feature: Added Domain Model pattern (#1795)

* domain-model pattern

* fixed optional get before check isPresent

* readme minor changes

* change currency representation with joda money

* changed names of test methods

* fixed code smells

* Update domain-model/README.md

Co-authored-by: Ilkka Seppälä <iluwatar@users.noreply.github.com>

* Update domain-model/README.md

Co-authored-by: Ilkka Seppälä <iluwatar@users.noreply.github.com>

* updated readme and diagrams

Co-authored-by: Ilkka Seppälä <iluwatar@users.noreply.github.com>

domain-model/src/test/java/com/iluwatar/domainmodel/AppTest.java

@@ -0,0 +1,38 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2021 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.domainmodel;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
+/** Tests that Domain Model example runs without errors. */
+final class AppTest {
+
+  @Test
+  void shouldExecuteApplicationWithoutException() {
+    assertDoesNotThrow(() -> App.main(new String[] {}));
+  }
+
+}

domain-model/src/test/java/com/iluwatar/domainmodel/CustomerDaoImplTest.java

@@ -0,0 +1,164 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2021 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.domainmodel;
+
+import org.joda.money.CurrencyUnit;
+import org.joda.money.Money;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import javax.sql.DataSource;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.time.LocalDate;
+
+import static org.joda.money.CurrencyUnit.USD;
+import static org.junit.jupiter.api.Assertions.*;
+
+class CustomerDaoImplTest {
+
+  public static final String INSERT_CUSTOMER_SQL = "insert into CUSTOMERS values('customer', 100)";
+  public static final String SELECT_CUSTOMERS_SQL = "select name, money from CUSTOMERS";
+  public static final String INSERT_PURCHASES_SQL =
+      "insert into PURCHASES values('product', 'customer')";
+  public static final String SELECT_PURCHASES_SQL =
+      "select product_name, customer_name from PURCHASES";
+
+  private DataSource dataSource;
+  private Product product;
+  private Customer customer;
+  private CustomerDao customerDao;
+
+  @BeforeEach
+  void setUp() throws SQLException {
+    // create db schema
+    dataSource = TestUtils.createDataSource();
+
+    TestUtils.deleteSchema(dataSource);
+    TestUtils.createSchema(dataSource);
+
+    // setup objects
+    customerDao = new CustomerDaoImpl(dataSource);
+
+    customer = Customer.builder().name("customer").money(Money.of(CurrencyUnit.USD,100.0)).customerDao(customerDao).build();
+
+    product =
+        Product.builder()
+            .name("product")
+            .price(Money.of(USD, 100.0))
+            .expirationDate(LocalDate.parse("2021-06-27"))
+            .productDao(new ProductDaoImpl(dataSource))
+            .build();
+  }
+
+  @AfterEach
+  void tearDown() throws SQLException {
+    TestUtils.deleteSchema(dataSource);
+  }
+
+  @Test
+  void shouldFindCustomerByName() throws SQLException {
+    var customer = customerDao.findByName("customer");
+
+    assertTrue(customer.isEmpty());
+
+    TestUtils.executeSQL(INSERT_CUSTOMER_SQL, dataSource);
+
+    customer = customerDao.findByName("customer");
+
+    assertTrue(customer.isPresent());
+    assertEquals("customer", customer.get().getName());
+    assertEquals(Money.of(USD, 100), customer.get().getMoney());
+  }
+
+  @Test
+  void shouldSaveCustomer() throws SQLException {
+    customerDao.save(customer);
+
+    try (var connection = dataSource.getConnection();
+        var statement = connection.createStatement();
+        ResultSet rs = statement.executeQuery(SELECT_CUSTOMERS_SQL)) {
+
+      assertTrue(rs.next());
+      assertEquals(customer.getName(), rs.getString("name"));
+      assertEquals(customer.getMoney(), Money.of(USD, rs.getBigDecimal("money")));
+    }
+
+    assertThrows(SQLException.class, () -> customerDao.save(customer));
+  }
+
+  @Test
+  void shouldUpdateCustomer() throws SQLException {
+    TestUtils.executeSQL(INSERT_CUSTOMER_SQL, dataSource);
+
+    customer.setMoney(Money.of(CurrencyUnit.USD, 99));
+
+    customerDao.update(customer);
+
+    try (var connection = dataSource.getConnection();
+        var statement = connection.createStatement();
+        ResultSet rs = statement.executeQuery(SELECT_CUSTOMERS_SQL)) {
+
+      assertTrue(rs.next());
+      assertEquals(customer.getName(), rs.getString("name"));
+      assertEquals(customer.getMoney(), Money.of(USD, rs.getBigDecimal("money")));
+      assertFalse(rs.next());
+    }
+  }
+
+  @Test
+  void shouldAddProductToPurchases() throws SQLException {
+    TestUtils.executeSQL(INSERT_CUSTOMER_SQL, dataSource);
+    TestUtils.executeSQL(ProductDaoImplTest.INSERT_PRODUCT_SQL, dataSource);
+
+    customerDao.addProduct(product, customer);
+
+    try (var connection = dataSource.getConnection();
+        var statement = connection.createStatement();
+        ResultSet rs = statement.executeQuery(SELECT_PURCHASES_SQL)) {
+
+      assertTrue(rs.next());
+      assertEquals(product.getName(), rs.getString("product_name"));
+      assertEquals(customer.getName(), rs.getString("customer_name"));
+      assertFalse(rs.next());
+    }
+  }
+
+  @Test
+  void shouldDeleteProductFromPurchases() throws SQLException {
+    TestUtils.executeSQL(INSERT_CUSTOMER_SQL, dataSource);
+    TestUtils.executeSQL(ProductDaoImplTest.INSERT_PRODUCT_SQL, dataSource);
+    TestUtils.executeSQL(INSERT_PURCHASES_SQL, dataSource);
+
+    customerDao.deleteProduct(product, customer);
+
+    try (var connection = dataSource.getConnection();
+        var statement = connection.createStatement();
+        ResultSet rs = statement.executeQuery(SELECT_PURCHASES_SQL)) {
+
+      assertFalse(rs.next());
+    }
+  }
+}

domain-model/src/test/java/com/iluwatar/domainmodel/CustomerTest.java

@@ -0,0 +1,112 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2021 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.domainmodel;
+
+import org.joda.money.CurrencyUnit;
+import org.joda.money.Money;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.sql.SQLException;
+import java.time.LocalDate;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Optional;
+
+import static org.joda.money.CurrencyUnit.USD;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.*;
+
+class CustomerTest {
+
+    private CustomerDao customerDao;
+    private Customer customer;
+    private Product product;
+
+    @BeforeEach
+    void setUp() {
+        customerDao = mock(CustomerDao.class);
+
+        customer = Customer.builder()
+                .name("customer")
+                .money(Money.of(CurrencyUnit.USD, 100.0))
+                .customerDao(customerDao)
+                .build();
+
+        product = Product.builder()
+                .name("product")
+                .price(Money.of(USD, 100.0))
+                .expirationDate(LocalDate.now().plusDays(10))
+                .productDao(mock(ProductDao.class))
+                .build();
+    }
+
+    @Test
+    void shouldSaveCustomer() throws SQLException {
+        when(customerDao.findByName("customer")).thenReturn(Optional.empty());
+
+        customer.save();
+
+        verify(customerDao, times(1)).save(customer);
+
+        when(customerDao.findByName("customer")).thenReturn(Optional.of(customer));
+
+        customer.save();
+
+        verify(customerDao, times(1)).update(customer);
+    }
+
+    @Test
+    void shouldAddProductToPurchases() {
+        product.setPrice(Money.of(USD, 200.0));
+
+        customer.buyProduct(product);
+
+        assertEquals(customer.getPurchases(), new ArrayList<>());
+        assertEquals(customer.getMoney(), Money.of(USD,100));
+
+        product.setPrice(Money.of(USD, 100.0));
+
+        customer.buyProduct(product);
+
+        assertEquals(new ArrayList<>(Arrays.asList(product)), customer.getPurchases());
+        assertEquals(Money.zero(USD), customer.getMoney());
+    }
+
+    @Test
+    void shouldRemoveProductFromPurchases() {
+        customer.setPurchases(new ArrayList<>(Arrays.asList(product)));
+
+        customer.returnProduct(product);
+
+        assertEquals(new ArrayList<>(), customer.getPurchases());
+        assertEquals(Money.of(USD, 200), customer.getMoney());
+
+        customer.returnProduct(product);
+
+        assertEquals(new ArrayList<>(), customer.getPurchases());
+        assertEquals(Money.of(USD, 200), customer.getMoney());
+    }
+}
+

domain-model/src/test/java/com/iluwatar/domainmodel/ProductDaoImplTest.java

@@ -0,0 +1,127 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2021 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.domainmodel;
+
+import org.joda.money.Money;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import javax.sql.DataSource;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.time.LocalDate;
+
+import static org.joda.money.CurrencyUnit.USD;
+import static org.junit.jupiter.api.Assertions.*;
+
+class ProductDaoImplTest {
+
+    public static final String INSERT_PRODUCT_SQL =
+            "insert into PRODUCTS values('product', 100, DATE '2021-06-27')";
+    public static final String SELECT_PRODUCTS_SQL =
+            "select name, price, expiration_date from PRODUCTS";
+
+    private DataSource dataSource;
+    private ProductDao productDao;
+    private Product product;
+
+    @BeforeEach
+    void setUp() throws SQLException {
+        // create schema
+        dataSource = TestUtils.createDataSource();
+
+        TestUtils.deleteSchema(dataSource);
+        TestUtils.createSchema(dataSource);
+
+        // setup objects
+        productDao = new ProductDaoImpl(dataSource);
+
+        product =
+                Product.builder()
+                        .name("product")
+                        .price(Money.of(USD, 100.0))
+                        .expirationDate(LocalDate.parse("2021-06-27"))
+                        .productDao(productDao)
+                        .build();
+    }
+
+    @AfterEach
+    void tearDown() throws SQLException {
+        TestUtils.deleteSchema(dataSource);
+    }
+
+    @Test
+    void shouldFindProductByName() throws SQLException {
+        var product = productDao.findByName("product");
+
+        assertTrue(product.isEmpty());
+
+        TestUtils.executeSQL(INSERT_PRODUCT_SQL, dataSource);
+
+        product = productDao.findByName("product");
+
+        assertTrue(product.isPresent());
+        assertEquals("product", product.get().getName());
+        assertEquals(Money.of(USD, 100), product.get().getPrice());
+        assertEquals(LocalDate.parse("2021-06-27"), product.get().getExpirationDate());
+    }
+
+    @Test
+    void shouldSaveProduct() throws SQLException {
+
+        productDao.save(product);
+
+        try (var connection = dataSource.getConnection();
+             var statement = connection.createStatement();
+             ResultSet rs = statement.executeQuery(SELECT_PRODUCTS_SQL)) {
+
+            assertTrue(rs.next());
+            assertEquals(product.getName(), rs.getString("name"));
+            assertEquals(product.getPrice(), Money.of(USD, rs.getBigDecimal("price")));
+            assertEquals(product.getExpirationDate(), rs.getDate("expiration_date").toLocalDate());
+        }
+
+        assertThrows(SQLException.class, () -> productDao.save(product));
+    }
+
+    @Test
+    void shouldUpdateProduct() throws SQLException {
+        TestUtils.executeSQL(INSERT_PRODUCT_SQL, dataSource);
+
+        product.setPrice(Money.of(USD, 99.0));
+
+        productDao.update(product);
+
+        try (var connection = dataSource.getConnection();
+             var statement = connection.createStatement();
+             ResultSet rs = statement.executeQuery(SELECT_PRODUCTS_SQL)) {
+
+            assertTrue(rs.next());
+            assertEquals(product.getName(), rs.getString("name"));
+            assertEquals(product.getPrice(), Money.of(USD, rs.getBigDecimal("price")));
+            assertEquals(product.getExpirationDate(), rs.getDate("expiration_date").toLocalDate());
+        }
+    }
+}

domain-model/src/test/java/com/iluwatar/domainmodel/ProductTest.java

@@ -0,0 +1,78 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2021 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.domainmodel;
+
+import org.joda.money.Money;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.sql.SQLException;
+import java.time.LocalDate;
+import java.util.Optional;
+
+import static org.joda.money.CurrencyUnit.USD;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.*;
+
+class ProductTest {
+
+    private ProductDao productDao;
+    private Product product;
+
+    @BeforeEach
+    void setUp() {
+        productDao = mock(ProductDaoImpl.class);
+
+        product = Product.builder()
+                .name("product")
+                .price(Money.of(USD, 100.0))
+                .expirationDate(LocalDate.now().plusDays(10))
+                .productDao(productDao)
+                .build();
+    }
+
+    @Test
+    void shouldSaveProduct() throws SQLException {
+        when(productDao.findByName("product")).thenReturn(Optional.empty());
+
+        product.save();
+
+        verify(productDao, times(1)).save(product);
+
+        when(productDao.findByName("product")).thenReturn(Optional.of(product));
+
+        product.save();
+
+        verify(productDao, times(1)).update(product);
+    }
+
+    @Test
+    void shouldGetSalePriceOfProduct() {
+        assertEquals(Money.of(USD, 100), product.getSalePrice());
+
+        product.setExpirationDate(LocalDate.now().plusDays(2));
+
+        assertEquals(Money.of(USD, 80), product.getSalePrice());
+    }
+}

domain-model/src/test/java/com/iluwatar/domainmodel/TestUtils.java

@@ -0,0 +1,53 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2021 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.domainmodel;
+
+import org.h2.jdbcx.JdbcDataSource;
+
+import javax.sql.DataSource;
+import java.sql.SQLException;
+
+public class TestUtils {
+
+  public static void executeSQL( String sql, DataSource dataSource) throws SQLException {
+    try (var connection = dataSource.getConnection();
+        var statement = connection.createStatement()) {
+      statement.executeUpdate(sql);
+    }
+  }
+
+  public static void createSchema(DataSource dataSource) throws SQLException {
+    TestUtils.executeSQL(App.CREATE_SCHEMA_SQL, dataSource);
+  }
+
+  public static void deleteSchema(DataSource dataSource) throws SQLException {
+    TestUtils.executeSQL(App.DELETE_SCHEMA_SQL, dataSource);
+  }
+
+  public static DataSource createDataSource() {
+    var dataSource = new JdbcDataSource();
+    dataSource.setURL(App.H2_DB_URL);
+    return dataSource;
+  }
+}