Implement an active record pattern (#79)

active-record/README.md

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+---
+title: Active Record
+category: Architectural
+language: en
+tag:
+  - Data access
+---
+
+## Intent
+
+The Active Record pattern is a design pattern that integrates data access logic directly into the
+domain model, typically within the model classes themselves. This means that each domain object is
+responsible for its own persistence, including tasks such as database querying, saving, updating,
+and deleting records.
+
+This pattern is particularly useful in scenarios where simplicity and rapid development are
+prioritized, as it allows engineers to quickly implement data access functionality with minimal
+effort. By encapsulating persistence logic within the domain objects, the Active Record pattern
+promotes a straightforward and intuitive approach to working with data, making it easier to
+understand and maintain codebases.
+
+## Explanation
+
+## Class diagram
+
+## Tutorials
+
+* [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
+
+## Related patterns
+
+## Credits

active-record/etc/active-record.urm.puml

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+@startuml
+package com.iluwatar.activerecord {
+  abstract class RecordBase<T extends RecordBase<?>> {
+    - dataSource : DataSource
+    - clazz : Class<T>
+    + setDataSource(DataSource) : void
+    # getConnection() : Connection
+    # abstract getTableName() : String
+    # abstract setFieldsFromResultSet(ResultSet) : void
+    # abstract setPreparedStatementParams(PreparedStatement) : void
+    + findAll() : List<T>
+    + findById(Long id): T
+    + save() : void
+    + delete() : void
+    - constructFindByIdQuery() : String
+    - constructFindAllQuery() : String
+    - getDeclaredClassInstance() : T
+  }
+
+  class Customer extends RecordBase {
+    - id : Long
+    - customerNumber : String
+    - firstName : String
+    - lastName : String
+    - List<Order> orders
+    + getId() : Long
+    + setId(Long id) : void
+    + getCustomerNumber() : String
+    + setCustomerNumber(String customerNumber) : void
+    + getfirstName() : String
+    + setFirstName(String firstName) : void
+    + getLastName() : String
+    + setLastName(String lastName) : void
+    + findByNumber(String customerNumber) : Customer
+    + addOrder(Order order) : void
+  }
+
+  class Order extends RecordBase {
+    - id : Long
+    - orderNumber : String
+    + getId() : Long
+    + setId(Long id) : void
+    + getOrderNumber() : String
+    + setOrderNumber(String orderNumber) : String
+  }
+}
+@enduml

active-record/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.26.0-SNAPSHOT</version>
+  </parent>
+
+  <artifactId>active-record</artifactId>
+
+  <properties>
+    <maven.compiler.source>17</maven.compiler.source>
+    <maven.compiler.target>17</maven.compiler.target>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-engine</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>com.h2database</groupId>
+      <artifactId>h2</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-core</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-assembly-plugin</artifactId>
+        <executions>
+          <execution>
+            <configuration>
+              <archive>
+                <manifest>
+                  <mainClass>com.iluwatar.activerecord.App</mainClass>
+                </manifest>
+              </archive>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+
+</project>

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

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+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.activerecord;
+
+import static com.iluwatar.activerecord.SchemaConstants.CREATE_SCHEMA_SQL;
+
+import com.iluwatar.activerecord.base.RecordBase;
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+import javax.sql.DataSource;
+import lombok.extern.slf4j.Slf4j;
+import org.h2.jdbcx.JdbcDataSource;
+
+/**
+ * The main application for the manual testing purposes.
+ */
+@Slf4j
+public class App {
+
+  private static final String DB_URL = "jdbc:h2:mem:dao;DB_CLOSE_DELAY=-1";
+
+  /**
+   * Java main method to execute all the logic out there.
+   *
+   * @param args arguments.
+   * @throws Exception Any sort of exception that has to be picked up by the JVM.
+   */
+  public static void main(final String[] args) throws Exception {
+    final DataSource 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(Customer.class);
+
+    LOGGER.info("The customer data by ID={}", customer.findById(1L, Customer.class));
+
+    LOGGER.info("find all the customers={}", customer.findAll(Customer.class));
+  }
+
+  private static void createSchema(DataSource dataSource) throws SQLException {
+    try (Connection conn = dataSource.getConnection();
+         Statement stmt = conn.createStatement()) {
+      stmt.execute(CREATE_SCHEMA_SQL);
+    }
+  }
+
+  private static DataSource createDataSource() {
+    JdbcDataSource dataSource = new JdbcDataSource();
+    dataSource.setURL(DB_URL);
+    return dataSource;
+  }
+
+}

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

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+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.activerecord;
+
+import com.iluwatar.activerecord.base.RecordBase;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.List;
+import lombok.Getter;
+import lombok.Setter;
+import lombok.ToString;
+
+/**
+ * The customer domain model.
+ */
+@Getter
+@Setter
+@ToString
+public class Customer extends RecordBase {
+
+  private Long id;
+  private String customerNumber;
+  private String firstName;
+  private String lastName;
+  private List<Order> orders;
+
+  public Customer findByNumber(String customerNumber) {
+    // TODO
+    return null;
+  }
+
+  public void addOrder(Order order) {
+    orders.add(order);
+  }
+
+  @Override
+  protected String getTableName() {
+    return "customer";
+  }
+
+  @Override
+  protected void setFieldsFromResultSet(ResultSet rs) throws SQLException {
+    this.id = rs.getLong("id");
+    this.customerNumber = rs.getString("customerNumber");
+    this.firstName = rs.getString("firstName");
+    this.lastName = rs.getString("lastName");
+  }
+
+  @Override
+  protected void setPreparedStatementParams(PreparedStatement pstmt) throws SQLException {
+    pstmt.setLong(1, id);
+    pstmt.setString(2, customerNumber);
+    pstmt.setString(3, firstName);
+    pstmt.setString(4, lastName);
+  }
+}

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

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+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.activerecord;
+
+import com.iluwatar.activerecord.base.RecordBase;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+/**
+ * An order domain model.
+ */
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+public class Order extends RecordBase {
+
+  private Long id;
+  private String orderNumber;
+
+  @Override
+  protected String getTableName() {
+    return "order";
+  }
+
+  @Override
+  protected void setFieldsFromResultSet(ResultSet rs) throws SQLException {
+    this.id = rs.getLong("id");
+    this.orderNumber = rs.getString("orderNumber");
+  }
+
+  @Override
+  protected void setPreparedStatementParams(PreparedStatement pstmt)
+      throws SQLException {
+
+  }
+
+}