SqlConnector

package util.sql;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.google.common.base.Preconditions;

public class SqlConnector {
    private final String url;
    private final String user;
    private final String password;
    private Connection connection;

    SqlConnector(final String url, final String user, final String password) {
        Preconditions.checkNotNull(url, "Url cannot be null");
        this.url = url;
        this.user = user;
        this.password = password;
    }

    public static SqlConnector forSql(String url, String user, String password) {
        return new SqlConnector(url, user, password);
    }

    public String getUrl() {
        return url;
    }

    public String getUser() {
        return user;
    }

    public String getPassword() {
        return password;
    }

    public Connection getConnection() {
        return connection;
    }

    public void openConnection() throws SQLException {
        if(!isConnected()) {
            connection = DriverManager.getConnection(getUrl(), getUser(), getPassword());
        }
    }

    public void closeConnection() throws SQLException {
        if(isConnected()) {
            getConnection().close();
        }
    }

    public int update(String query) throws SQLException {
        return connection.prepareStatement(query).executeUpdate();
    }

    public ResultSet select(String query) throws SQLException {
        return connection.prepareStatement(query).executeQuery();
    }

    public boolean isConnected() {
        return connection != null;
    }

}