//Greet Philologus and Julia, Nereus and his sister, and Olympas, and all the saints who are with them (Romans 16:15)

package com.javarush.task.task21.task2111;

import java.sql.Connection;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import java.util.LinkedList;

import java.util.List;

/*

Освобождаем ресурсы

*/

public class Solution {

private Connection connection;

public Solution(Connection connection) {

this.connection = connection;

}

public List<User> getUsers() {

String query = "select ID, DISPLAYED_NAME, LEVEL, LESSON from USER";

List<User> result = new LinkedList();

try {

try(Statement stmt = connection.createStatement();

ResultSet rs = stmt.executeQuery(query);) {

while (rs.next()) {

int id = rs.getInt("ID");

String name = rs.getString("DISPLAYED_NAME");

int level = rs.getInt("LEVEL");

int lesson = rs.getInt("LESSON");

result.add(new User(id, name, level, lesson));

}

}

} catch (SQLException e) {

e.printStackTrace();

result = null;

}

return result;

}

@Override

protected void finalize() throws Throwable {

super.finalize();

if (connection != null) {connection.close();}

}

public static class User {

private int id;

private String name;

private int level;

private int lesson;

public User(int id, String name, int level, int lesson) {

this.id = id;

this.name = name;

this.level = level;

this.lesson = lesson;

}

@Override

public String toString() {

return "User{" +

"id=" + id +

", name='" + name + '\'' +

", level=" + level +

", lesson=" + lesson +

'}';

}

}

public static void main(String[] args) {

}

}

/*

Освобождаем ресурсы

Реализуй метод finalize, предварительно обдумав, что именно в нем должно быть.

Проведи рефакторинг метода getUsers в соответствии с java7 try-with-resources.

Требования:

1. Метод finalize в классе Solution должен содержать вызов super.finalize().

2. Метод finalize в классе Solution должен корректно завершаться в случае, если значение поля connection равно null.

3. Метод finalize в классе Solution должен закрывать текущее соединение, если значение поля connection не равно null.

4. Метод getUsers должен корректно использовать try-with-resources.

package com.javarush.task.task21.task2111;

import java.sql.Connection;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import java.util.LinkedList;

import java.util.List;

*

Освобождаем ресурсы

*

public class Solution {

private Connection connection;

public Solution(Connection connection) {

this.connection = connection;

}

public List<User> getUsers() {

String query = "select ID, DISPLAYED_NAME, LEVEL, LESSON from USER";

List<User> result = new LinkedList();

Statement stmt = null;

ResultSet rs = null;

try {

stmt = connection.createStatement();

rs = stmt.executeQuery(query);

while (rs.next()) {

int id = rs.getInt("ID");

String name = rs.getString("DISPLAYED_NAME");

int level = rs.getInt("LEVEL");

int lesson = rs.getInt("LESSON");

result.add(new User(id, name, level, lesson));

}

} catch (SQLException e) {

e.printStackTrace();

result = null;

} finally {

if(stmt != null) {

try {

stmt.close();

} catch (SQLException e) {

e.printStackTrace();

}

}

if(rs != null) {

try {

rs.close();

} catch (SQLException e) {

e.printStackTrace();

}

}

}

return result;

}

public static class User {

private int id;

private String name;

private int level;

private int lesson;

public User(int id, String name, int level, int lesson) {

this.id = id;

this.name = name;

this.level = level;

this.lesson = lesson;

}

@Override

public String toString() {

return "User{" +

"id=" + id +

", name='" + name + '\'' +

", level=" + level +

", lesson=" + lesson +

'}';

}

}

public static void main(String[] args) {

}

}

*/