package webapp.sql;

import webapp.exceptions.StorageException;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.SQLException;

public class SQLHelper {

private final ConnectionFactory connectionFactory;

public SQLHelper(ConnectionFactory connectionFactory) {

this.connectionFactory = connectionFactory;

}

public <T> T execution(String sql, SqlExecution<T> runner) {

try (Connection conn = connectionFactory.getConnection();

PreparedStatement preparedStmt = conn.prepareStatement(sql)) {

return runner.execution(preparedStmt);

} catch (SQLException e) {

System.out.println("SQLException message: " + e.getMessage());

System.out.println("SQLException SQL state: " + e.getSQLState());

System.out.println("SQLException SQL error code: " + e.getErrorCode());

throw new StorageException("SQL command problem!");

}

}

public <T> T transactionalExecute(SqlTransaction<T> runner) {

try (Connection conn = connectionFactory.getConnection()) {

try {

conn.setAutoCommit(false);

T res = runner.execution(conn);

conn.commit();

return res;

} catch (SQLException e) {

conn.rollback();

throw ExceptionUtil.convertException(e);

}

} catch (SQLException e) {

throw new StorageException(e);

}

}

public interface SqlExecution<T> {

T execution(PreparedStatement st) throws SQLException;

}

public interface SqlTransaction<T> {

T execution(Connection con) throws SQLException;

}

}