doc: add document for dao-factory

Author: letdtcode

dao-factory/README.md

@@ -2,10 +2,6 @@
 package com.iluwatar.daofactory {
     class App {
         {static} void main(String[] args)
-        {static} <T> void performCreateCustomer(CustomerDAO<T> customerDAO, \n                                                              List<Customer<T>> customerList)
-        {static} <T> void performUpdateCustomer(CustomerDAO<T> customerDAO, \n                                                               Customer<T> customerUpdate)
-        {static} <T> void performDeleteCustomer(CustomerDAO<T> customerDAO, \n                                                              T id)
-        {static} void deleteSchema(CustomerDAO customerDAO)
     }
 
     class Customer<T> {

dao-factory/etc/dao-factory.png

@@ -7,7 +7,6 @@
 @Slf4j
 public class App {
 
-
   public static void main(String[] args) {
     var daoFactory = DAOFactory.getDataSource(DataSourceType.H2);
     var customerDAO = daoFactory.createCustomerDAO();
@@ -23,8 +22,8 @@ public static void main(String[] args) {
     Customer<Long> customerUpdateInmemory = new Customer<>(1L, "Yellow");
 
     LOGGER.debug("H2 - Create customer");
-    performCreateCustomer(customerDAO,
-        List.of(customerInmemory1, customerInmemory2, customerInmemory3));
+    performCreateCustomer(
+        customerDAO, List.of(customerInmemory1, customerInmemory2, customerInmemory3));
     LOGGER.debug("H2 - Update customer");
     performUpdateCustomer(customerDAO, customerUpdateInmemory);
     LOGGER.debug("H2 - Delete customer");
@@ -56,8 +55,8 @@ public static void main(String[] args) {
     Customer<Long> customerFlatFile3 = new Customer<>(3L, "Nhat");
     Customer<Long> customerUpdateFlatFile = new Customer<>(1L, "Thanh");
     LOGGER.debug("Flat file - Create customer");
-    performCreateCustomer(customerDAO,
-        List.of(customerFlatFile1, customerFlatFile2, customerFlatFile3));
+    performCreateCustomer(
+        customerDAO, List.of(customerFlatFile1, customerFlatFile2, customerFlatFile3));
     LOGGER.debug("Flat file - Update customer");
     performUpdateCustomer(customerDAO, customerUpdateFlatFile);
     LOGGER.debug("Flat file - Delete customer");
@@ -69,8 +68,8 @@ public static void deleteSchema(CustomerDAO<?> customerDAO) {
     customerDAO.deleteSchema();
   }
 
-  public static <T> void performCreateCustomer(CustomerDAO<T> customerDAO,
-                                               List<Customer<T>> customerList) {
+  public static <T> void performCreateCustomer(
+      CustomerDAO<T> customerDAO, List<Customer<T>> customerList) {
     for (Customer<T> customer : customerList) {
       customerDAO.save(customer);
     }
@@ -80,21 +79,20 @@ public static <T> void performCreateCustomer(CustomerDAO<T> customerDAO,
     }
   }
 
-  public static <T> void performUpdateCustomer(CustomerDAO<T> customerDAO,
-                                               Customer<T> customerUpdate) {
+  public static <T> void performUpdateCustomer(
+      CustomerDAO<T> customerDAO, Customer<T> customerUpdate) {
     customerDAO.update(customerUpdate);
     List<Customer<T>> customers = customerDAO.findAll();
     for (Customer<T> customer : customers) {
       LOGGER.debug(customer.toString());
     }
   }
 
-  public static <T> void performDeleteCustomer(CustomerDAO<T> customerDAO,
-                                               T customerId) {
+  public static <T> void performDeleteCustomer(CustomerDAO<T> customerDAO, T customerId) {
     customerDAO.delete(customerId);
     List<Customer<T>> customers = customerDAO.findAll();
     for (Customer<T> customer : customers) {
       LOGGER.debug(customer.toString());
     }
   }
-}
+}

dao-factory/etc/dao-factory.puml

@@ -9,8 +9,8 @@
 
 /**
  * A customer generic POJO that represents the data that can be stored in any supported data source.
- * This class is designed t work with various ID types (e.g., Long, String, or ObjectId) through generic,
- * making it adaptable to different persistence system.
+ * This class is designed t work with various ID types (e.g., Long, String, or ObjectId) through
+ * generic, making it adaptable to different persistence system.
  */
 @Getter
 @Setter

dao-factory/src/main/java/com/iluwatar/daofactory/App.java

@@ -4,12 +4,12 @@
 import java.util.Optional;
 
 /**
- * The Data Access Object (DAO) pattern provides an abstraction layer between the application
- * and the database. It encapsulates data access logic, allowing the application to work
- * with domain objects instead of direct database operations.
+ * The Data Access Object (DAO) pattern provides an abstraction layer between the application and
+ * the database. It encapsulates data access logic, allowing the application to work with domain
+ * objects instead of direct database operations.
  *
- * <p>Implementations handle specific storage mechanisms (e.g., in-memory, databases)
- * while keeping client code unchanged.
+ * <p>Implementations handle specific storage mechanisms (e.g., in-memory, databases) while keeping
+ * client code unchanged.
  *
  * @see H2CustomerDAO
  * @see MongoCustomerDAO
@@ -53,8 +53,8 @@ public interface CustomerDAO<T> {
   Optional<Customer<T>> findById(T id);
 
   /**
-   * Delete the customer schema. After executing the statements,
-   * this function will be called to clean up the data and delete the records.
+   * Delete the customer schema. After executing the statements, this function will be called to
+   * clean up the data and delete the records.
    */
   void deleteSchema();
 }

dao-factory/src/main/java/com/iluwatar/daofactory/Customer.java

@@ -3,10 +3,9 @@
 /**
  * An abstract factory class that provides a way to create concrete DAO (Data Access Object)
  * factories for different data sources types (e.g., H2, Mongo, FlatFile).
- * <p>
- * This class follows the Abstract Factory design pattern, allowing applications to retrieve
- * the approriate DAO implementation without being tightly coupled to a specific data source.
- * </p>
+ *
+ * <p>This class follows the Abstract Factory design pattern, allowing applications to retrieve the
+ * approriate DAO implementation without being tightly coupled to a specific data source.
  *
  * @see H2DataSourceFactory
  * @see MongoDataSourceFactory
@@ -16,8 +15,8 @@ public abstract class DAOFactory {
   /**
    * Returns a concrete {@link DAOFactory} intance based on the specified data source type.
    *
-   * @param dataSourceType The type of data source for which a factory is needed.
-   *                       Supported values: {@code H2}, {@code Mongo}, {@code FlatFile}
+   * @param dataSourceType The type of data source for which a factory is needed. Supported values:
+   *     {@code H2}, {@code Mongo}, {@code FlatFile}
    * @return A {@link DAOFactory} implementation corresponding to the given data source type.
    * @throws IllegalArgumentException if the given data source type is not supported.
    */

dao-factory/src/main/java/com/iluwatar/daofactory/CustomerDAO.java

@@ -1,8 +1,6 @@
 package com.iluwatar.daofactory;
 
-/**
- * Enumerates the types of data sources supported by the application.
- */
+/** Enumerates the types of data sources supported by the application. */
 public enum DataSourceType {
   H2,
   Mongo,

dao-factory/src/main/java/com/iluwatar/daofactory/DAOFactory.java

@@ -24,8 +24,7 @@
 public class FlatFileCustomerDAO implements CustomerDAO<Long> {
   private final Path filePath;
   private final Gson gson;
-  Type customerListType = new TypeToken<List<Customer<Long>>>() {
-  }.getType();
+  Type customerListType = new TypeToken<List<Customer<Long>>>() {}.getType();
 
   protected Reader createReader(Path filePath) throws IOException {
     return new FileReader(filePath.toFile());
@@ -35,9 +34,7 @@ protected Writer createWriter(Path filePath) throws IOException {
     return new FileWriter(filePath.toFile());
   }
 
-  /**
-   * {@inheritDoc}
-   */
+  /** {@inheritDoc} */
   @Override
   public void save(Customer<Long> customer) {
     List<Customer<Long>> customers = new LinkedList<>();
@@ -56,9 +53,7 @@ public void save(Customer<Long> customer) {
     }
   }
 
-  /**
-   * {@inheritDoc}
-   */
+  /** {@inheritDoc} */
   @Override
   public void update(Customer<Long> customer) {
     if (!filePath.toFile().exists()) {
@@ -71,25 +66,21 @@ public void update(Customer<Long> customer) {
       throw new RuntimeException("Failed to read customer data", ex);
     }
     customers.stream()
-        .filter(c -> c.getId()
-            .equals(customer.getId()))
+        .filter(c -> c.getId().equals(customer.getId()))
         .findFirst()
         .ifPresentOrElse(
             c -> c.setName(customer.getName()),
             () -> {
               throw new RuntimeException("Customer not found with id: " + customer.getId());
-            }
-        );
+            });
     try (Writer writer = createWriter(filePath)) {
       gson.toJson(customers, writer);
     } catch (IOException ex) {
       throw new RuntimeException("Failed to write customer data", ex);
     }
   }
 
-  /**
-   * {@inheritDoc}
-   */
+  /** {@inheritDoc} */
   @Override
   public void delete(Long id) {
     if (!filePath.toFile().exists()) {
@@ -101,9 +92,11 @@ public void delete(Long id) {
     } catch (IOException ex) {
       throw new RuntimeException("Failed to read customer data", ex);
     }
-    Customer<Long> customerToRemove = customers.stream().filter(c -> c.getId().equals(id))
-        .findFirst()
-        .orElseThrow(() -> new RuntimeException("Customer not found with id: " + id));
+    Customer<Long> customerToRemove =
+        customers.stream()
+            .filter(c -> c.getId().equals(id))
+            .findFirst()
+            .orElseThrow(() -> new RuntimeException("Customer not found with id: " + id));
     customers.remove(customerToRemove);
     try (Writer writer = createWriter(filePath)) {
       gson.toJson(customers, writer);
@@ -112,9 +105,7 @@ public void delete(Long id) {
     }
   }
 
-  /**
-   * {@inheritDoc}
-   */
+  /** {@inheritDoc} */
   @Override
   public List<Customer<Long>> findAll() {
     if (!filePath.toFile().exists()) {
@@ -129,9 +120,7 @@ public List<Customer<Long>> findAll() {
     return customers;
   }
 
-  /**
-   * {@inheritDoc}
-   */
+  /** {@inheritDoc} */
   @Override
   public Optional<Customer<Long>> findById(Long id) {
     if (!filePath.toFile().exists()) {
@@ -143,15 +132,10 @@ public Optional<Customer<Long>> findById(Long id) {
     } catch (IOException ex) {
       throw new RuntimeException("Failed to read customer data", ex);
     }
-    return customers.stream()
-        .filter(c -> c.getId()
-            .equals(id))
-        .findFirst();
+    return customers.stream().filter(c -> c.getId().equals(id)).findFirst();
   }
 
-  /**
-   * {@inheritDoc}
-   */
+  /** {@inheritDoc} */
   @Override
   public void deleteSchema() {
     if (!filePath.toFile().exists()) {

dao-factory/src/main/java/com/iluwatar/daofactory/DataSourceType.java

@@ -5,18 +5,14 @@
 import java.nio.file.Path;
 import java.nio.file.Paths;
 
-/**
- * FlatFileDataSourceFactory concrete factory.
- */
+/** FlatFileDataSourceFactory concrete factory. */
 public class FlatFileDataSourceFactory extends DAOFactory {
   private final String FILE_PATH = System.getProperty("user.home") + "/Desktop/customer.json";
+
   @Override
   public CustomerDAO createCustomerDAO() {
     Path filePath = Paths.get(FILE_PATH);
-    Gson gson = new GsonBuilder()
-        .setPrettyPrinting()
-        .serializeNulls()
-        .create();
+    Gson gson = new GsonBuilder().setPrettyPrinting().serializeNulls().create();
     return new FlatFileCustomerDAO(filePath, gson);
   }
 }