Member Avatar for chdboy

Is there any way that I don't use lots of IF statements?,right now it is according to Index of combo box items.

else if(e.getSource().equals(jcb1))
        {
            int selectedindex = jcb1.getSelectedIndex();
            String comb_string = (String)jcb1.getSelectedItem();            
            if(selectedindex==1)
            {
                try {

                //String sql_command ="select * , count(*) over (partition by 1) total_rows from Employer where Employername = ? ";             
                String sql_command ="select * from Employer where Employername = ? ";
                    PreparedStatement st=con.prepareStatement(sql_command);                 
                    st.setString(1,comb_string);
                    Result = st.executeQuery();
                    int test =0;
                    String Store="";
                    String Response ="";
                    test++;
                    if(Result.next())
                    {                       
                        String add1=Result.getString(3);
                        first.setText(add1);
                        String add2=Result.getString(28);
                        second.setText(add2);
                        String add3=Result.getString(4);
                        third.setText(add3);
                        String add4=Result.getString(6);
                        fourth.setText(add4);

                        if(test !=0)
                        {
                            /*Result.absolute(test);
                            DisplayData();*/
                            Response = "Number of Records that Matches :"+test+Store;
                            JOptionPane.showMessageDialog(null, Response);              
                        }
                        else
                        {
                            JOptionPane.showMessageDialog(null,"Could not be found");
                        }


                    }
                } catch (SQLException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }                   
            }           
        }
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  • 1 Reply
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  • 1 Day Discussion Span
  • Latest Post Latest Post by JamesCherrill

Dani AI

Generated

Your current handler checks the combo index and repeats DB + UI code for each case. That works, but it quickly becomes hard to maintain. As suggested, separating cases into methods is a step forward — a more robust pattern is to avoid index-based branching entirely by putting the data into objects (or IDs) and wiring the UI to those objects.

Populate the JComboBox with employer objects (or small id/display pairs) once, then on selection simply pull the selected object and populate fields. Example pattern:

class Employer {
  private final int id;
  private final String name, addr, phone, contact;
  // constructor + getters
  public String toString() { return name; } // what the combo shows
}

DefaultComboBoxModel<Employer> model =
  new DefaultComboBoxModel<>(employers.toArray(new Employer[0]));
jcb1.setModel(model);

jcb1.addActionListener(e -> {
  Employer sel = (Employer) jcb1.getSelectedItem();
  if (sel != null) {
    first.setText(sel.getAddr());
    second.setText(sel.getPhone());
    third.setText(sel.getContact());
  }
});

If you must query the DB on selection, do that work off the Event Dispatch Thread with a SwingWorker and pass back an Employer instance to the UI thread. Another option for fixed, small sets is a Map<Integer,Runnable> or Map<String,Consumer<Employer>> to map choices to handlers — but those are more verbose than using an object model.

Practical tips: load lists once when possible, store and use a unique ID (not just display text), use column names instead of magic column indices, always close ResultSet/PreparedStatement in try-with-resources, and never run blocking DB calls on the EDT. These changes remove the cascade of ifs, make the code testable, and keep the UI responsive.

Member Avatar for JamesCherrill

You don't give a lot of context for this question, but it looks like you should be using a switch based on the selected index, and in that calling separate methods for each of the possible cases.

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