private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        // TODO add your handling code here:
        String cat = filter_category.getSelectedItem().toString();
        if(cat.equals("All"))
        {
            if(!(filter_isbn.getText().isEmpty()))
            {
                try{
                Class.forName("com.mysql.jdbc.Driver");
                conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/rctlibrary","root","");
                stmt = conn.createStatement();
                String query = "SELECT Title,ISBN,Author,Abstract FROM `tblbooks` WHERE `ISBN`='" + Integer.parseInt(filter_isbn.getText()) + "'";
                rs = stmt.executeQuery(query);
                if(!rs.next())
                {
                    JOptionPane.showMessageDialog(null,"No results found in the database!");
                    res_isbn.setText("");
                    res_title.setText("");
                    res_author.setText("");
                    res_abstract.setText("");
                    num_result.setText("" + rs.getRow());
                    rs.close();
                    stmt.close();
                    conn.close();
                }
                else
                {
                    while(rs.next())
                    {
                        int Res_isbn = rs.getInt("ISBN");
                        String Res_title = rs.getString("Title");
                        String Res_author = rs.getString("Author");
                        String Res_abs = rs.getString("Abstract");
                        res_isbn.setText("" + Res_isbn);
                        res_title.setText(Res_title);
                        res_author.setText(Res_author);
                        res_abstract.setText(Res_abs);
                        num_result.setText("" + rs.getRow());
                        res_availab.setText("Available");
                        max_row = rs.getRow();
                        prev_btn.setEnabled(true);
                        nxt_btn.setEnabled(true);
                    }
                    rs.close();
                }
                }
                catch(SQLException e)
                {
                    JOptionPane.showMessageDialog(null, e);
                }
                catch(Exception e)
                {
                    JOptionPane.showMessageDialog(null, e);
                }
                }
            else{
            try{
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/rctlibrary","root","");
            stmt = conn.createStatement();
            String query = "SELECT Title,ISBN,Author,Abstract FROM `tblbooks`";
            rs = stmt.executeQuery(query);
            if(rs.next() == false)
            {
                JOptionPane.showMessageDialog(null,"No results found in the database!");
                res_isbn.setText("");
                res_title.setText("");
                res_author.setText("");
                res_abstract.setText("");
                num_result.setText("" + rs.getRow());
                rs.close();
                stmt.close();
                conn.close();
            }
            else
            {
            while(rs.next())
            {
                int Res_isbn = rs.getInt("ISBN");
                String Res_title = rs.getString("Title");
                String Res_author = rs.getString("Author");
                String Res_abs = rs.getString("Abstract");
                res_isbn.setText("" + Res_isbn);
                res_title.setText(Res_title);
                res_author.setText(Res_author);
                res_abstract.setText(Res_abs);
                num_result.setText("" + rs.getRow());
                res_availab.setText("Available");
                max_row = rs.getRow();
                prev_btn.setEnabled(true);
                nxt_btn.setEnabled(true);
            }
            rs.close();
            }

        }
        catch(SQLException e)
        {
            System.out.println(e);
            JOptionPane.showMessageDialog(null, e);
        }
        catch(Exception e)
        {
            System.out.println(e);
            JOptionPane.showMessageDialog(null, e);
        }
        }
        }
        else
        {
        try{
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/rctlibrary","root","");
            stmt = conn.createStatement();
            String query = "SELECT Title,ISBN,Author,Abstract,Category FROM `tblbooks` WHERE `Category`='" + cat + "'";
            rs = stmt.executeQuery(query);
            if(!rs.next())
            {
                JOptionPane.showMessageDialog(null,"No results found in the database!");
                res_isbn.setText("");
                res_title.setText("");
                res_author.setText("");
                res_abstract.setText("");
                num_result.setText("" + rs.getRow());
                rs.close();
                stmt.close();
                conn.close();
            }
            else
            {
            while(rs.next())
            {
                int Res_isbn = rs.getInt("ISBN");
                String Res_title = rs.getString("Title");
                String Res_author = rs.getString("Author");
                String Res_abs = rs.getString("Abstract");
                res_isbn.setText("" + Res_isbn);
                res_title.setText(Res_title);
                res_author.setText(Res_author);
                res_abstract.setText(Res_abs);
                num_result.setText("" + rs.getRow());
                max_row = rs.getRow();
                prev_btn.setEnabled(true);
                nxt_btn.setEnabled(true);
            }
            rs.close();
            }
            //parang dito sya napupunta. kasi naglagay ako dito ng command tapos triny ko. lumabas yung ininput ko dito na code
            System.out.println("ASD");

        }
        catch(SQLException e)
        {
            System.out.println(e);
            JOptionPane.showMessageDialog(null, e);
        }
        catch(Exception e)
        {
            System.out.println(e);
            JOptionPane.showMessageDialog(null, e);
        }
        }
    }