minecraft-kajetans-mod/src/main/java/me/km/databank/DataBank.java

package me.km.databank;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import me.km.api.Module;
import me.km.scheduler.SnuviScheduler;
import net.minecraft.util.text.TextFormatting;

public class DataBank extends Module
{
    private final static DummyStatement DUMMY_STATEMENT = new DummyStatement();
    
    private Connection c;
    private final String user;
    private final String password;
    
    public DataBank(String mname, String prefix, TextFormatting color, String user, String password) 
    {
        super(mname, prefix, color);
        this.user = user;
        this.password = password;
    }
    
    public boolean openDataBankConnection()
    {
        c = null;
        try 
        {
            // The newInstance() call is a work around for some broken Java implementations
            Class.forName("com.mysql.jdbc.Driver").newInstance();
            c = DriverManager.getConnection("jdbc:mysql://localhost/minecraft?autoReconnect=true", user, password);
            this.sendToConsole("Die Verbindung wurde erfolgreich aufgebaut.");
            return true;
        } 
        catch(ClassNotFoundException | IllegalAccessException | InstantiationException | SQLException ex) 
        {
            this.sendWarningToConsole(ex.toString());
            return false;
        }
    }
    
    public void closeDataBankConnection()
    {
        try 
        {
            c.close();
            this.sendToConsole("Die Verbindung wurde erfolgreich unterbrochen.");
        } 
        catch (SQLException ex) 
        {
            this.sendWarningToConsole(ex.getMessage());
        }
        catch (NullPointerException ex) 
        {
        }
    }
    
    public boolean isDummyDatabank()
    {
        return c == null;
    }
    
    public Statement createStatement() throws SQLException
    {
        if(c == null)
        {
            return DUMMY_STATEMENT;
        }
        return c.createStatement();
    } 
    
    public void startReconnecting(SnuviScheduler scheduler)
    {
        scheduler.scheduleRepeatingTask(() -> 
        {
            try(Statement stmt = createStatement()) 
            {
                // pointless query just for reconnecting
                stmt.executeUpdate("SHOW TABLES IN minecraft");
            }
            catch(SQLException ex) 
            {
                sendToConsole("reconnect was done");
            }
        }, 100, 12000); // doing this every 10 minutes
    }
}