extend the logic of the RecordBase + manual test (iluwatar#79)

Author: sergejsvisockis

active-record/README.md

@@ -25,8 +25,8 @@ understand and maintain codebases.
 
 ## Tutorials
 
-* [Panache – Active Record Pattern](https://thorben-janssen.com/panache-active-record-pattern/)
-* [Active Record pattern in Java](https://objsql.hashnode.dev/active-record-pattern-in-java)
+* [Active Record](https://www.martinfowler.com/eaaCatalog/activeRecord.html/)
+* [Overview of the Active Record Pattern](https://blog.savetchuk.com/overview-of-the-active-record-pattern)
 
 ## Consequences
 

active-record/src/main/java/com/iluwatar/activerecord/App.java

@@ -0,0 +1,72 @@
+package com.iluwatar.activerecord;
+
+import java.sql.SQLException;
+import javax.sql.DataSource;
+import lombok.extern.slf4j.Slf4j;
+import org.h2.jdbcx.JdbcDataSource;
+
+@Slf4j
+public class App {
+
+  private static final String DB_URL = "jdbc:h2:mem:dao;DB_CLOSE_DELAY=-1";
+
+  private static final String CREATE_SCHEMA_SQL = "CREATE TABLE customer\n"
+      + "(\n"
+      + "    id              BIGINT      NOT NULL,\n"
+      + "    customer_number VARCHAR(15) NOT NULL,\n"
+      + "    first_name      VARCHAR(45) NOT NULL,\n"
+      + "    last_name       VARCHAR(45) NOT NULL,\n"
+      + "    CONSTRAINT customer_pkey PRIMARY KEY (id)\n"
+      + ");\n"
+      + "\n"
+      + "CREATE TABLE \"order\"\n"
+      + "(\n"
+      + "    id           BIGINT      NOT NULL,\n"
+      + "    order_number VARCHAR(15) NOT NULL,\n"
+      + "    customer_id  BIGINT      NOT NULL,\n"
+      + "    CONSTRAINT order_pkey PRIMARY KEY (id),\n"
+      + "    CONSTRAINT customer_id_fk FOREIGN KEY (customer_id) REFERENCES customer (id)\n"
+      + ")";
+
+
+  public static void main(final String[] args) throws Exception {
+    final var dataSource = createDataSource();
+    createSchema(dataSource);
+    RecordBase.setDataSource(dataSource);
+    executeOperation();
+  }
+
+  private static void executeOperation() {
+    LOGGER.info("saving the customer data...");
+    Customer customer = new Customer();
+    customer.setId(1L);
+    customer.setCustomerNumber("C123");
+    customer.setFirstName("John");
+    customer.setLastName("Smith");
+
+    Order order = new Order();
+    order.setId(1L);
+    order.setOrderNumber("O123");
+
+//    customer.addOrder(order);
+    customer.save();
+
+    LOGGER.info("The customer data by ID={}", customer.findById(1L));
+
+    LOGGER.info("find all the customers={}", customer.findAll());
+  }
+
+  private static void createSchema(DataSource dataSource) throws SQLException {
+    try (var connection = dataSource.getConnection();
+        var statement = connection.createStatement()) {
+      statement.execute(CREATE_SCHEMA_SQL);
+    }
+  }
+
+  private static DataSource createDataSource() {
+    var dataSource = new JdbcDataSource();
+    dataSource.setURL(DB_URL);
+    return dataSource;
+  }
+
+}

active-record/src/main/java/com/iluwatar/activerecord/Customer.java

@@ -1,29 +1,31 @@
 package com.iluwatar.activerecord;
 
+import java.sql.PreparedStatement;
 import java.sql.ResultSet;
+import java.sql.SQLException;
 import java.util.List;
-import javax.sql.DataSource;
 import lombok.Getter;
 import lombok.Setter;
+import lombok.ToString;
 
 @Getter
 @Setter
-public class Customer extends RecordBase {
+@ToString
+public class Customer extends RecordBase<Customer> {
 
   private Long id;
   private String customerNumber;
   private String firstName;
   private String lastName;
   private List<Order> orders;
 
-  public Customer(DataSource dataSource) {
-    super(dataSource);
-  }
-
   public Customer findByNumber(String customerNumber) {
     // TODO
     return null;
-//    return new Customer();
+  }
+
+  public void addOrder(Order order) {
+    orders.add(order);
   }
 
   @Override
@@ -32,7 +34,15 @@ protected String getTableName() {
   }
 
   @Override
-  protected void setFieldsFromResultSet(ResultSet rs) {
+  protected void setFieldsFromResultSet(ResultSet rs) throws SQLException {
+    this.id = rs.getLong("id");
+    this.customerNumber = rs.getString("customer_number");
+    this.firstName = rs.getString("first_name");
+    this.lastName = rs.getString("last_name");
+  }
+
+  @Override
+  protected void setPreparedStatementParams(PreparedStatement pstmt) throws SQLException {
 
   }
 }

active-record/src/main/java/com/iluwatar/activerecord/RecordBase.java

@@ -9,11 +9,16 @@
 import java.util.List;
 import javax.sql.DataSource;
 import lombok.RequiredArgsConstructor;
+import lombok.Setter;
 
 @RequiredArgsConstructor
-public abstract class RecordBase {
+public abstract class RecordBase<T extends RecordBase<?>> {
 
-  private final DataSource dataSource;
+  @Setter
+  private static DataSource dataSource;
+
+  @SuppressWarnings({"unchecked"})
+  private final Class<T> clazz = (Class<T>) getClass();
 
   protected Connection getConnection() throws SQLException {
     return dataSource.getConnection();
@@ -26,22 +31,22 @@ protected Connection getConnection() throws SQLException {
    */
   protected abstract String getTableName();
 
-  protected abstract void setFieldsFromResultSet(ResultSet rs);
+  protected abstract void setFieldsFromResultSet(ResultSet rs) throws SQLException;
+
+  protected abstract void setPreparedStatementParams(PreparedStatement pstmt) throws SQLException;
 
   /**
    * Find all the records for a corresponding domain model.
    *
-   * @param clazz domain model class.
-   * @param <T>   domain model type.
    * @return all the domain model related records.
    */
-  public <T extends RecordBase> List<T> findAll(Class<T> clazz) {
+  public List<T> findAll() {
     List<T> recordList = new ArrayList<>();
     try (Connection conn = getConnection();
-        PreparedStatement pstmt = conn.prepareStatement(constructGetByIdQuery(clazz))) {
+        PreparedStatement pstmt = conn.prepareStatement(constructFindAllQuery())) {
       try (ResultSet rs = pstmt.executeQuery()) {
         while (rs.next()) {
-          T record = getDeclaredClassInstance(clazz);
+          T record = getDeclaredClassInstance();
           record.setFieldsFromResultSet(rs);
           recordList.add(record);
         }
@@ -57,26 +62,24 @@ public <T extends RecordBase> List<T> findAll(Class<T> clazz) {
   /**
    * Find a domain model by its ID.
    *
-   * @param id    domain model identifier.
-   * @param clazz domain model class.
-   * @param <T>   domain model type.
+   * @param id domain model identifier.
    * @return the domain model.
    */
-  public <T extends RecordBase> T findById(Long id, Class<T> clazz) {
+  public T findById(Long id) {
     try (Connection conn = getConnection();
-        PreparedStatement pstmt = conn.prepareStatement(constructGetByIdQuery(clazz))) {
+        PreparedStatement pstmt = conn.prepareStatement(constructFindByIdQuery())) {
       pstmt.setLong(1, id);
       try (ResultSet rs = pstmt.executeQuery()) {
         if (rs.next()) {
-          T record = getDeclaredClassInstance(clazz);
+          T record = getDeclaredClassInstance();
           record.setFieldsFromResultSet(rs);
           return record;
         }
-        return getDeclaredClassInstance(clazz);
+        return getDeclaredClassInstance();
       }
     } catch (SQLException e) {
       throw new RuntimeException(
-          "Unable to fine a record for the following domain model : " + clazz.getName() + " by id="
+          "Unable to find a record for the following domain model : " + clazz.getName() + " by id="
               + id
               + " due to the data persistence error", e);
     }
@@ -86,15 +89,32 @@ public <T extends RecordBase> T findById(Long id, Class<T> clazz) {
    * Save the record.
    */
   public void save() {
-    // TODO
+    try (Connection connection = getConnection();
+        // TODO
+        PreparedStatement pstmt = connection.prepareStatement(null,
+            PreparedStatement.RETURN_GENERATED_KEYS)) {
+
+      setPreparedStatementParams(pstmt);
+      pstmt.executeUpdate();
+
+    } catch (SQLException e) {
+      throw new RuntimeException(
+          "Unable to save the record for the following domain model : " + clazz.getName()
+              + " due to the data persistence error", e);
+    }
+  }
+
+
+  private String constructFindAllQuery() {
+    return "SELECT * FROM " + getDeclaredClassInstance().getTableName();
   }
 
-  private <T extends RecordBase> String constructGetByIdQuery(Class<T> clazz) {
-    return "SELECT * FROM " + getDeclaredClassInstance(clazz).getTableName()
+  private String constructFindByIdQuery() {
+    return "SELECT * FROM " + getDeclaredClassInstance().getTableName()
         + " WHERE id = ?";
   }
 
-  private <T extends RecordBase> T getDeclaredClassInstance(Class<T> clazz) {
+  private T getDeclaredClassInstance() {
     try {
       return clazz.getDeclaredConstructor().newInstance();
     } catch (InvocationTargetException | NoSuchMethodException | IllegalAccessException |