throw new ExchangeFailedException("Either 'from' or 'to' has to be USD");
}
// End: unlock other currencies
var from = user.currencies().get(request.from().toUpperCase());
if (from == null) {
// There is no currency 'from' opened so no need to check if user has funds to exchange
throw new InsufficientFundsException();
}
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.toBuy()).orElse(0D));
user.currencies().putAll(exchanged);
return userService.update(user);
})
.orElseThrow(ExchangeFailedException::new);
}
private Currency create(String symbol) {
// TODO: check if supported - now limited to PLN <-> USD
return new Currency(symbol.toUpperCase(), 0D);
}
private Map<String, Currency> performExchange(Currency from, Currency to, double toSell, double toBuy) {
double exchangeRate;
double neededFromAmount;
double requestedToAmount;
if (from.symbol().equalsIgnoreCase("PLN")) {
exchangeRate = nbpService.getSellRate(to.symbol());
neededFromAmount = round(toBuy != 0 ? toBuy * exchangeRate : toSell);
requestedToAmount = round(toBuy != 0 ? toBuy : toSell / exchangeRate);
} else {
exchangeRate = nbpService.getBuyRate(from.symbol());
neededFromAmount = round(toBuy != 0 ? toBuy / exchangeRate : toSell);
requestedToAmount = round(toBuy != 0 ? toBuy : toSell * exchangeRate);
}
if (neededFromAmount > from.amount()) {
throw new InsufficientFundsException();
}
var newFrom = new Currency(from.symbol(), from.amount() - neededFromAmount);
var newTo = new Currency(to.symbol(), to.amount() + requestedToAmount);
return Stream.of(newFrom, newTo).collect(Collectors.toMap(Currency::symbol, currency -> currency));
}
private double round(double input) {
return BigDecimal.valueOf(input).setScale(2, RoundingMode.HALF_UP).doubleValue();
}
}

4
src/main/java/eu/ztsh/wymiana/service/NbpService.java
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@ -31,11 +31,11 @@ public class NbpService {
private final ConcurrentMap<String, RatesCache> cache = new ConcurrentHashMap<>(1);
public double getSellRate(String currency) {
return getCurrency(currency).sell();
return getCurrency(currency.toUpperCase()).sell();
}
public double getBuyRate(String currency) {
return getCurrency(currency).buy();
return getCurrency(currency.toUpperCase()).buy();
}
private synchronized RatesCache getCurrency(String currency) {

4
src/main/java/eu/ztsh/wymiana/service/UserService.java
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@ -30,4 +30,8 @@ public class UserService {
return userRepository.findById(pesel).map(UserMapper::entityToPojo);
}
public User update(User user) {
return UserMapper.entityToPojo(userRepository.save(UserMapper.pojoToEntity(user)));
}
}

8
src/main/java/eu/ztsh/wymiana/util/CurrencyMapper.java
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@ -13,11 +13,19 @@ public class CurrencyMapper {
return new Currency(entity.getSymbol(), entity.getAmount());
}
public static CurrencyEntity pojoToEntity(Currency pojo, String pesel) {
return new CurrencyEntity(pesel, pojo.symbol(), pojo.amount());
}
public static Map<String, Currency> entitiesToPojoMap(List<CurrencyEntity> values) {
return values.stream().map(CurrencyMapper::entityToPojo)
.collect(Collectors.toMap(Currency::symbol, pojo -> pojo));
}
public static List<CurrencyEntity> pojoMapToEntities(Map<String, Currency> currencies, String pesel) {
return currencies.values().stream().map(entry -> pojoToEntity(entry, pesel)).toList();
}
private CurrencyMapper() {
}

5
src/main/java/eu/ztsh/wymiana/util/UserMapper.java
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@ -14,6 +14,11 @@ public class UserMapper {
CurrencyMapper.entitiesToPojoMap(entity.getCurrencies()));
}
public static UserEntity pojoToEntity(User pojo) {
return new UserEntity(pojo.pesel(), pojo.name(), pojo.surname(),
CurrencyMapper.pojoMapToEntities(pojo.currencies(), pojo.pesel()));
}
public static UserEntity requestToEntity(UserCreateRequest request) {
return new UserEntity(request.pesel(), request.name(), request.surname(),
List.of(new CurrencyEntity(request.pesel(), "PLN", request.pln())));

3
src/main/java/eu/ztsh/wymiana/validation/ValidExchangeRequestValidator.java
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@ -14,7 +14,8 @@ public class ValidExchangeRequestValidator implements
return false;
}
return !request.from().equals(request.to())
// Apart from @NotNull annotation we need to check if request.from() != null to avoid NPE in equals
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)

8
src/test/java/eu/ztsh/wymiana/EntityCreator.java
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@ -62,8 +62,8 @@ public class EntityCreator {
String name;
String surname;
String pesel;
double pln;
double usd;
double pln = -1;
double usd = -1;
public UserEntityBuilder name(String name) {
this.name = name;
@ -93,10 +93,10 @@ public class EntityCreator {
public UserEntity build() {
var nonnulPesel = Optional.ofNullable(pesel).orElse(Constants.PESEL);
List<CurrencyEntity> currencies = new ArrayList<>();
if (pln > 0) {
if (pln > -1) {
currencies.add(new CurrencyEntity(nonnulPesel, "PLN", pln));
}
if (usd > 0) {
if (usd > -1) {
currencies.add(new CurrencyEntity(nonnulPesel, "USD", usd));
}
if (currencies.isEmpty()) {

209
src/test/java/eu/ztsh/wymiana/service/CurrencyServiceTest.java Normal file
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@ -0,0 +1,209 @@
package eu.ztsh.wymiana.service;
import eu.ztsh.wymiana.EntityCreator;
import eu.ztsh.wymiana.RepositoryBasedTest;
import eu.ztsh.wymiana.data.repository.UserRepository;
import eu.ztsh.wymiana.exception.ExchangeFailedException;
import eu.ztsh.wymiana.exception.InsufficientFundsException;
import eu.ztsh.wymiana.validation.InstanceValidator;
import eu.ztsh.wymiana.validation.ValidationFailedException;
import jakarta.transaction.Transactional;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.MethodSource;
import org.mockito.Mockito;
import org.springframework.beans.factory.annotation.Autowired;
import java.util.stream.Stream;
import static eu.ztsh.wymiana.EntityCreator.Constants.*;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;
class CurrencyServiceTest extends RepositoryBasedTest {
private final CurrencyService currencyService;
@Autowired
public CurrencyServiceTest(UserRepository userRepository, InstanceValidator instanceValidator) {
super(userRepository);
var nbp = Mockito.mock(NbpService.class);
Mockito.when(nbp.getSellRate("USD")).thenReturn(SELL_RATE);
Mockito.when(nbp.getBuyRate("USD")).thenReturn(BUY_RATE);
currencyService = new CurrencyService(new UserService(userRepository, instanceValidator), nbp, instanceValidator);
}
@Transactional
@Test
void plnToUsdToSellSuccessTest() {
var entity = EntityCreator.user().build();
userRepository.save(entity);
var result = currencyService.exchange(EntityCreator.exchangeRequest()
.from(PLN_SYMBOL)
.to(USD_SYMBOL)
.toSell(PLN)
.build());
assertThat(result.currencies())
.matches(map -> map.get(PLN_SYMBOL).amount() == 0 && map.get(USD_SYMBOL).amount() == USD_BUY);
var expected = EntityCreator.user().pln(0).usd(USD_BUY).build();
expect(expected);
}
@Transactional
@Test
void plnToUsdToBuySuccessTest() {
var entity = EntityCreator.user().build();
userRepository.save(entity);
var result = currencyService.exchange(EntityCreator.exchangeRequest()
.from(PLN_SYMBOL)
.to(USD_SYMBOL)
.toBuy(USD_BUY)
.build());
assertThat(result.currencies())
.matches(map -> map.get(PLN_SYMBOL).amount() == 0 && map.get(USD_SYMBOL).amount() == USD_BUY);
var expected = EntityCreator.user().pln(0).usd(USD_BUY).build();
expect(expected);
}
@Transactional
@Test
void usdToPlnToSellSuccessTest() {
var entity = EntityCreator.user().pln(-1).usd(USD_SELL).build();
userRepository.save(entity);
var result = currencyService.exchange(EntityCreator.exchangeRequest()
.from(USD_SYMBOL)
.to(PLN_SYMBOL)
.toSell(USD_SELL)
.build());
assertThat(result.currencies())
.matches(map -> map.get(PLN_SYMBOL).amount() == PLN && map.get(USD_SYMBOL).amount() == 0);
var expected = EntityCreator.user().pln(PLN).usd(0).build();
expect(expected);
}
@Transactional
@Test
void usdToPlnToBuySuccessTest() {
var entity = EntityCreator.user().pln(-1).usd(USD_SELL).build();
userRepository.save(entity);
var result = currencyService.exchange(EntityCreator.exchangeRequest()
.from(USD_SYMBOL)
.to(PLN_SYMBOL)
.toBuy(PLN)
.build());
assertThat(result.currencies())
.matches(map -> map.get(PLN_SYMBOL).amount() == PLN && map.get(USD_SYMBOL).amount() == 0);
var expected = EntityCreator.user().pln(PLN).usd(0).build();
expect(expected);
}
@Transactional
@Test
void usdToPlnNoUsdCurrencyTest() {
var entity = EntityCreator.user().build();
userRepository.save(entity);
var request = EntityCreator.exchangeRequest()
.from(USD_SYMBOL)
.to(PLN_SYMBOL)
.toBuy(PLN)
.build();
assertThatThrownBy(() -> currencyService.exchange(request))
.isInstanceOf(InsufficientFundsException.class);
}
@Transactional
@Test
void doubleExchangeTest() {
var initialValue = 100;
var entity = EntityCreator.user().pln(initialValue).build();
userRepository.save(entity);
var result1 = currencyService.exchange(EntityCreator.exchangeRequest()
.from(PLN_SYMBOL)
.to(USD_SYMBOL)
.toBuy(USD_BUY)
.build());
var result2 = currencyService.exchange(EntityCreator.exchangeRequest()
.from(USD_SYMBOL)
.to(PLN_SYMBOL)
.toSell(USD_BUY)
.build());
var resultOptional = userRepository.findById(entity.getPesel());
assertThat(resultOptional)
.isNotEmpty();
var resultEntity = resultOptional.get();
assertThat(resultEntity.getCurrencies()
.stream()
.filter(c -> c.getSymbol().equalsIgnoreCase("PLN"))
.findFirst()).isNotEmpty().get().matches(currencyEntity -> currencyEntity.getAmount() < initialValue);
}
@Transactional
@Test
void insufficientFundsTest() {
var entity = EntityCreator.user().build();
userRepository.save(entity);
var request = EntityCreator.exchangeRequest()
.from(PLN_SYMBOL)
.to(USD_SYMBOL)
.toBuy(PLN)
.build();
assertThatThrownBy(() -> currencyService.exchange(request))
.isInstanceOf(InsufficientFundsException.class);
}
@DisplayName("Invalid PESEL value")
@ParameterizedTest
@MethodSource
void invalidPeselTest(String pesel) {
var entity = EntityCreator.exchangeRequest()
.pesel(pesel)
.from(PLN_SYMBOL)
.to(USD_SYMBOL)
.toSell(USD_SELL)
.build();
assertThatThrownBy(() -> currencyService.exchange(entity))
.isInstanceOf(ValidationFailedException.class)
.hasMessageContaining("PESEL");
}
@Test
void notExistingUserTest() {
var entity = EntityCreator.exchangeRequest()
.from(PLN_SYMBOL)
.to(USD_SYMBOL)
.toSell(USD_SELL)
.build();
assertThatThrownBy(() -> currencyService.exchange(entity))
.isInstanceOf(ExchangeFailedException.class);
}
@Test
@DisplayName("Empty 'from' value")
void emptyFromTest() {
var entity = EntityCreator.exchangeRequest()
.to(USD_SYMBOL)
.toSell(USD_SELL)
.build();
assertThatThrownBy(() -> currencyService.exchange(entity))
.isInstanceOf(ValidationFailedException.class)
.hasMessageContaining("null");
}
@Test
@DisplayName("Empty 'to' value")
void emptyToTest() {
var entity = EntityCreator.exchangeRequest()
.from(PLN_SYMBOL)
.toSell(USD_SELL)
.build();
assertThatThrownBy(() -> currencyService.exchange(entity))
.isInstanceOf(ValidationFailedException.class)
.hasMessageContaining("null");
}
private static Stream<String> invalidPeselTest() {
return Stream.of("INVALID", PESEL.replace('6', '7'));
}
}

14
src/test/java/eu/ztsh/wymiana/util/UserMapperTest.java
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@ -25,6 +25,20 @@ class UserMapperTest {
.isEqualTo(expected);
}
@Test
void pojoToEntityTest() {
var entity = new User(
EntityCreator.Constants.NAME,
EntityCreator.Constants.SURNAME,
EntityCreator.Constants.PESEL,
Map.of("PLN", new Currency("PLN", EntityCreator.Constants.PLN))
);
var expected = EntityCreator.user().build();
assertThat(UserMapper.pojoToEntity(entity))
.usingRecursiveComparison()
.isEqualTo(expected);
}
@Test
void requestToEntityTest() {
var request = EntityCreator.userRequest().build();

47
src/test/java/eu/ztsh/wymiana/validation/ValidExchangeRequestValidatorTest.java
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@ -2,15 +2,13 @@ package eu.ztsh.wymiana.validation;
import eu.ztsh.wymiana.EntityCreator;
import eu.ztsh.wymiana.web.model.CurrencyExchangeRequest;
import org.junit.jupiter.api.Disabled;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.MethodSource;
import java.util.stream.Stream;
import static eu.ztsh.wymiana.EntityCreator.Constants.*;
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;
import static eu.ztsh.wymiana.EntityCreator.Constants.USD_SYMBOL;
class ValidExchangeRequestValidatorTest extends ValidatorTest<ValidExchangeRequestValidator, CurrencyExchangeRequest> {
@ -38,19 +36,6 @@ class ValidExchangeRequestValidatorTest extends ValidatorTest<ValidExchangeReque
.build()).isTrue();
}
@Disabled("Already validated (has field annotation)")
@DisplayName("Invalid PESEL value")
@ParameterizedTest
@MethodSource
void invalidPeselTest(String pesel) {
assertThatValidation(EntityCreator.exchangeRequest()
.pesel(pesel)
.from(PLN_SYMBOL)
.to(USD_SYMBOL)
.toSell(USD_SELL)
.build()).isFalse();
}
@Test
@DisplayName("From and To have same value")
void sameFromToTest() {
@ -70,26 +55,6 @@ class ValidExchangeRequestValidatorTest extends ValidatorTest<ValidExchangeReque
.build()).isFalse();
}
@Disabled("Already validated (has field annotation)")
@Test
@DisplayName("Empty 'from' value")
void emptyFromTest() {
assertThatValidation(EntityCreator.exchangeRequest()
.to(USD_SYMBOL)
.toSell(USD_SELL)
.build()).isFalse();
}
@Disabled("Already validated (has field annotation)")
@Test
@DisplayName("Empty 'to' value")
void emptyToTest() {
assertThatValidation(EntityCreator.exchangeRequest()
.from(PLN_SYMBOL)
.toSell(USD_SELL)
.build()).isFalse();
}
@Test
@DisplayName("Both Buy and Sell params filled in")
void bothFilledBuySellTest() {
@ -121,8 +86,4 @@ class ValidExchangeRequestValidatorTest extends ValidatorTest<ValidExchangeReque
.build()).isFalse();
}
private static Stream<String> invalidPeselTest() {
return Stream.of("INVALID", PESEL.replace('6', '7'));
}
}