devexperts · ChaykinVE · Aug 8, 2020 · Aug 8, 2020
diff --git a/interview-ChaykinVE.iml b/interview-ChaykinVE.iml
@@ -0,0 +1,109 @@
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diff --git a/resources/sql/data/accounts.sql b/resources/sql/data/accounts.sql
@@ -0,0 +1,7 @@
+create table ACCOUNTS 
+(
+	ID int primary key, 
+	FIRST_NAME varchar, 
+	LAST_NAME varchar, 
+	BALANCE double
+);
diff --git a/resources/sql/data/select.sql b/resources/sql/data/select.sql
@@ -0,0 +1,6 @@
+select *from ACCOUNTS where ID in 
+	(select SOURCE_ID from 
+		(select SOURCE_ID, sum (AMOUNT) as SUMM from 
+			(select *from TRANSFERS where TRANSFER_TIME > '2019-01-01') 
+		group by SOURCE_ID) 
+	where SUMM >= 1000);
diff --git a/resources/sql/data/transfers.sql b/resources/sql/data/transfers.sql
@@ -0,0 +1,8 @@
+create table TRANSFERS 
+(
+ID int primary key, 
+SOURCE_ID int references ACCOUNTS(ID), 
+TARGET_ID int references ACCOUNTS(ID), 
+AMOUNT double, 
+TRANSFER_TIME datetime
+);
diff --git a/src/com/devexperts/ApplicationRunner.java b/src/com/devexperts/ApplicationRunner.java
@@ -0,0 +1,19 @@
+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();
+    }
+}
diff --git a/src/com/devexperts/account/Account.java b/src/com/devexperts/account/Account.java
@@ -0,0 +1,35 @@
+package com.devexperts.account;
+
+public class Account {
+    private final AccountKey accountKey;
+    private final String firstName;
+    private final String lastName;
+    private Double balance;
+
+    public Account(AccountKey accountKey, String firstName, String lastName, Double balance) {
+        this.accountKey = accountKey;
+        this.firstName = firstName;
+        this.lastName = lastName;
+        this.balance = balance;
+    }
+
+    public AccountKey getAccountKey() {
+        return accountKey;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public Double getBalance() {
+        return balance;
+    }
+
+    public void setBalance(Double balance) {
+        this.balance = balance;
+    }
+}
diff --git a/src/com/devexperts/account/AccountKey.java b/src/com/devexperts/account/AccountKey.java
@@ -0,0 +1,20 @@
+package com.devexperts.account;
+
+/**
+ * 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.
+ * */
+public class AccountKey {
+    private final long accountId;
+
+    private AccountKey(long accountId) {
+        this.accountId = accountId;
+    }
+
+    public static AccountKey valueOf(long accountId) {
+        return new AccountKey(accountId);
+    }
+}
diff --git a/src/com/devexperts/rest/AbstractAccountController.java b/src/com/devexperts/rest/AbstractAccountController.java
@@ -0,0 +1,7 @@
+package com.devexperts.rest;
+
+import org.springframework.http.ResponseEntity;
+
+public abstract class AbstractAccountController {
+    abstract ResponseEntity<Void> transfer(long sourceId, long targetId, double amount);
+}
diff --git a/src/com/devexperts/rest/AccountController.java b/src/com/devexperts/rest/AccountController.java
@@ -0,0 +1,46 @@
+package com.devexperts.rest;
+
+import com.devexperts.account.Account;
+import com.devexperts.service.AccountService;
+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.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/api")
+public class AccountController extends AbstractAccountController {
+
+    private final AccountService accountService;
+
+    @Autowired
+    public AccountController (AccountService accountService){
+        this.accountService = accountService;
+    }
+
+    @PostMapping(value = "/operations/transfer")
+    public ResponseEntity<Void> transfer (@RequestBody long sourceId, @RequestBody long targetId,
+                                         @RequestBody double amount) {
+
+        if ((sourceId == 0) || (targetId == 0) || (amount <= 0.0)){
+            return new ResponseEntity<>(HttpStatus.BAD_REQUEST);
+        }
+
+        Account sourceAccount = accountService.getAccount(sourceId);
+        Account targetAccount = accountService.getAccount(targetId);
+
+        if ((sourceAccount == null) || (targetAccount == null)){
+            return new ResponseEntity<>(HttpStatus.NOT_FOUND);
+        }
+
+        if (sourceAccount.getBalance() < amount){
+            return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);
+        }
+
+        accountService.transfer(sourceAccount, targetAccount, amount);
+        return new ResponseEntity<>(HttpStatus.OK);
+    }
+}
diff --git a/src/com/devexperts/service/AccountService.java b/src/com/devexperts/service/AccountService.java
@@ -0,0 +1,37 @@
+package com.devexperts.service;
+
+import com.devexperts.account.Account;
+
+public interface AccountService {
+
+    /**
+     * Clears account cache
+     *
+     * */
+    void clear();
+
+    /**
+     * Creates a new account
+     *
+     * @param account account entity to add or update
+     * @throws IllegalArgumentException if account is already present
+     * */
+    void createAccount(Account account);
+
+    /**
+     * Get account from the cache
+     *
+     * @param  id identification of an account to search for
+     * @return account associated with given id or {@code null} if account is not found in the cache
+     * */
+    Account getAccount(long id);
+
+    /**
+     * Transfers given amount of money from source account to target account
+     *
+     * @param source account to transfer money from
+     * @param target account to transfer money to
+     * @param amount dollar amount to transfer
+     * */
+    void transfer(Account source, Account target, double amount);
+}
diff --git a/src/com/devexperts/service/AccountServiceImpl.java b/src/com/devexperts/service/AccountServiceImpl.java
@@ -0,0 +1,52 @@
+package com.devexperts.service;
+
+import com.devexperts.account.Account;
+import com.devexperts.account.AccountKey;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class AccountServiceImpl implements AccountService{
+
+    private final List<Account> accounts = new ArrayList<>();
+    private final Object monitor = new Object();
+
+    @Override
+    public void clear(){
+        synchronized (monitor) {
+            accounts.clear();
+        }
+    }
+
+    @Override
+    public void createAccount(Account account){
+        synchronized (monitor) {
+            accounts.add(account);
+        }
+    }
+
+    @Override
+    public Account getAccount(long id) {
+        synchronized (monitor) {
+            for (Account acc : accounts) {
+                if (acc.getAccountKey().equals(AccountKey.valueOf(id))) {
+                    return acc;
+                }
+            }
+            return null;
+        }
+    }
+
+    @Override
+    public void transfer(Account source, Account target, double amount){
+        synchronized (monitor){
+            if (source.getBalance() < amount){
+                //throw  new InvalidParameterException("not enough money to perform this operation");
+            }
+            else {
+                source.setBalance(source.getBalance() - amount);
+                target.setBalance(target.getBalance() + amount);
+            }
+        }
+    }
+}