Internet-Technologien/src/main/java/de/hsel/itech/db/Database.java

610 lines
18 KiB
Java

package de.hsel.itech.db;
import de.hsel.itech.config.Configuration;
import de.hsel.itech.db.pojo.Author;
import de.hsel.itech.db.pojo.Book;
import de.hsel.itech.db.pojo.Category;
import de.hsel.itech.db.pojo.Publisher;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.mariadb.jdbc.MariaDbPoolDataSource;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.net.URL;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.time.Year;
import java.util.AbstractMap;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
/**
* base class for everything regarding the database.
*
* @author Johannes Theiner
* @version 0.1
* @since 0.1
*/
public class Database {
private final String book = "book";
private final String author = "author";
private final String authorBook = "author_book";
private final String publisher = "publisher";
private final String category = "category";
private static Database instance;
/**
* Singleton for database access.
*
* @return {@link Database}
*/
public static Database getInstance() {
if (instance == null)
instance = new Database();
return instance;
}
private MariaDbPoolDataSource dataSource;
/**
* initializes connection pool and executes database setup.
*/
private Database() {
Configuration config = Configuration.get();
dataSource = new MariaDbPoolDataSource("jdbc:mysql://" + config.getDatabase().getHostname()
+ ":" + config.getDatabase().getPort() + "/" + config.getDatabase().getDatabase());
try {
dataSource.setUser(config.getDatabase().getUsername());
dataSource.setPassword(config.getDatabase().getPassword());
dataSource.initialize();
Connection connection = getConnection();
assert connection != null;
URL file = getClass().getClassLoader().getResource("database.sql");
assert file != null;
try (BufferedReader br = new BufferedReader(new FileReader(file.getFile()))) {
for (String line = br.readLine(); line != null; line = br.readLine()) {
PreparedStatement statement = connection.prepareStatement(line);
statement.executeUpdate();
statement.close();
}
} catch (IOException e) {
e.printStackTrace();
} finally {
connection.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
/**
* gets connection from connection pool.
*
* @return {@link java.sql.Connection}
*/
@Nullable
private Connection getConnection() {
try {
return dataSource.getConnection();
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
/**
* testing method.
*
* @return String
*/
@Deprecated
public String getHello() {
Connection connection = getConnection();
String hello = "";
try {
assert connection != null;
PreparedStatement statement = connection.prepareStatement("SELECT * FROM test WHERE id = 1");
ResultSet resultSet = statement.executeQuery();
if (resultSet.next())
hello = resultSet.getString("hello");
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
return hello;
}
/**
* gets author by id.
*
* @param id ID from database
* @return {@link de.hsel.itech.db.pojo.Author}
*/
@Nullable
public Author getAuthor(long id) {
Map.Entry<ResultSet, Connection> entry = getResultSet(id, author);
assert entry != null;
ResultSet rs = entry.getKey();
Author author = null;
try {
author = new Author(rs.getLong("id"), rs.getString("name"));
entry.getValue().close();
} catch (SQLException e) {
e.printStackTrace();
}
return author;
}
/**
* gets category by id.
*
* @param id ID from database
* @return {@link de.hsel.itech.db.pojo.Category}
*/
@Nullable
public Category getCategory(long id) {
Map.Entry<ResultSet, Connection> entry = getResultSet(id, category);
assert entry != null;
ResultSet rs = entry.getKey();
Category category = null;
try {
category = new Category(rs.getLong("id"), rs.getString("name"), rs.getString("image"));
entry.getValue().close();
} catch (SQLException e) {
e.printStackTrace();
}
return category;
}
/**
* gets publisher by id.
*
* @param id ID from database
* @return {@link de.hsel.itech.db.pojo.Publisher}
*/
@Nullable
public Publisher getPublisher(long id) {
Map.Entry<ResultSet, Connection> entry = getResultSet(id, publisher);
assert entry != null;
ResultSet rs = entry.getKey();
Publisher publisher = null;
try {
publisher = new Publisher(rs.getLong("id"), rs.getString("name"));
entry.getValue().close();
} catch (SQLException e) {
e.printStackTrace();
}
return publisher;
}
/**
* gets list of author ids from database.
*
* @param id book id from database
* @return {@link java.util.List}
*/
@Nullable
private List<Integer> getAuthors(long id) {
Map.Entry<List<ResultSet>, Connection> entry = getResultSets(id, authorBook, book);
assert entry != null;
try {
List<Integer> list = new ArrayList<>();
for (ResultSet rs : entry.getKey()) {
list.add(rs.getInt(author));
}
entry.getValue().close();
return list;
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
/**
* gets book by id.
*
* @param id ID from database
* @return {@link de.hsel.itech.db.pojo.Book}
*/
@Nullable
public Book getBook(long id) {
Map.Entry<ResultSet, Connection> entry = getResultSet(id, book);
assert entry != null;
ResultSet rs = entry.getKey();
Book book = null;
try {
Category category = getCategory(rs.getLong(this.category));
Publisher publisher = getPublisher(rs.getLong(this.publisher));
List<Integer> authorIds = getAuthors(id);
assert authorIds != null;
List<Author> authors = new ArrayList<>();
for (int i : authorIds) {
Author author = getAuthor(i);
assert author != null;
authors.add(author);
}
book = new Book(rs.getLong("id"), authors, publisher, category, rs.getString("title"),
Year.of(rs.getInt("year")), rs.getInt("price"), rs.getString("description"),
rs.getString("image"));
entry.getValue().close();
} catch (SQLException e) {
e.printStackTrace();
}
return book;
}
/**
* gets all books.
*
* @return {@link java.util.List}
*/
@Nullable
public List<Book> getBooks() {
Map.Entry<List<ResultSet>, Connection> entry = getResultSets(book, "id");
assert entry != null;
List<Long> ids = new ArrayList<>();
try {
for (ResultSet resultSet : entry.getKey()) {
ids.add(resultSet.getLong("id"));
}
entry.getValue().close();
} catch (SQLException ex) {
ex.printStackTrace();
}
List<Book> books = new ArrayList<>();
for (long id : ids) {
books.add(getBook(id));
}
return books;
}
/**
* gets books by category.
*
* @param category category id
* @return {@link java.util.List}
*/
@Nullable
public List<Book> getBooks(long category) {
Connection connection = getConnection();
assert connection != null;
List<Book> books = new ArrayList<>();
try {
PreparedStatement statement = connection.prepareStatement("SELECT (id) FROM book WHERE category = ?");
statement.setLong(1, category);
ResultSet resultSet = statement.executeQuery();
while (resultSet.next()) {
books.add(getBook(resultSet.getLong("id")));
}
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
return books;
}
/**
* get books by category.
*
* @param category Category object
* @return {@link java.util.List}
*/
@Nullable
public List<Book> getBooks(@NotNull Category category) {
return getBooks(category.getId());
}
/**
* Inserts book into database.
* authors, publishers, and category have to exist.
*
* @param book Book
* @return insert count
*/
public int insert(@NotNull Book book) {
Connection connection = getConnection();
assert connection != null;
int insertCount = 0;
try {
PreparedStatement statement = connection.prepareStatement("INSERT INTO book(title, description, "
+ "price, year, publisher, category, image) VALUES (?, ?, ?, ?, ?, ?, ?)");
statement.setString(1, book.getTitle());
statement.setString(2, book.getDescription());
statement.setInt(3, book.getPrice());
statement.setInt(4, book.getYear().getValue());
statement.setLong(5, book.getPublisher().getId());
statement.setLong(6, book.getCategory().getId());
statement.setString(7, book.getImage());
insertCount += statement.executeUpdate();
for (Author author : book.getAuthors()) {
PreparedStatement authorStatement = connection.prepareStatement("INSERT INTO author_book (author, book) VALUES (?, ?)");
statement.setLong(1, author.getId());
statement.setLong(2, book.getIsbn());
insertCount += authorStatement.executeUpdate();
}
connection.close();
} catch (SQLException ex) {
ex.printStackTrace();
}
return insertCount;
}
/**
* inserts Category into database.
*
* @param category Category
* @return insert count
*/
public int insert(@NotNull Category category) {
Connection connection = getConnection();
assert connection != null;
int insertCount = 0;
try {
PreparedStatement statement = connection.prepareStatement("INSERT INTO category (name, image) VALUES (?, ?)");
statement.setString(1, category.getName());
statement.setString(2, category.getImage());
insertCount += statement.executeUpdate();
connection.close();
} catch (SQLException ex) {
ex.printStackTrace();
}
return insertCount;
}
/**
* inserts Author.
*
* @param author Author
* @return insert count
*/
public int insert(@NotNull Author author) {
Connection connection = getConnection();
assert connection != null;
int insertCount = 0;
try {
PreparedStatement statement = connection.prepareStatement("INSERT INTO author (name) VALUES (?)");
statement.setString(1, author.getName());
insertCount += statement.executeUpdate();
connection.close();
} catch (SQLException ex) {
ex.printStackTrace();
}
return insertCount;
}
/**
* inserts Publisher.
*
* @param publisher Publisher
* @return insert count
*/
public int insert(@NotNull Publisher publisher) {
Connection connection = getConnection();
assert connection != null;
int insertCount = 0;
try {
PreparedStatement statement = connection.prepareStatement("INSERT INTO publisher (name) VALUES (?)");
statement.setString(1, publisher.getName());
insertCount += statement.executeUpdate();
connection.close();
} catch (SQLException ex) {
ex.printStackTrace();
}
return insertCount;
}
/**
* deletes book from database.
*
* @param id book id
* @return deletion count
*/
public int deleteBook(long id) {
int deleteCount = 0;
try {
Connection connection = getConnection();
assert connection != null;
PreparedStatement statement = connection.prepareStatement("DELETE FROM author_book WHERE book = ?");
statement.setLong(1, id);
deleteCount = +statement.executeUpdate();
connection.close();
} catch (SQLException ex) {
ex.printStackTrace();
}
deleteCount += delete(id, book);
return deleteCount;
}
/**
* deletes author from database.
*
* @param id author id
* @return deletion count
*/
public int deleteAuthor(long id) {
return delete(id, author);
}
/**
* deletes publisher from database.
*
* @param id publisher id
* @return deletion count
*/
public int deletePublisher(long id) {
return delete(id, publisher);
}
/**
* deletes category from database.
*
* @param id category count
* @return deletion count
*/
public int deleteCategory(long id) {
return delete(id, category);
}
/**
* deletes id from table.
*
* @param id database id
* @param table table name
* @return deletion count
*/
private int delete(long id, String table) {
Connection connection = getConnection();
assert connection != null;
int deleteCount = 0;
try {
PreparedStatement statement = connection.prepareStatement("DELETE FROM ? WHERE id=?");
statement.setString(1, table);
statement.setLong(2, id);
deleteCount = +statement.executeUpdate();
} catch (SQLException ex) {
ex.printStackTrace();
}
return deleteCount;
}
/**
* gets specific entry from database.
*
* @param id id from database
* @param table table name
* @return {@link java.util.Map.Entry}
*/
@Nullable
private Map.Entry<ResultSet, Connection> getResultSet(long id, String table) {
Connection connection = getConnection();
try {
assert connection != null;
PreparedStatement statement = connection.prepareStatement("SELECT * FROM ? WHERE ID = ?");
statement.setString(1, table);
statement.setLong(2, id);
ResultSet resultSet = statement.executeQuery();
if (resultSet.next()) {
return new AbstractMap.SimpleEntry<>(resultSet, connection);
}
return null;
} catch (SQLException ex) {
ex.printStackTrace();
}
return null;
}
/**
* gets specific entries from table.
*
* @param id id all entries should reference
* @param table table name
* @param column column to match
* @return {@link java.util.Map.Entry}
*/
@Nullable
private Map.Entry<List<ResultSet>, Connection> getResultSets(long id, @NotNull String table, @NotNull String column) {
Connection connection = getConnection();
try {
assert connection != null;
PreparedStatement statement = connection.prepareStatement("SELECT * FROM ? WHERE ? = ?");
statement.setString(1, table);
statement.setString(2, column);
statement.setLong(3, id);
return getAllEntries(connection, statement);
} catch (SQLException ex) {
ex.printStackTrace();
}
return null;
}
/**
* gets all specified columns from table.
*
* @param table table name
* @param columns columns as String array
* @return {@link java.util.Map.Entry}
*/
@Nullable
private Map.Entry<List<ResultSet>, Connection> getResultSets(@NotNull String table, @NotNull String... columns) {
Connection connection = getConnection();
try {
assert connection != null;
PreparedStatement statement = connection.prepareStatement("SELECT (?) FROM ?");
statement.setString(1, String.join(",", columns));
statement.setString(2, table);
return getAllEntries(connection, statement);
} catch (SQLException ex) {
ex.printStackTrace();
}
return null;
}
/**
* gets all entries contained in result set.
*
* @param connection Connection
* @param statement query statement
* @return {@link java.util.Map.Entry}
*/
@Nullable
private Map.Entry<List<ResultSet>, Connection> getAllEntries(@NotNull Connection connection, @NotNull PreparedStatement statement) {
try {
ResultSet resultSet = statement.executeQuery();
Map.Entry<List<ResultSet>, Connection> entry = new AbstractMap.SimpleEntry<>(new ArrayList<>(), connection);
while (resultSet.next()) {
entry.getKey().add(resultSet);
}
return entry;
} catch (SQLException ex) {
ex.printStackTrace();
}
return null;
}
}