gaspersic/java-design-patterns
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

feature: #1319 add table module pattern (#1742)

Browse Source 
* modify table module pattern

* fix code smells

* resolve conversation

Co-authored-by: tao-sun2 <sustc18st@gmai.com>
Co-authored-by: Ilkka Seppälä <iluwatar@users.noreply.github.com>
This commit is contained in:
Tao
2021-05-18 03:06:35 +08:00
committed by GitHub
parent 122e6edb38
commit e498c25675
11 changed files with 671 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

81
table-module/src/main/java/com/iluwatar/tablemodule/App.java Normal file
View File

@ -0,0 +1,81 @@
package com.iluwatar.tablemodule;
import java.sql.SQLException;
import javax.sql.DataSource;
import lombok.extern.slf4j.Slf4j;
import org.h2.jdbcx.JdbcDataSource;
/**
* Table Module pattern is a domain logic pattern.
* In Table Module a single class encapsulates all the domain logic for all
* records stored in a table or view. It's important to note that there is no
* translation of data between objects and rows, as it happens in Domain Model,
* hence implementation is relatively simple when compared to the Domain
* Model pattern.
*
* <p>In this example we will use the Table Module pattern to implement register
* and login methods for the records stored in the user table. The main
* method will initialise an instance of {@link UserTableModule} and use it to
* handle the domain logic for the user table.</p>
*/
@Slf4j
public final class App {
private static final String DB_URL = "jdbc:h2:~/test";
/**
* Private constructor.
*/
private App() {
}
/**
* Program entry point.
*
* @param args command line args.
* @throws SQLException if any error occurs.
*/
public static void main(final String[] args) throws SQLException {
// Create data source and create the user table.
final var dataSource = createDataSource();
createSchema(dataSource);
var userTableModule = new UserTableModule(dataSource);
// Initialize two users.
var user1 = new User(1, "123456", "123456");
var user2 = new User(2, "test", "password");
// Login and register using the instance of userTableModule.
userTableModule.registerUser(user1);
userTableModule.login(user1.getUsername(), user1.getPassword());
userTableModule.login(user2.getUsername(), user2.getPassword());
userTableModule.registerUser(user2);
userTableModule.login(user2.getUsername(), user2.getPassword());
deleteSchema(dataSource);
}
private static void deleteSchema(final DataSource dataSource)
throws SQLException {
try (var connection = dataSource.getConnection();
var statement = connection.createStatement()) {
statement.execute(UserTableModule.DELETE_SCHEMA_SQL);
}
}
private static void createSchema(final DataSource dataSource)
throws SQLException {
try (var connection = dataSource.getConnection();
var statement = connection.createStatement()) {
statement.execute(UserTableModule.CREATE_SCHEMA_SQL);
}
}
private static DataSource createDataSource() {
var dataSource = new JdbcDataSource();
dataSource.setURL(DB_URL);
return dataSource;
}
}

23
table-module/src/main/java/com/iluwatar/tablemodule/User.java Normal file
View File

@ -0,0 +1,23 @@
package com.iluwatar.tablemodule;
import lombok.AllArgsConstructor;
import lombok.EqualsAndHashCode;
import lombok.Getter;
import lombok.Setter;
import lombok.ToString;
/**
* A user POJO that represents the data that will be read from the data source.
*/
@Setter
@Getter
@ToString
@EqualsAndHashCode
@AllArgsConstructor
public class User {
private int id;
private String username;
private String password;
}

96
table-module/src/main/java/com/iluwatar/tablemodule/UserTableModule.java Normal file
View File

@ -0,0 +1,96 @@
package com.iluwatar.tablemodule;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.sql.DataSource;
import lombok.extern.slf4j.Slf4j;
/**
* This class organizes domain logic with the user table in the
* database. A single instance of this class contains the various
* procedures that will act on the data.
*/
@Slf4j
public class UserTableModule {
/**
* Public element for creating schema.
*/
public static final String CREATE_SCHEMA_SQL =
"CREATE TABLE IF NOT EXISTS USERS (ID NUMBER, USERNAME VARCHAR(30) "
+ "UNIQUE,PASSWORD VARCHAR(30))";
/**
* Public element for deleting schema.
*/
public static final String DELETE_SCHEMA_SQL = "DROP TABLE USERS IF EXISTS";
private final DataSource dataSource;
/**
* Public constructor.
*
* @param userDataSource the data source in the database
*/
public UserTableModule(final DataSource userDataSource) {
this.dataSource = userDataSource;
}
/**
* Login using username and password.
*
* @param username the username of a user
* @param password the password of a user
* @return the execution result of the method
* @throws SQLException if any error
*/
public int login(final String username, final String password)
throws SQLException {
var sql = "select count(*) from USERS where username=? and password=?";
ResultSet resultSet = null;
try (var connection = dataSource.getConnection();
var preparedStatement =
connection.prepareStatement(sql)
) {
var result = 0;
preparedStatement.setString(1, username);
preparedStatement.setString(2, password);
resultSet = preparedStatement.executeQuery();
while (resultSet.next()) {
result = resultSet.getInt(1);
}
if (result == 1) {
LOGGER.info("Login successfully!");
} else {
LOGGER.info("Fail to login!");
}
return result;
} finally {
if (resultSet != null) {
resultSet.close();
}
}
}
/**
* Register a new user.
*
* @param user a user instance
* @return the execution result of the method
* @throws SQLException if any error
*/
public int registerUser(final User user) throws SQLException {
var sql = "insert into USERS (username, password) values (?,?)";
try (var connection = dataSource.getConnection();
var preparedStatement =
connection.prepareStatement(sql)
) {
preparedStatement.setString(1, user.getUsername());
preparedStatement.setString(2, user.getPassword());
var result = preparedStatement.executeUpdate();
LOGGER.info("Register successfully!");
return result;
}
}
}

16
table-module/src/test/java/com/iluwatar/tablemodule/AppTest.java Normal file
View File

@ -0,0 +1,16 @@
package com.iluwatar.tablemodule;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
/**
* Tests that the table module example runs without errors.
*/
class AppTest {
@Test
void shouldExecuteWithoutException() {
assertDoesNotThrow(() -> App.main(new String[]{}));
}
}

78
table-module/src/test/java/com/iluwatar/tablemodule/UserTableModuleTest.java Normal file
View File

@ -0,0 +1,78 @@
package com.iluwatar.tablemodule;
import org.h2.jdbcx.JdbcDataSource;
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.DriverManager;
import java.sql.SQLException;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
class UserTableModuleTest {
private static final String DB_URL = "jdbc:h2:~/test";
private static DataSource createDataSource() {
var dataSource = new JdbcDataSource();
dataSource.setURL(DB_URL);
return dataSource;
}
@BeforeEach
void setUp() throws SQLException {
try (var connection = DriverManager.getConnection(DB_URL);
var statement = connection.createStatement()) {
statement.execute(UserTableModule.DELETE_SCHEMA_SQL);
statement.execute(UserTableModule.CREATE_SCHEMA_SQL);
}
}
@AfterEach
void tearDown() throws SQLException {
try (var connection = DriverManager.getConnection(DB_URL);
var statement = connection.createStatement()) {
statement.execute(UserTableModule.DELETE_SCHEMA_SQL);
}
}
@Test
void loginShouldFail() throws SQLException {
var dataSource = createDataSource();
var userTableModule = new UserTableModule(dataSource);
var user = new User(1, "123456", "123456");
assertEquals(0, userTableModule.login(user.getUsername(),
user.getPassword()));
}
@Test
void loginShouldSucceed() throws SQLException {
var dataSource = createDataSource();
var userTableModule = new UserTableModule(dataSource);
var user = new User(1, "123456", "123456");
userTableModule.registerUser(user);
assertEquals(1, userTableModule.login(user.getUsername(),
user.getPassword()));
}
@Test
void registerShouldFail() throws SQLException {
var dataSource = createDataSource();
var userTableModule = new UserTableModule(dataSource);
var user = new User(1, "123456", "123456");
userTableModule.registerUser(user);
assertThrows(SQLException.class, () -> {
userTableModule.registerUser(user);
});
}
@Test
void registerShouldSucceed() throws SQLException {
var dataSource = createDataSource();
var userTableModule = new UserTableModule(dataSource);
var user = new User(1, "123456", "123456");
assertEquals(1, userTableModule.registerUser(user));
}
}

131
table-module/src/test/java/com/iluwatar/tablemodule/UserTest.java Normal file
View File

@ -0,0 +1,131 @@
package com.iluwatar.tablemodule;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
class UserTest {
@Test
void testCanEqual() {
assertFalse((new User(1, "janedoe", "iloveyou"))
.canEqual("Other"));
}
@Test
void testCanEqual2() {
var user = new User(1, "janedoe", "iloveyou");
assertTrue(user.canEqual(new User(1, "janedoe",
"iloveyou")));
}
@Test
void testEquals1() {
var user = new User(1, "janedoe", "iloveyou");
assertNotEquals("42", user);
}
@Test
void testEquals2() {
var user = new User(1, "janedoe", "iloveyou");
assertEquals(user, new User(1, "janedoe",
"iloveyou"));
}
@Test
void testEquals3() {
var user = new User(123, "janedoe", "iloveyou");
assertNotEquals(user, new User(1, "janedoe",
"iloveyou"));
}
@Test
void testEquals4() {
var user = new User(1, null, "iloveyou");
assertNotEquals(user, new User(1, "janedoe",
"iloveyou"));
}
@Test
void testEquals5() {
var user = new User(1, "iloveyou", "iloveyou");
assertNotEquals(user, new User(1, "janedoe",
"iloveyou"));
}
@Test
void testEquals6() {
var user = new User(1, "janedoe", "janedoe");
assertNotEquals(user, new User(1, "janedoe",
"iloveyou"));
}
@Test
void testEquals7() {
var user = new User(1, "janedoe", null);
assertNotEquals(user, new User(1, "janedoe",
"iloveyou"));
}
@Test
void testEquals8() {
var user = new User(1, null, "iloveyou");
assertEquals(user, new User(1, null,
"iloveyou"));
}
@Test
void testEquals9() {
var user = new User(1, "janedoe", null);
assertEquals(user, new User(1, "janedoe",
null));
}
@Test
void testHashCode1() {
assertEquals(-1758941372, (new User(1, "janedoe",
"iloveyou")).hashCode());
}
@Test
void testHashCode2() {
assertEquals(-1332207447, (new User(1, null,
"iloveyou")).hashCode());
}
@Test
void testHashCode3() {
assertEquals(-426522485, (new User(1, "janedoe",
null)).hashCode());
}
@Test
void testSetId() {
var user = new User(1, "janedoe", "iloveyou");
user.setId(2);
assertEquals(2, user.getId());
}
@Test
void testSetPassword() {
var user = new User(1, "janedoe", "tmp");
user.setPassword("iloveyou");
assertEquals("iloveyou", user.getPassword());
}
@Test
void testSetUsername() {
var user = new User(1, "tmp", "iloveyou");
user.setUsername("janedoe");
assertEquals("janedoe", user.getUsername());
}
@Test
void testToString() {
var user = new User(1, "janedoe", "iloveyou");
assertEquals(String.format("User(id=%s, username=%s, password=%s)",
user.getId(), user.getUsername(), user.getPassword()),
user.toString());
}
}