Add unit tests

data.csv

@@ -0,0 +1,9 @@
+type,fruit,quantity
+b,banana,20
+b,apple,100
+s,banana,100
+p,banana,13
+r,apple,10
+p,apple,20
+p,banana,5
+s,banana,50

pom.xml

@@ -32,6 +32,12 @@
             <version>${junit.jupiter.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <version>5.9.3</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
     <build>
         <plugins>

src/main/java/fruitshop/db/Storage.java

@@ -0,0 +1,25 @@
+package fruitshop.db;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class Storage {
+    private static Map<String, Integer> storageMap = new HashMap<>();
+
+    public static void addFruit(String fruit, Integer amount) {
+        storageMap.put(fruit, amount + storageMap.get(fruit));
+    }
+
+    public static Map<String, Integer> getFruitsAndAmount() {
+        Map<String, Integer> newMap = new HashMap<>();
+        for (Map.Entry<String, Integer> entry : storageMap.entrySet()) {
+            newMap.put(entry.getKey(), entry.getValue());
+        }
+
+        return newMap;
+    }
+
+    public static void setAmount(String fruit, Integer number) {
+        storageMap.put(fruit, number);
+    }
+}

src/main/java/fruitshop/main/Main.java

@@ -0,0 +1,42 @@
+package fruitshop.main;
+
+import fruitshop.model.Operation;
+import fruitshop.operation.OperationHandler;
+import fruitshop.operation.impl.BalanceOperationHandlerImpl;
+import fruitshop.operation.impl.OperationStrategyImpl;
+import fruitshop.operation.impl.PurchaseOperationHandlerImpl;
+import fruitshop.operation.impl.ReturnOperationHandlerImpl;
+import fruitshop.operation.impl.SupplyOperationHandlerImpl;
+import fruitshop.service.Parser;
+import fruitshop.service.TransactionProcessor;
+import fruitshop.service.impl.CsvParser;
+import fruitshop.service.impl.ReaderServiceImpl;
+import fruitshop.service.impl.ReportImpl;
+import fruitshop.service.impl.TransactionProcessorImpl;
+import fruitshop.service.impl.WriterServiceImpl;
+import java.util.HashMap;
+import java.util.Map;
+
+public class Main {
+    private static final String READ_FILE_NAME = "data.csv";
+    private static final String WRITE_FILE_NAME = "newData.csv";
+
+    public static void main(String[] args) {
+        Map<Operation, OperationHandler> operationHandlers = new HashMap<>();
+        OperationStrategyImpl operationStrategy = new OperationStrategyImpl(operationHandlers);
+
+        operationHandlers.put(Operation.BALANCE, new BalanceOperationHandlerImpl());
+        operationHandlers.put(Operation.SUPPLY, new SupplyOperationHandlerImpl());
+        operationHandlers.put(Operation.PURCHASE, new PurchaseOperationHandlerImpl());
+        operationHandlers.put(Operation.RETURN, new ReturnOperationHandlerImpl());
+
+        ReaderServiceImpl reader = new ReaderServiceImpl();
+        Parser csvParser = new CsvParser();
+        TransactionProcessor transactionProcessorImpl =
+                new TransactionProcessorImpl(operationStrategy);
+        csvParser.parse(reader.readFromFile(READ_FILE_NAME))
+                .forEach(transactionProcessorImpl::process);
+        WriterServiceImpl writer = new WriterServiceImpl();
+        writer.writeToFile(new ReportImpl().create(), WRITE_FILE_NAME);
+    }
+}

src/main/java/fruitshop/model/FruitTransaction.java

@@ -0,0 +1,57 @@
+package fruitshop.model;
+
+import java.util.Objects;
+
+public class FruitTransaction {
+    private final Operation operation;
+    private final String fruit;
+    private final int amount;
+
+    private FruitTransaction(Operation operation, String fruit, int amount) {
+        this.operation = operation;
+        this.fruit = fruit;
+        this.amount = amount;
+    }
+
+    public static FruitTransaction of(Operation operation, String fruit, int amount) {
+        if (amount >= 0) {
+            return new FruitTransaction(operation, fruit, amount);
+        }
+
+        throw new RuntimeException("Amount cannot be negative");
+    }
+
+    public Operation getOperation() {
+        return operation;
+    }
+
+    public String getFruit() {
+        return fruit;
+    }
+
+    public int getAmount() {
+        return amount;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+
+        FruitTransaction that = (FruitTransaction) o;
+        return amount == that.amount
+                && operation
+                == that.operation
+                && Objects.equals(fruit, that.fruit);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(operation, fruit, amount);
+    }
+}

src/main/java/fruitshop/model/Operation.java

@@ -0,0 +1,28 @@
+package fruitshop.model;
+
+public enum Operation {
+    BALANCE("b"),
+    SUPPLY("s"),
+    PURCHASE("p"),
+    RETURN("r");
+
+    private final String operation;
+
+    Operation(String operation) {
+        this.operation = operation;
+    }
+
+    public String getOperation() {
+        return operation;
+    }
+
+    public static Operation getByCode(String character) {
+        for (Operation operation : values()) {
+            if (operation.getOperation().equals(character)) {
+                return operation;
+            }
+        }
+
+        throw new RuntimeException("Unknown operation");
+    }
+}

src/main/java/fruitshop/operation/OperationHandler.java

@@ -0,0 +1,7 @@
+package fruitshop.operation;
+
+import fruitshop.model.FruitTransaction;
+
+public interface OperationHandler {
+    void accept(FruitTransaction fruitTransaction);
+}

src/main/java/fruitshop/operation/OperationStrategy.java

@@ -0,0 +1,7 @@
+package fruitshop.operation;
+
+import fruitshop.model.Operation;
+
+public interface OperationStrategy {
+    OperationHandler get(Operation operationType);
+}

src/main/java/fruitshop/operation/impl/BalanceOperationHandlerImpl.java

@@ -0,0 +1,12 @@
+package fruitshop.operation.impl;
+
+import fruitshop.db.Storage;
+import fruitshop.model.FruitTransaction;
+import fruitshop.operation.OperationHandler;
+
+public class BalanceOperationHandlerImpl implements OperationHandler {
+    @Override
+    public void accept(FruitTransaction fruitTransaction) {
+        Storage.setAmount(fruitTransaction.getFruit(), fruitTransaction.getAmount());
+    }
+}

src/main/java/fruitshop/operation/impl/OperationStrategyImpl.java

@@ -0,0 +1,19 @@
+package fruitshop.operation.impl;
+
+import fruitshop.model.Operation;
+import fruitshop.operation.OperationHandler;
+import fruitshop.operation.OperationStrategy;
+import java.util.Map;
+
+public class OperationStrategyImpl implements OperationStrategy {
+    private final Map<Operation, OperationHandler> operations;
+
+    public OperationStrategyImpl(Map<Operation, OperationHandler> operations) {
+        this.operations = operations;
+    }
+
+    @Override
+    public OperationHandler get(Operation operationType) {
+        return operations.get(operationType);
+    }
+}

src/main/java/fruitshop/operation/impl/PurchaseOperationHandlerImpl.java

@@ -0,0 +1,16 @@
+package fruitshop.operation.impl;
+
+import fruitshop.db.Storage;
+import fruitshop.model.FruitTransaction;
+import fruitshop.operation.OperationHandler;
+
+public class PurchaseOperationHandlerImpl implements OperationHandler {
+
+    @Override
+    public void accept(FruitTransaction fruitTransaction) {
+        if (Storage.getFruitsAndAmount().get(fruitTransaction.getFruit())
+                >= fruitTransaction.getAmount()) {
+            Storage.addFruit(fruitTransaction.getFruit(), -fruitTransaction.getAmount());
+        }
+    }
+}

src/main/java/fruitshop/operation/impl/ReturnOperationHandlerImpl.java

@@ -0,0 +1,12 @@
+package fruitshop.operation.impl;
+
+import fruitshop.db.Storage;
+import fruitshop.model.FruitTransaction;
+import fruitshop.operation.OperationHandler;
+
+public class ReturnOperationHandlerImpl implements OperationHandler {
+    @Override
+    public void accept(FruitTransaction fruitTransaction) {
+        Storage.addFruit(fruitTransaction.getFruit(), fruitTransaction.getAmount());
+    }
+}

src/main/java/fruitshop/operation/impl/SupplyOperationHandlerImpl.java

@@ -0,0 +1,12 @@
+package fruitshop.operation.impl;
+
+import fruitshop.db.Storage;
+import fruitshop.model.FruitTransaction;
+import fruitshop.operation.OperationHandler;
+
+public class SupplyOperationHandlerImpl implements OperationHandler {
+    @Override
+    public void accept(FruitTransaction fruitTransaction) {
+        Storage.addFruit(fruitTransaction.getFruit(), fruitTransaction.getAmount());
+    }
+}

src/main/java/fruitshop/service/Parser.java

@@ -0,0 +1,8 @@
+package fruitshop.service;
+
+import fruitshop.model.FruitTransaction;
+import java.util.List;
+
+public interface Parser {
+    List<FruitTransaction> parse(List<String> rowsList);
+}

src/main/java/fruitshop/service/ReaderService.java

@@ -0,0 +1,7 @@
+package fruitshop.service;
+
+import java.util.List;
+
+public interface ReaderService {
+    List<String> readFromFile(String fromFilePath);
+}

src/main/java/fruitshop/service/Report.java

@@ -0,0 +1,5 @@
+package fruitshop.service;
+
+public interface Report {
+    String create();
+}

src/main/java/fruitshop/service/TransactionProcessor.java

@@ -0,0 +1,7 @@
+package fruitshop.service;
+
+import fruitshop.model.FruitTransaction;
+
+public interface TransactionProcessor {
+    void process(FruitTransaction fruitTransaction);
+}

src/main/java/fruitshop/service/WriterService.java

@@ -0,0 +1,5 @@
+package fruitshop.service;
+
+public interface WriterService {
+    void writeToFile(String data, String outputPath);
+}

src/main/java/fruitshop/service/impl/CsvParser.java

@@ -0,0 +1,29 @@
+package fruitshop.service.impl;
+
+import fruitshop.model.FruitTransaction;
+import fruitshop.model.Operation;
+import fruitshop.service.Parser;
+import java.util.ArrayList;
+import java.util.List;
+
+public class CsvParser implements Parser {
+    private static final int OPERATION_INDEX = 0;
+    private static final int FRUIT_INDEX = 1;
+    private static final int AMOUNT_INDEX = 2;
+    private static final String SEPARATOR = ",";
+
+    @Override
+    public List<FruitTransaction> parse(List<String> rowsList) {
+        List<FruitTransaction> fruitTransactions = new ArrayList<>();
+        for (int i = 1; i < rowsList.size(); i++) {
+            String[] values = rowsList.get(i).split(SEPARATOR);
+            Operation operation = Operation.getByCode(values[OPERATION_INDEX]);
+            String fruit = values[FRUIT_INDEX];
+            int amount = Integer.parseInt(values[AMOUNT_INDEX]);
+
+            fruitTransactions.add(FruitTransaction.of(operation, fruit, amount));
+        }
+
+        return fruitTransactions;
+    }
+}

src/main/java/fruitshop/service/impl/ReaderServiceImpl.java

@@ -0,0 +1,18 @@
+package fruitshop.service.impl;
+
+import fruitshop.service.ReaderService;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+
+public class ReaderServiceImpl implements ReaderService {
+    @Override
+    public List<String> readFromFile(String fromFilePath) {
+        try {
+            return Files.readAllLines(Path.of(fromFilePath));
+        } catch (IOException e) {
+            throw new RuntimeException("Can't read data from file: " + fromFilePath, e);
+        }
+    }
+}

src/main/java/fruitshop/service/impl/ReportImpl.java

@@ -0,0 +1,29 @@
+package fruitshop.service.impl;
+
+import fruitshop.db.Storage;
+import fruitshop.service.Report;
+import java.util.Map;
+
+public class ReportImpl implements Report {
+    private static final String SEPARATOR = ",";
+    private static final String HEADER = "fruit,quantity";
+
+    @Override
+    public String create() {
+        StringBuilder reportBuilder = new StringBuilder();
+
+        reportBuilder
+                .append(HEADER)
+                .append(System.lineSeparator());
+
+        for (Map.Entry<String, Integer> entry : Storage.getFruitsAndAmount().entrySet()) {
+            reportBuilder
+                    .append(entry.getKey())
+                    .append(SEPARATOR)
+                    .append(entry.getValue())
+                    .append(System.lineSeparator());
+        }
+
+        return reportBuilder.toString();
+    }
+}