How can I pass arguments into SwingWorker?

Question

I'm trying to implement Swing worker in my GUI. At the moment I have a JFrame containing a button. When this is pressed it should update a tab displayed and then run a program in the background thread. Here is what I have so far.

class ClassA
{
    private static void addRunButton() 
    {
        JButton runButton = new JButton("Run");
        runButton.setEnabled(false);
        runButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) 
            {
                new ClassB().execute();
            }
    });

    mainWindow.add(runButton);
    }
}

class ClassB extends SwingWorker<Void, Integer>
{
    protected Void doInBackground()
    {
        ClassC.runProgram(cfgFile);
    }

    protected void done()
    {
        try 
        { 
        tabs.setSelectedIndex(1);
        } 
        catch (Exception ignore) 
        {
        }
    }
}

I don't understand how I can pass in my cfgFile object though. Please can someone advise on this?

Hovercraft Full Of Eels · Accepted Answer · 2012-07-10T16:04:53.523

23

Why not give it a File field and fill that field via a constructor that takes a File parameter?

class ClassB extends SwingWorker<Void, Integer>
{
    private File cfgFile;

    public ClassB(File cfgFile) {
       this.cfgFile = cfgFile;
    }

    protected Void doInBackground()
    {
        ClassC.runProgram(cfgFile);
    }

    protected void done()
    {
        try 
        { 
        tabs.setSelectedIndex(1);
        } 
        catch (Exception ignore) 
        {
           // *** ignoring exceptions is usually not a good idea. ***
        }
    }
}

And then run it like so:

public void actionPerformed(ActionEvent e) 
{
    new ClassB(cfgFile).execute();
}

edited Jul 10 '12 at 16:04

answered Oct 25 '11 at 20:28

Hovercraft Full Of Eels

283,665
25
256
373

+1 and exception here http://stackoverflow.com/questions/7053865/cant-get-arrayindexoutofboundsexception-from-future-and-swingworker-if-threa/7054627#7054627, – mKorbel Oct 25 '11 at 20:56
2

Since File is an input to the constructor (not the execute method), shouldn't you run it like this? new ClassB(cfgFile).execute(); – james.garriss Jul 10 '12 at 15:43
@james.garriss: indeed you should. Error corrected, and thanks! – Hovercraft Full Of Eels Jul 10 '12 at 16:05
I may need a generci SwingWorker class! – Houssam Badri Apr 22 '14 at 06:31

score 1 · Answer 2 · answered Oct 25 '11 at 20:31

1

Use constructor to pass the parameter. For example, like this:

class ClassB extends SwingWorker<Void, Integer> 
{

private File cfgFile; 

public ClassB(File cfgFile){
this.cfgFile=cfgFile;
}

protected Void doInBackground() 
{ 
    ClassC.runProgram(cfgFile); 
} 

protected void done() 
{ 
    try  
    {  
    tabs.setSelectedIndex(1); 
    }  
    catch (Exception ignore)  
    { 
    } 
}

}

answered Oct 25 '11 at 20:31

carawan

508
3
10

I'm not user this variation adds anything to @Hovercraft's earlier [answer](http://stackoverflow.com/questions/7895428/how-can-i-pass-arguments-into-swingworker/7895454#7895454). – trashgod Oct 25 '11 at 20:52
1

Sorry. Time time gap between these two answers was very short. First answer was submitted when I am preparing my answer without being aware of it. – carawan Oct 29 '11 at 04:49

How can I pass arguments into SwingWorker?

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