Re: Long delay when using JComboBox.setSelectedIndex() ??

From:
kedward777@gmail.com
Newsgroups:
comp.lang.java.help
Date:
Wed, 5 Dec 2012 10:46:14 -0800 (PST)
Message-ID:
<bc9f2f27-8ee5-41ef-b03c-575939131caa@googlegroups.com>
Thank you for your input!

I know doing io on the EDT is not optimal, but I was just trying to provide=
 a short code snippet to illustrate the problem. The issue is happening wel=
l AFTER I load the employee names from disk. The delay is happening right a=
fter I setSelectedIndex(3) on the jcombobox..

Can you show me how to override equals ??

Thank you again!
Ken

On Wednesday, December 5, 2012 1:35:50 PM UTC-5, Lew wrote:

kedwa...@gmail.com wrote:
 

I am attempting to load 5000 employee items into a jcombobox, and then =

setSelectedIndex, but I am getting a odd delay in the gui after setting the=
 selectedIndex

 

 

 

1) If I load the 5000 employee names using a simple vector, it works fi=

ne. When I call

 
 
 
'vector' or "vector" or 'Vector'?
 
 
 

setSelectedIndex(5), it sets the combobox to the 5th element, very quic=

kly. This works fine:

 

 

 

 while ((line = input.readLine()) != null) {

 
 
 
This is a slow action on the EDT. Bad.
 
 
 

                StringTokenizer st = new StringTokenizer(line, "|");

 

                lastName = st.nextToken().trim();

 

                firstName = st.nextToken().trim();

 

                id = Integer.parseInt(st.nextToken().trim());

 
 
 
'lastName, 'firstName', and 'id' should be declared locally to the loop.
 
 
 

                 comboBoxItems.add(lastName);}

 

                mybox1.setModel(new javax.swing.DefaultComboBoxModel(mo=

del));

 

                mybox1.setSelectedIndex(5);

 

 

 

2)HOWEVER, if I load an employee object into a mapped vector, and then =

setSelectedIndex(5), I DO

 
 
 
What is a "mapped vector"?
 
 
 

see it instantly set the GUI combobox to the 5th item, BUT then there i=

s a LOOOONG delay in the gui (1 minute or more) before it allows me to do a=
nything further in the gui

 

 

 

 while ((line = input.readLine()) != null) {

 
 
 
This is a slow action on the EDT. Bad.
 
 
 

                StringTokenizer st = new StringTokenizer(line, "|");

 

                lastName = st.nextToken().trim();

 

                firstName = st.nextToken().trim();

 

                id = Integer.parseInt(st.nextToken().trim());

 

                empBuffer= new Employee(id, lastName );

 
 
 
'lastName, 'firstName', 'id' and 'empBuffer' should be declared locally t=

o the loop.

 
 
 

                map.put(empBuffer.getId()+"",empBuffer );

 

                count++; }

 

                

 

             model.addAll(map.values());

 

             Collections.sort(model);

 

             mybox1.setModel(new javax.swing.DefaultComboBoxModel(model=

));

 

             mybox1.setSelectedIndex(5);

 

 

 

public class Employee implements Comparable {

 

         private int id;

 

         private String name;

 

 

 

         public Employee(int id, String name) {

 

             this.id = id;

 

             this.name = name;

 

         }

 

 

 

         public String getName() {

 

             return name;

 

         }

 

 

 

         public int getId() {

 

             return id;

 

         }

 

 

 

         public int compareTo(Object emp) {

 

             return getName().compareTo(((Employee)emp).getName());

 

         }

 

 

 

         public String toString() {

 

             return getName()+","+getId();

 

         }

 

     }

 
 
 
You should override 'equals()' to match 'compareTo()' so the model will w=

ork right.

 
 
 
kedwa...@gmail.com wrote:
 

CORRECTION, both examples have the same problem. I thought the first ex=

ample was working, but in each case AFTER I call setSelectedIndex, the GUI =
DOES quickly go to the item in the combobox , but then the whole gui hangs =
for about a minute ???? Why? If I replace the combobox with a jtextfield, i=
t works without delay...

 
 
 
How long does 'input.readLine()' take, and why are you doing it on the ED=

T?

 
 
 
I/O is much slower than CPU activity. You are causing the GUI to wait for=

 5000 lines of read. Bad.

 
 
 
Don't do it on the EDT.
 
 
 
--
 
Lew

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