Command
This module contains command side repository and service implementation and it is a foundation of command side restful service.
First let’s take a look at Todo class which is a data object.
Todo.java
package com.networknt.tram.todolist.command;
import com.networknt.eventuate.jdbc.IdGenerator;
import com.networknt.eventuate.jdbc.IdGeneratorImpl;
public class Todo {
private static IdGenerator idGenerator = new IdGeneratorImpl();
private String id;
private String title;
private boolean completed;
private int executionOrder;
public Todo() {
}
public Todo(String title, boolean completed, int executionOrder) {
this.id = idGenerator.genId().asString();
this.title = title;
this.completed = completed;
this.executionOrder = executionOrder;
}
public void setId(String id) {
this.id = id;
}
public String getId() {
return id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public boolean isCompleted() {
return completed;
}
public void setCompleted(boolean completed) {
this.completed = completed;
}
public int getExecutionOrder() {
return executionOrder;
}
public void setExecutionOrder(int executionOrder) {
this.executionOrder = executionOrder;
}
}We need a repository interface to save Todo object into database.
TodoRepository.java
package com.networknt.tram.todolist.command;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;
public interface TodoRepository {
void setConnection(Connection connection);
List<Todo> getAll();
Todo findOne(String id);
Todo save(Todo todo) throws SQLException;
Todo update(Todo todo) throws TodoNotFoundException, SQLException;
void delete(String id) throws SQLException;
}And the implementation for the interface is here.
TodoRepositoryImpl.java
package com.networknt.tram.todolist.command;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
public class TodoRepositoryImpl implements TodoRepository {
protected Logger logger = LoggerFactory.getLogger(getClass());
private Connection connection;
public TodoRepositoryImpl() {
}
public TodoRepositoryImpl(Connection connection) {
this.connection = connection;
}
public void setConnection(Connection connection) {
this.connection = connection;
}
@Override
public List<Todo> getAll() {
List<Todo> todos = new ArrayList<>();
try {
String psSelect = "SELECT ID, TITLE, COMPLETED, ORDER_ID FROM todo_db.TODO WHERE ACTIVE_FLG = 'Y' order by ORDER_ID asc";
PreparedStatement stmt = connection.prepareStatement(psSelect);
ResultSet rs = stmt.executeQuery();
while (rs.next()) {
Todo todo = new Todo();
todo.setTitle(rs.getString("ID"));
todo.setTitle(rs.getString("TITLE"));
todo.setCompleted(rs.getBoolean("COMPLETED"));
todo.setExecutionOrder(rs.getInt("ORDER_ID"));
todos.add(todo);
}
} catch (SQLException e) {
logger.error("SqlException:", e);
}
return todos;
}
@Override
public Todo findOne(String id) {
Todo todo = null;
try {
String psSelect = "SELECT ID, TITLE, COMPLETED, ORDER_ID FROM todo_db.TODO WHERE ACTIVE_FLG = 'Y' AND ID = ?";
PreparedStatement stmt = connection.prepareStatement(psSelect);
stmt.setString(1, id);
ResultSet rs = stmt.executeQuery();
if (rs == null || rs.getFetchSize() > 1) {
logger.error("incorrect fetch result {}", id);
}
while (rs.next()) {
todo = new Todo();
todo.setId(rs.getString("ID"));
todo.setTitle(rs.getString("TITLE"));
todo.setCompleted(rs.getBoolean("COMPLETED"));
todo.setExecutionOrder(rs.getInt("ORDER_ID"));
}
} catch (SQLException e) {
logger.error("SqlException:", e);
}
return todo;
}
@Override
public Todo save(Todo todo) throws SQLException{
String psInsert = "INSERT INTO todo_db.TODO (ID, TITLE, COMPLETED, ORDER_ID) VALUES (?, ?, ?, ?)";
try (PreparedStatement stmt = connection.prepareStatement(psInsert)) {
stmt.setString(1, todo.getId());
stmt.setString(2, todo.getTitle());
stmt.setBoolean(3, todo.isCompleted());
stmt.setInt(4, todo.getExecutionOrder());
int count = stmt.executeUpdate();
if (count != 1) {
logger.error("Failed to insert TODO: {}", todo.getId());
} else {
return todo;
}
} catch (SQLException e) {
logger.error("SqlException:", e);
throw new SQLException(e);
}
return null;
}
@Override
public Todo update(Todo todo) throws SQLException{
String psUpdate = "UPDATE todo_db.TODO SET TITLE=?, COMPLETED=?, ORDER_ID=? WHERE ID=? ";
try (PreparedStatement stmt = connection.prepareStatement(psUpdate)) {
stmt.setString(1, todo.getTitle());
stmt.setBoolean(2, todo.isCompleted());
stmt.setInt(3, todo.getExecutionOrder());
stmt.setString(4, todo.getId());
int count = stmt.executeUpdate();
if (count != 1) {
logger.error("Failed to update TODO: {}", todo.getId());
} else {
return todo;
}
} catch (SQLException e) {
logger.error("SqlException:", e);
throw new SQLException(e);
}
return null;
}
@Override
public void delete(String id) throws SQLException{
String psDelete = "UPDATE todo_db.TODO SET ACTIVE_FLG = 'N' WHERE ID = ?";
try (PreparedStatement psEntity = connection.prepareStatement(psDelete)) {
psEntity.setString(1, id);
int count = psEntity.executeUpdate();
if (count != 1) {
logger.error("Failed to delete TODO: {}", id);
}
} catch (SQLException e) {
logger.error("SqlException:", e);
throw new SQLException(e);
}
}
}As you have noticed, the database connection is passed in from the constructor so that all db operation will join a JDBC transaction with the same connection.
The following is a service class that wires in both database actions together. Update todo object and insert an event to message table in the same transaction.
TodoCommandService.java
package com.networknt.tram.todolist.command;
import com.networknt.eventuate.jdbc.IdGenerator;
import com.networknt.eventuate.jdbc.IdGeneratorImpl;
import com.networknt.tram.event.common.DomainEvent;
import com.networknt.tram.event.publisher.DomainEventPublisher;
import com.networknt.tram.event.publisher.DomainEventPublisherImpl;
import com.networknt.tram.message.producer.MessageProducer;
import com.networknt.tram.message.producer.jdbc.MessageProducerJdbcConnectionImpl;
import com.networknt.tram.todolist.common.TodoCreated;
import com.networknt.tram.todolist.common.TodoDeleted;
import com.networknt.tram.todolist.common.TodoUpdated;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
import static java.util.Arrays.asList;
public class TodoCommandService {
protected Logger logger = LoggerFactory.getLogger(getClass());
private TodoRepository todoRepository;
private DomainEventPublisher domainEventPublisher;
private IdGenerator idGenerator;
private DataSource dataSource;
public TodoCommandService( DataSource dataSource,IdGenerator idGenerator) {
this.dataSource = dataSource;
this.idGenerator = idGenerator;
}
public Todo create(CreateTodoRequest createTodoRequest) {
Todo todo = new Todo(createTodoRequest.getTitle(), createTodoRequest.isCompleted(), createTodoRequest.getOrder());
try (final Connection connection = dataSource.getConnection()) {
connection.setAutoCommit(false);
this.todoRepository = new TodoRepositoryImpl(connection);
MessageProducer messageProducer = new MessageProducerJdbcConnectionImpl(connection,idGenerator);
this.domainEventPublisher = new DomainEventPublisherImpl(messageProducer);
todo = todoRepository.save(todo);
publishTodoEvent(todo, new TodoCreated(todo.getTitle(), todo.isCompleted(), todo.getExecutionOrder()));
connection.commit();
} catch (SQLException e) {
logger.error("SqlException:", e);
}
return todo;
}
private void publishTodoEvent(Todo todo, DomainEvent... domainEvents) {
domainEventPublisher.publish(Todo.class, todo.getId(), asList(domainEvents));
}
private void publishTodoEvent(String id, DomainEvent... domainEvents) {
domainEventPublisher.publish(Todo.class, id, asList(domainEvents));
}
public Todo update(String id, UpdateTodoRequest updateTodoRequest) throws TodoNotFoundException {
try (final Connection connection = dataSource.getConnection()) {
connection.setAutoCommit(false);
this.todoRepository = new TodoRepositoryImpl(connection);
Todo todo = todoRepository.findOne(id);
if (todo == null) {
throw new TodoNotFoundException(id);
}
todo.setTitle(updateTodoRequest.getTitle());
todo.setCompleted(updateTodoRequest.isCompleted());
todo.setExecutionOrder(updateTodoRequest.getOrder());
todoRepository.update(todo);
MessageProducer messageProducer = new MessageProducerJdbcConnectionImpl(connection, new IdGeneratorImpl());
this.domainEventPublisher = new DomainEventPublisherImpl(messageProducer);
publishTodoEvent(todo, new TodoUpdated(todo.getTitle(), todo.isCompleted(), todo.getExecutionOrder()));
connection.commit();
return todo;
} catch (SQLException e) {
logger.error("SqlException:", e);
}
return null;
}
public void delete(String id) {
try (final Connection connection = dataSource.getConnection()) {
this.todoRepository = new TodoRepositoryImpl(connection);
MessageProducer messageProducer = new MessageProducerJdbcConnectionImpl(connection,idGenerator);
this.domainEventPublisher = new DomainEventPublisherImpl(messageProducer);
todoRepository.delete(id);
publishTodoEvent(id, new TodoDeleted());
} catch (SQLException e) {
logger.error("SqlException:", e);
}
}
public Todo findOne(String id) {
Todo todo = null;
try (final Connection connection = dataSource.getConnection()) {
this.todoRepository = new TodoRepositoryImpl(connection);
todo = todoRepository.findOne(id);
} catch (SQLException e) {
logger.error("SqlException:", e);
}
return todo;
}
}Pay attention on how connection is handled. First, the autocommit is turned off and the same connection object is passed into TodoResposity and MessageProducer implementations.
There is a unit test to ensure that above service is working.
package com.networknt.tram.todolist.command;
import com.networknt.service.SingletonServiceFactory;
import com.networknt.tram.todolist.common.Utils;
import org.h2.tools.RunScript;
import org.junit.Assert;
import org.junit.Test;
import javax.sql.DataSource;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.sql.Connection;
import java.sql.SQLException;
public class CommandModuleTest {
public static DataSource ds;
static {
ds = SingletonServiceFactory.getBean(DataSource.class);
try (Connection connection = ds.getConnection()) {
// Runscript doesn't work need to execute batch here.
String schemaResourceName = "/todolist-example-h2-ddl.sql";
InputStream in = CommandModuleTest.class.getResourceAsStream(schemaResourceName);
if (in == null) {
throw new RuntimeException("Failed to load resource: " + schemaResourceName);
}
InputStreamReader reader = new InputStreamReader(in);
RunScript.execute(connection, reader);
} catch (SQLException e) {
e.printStackTrace();
}
}
private TodoCommandService todoCommandService = SingletonServiceFactory.getBean(TodoCommandService.class);
@Test
public void testCreate() {
String title = Utils.generateUniqueString();
String id = todoCommandService.create(new CreateTodoRequest(title, false, 0)).getId();
Todo todo = todoCommandService.findOne(id);
Assert.assertNotNull(todo);
Assert.assertEquals(title, todo.getTitle());
}
@Test
public void testUpdate() throws TodoNotFoundException {
Todo todo = todoCommandService.create(new CreateTodoRequest(Utils.generateUniqueString(), false, 9));
String title = Utils.generateUniqueString();
todoCommandService.update(todo.getId(), new UpdateTodoRequest(title, false, 0));
todo = todoCommandService.findOne(todo.getId());
Assert.assertNotNull(todo);
Assert.assertEquals(title, todo.getTitle());
}
@Test
public void testDelete() {
Todo todo = todoCommandService.create(new CreateTodoRequest(Utils.generateUniqueString(), false, 9));
todoCommandService.delete(todo.getId());
Assert.assertNull(todoCommandService.findOne(todo.getId()));
}
}The unit test is using H2 database and the script todolist-example-h2-ddl.sql can be found in src/test/resources folder. There is also a service.yml config file to define the DataSource and TodoCommandServer as singletons.
Here is the content of service.yml
singletons:
- javax.sql.DataSource:
- com.zaxxer.hikari.HikariDataSource:
DriverClassName: org.h2.jdbcx.JdbcDataSource
jdbcUrl: jdbc:h2:~/test
username: sa
password: sa
- com.networknt.eventuate.jdbc.IdGenerator:
- com.networknt.eventuate.jdbc.IdGeneratorImpl
- com.networknt.tram.todolist.command.TodoCommandService:
- com.networknt.tram.todolist.command.TodoCommandServiceIn the next step, we are going to take a look at view side common commponents.