Initial commit Tihomir

pom.xml

@@ -38,6 +38,16 @@
             <version>${junit.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>io.springfox</groupId>
+            <artifactId>springfox-swagger2</artifactId>
+            <version>2.9.2</version>
+        </dependency>
+        <dependency>
+            <groupId>io.springfox</groupId>
+            <artifactId>springfox-swagger-ui</artifactId>
+            <version>2.9.2</version>
+        </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-engine</artifactId>

src/main/java/com/devexperts/ApplicationRunner.java

@@ -5,8 +5,10 @@
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.annotation.Bean;
+import springfox.documentation.swagger2.annotations.EnableSwagger2;
 
 @SpringBootApplication
+@EnableSwagger2
 public class ApplicationRunner {
     public static void main(String[] args) {
             SpringApplication.run(ApplicationRunner.class, args);

src/main/java/com/devexperts/account/Account.java

@@ -1,5 +1,7 @@
 package com.devexperts.account;
 
+import java.util.Objects;
+
 public class Account {
     private final AccountKey accountKey;
     private final String firstName;
@@ -17,6 +19,10 @@ public AccountKey getAccountKey() {
         return accountKey;
     }
 
+    public long getAccountKeyId() {
+        return accountKey.getAccountId();
+    }
+
     public String getFirstName() {
         return firstName;
     }
@@ -32,4 +38,29 @@ public Double getBalance() {
     public void setBalance(Double balance) {
         this.balance = balance;
     }
+
+    public void withdraw(Double amount) {
+        this.balance -= amount;
+    }
+
+    public void deposit(Double amount) {
+        this.balance += amount;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        Account account = (Account) o;
+        return accountKey.equals(account.accountKey);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(accountKey);
+    }
 }

src/main/java/com/devexperts/account/AccountKey.java

@@ -1,20 +1,45 @@
 package com.devexperts.account;
 
+import java.util.Objects;
+
 /**
  * Unique Account identifier
  *
  * <p>
- * NOTE: we suspect that later {@link #accountId} is not going to be uniquely identifying an account,
- * as we might add human-readable account representation and some clearing codes for partners.
- * */
+ * NOTE: we suspect that later {@link #accountId} is not going to be uniquely identifying an
+ * account, as we might add human-readable account representation and some clearing codes for
+ * partners.
+ */
 public class AccountKey {
-    private final long accountId;
 
-    private AccountKey(long accountId) {
-        this.accountId = accountId;
-    }
+  private final long accountId;
+
+  private AccountKey(long accountId) {
+    this.accountId = accountId;
+  }
+
+  public static AccountKey valueOf(long accountId) {
+    return new AccountKey(accountId);
+  }
 
-    public static AccountKey valueOf(long accountId) {
-        return new AccountKey(accountId);
+  public long getAccountId() {
+    return accountId;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
     }
+    AccountKey that = (AccountKey) o;
+    return accountId == that.accountId;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(accountId);
+  }
 }

src/main/java/com/devexperts/rest/AccountController.java

@@ -1,14 +1,66 @@
 package com.devexperts.rest;
 
+import com.devexperts.account.Account;
+import com.devexperts.service.AccountServiceImpl;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.server.ResponseStatusException;
 
 @RestController
 @RequestMapping("/api")
 public class AccountController extends AbstractAccountController {
 
-    public ResponseEntity<Void> transfer(long sourceId, long targetId, double amount) {
-        return null;
+  private AccountServiceImpl accountService;
+
+  @Autowired
+  AccountController(AccountServiceImpl accountService) {
+    this.accountService = accountService;
+  }
+
+  /**
+   * Details: The operation should be available at POST localhost:8080/api/operations/transfer with
+   * required query parameters: source_id, target_id, amount. Response codes are the following:
+   * <p>
+   * 200 (OK) - successful transfer 400 (Bad Request) - one of the parameters in not present or
+   * amount is invalid 404 (Not Found) - account is not found 500 (Internal Server Error) -
+   * insufficient account balance
+   *
+   * @param sourceId
+   * @param targetId
+   * @param amount
+   * @return
+   */
+  @PostMapping(value = "/operations/transfer")
+  @Override
+  public ResponseEntity<Void> transfer(@RequestParam long sourceId, @RequestParam long targetId,
+      @RequestParam double amount) {
+
+    if (amount < 0) {
+      throw new ResponseStatusException(HttpStatus.BAD_REQUEST);
+    }
+
+    Account sourceAccount = accountService.getAccount(sourceId);
+    Account targetAccount = accountService.getAccount(targetId);
+
+    if (sourceAccount == null || targetAccount == null) {
+      throw new ResponseStatusException(HttpStatus.NOT_FOUND);
+    }
+
+    if (sourceAccount.getBalance() < amount) {
+      throw new ResponseStatusException(HttpStatus.INTERNAL_SERVER_ERROR);
+    }
+
+    try {
+      accountService.transfer(sourceAccount, targetAccount, amount);
+
+      return new ResponseEntity<>(HttpStatus.OK);
+    } catch (Exception e) {
+      throw new RuntimeException(e);
     }
+  }
 }

src/main/java/com/devexperts/service/AccountServiceImpl.java

@@ -2,36 +2,46 @@
 
 import com.devexperts.account.Account;
 import com.devexperts.account.AccountKey;
+import java.util.HashMap;
+import java.util.Map;
 import org.springframework.stereotype.Service;
 
-import java.util.ArrayList;
-import java.util.List;
-
 @Service
 public class AccountServiceImpl implements AccountService {
 
-    private final List<Account> accounts = new ArrayList<>();
-
-    @Override
-    public void clear() {
-        accounts.clear();
-    }
-
-    @Override
-    public void createAccount(Account account) {
-        accounts.add(account);
-    }
-
-    @Override
-    public Account getAccount(long id) {
-        return accounts.stream()
-                .filter(account -> account.getAccountKey() == AccountKey.valueOf(id))
-                .findAny()
-                .orElse(null);
-    }
-
-    @Override
-    public void transfer(Account source, Account target, double amount) {
-        //do nothing for now
+  private final Map<Long, Account> accounts;
+
+  public AccountServiceImpl() {
+    accounts = new HashMap<>();
+  }
+
+  @Override
+  public void clear() {
+    accounts.clear();
+  }
+
+  @Override
+  public void createAccount(Account account) {
+    accounts.put(account.getAccountKeyId(), account);
+  }
+
+  @Override
+  public Account getAccount(long id) {
+    return accounts.get(id);
+  }
+
+  @Override
+  public void transfer(Account source, Account target, double amount) {
+    // In order to avoid a deadlock we acquire locks in the same order always.
+    final Account lock1 =
+        source.getAccountKeyId() < target.getAccountKeyId() ? source : target;
+    final Account lock2 =
+        source.getAccountKeyId() < target.getAccountKeyId() ? target : source;
+    synchronized (lock1) {
+      synchronized (lock2) {
+        source.withdraw(amount);
+        target.deposit(amount);
+      }
     }
+  }
 }

src/main/java/com/devexperts/swagger/SpringFoxConfig.java

@@ -0,0 +1,29 @@
+package com.devexperts.swagger;
+
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import springfox.documentation.builders.PathSelectors;
+import springfox.documentation.builders.RequestHandlerSelectors;
+import springfox.documentation.spi.DocumentationType;
+import springfox.documentation.spring.web.plugins.Docket;
+import springfox.documentation.swagger2.annotations.EnableSwagger2;
+
+@Configuration
+@EnableSwagger2
+public class SpringFoxConfig {
+
+  /**
+   * Docket configuration bean.
+   *
+   * @return Docket
+   */
+  @Bean
+  public Docket api() {
+    return new Docket(DocumentationType.SWAGGER_2)
+        .select()
+        .apis(RequestHandlerSelectors.basePackage("com.devexperts.rest"))
+        .paths(PathSelectors.any())
+        .build();
+  }
+}

src/main/resources/sql/data/accounts.sql

@@ -0,0 +1,7 @@
+create table accounts
+(
+    ID         LONG AUTO_INCREMENT Primary Key,
+    FIRST_NAME varchar(255) NOT NULL,
+    LAST_NAME  varchar(255) NOT NULL,
+    BALANCE    DOUBLE NOT NULL
+);

src/main/resources/sql/data/select.sql

@@ -0,0 +1,6 @@
+SELECT accounts.ID, accounts.FIRST_NAME, accounts.LAST_NAME
+FROM accounts, transfers
+WHERE transfers.SOURCE_ID = accounts.ID
+AND transfers.TRANSFER_TIME >= 2019-01-01
+GROUP BY accounts.ID
+HAVING SUM(transfers.AMOUNT) > 1000.00

src/main/resources/sql/data/transfers.sql

@@ -0,0 +1,10 @@
+create table transfers
+(
+    ID         LONG AUTO_INCREMENT Primary Key,
+    SOURCE_ID long NOT NULL,
+    TARGET_ID  long NOT NULL,
+    AMOUNT    DOUBLE NOT NULL,
+    TRANSFER_TIME DATE NOT NULL,
+    FOREIGN KEY (SOURCE_ID) REFERENCES accounts(ID),
+    FOREIGN KEY (TARGET_ID) REFERENCES accounts(ID)
+);