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/**
* The MIT License
* Copyright (c) 2014-2016 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.dao;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Stream;
import javax.sql.DataSource;
import org.apache.log4j.Logger;
import org.h2.jdbcx.JdbcDataSource;
/**
* Data Access Object (DAO) is an object that provides an abstract interface to some type of
* database or other persistence mechanism. By mapping application calls to the persistence layer,
* DAO provide some specific data operations without exposing details of the database. This
* isolation supports the Single responsibility principle. It separates what data accesses the
* application needs, in terms of domain-specific objects and data types (the public interface of
* the DAO), from how these needs can be satisfied with a specific DBMS.
*
* <p>With the DAO pattern, we can use various method calls to retrieve/add/delete/update data
* without directly interacting with the data source. The below example demonstrates basic CRUD
* operations: select, add, update, and delete.
*
*
*/
public class App {
private static final String DB_URL = "jdbc:h2:~/dao";
private static Logger log = Logger.getLogger(App.class);
/**
* Program entry point.
*
* @param args command line args.
* @throws Exception if any error occurs.
*/
public static void main(final String[] args) throws Exception {
final CustomerDao inMemoryDao = new InMemoryCustomerDao();
performOperationsUsing(inMemoryDao);
final DataSource dataSource = createDataSource();
createSchema(dataSource);
final CustomerDao dbDao = new DbCustomerDao(dataSource);
performOperationsUsing(dbDao);
deleteSchema(dataSource);
}
private static void deleteSchema(DataSource dataSource) throws SQLException {
try (Connection connection = dataSource.getConnection();
Statement statement = connection.createStatement()) {
statement.execute(CustomerSchemaSql.DELETE_SCHEMA_SQL);
}
}
private static void createSchema(DataSource dataSource) throws SQLException {
try (Connection connection = dataSource.getConnection();
Statement statement = connection.createStatement()) {
statement.execute(CustomerSchemaSql.CREATE_SCHEMA_SQL);
}
}
private static DataSource createDataSource() {
JdbcDataSource dataSource = new JdbcDataSource();
dataSource.setURL(DB_URL);
return dataSource;
}
private static void performOperationsUsing(final CustomerDao customerDao) throws Exception {
addCustomers(customerDao);
log.info("customerDao.getAllCustomers(): ");
try (Stream<Customer> customerStream = customerDao.getAll()) {
customerStream.forEach((customer) -> log.info(customer));
}
log.info("customerDao.getCustomerById(2): " + customerDao.getById(2));
final Customer customer = new Customer(4, "Dan", "Danson");
customerDao.add(customer);
log.info("customerDao.getAllCustomers(): " + customerDao.getAll());
customer.setFirstName("Daniel");
customer.setLastName("Danielson");
customerDao.update(customer);
log.info("customerDao.getAllCustomers(): ");
try (Stream<Customer> customerStream = customerDao.getAll()) {
customerStream.forEach((cust) -> log.info(cust));
}
customerDao.delete(customer);
log.info("customerDao.getAllCustomers(): " + customerDao.getAll());
}
private static void addCustomers(CustomerDao customerDao) throws Exception {
for (Customer customer : generateSampleCustomers()) {
customerDao.add(customer);
}
}
/**
* Generate customers.
*
* @return list of customers.
*/
public static List<Customer> generateSampleCustomers() {
final Customer customer1 = new Customer(1, "Adam", "Adamson");
final Customer customer2 = new Customer(2, "Bob", "Bobson");
final Customer customer3 = new Customer(3, "Carl", "Carlson");
final List<Customer> customers = new ArrayList<>();
customers.add(customer1);
customers.add(customer2);
customers.add(customer3);
return customers;
}
}