VP - Implement Tasks 1-5; Add DB scripts; Expose Rest API; Refactor a…

README.md

@@ -89,4 +89,13 @@ should be added:
 
 **Goal:** Provide SQL to create both tables (`resources/sql/data/accounts.sql`) and (`resources/sql/data/transfers.sql`)
 and sql query (`resources/sql/select.sql`) that finds all accounts
- that in total transferred more than 1000$ to other people starting from 2019-01-01 
+ that in total transferred more than 1000$ to other people starting from 2019-01-01 
+
+## Solution 
+
+Exposed REST API is accessible through Swagger API. On your local environment you can access it [on the following URL](http://localhost:8080/swagger-ui.html#/operations-controller/transferUsingPOST)
+
+### Technical notes
+
+- additional `insert-data.sql` script is provided which creates a few accounts into the database
+- For the sake of the future integration between the Java POJOs and Database a JPA mapping is provided for `Account` and `AccountKey` entities

build.gradle

@@ -28,6 +28,9 @@ bootJar {
 dependencies {
     compile("org.springframework.boot:spring-boot-starter-web")
     compile("org.springframework.boot:spring-boot-starter-actuator")
+    compile('io.springfox:springfox-swagger2:2.9.2')
+    compile('io.springfox:springfox-swagger-ui:2.9.2')
+    compile('javax.persistence:javax.persistence-api:2.2')
 
     testCompile("org.springframework.boot:spring-boot-starter-test")
     testCompile "org.mockito:mockito-core:2.23.0"

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

@@ -1,19 +1,11 @@
 package com.devexperts;
 
-import com.devexperts.service.AccountService;
-import com.devexperts.service.AccountServiceImpl;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
-import org.springframework.context.annotation.Bean;
 
 @SpringBootApplication
 public class ApplicationRunner {
     public static void main(String[] args) {
             SpringApplication.run(ApplicationRunner.class, args);
     }
-
-    @Bean
-    AccountService accountService() {
-        return new AccountServiceImpl();
-    }
 }

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

@@ -1,9 +1,18 @@
 package com.devexperts.account;
 
+import javax.persistence.Column;
+import javax.persistence.Embedded;
+import javax.persistence.Entity;
+
+@Entity
 public class Account {
+    @Embedded
     private final AccountKey accountKey;
+    @Column(name = "FIRST_NAME")
     private final String firstName;
+    @Column(name = "LAST_NAME")
     private final String lastName;
+    @Column(name = "BALANCE")
     private Double balance;
 
     public Account(AccountKey accountKey, String firstName, String lastName, Double balance) {

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

@@ -1,13 +1,19 @@
 package com.devexperts.account;
 
+import javax.persistence.Embeddable;
+import javax.persistence.Id;
+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.
  * */
+@Embeddable
 public class AccountKey {
+    @Id
     private final long accountId;
 
     private AccountKey(long accountId) {
@@ -17,4 +23,24 @@ private AccountKey(long accountId) {
     public static AccountKey valueOf(long accountId) {
         return new AccountKey(accountId);
     }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof AccountKey)) return false;
+        AccountKey that = (AccountKey) o;
+        return accountId == that.accountId;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(accountId);
+    }
+
+    @Override
+    public String toString() {
+        return "AccountKey{" +
+                "accountId=" + accountId +
+                '}';
+    }
 }

src/main/java/com/devexperts/configuration/ApplicationConfiguration.java

@@ -0,0 +1,14 @@
+package com.devexperts.configuration;
+
+import com.devexperts.service.AccountService;
+import com.devexperts.service.AccountServiceImpl;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class ApplicationConfiguration {
+    @Bean
+    public AccountService accountService() {
+        return new AccountServiceImpl();
+    }
+}

src/main/java/com/devexperts/configuration/SwaggerConfiguration.java

@@ -0,0 +1,39 @@
+package com.devexperts.configuration;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import springfox.documentation.builders.ApiInfoBuilder;
+import springfox.documentation.builders.PathSelectors;
+import springfox.documentation.builders.RequestHandlerSelectors;
+import springfox.documentation.service.ApiInfo;
+import springfox.documentation.spi.DocumentationType;
+import springfox.documentation.spring.web.plugins.Docket;
+import springfox.documentation.swagger2.annotations.EnableSwagger2;
+
+@Configuration
+@EnableSwagger2
+public class SwaggerConfiguration {
+    private final static String CONTROLLER_LAYER_PACKAGE = "com.devexperts.rest.controller";
+    private final static String API_VERSION = "1.0";
+    private final static String API_INFO_TITLE = "API which exposes a simple transfer operation";
+    private final static String API_INFO_DESCRIPTION = "Simple amount transfer operation";
+
+    @Bean
+    public Docket api() {
+        return new Docket(DocumentationType.SWAGGER_2)
+                .useDefaultResponseMessages(false)
+                .select()
+                .apis(RequestHandlerSelectors.basePackage(CONTROLLER_LAYER_PACKAGE))
+                .paths(PathSelectors.any())
+                .build();
+    }
+
+    @Bean
+    public ApiInfo apiInfo() {
+        return new ApiInfoBuilder()
+            .title(API_INFO_TITLE)
+            .version(API_VERSION)
+            .description(API_INFO_DESCRIPTION)
+            .build();
+    }
+}

src/main/java/com/devexperts/exception/BalanceException.java

@@ -0,0 +1,7 @@
+package com.devexperts.exception;
+
+public class BalanceException extends RuntimeException {
+    public BalanceException(String message) {
+        super(message);
+    }
+}

src/main/java/com/devexperts/exception/EntityNotFoundException.java

@@ -0,0 +1,7 @@
+package com.devexperts.exception;
+
+public class EntityNotFoundException extends RuntimeException {
+    public EntityNotFoundException(String message) {
+        super(message);
+    }
+}

src/main/java/com/devexperts/exception/InvalidAccountException.java

@@ -0,0 +1,7 @@
+package com.devexperts.exception;
+
+public class InvalidAccountException extends RuntimeException {
+    public InvalidAccountException(String message) {
+        super(message);
+    }
+}

src/main/java/com/devexperts/exception/InvalidAmountException.java

@@ -0,0 +1,7 @@
+package com.devexperts.exception;
+
+public class InvalidAmountException extends RuntimeException {
+    public InvalidAmountException(String message) {
+        super(message);
+    }
+}

src/main/java/com/devexperts/exception/handler/GlobalExceptionHandler.java

@@ -0,0 +1,74 @@
+package com.devexperts.exception.handler;
+
+import com.devexperts.rest.controller.OperationsController;
+import com.devexperts.exception.BalanceException;
+import com.devexperts.exception.EntityNotFoundException;
+import com.devexperts.exception.InvalidAmountException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.ResponseBody;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ControllerAdvice
+public class GlobalExceptionHandler {
+    private final static Logger LOGGER = LoggerFactory.getLogger(OperationsController.class);
+
+    @ExceptionHandler
+    @ResponseBody
+    @ResponseStatus(code = HttpStatus.UNPROCESSABLE_ENTITY)
+    protected ResponseEntity handleBalanceException(BalanceException ex) {
+        return handleException(HttpStatus.INTERNAL_SERVER_ERROR, ex);
+    }
+
+    @ExceptionHandler
+    @ResponseBody
+    @ResponseStatus(code = HttpStatus.NOT_FOUND)
+    protected ResponseEntity handleEntityNotFoundException(EntityNotFoundException ex) {
+        return handleException(HttpStatus.NOT_FOUND, ex);
+    }
+
+    @ExceptionHandler
+    @ResponseBody
+    @ResponseStatus(code = HttpStatus.BAD_REQUEST)
+    protected ResponseEntity handleInvalidAmountException(InvalidAmountException ex) {
+        return handleException(HttpStatus.BAD_REQUEST, ex);
+    }
+
+    private class ResponseEntity {
+        private int code;
+        private String message;
+
+        public ResponseEntity(HttpStatus code, String message){
+            this.code = code.value();
+            this.message = message;
+        }
+
+        public int getCode() {
+            return code;
+        }
+
+        public void setCode(int code) {
+            this.code = code;
+        }
+
+        public String getMessage() {
+            return message;
+        }
+
+        public void setMessage(String message) {
+            this.message = message;
+        }
+    }
+
+    private <T extends Exception> ResponseEntity handleException(HttpStatus statusCode, T exception) {
+        logException(exception);
+        return new ResponseEntity(HttpStatus.BAD_REQUEST, exception.getMessage());
+    }
+
+    private <T extends Exception> void logException(T exception) {
+        LOGGER.error(exception.getMessage(), exception);
+    }
+}

src/main/java/com/devexperts/rest/controller/OperationsController.java

@@ -0,0 +1,40 @@
+package com.devexperts.rest.controller;
+
+import com.devexperts.service.AccountService;
+import io.swagger.annotations.ApiResponse;
+import io.swagger.annotations.ApiResponses;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+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;
+
+@RestController
+@RequestMapping("/api/operations")
+public class OperationsController {
+    private final static Logger LOGGER = LoggerFactory.getLogger(OperationsController.class);
+
+    private final AccountService accountService;
+
+    @Autowired
+    public OperationsController(final AccountService accountService) {
+        this.accountService = accountService;
+    }
+
+    @ApiResponses(
+            value = {
+                    @ApiResponse(code = 200, message = "OK"),
+                    @ApiResponse(code = 400, message = "BAD_REQUEST"),
+                    @ApiResponse(code = 404, message = "NOT_FOUND"),
+                    @ApiResponse(code = 500, message = "INTERNAL_SERVER_ERROR")})
+    @PostMapping("/transfer")
+    public void transfer(@RequestParam long sourceId,
+                         @RequestParam long targetId,
+                         @RequestParam long amount) {
+        LOGGER.trace("New incoming transfer request");
+
+        this.accountService.transfer(sourceId, targetId, amount);
+    }
+}

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

@@ -34,4 +34,13 @@ public interface AccountService {
      * @param amount dollar amount to transfer
      * */
     void transfer(Account source, Account target, double amount);
+
+    /**
+     * Transfers given amount of money from source account to target account by given ids
+     *
+     * @param sourceId account_id to transfer money from
+     * @param targetId account_id to transfer money to
+     * @param amount dollar amount to transfer
+     * */
+    void transfer(long sourceId, long targetId, double amount);
 }