implemented the requirement of the task

file.CSV

@@ -0,0 +1,7 @@
+type,fruit,quantity
+b,apple,100
+b,banana,20
+s,apple,20
+p,apple,50
+r,banana,40
+p,banana,25

file1.CSV

@@ -0,0 +1 @@
+fruit, quantity

newFIle.CSV

@@ -0,0 +1,3 @@
+fruit, quantity
+apple,100
+banana,25

pom.xml

@@ -79,6 +79,9 @@
                             <goal>check</goal>
                         </goals>
                         <configuration>
+                            <excludes>
+                                <exclude>**/Main*</exclude>
+                            </excludes>
                             <rules>
                                 <rule>
                                     <element>BUNDLE</element>

src/main/java/core/basesyntax/Main.java

@@ -0,0 +1,55 @@
+package core.basesyntax;
+
+import core.basesyntax.dao.FruitTransactionDaoImpl;
+import core.basesyntax.model.Operation;
+import core.basesyntax.service.FruitService;
+import core.basesyntax.service.amount.ActivityHandler;
+import core.basesyntax.service.amount.BalanceActivityHandler;
+import core.basesyntax.service.amount.PurchaseActivityHandler;
+import core.basesyntax.service.amount.ReturnActivityHandler;
+import core.basesyntax.service.amount.SupplyActivityHandler;
+import core.basesyntax.service.impl.FruitServiceImpl;
+import core.basesyntax.service.impl.ParserServiceImpl;
+import core.basesyntax.service.impl.ReaderServiceImpl;
+import core.basesyntax.service.impl.WriterServiceImpl;
+import core.basesyntax.strategy.TypeActivityStrategy;
+import core.basesyntax.strategy.TypeActivityStrategyImpl;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Feel free to remove this class and create your own.
+ */
+public class Main {
+    private static final String FILE = "file.CSV";
+    private static final String TO_FILE = "newFile.CSV";
+
+    public static void main(String[] args) {
+        Map<Operation, ActivityHandler>
+                amountOfFruitsHandlersMap = new HashMap<>();
+
+        amountOfFruitsHandlersMap
+                .put(Operation.RETURN,
+                        new ReturnActivityHandler(new FruitTransactionDaoImpl()));
+
+        amountOfFruitsHandlersMap
+                .put(Operation.BALANCE,
+                        new BalanceActivityHandler(new FruitTransactionDaoImpl()));
+
+        amountOfFruitsHandlersMap
+                .put(Operation.PURCHASE,
+                        new PurchaseActivityHandler(new FruitTransactionDaoImpl()));
+
+        amountOfFruitsHandlersMap
+                .put(Operation.SUPPLY,
+                        new SupplyActivityHandler(new FruitTransactionDaoImpl()));
+
+        TypeActivityStrategy typeActivityStrategy =
+                new TypeActivityStrategyImpl(amountOfFruitsHandlersMap);
+
+        FruitService fruitService =
+                new FruitServiceImpl(new ReaderServiceImpl(new ParserServiceImpl()),
+                        new WriterServiceImpl(), typeActivityStrategy);
+        fruitService.writeReport(FILE);
+    }
+}

src/main/java/core/basesyntax/dao/FruitTransactionDao.java

@@ -0,0 +1,9 @@
+package core.basesyntax.dao;
+
+import core.basesyntax.model.FruitTransaction;
+
+public interface FruitTransactionDao {
+    FruitTransaction getFromStorage(FruitTransaction fruitTransaction);
+
+    void addToStorage(FruitTransaction fruitTransaction);
+}

src/main/java/core/basesyntax/dao/FruitTransactionDaoImpl.java

@@ -0,0 +1,24 @@
+package core.basesyntax.dao;
+
+import core.basesyntax.db.Storage;
+import core.basesyntax.model.FruitTransaction;
+
+public class FruitTransactionDaoImpl implements FruitTransactionDao {
+    @Override
+    public FruitTransaction getFromStorage(FruitTransaction fruitTransaction) {
+        for (FruitTransaction fruit : Storage.fruitTransactions) {
+            if (fruit.getFruit().equals(fruitTransaction.getFruit())) {
+                return fruit;
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public void addToStorage(FruitTransaction fruitTransaction) {
+        if (fruitTransaction == null) {
+            throw new RuntimeException("Fruit cannot be null");
+        }
+        Storage.fruitTransactions.add(fruitTransaction);
+    }
+}

src/main/java/core/basesyntax/db/Storage.java

@@ -0,0 +1,9 @@
+package core.basesyntax.db;
+
+import core.basesyntax.model.FruitTransaction;
+import java.util.ArrayList;
+import java.util.List;
+
+public class Storage {
+    public static final List<FruitTransaction> fruitTransactions = new ArrayList<>();
+}

src/main/java/core/basesyntax/model/FruitTransaction.java

@@ -0,0 +1,79 @@
+package core.basesyntax.model;
+
+import java.util.Objects;
+
+public class FruitTransaction {
+    private String fruit;
+    private int quantity;
+    private Operation operation;
+
+    private FruitTransaction(Operation operation, String fruit, int quantity) {
+        this.operation = operation;
+        this.fruit = fruit;
+        this.quantity = quantity;
+    }
+
+    public static FruitTransaction of(Operation operation, String fruit, int quantity) {
+        if (quantity < 0) {
+            throw new RuntimeException("Quantity cannot be less than 0");
+        }
+        return new FruitTransaction(operation, fruit, quantity);
+    }
+
+    public String getFruit() {
+        return fruit;
+    }
+
+    public void subtract(int quantity) {
+        if (quantity > this.quantity) {
+            throw new RuntimeException("Cannot sell fruits more than in stock");
+        }
+        this.quantity -= quantity;
+    }
+
+    public void add(int quantity) {
+        this.quantity += quantity;
+    }
+
+    public void setFruit(String fruit) {
+        this.fruit = fruit;
+    }
+
+    public int getQuantity() {
+        return quantity;
+    }
+
+    public void setQuantity(int quantity) {
+        if (quantity > 0) {
+            this.quantity = quantity;
+        } else {
+            throw new RuntimeException("Quantity cannot be less than 0");
+        }
+    }
+
+    public Operation getOperation() {
+        return operation;
+    }
+
+    public void setOperation(Operation operation) {
+        this.operation = operation;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        FruitTransaction that = (FruitTransaction) o;
+        return quantity == that.quantity
+                && Objects.equals(fruit, that.fruit) && operation == that.operation;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(fruit, quantity, operation);
+    }
+}

src/main/java/core/basesyntax/model/Operation.java

@@ -0,0 +1,19 @@
+package core.basesyntax.model;
+
+public enum Operation {
+    BALANCE("b"),
+    SUPPLY("s"),
+    PURCHASE("p"),
+    RETURN("r");
+
+    private String code;
+
+    Operation(String code) {
+        this.code = code;
+    }
+
+    public String getCode() {
+        return code;
+    }
+
+}

src/main/java/core/basesyntax/service/FruitService.java

@@ -0,0 +1,5 @@
+package core.basesyntax.service;
+
+public interface FruitService {
+    void writeReport(String file);
+}

src/main/java/core/basesyntax/service/ParserService.java

@@ -0,0 +1,8 @@
+package core.basesyntax.service;
+
+import core.basesyntax.model.FruitTransaction;
+import java.util.List;
+
+public interface ParserService {
+    List<FruitTransaction> parseStringsIntoObjects(List<String> strings);
+}

src/main/java/core/basesyntax/service/ReaderService.java

@@ -0,0 +1,8 @@
+package core.basesyntax.service;
+
+import core.basesyntax.model.FruitTransaction;
+import java.util.List;
+
+public interface ReaderService {
+    List<FruitTransaction> readFromFile(String fromFile);
+}

src/main/java/core/basesyntax/service/WriterService.java

@@ -0,0 +1,5 @@
+package core.basesyntax.service;
+
+public interface WriterService {
+    void writeToFile(String toFile);
+}

src/main/java/core/basesyntax/service/amount/ActivityHandler.java

@@ -0,0 +1,7 @@
+package core.basesyntax.service.amount;
+
+import core.basesyntax.model.FruitTransaction;
+
+public interface ActivityHandler {
+    void setAmountOfFruit(FruitTransaction fruitTransaction);
+}

src/main/java/core/basesyntax/service/amount/BalanceActivityHandler.java

@@ -0,0 +1,17 @@
+package core.basesyntax.service.amount;
+
+import core.basesyntax.dao.FruitTransactionDao;
+import core.basesyntax.model.FruitTransaction;
+
+public class BalanceActivityHandler implements ActivityHandler {
+    private final FruitTransactionDao fruitTransactionDao;
+
+    public BalanceActivityHandler(FruitTransactionDao fruitTransactionDao) {
+        this.fruitTransactionDao = fruitTransactionDao;
+    }
+
+    @Override
+    public void setAmountOfFruit(FruitTransaction fruitTransaction) {
+        fruitTransactionDao.addToStorage(fruitTransaction);
+    }
+}

src/main/java/core/basesyntax/service/amount/PurchaseActivityHandler.java

@@ -0,0 +1,19 @@
+package core.basesyntax.service.amount;
+
+import core.basesyntax.dao.FruitTransactionDao;
+import core.basesyntax.model.FruitTransaction;
+
+public class PurchaseActivityHandler implements ActivityHandler {
+    private final FruitTransactionDao fruitTransactionDao;
+
+    public PurchaseActivityHandler(FruitTransactionDao fruitTransactionDao) {
+        this.fruitTransactionDao = fruitTransactionDao;
+    }
+
+    @Override
+    public void setAmountOfFruit(FruitTransaction fruitTransaction) {
+        fruitTransactionDao.getFromStorage(fruitTransaction)
+                .subtract(fruitTransaction.getQuantity());
+
+    }
+}

src/main/java/core/basesyntax/service/amount/ReturnActivityHandler.java

@@ -0,0 +1,17 @@
+package core.basesyntax.service.amount;
+
+import core.basesyntax.dao.FruitTransactionDao;
+import core.basesyntax.model.FruitTransaction;
+
+public class ReturnActivityHandler implements ActivityHandler {
+    private final FruitTransactionDao fruitTransactionDao;
+
+    public ReturnActivityHandler(FruitTransactionDao fruitTransactionDao) {
+        this.fruitTransactionDao = fruitTransactionDao;
+    }
+
+    @Override
+    public void setAmountOfFruit(FruitTransaction fruitTransaction) {
+        fruitTransactionDao.getFromStorage(fruitTransaction).add(fruitTransaction.getQuantity());
+    }
+}

src/main/java/core/basesyntax/service/amount/SupplyActivityHandler.java

@@ -0,0 +1,17 @@
+package core.basesyntax.service.amount;
+
+import core.basesyntax.dao.FruitTransactionDao;
+import core.basesyntax.model.FruitTransaction;
+
+public class SupplyActivityHandler implements ActivityHandler {
+    private final FruitTransactionDao fruitTransactionDao;
+
+    public SupplyActivityHandler(FruitTransactionDao fruitTransactionDao) {
+        this.fruitTransactionDao = fruitTransactionDao;
+    }
+
+    @Override
+    public void setAmountOfFruit(FruitTransaction fruitTransaction) {
+        fruitTransactionDao.getFromStorage(fruitTransaction).add(fruitTransaction.getQuantity());
+    }
+}

src/main/java/core/basesyntax/service/impl/FruitServiceImpl.java

@@ -0,0 +1,36 @@
+package core.basesyntax.service.impl;
+
+import core.basesyntax.model.FruitTransaction;
+import core.basesyntax.service.FruitService;
+import core.basesyntax.service.ReaderService;
+import core.basesyntax.service.WriterService;
+import core.basesyntax.strategy.TypeActivityStrategy;
+import java.util.List;
+
+public class FruitServiceImpl implements FruitService {
+    private static final String COMA = ",";
+    private static final String TO_FILE = "newFile.CSV";
+
+    private ReaderService readerService;
+
+    private WriterService writerService;
+
+    private TypeActivityStrategy typeActivityStrategy;
+
+    public FruitServiceImpl(ReaderService readerService, WriterService writerService,
+                            TypeActivityStrategy typeActivityStrategy) {
+        this.readerService = readerService;
+        this.writerService = writerService;
+        this.typeActivityStrategy = typeActivityStrategy;
+    }
+
+    @Override
+    public void writeReport(String file) {
+        List<FruitTransaction> fruitTransactions = readerService.readFromFile(file);
+        fruitTransactions.stream()
+                .forEach(fruit -> typeActivityStrategy
+                        .get(fruit.getOperation()).setAmountOfFruit(fruit));
+        writerService.writeToFile(TO_FILE);
+    }
+
+}