How can I output realtime system resources to a label or textarea? JAVA

randomx · 07-14-2004, 05:37 PM

How can I output realtime system resources into a label or textarea using JAVA?

by system resources I mean memory, swapping, cpu utilitization. You know, stuff that changes constantly by the second.

I would like to mirror exactly what's going on in realtime to a label or textarea.

any piece of code or idea is welcome.

thanks in advance.
randomx

pseudocode here

Code:

try {
        Runtime.getRuntime ().exec ( "/usr/bin/top" ) ;
      }
      catch ( IOException ex ) {
      }

  //realtime output to a string or file

 jLabel1.setText(getting all realtime inputs from top command);

csfalcon · 07-14-2004, 06:01 PM

You want to implement some type of "polling", for example every 5 sec you check the value of the system resource and then update the GUI.

In java, there is a Timer class that you can set the timer and the action to take when the Timer goes off.

Code:

		// ActionListener is an interfact, so create a class that implements this interface here
		ActionListener recPoller = new ActionListener(); 
		Timer poller = new Timer(5000, recPoller);
		poller.start();

Code:

YourResourcePoller implements ActionListener
	{
		public void actionPerformed(ActionEvent event)
		{
			//check for resource values

			//update your GUI
			textBox.setText(resource info);
		}
	}

randomx · 07-15-2004, 02:59 PM

Thanks csfalcon. I implemented your idea of using a timer.

However, the new issue is related to multiline labels with the exact output of the command as you see it in console.

Background info: I'm triggering a system command to display memory utilization. Anyway, as you know, the "free" command displays many lines of text one after the other.

I want to have a label displaying the command output as it is: multiple lines. Just like you see it in the console. I want to mirror whatever comes up on console after executing free from java.

Using html tags won't work out for me in this particular situation. It just doesn't do the trick. Still displays the LAST line of command output *with or without* html tags.

any ideas? it doesn't have to be a label. It can be anything as long as it works.

Code:

  

//events will trigger every second

Timer t = new Timer(1000, new ActionListener(){
      public void actionPerformed(ActionEvent event)
      {

//determine memory utilization. 

        String cmd = "free -m";
    try {
     String line;
     Process p = Runtime.getRuntime().exec(cmd);
     BufferedReader input =
       new BufferedReader
         (new InputStreamReader(p.getInputStream()));
     while ((line = input.readLine()) != null) {
       label.setText(line);
       }
     input.close();
     }
    catch (Exception err) {
     err.printStackTrace();
     }
      }
    });
    t.start();

Komakino · 07-15-2004, 03:18 PM

Use a bufferedReader to read line by line from the /proc/meminfo pseudofile, parsing out the info you don't want.

The convenience of linux: everything is a file

csfalcon · 07-15-2004, 03:41 PM

Code:

while ((line = input.readLine()) != null) {
       label.setText(line);
       }

This part of your code will just keep updating the label with the new line of text and replace the previous line. You are want create a multiline string and then set the label.

Code:

String str = "";
       while ((line = input.readLine()) != null) {
       str += (line + "\n");
       }
       label.setText(str);

I am not sure if this is what you were asking about, hope it helps.

Komakino · 07-15-2004, 04:01 PM

Quote:

Originally posted by csfalcon

Code:

while ((line = input.readLine()) != null) { label.setText(line); }

This part of your code will just keep updating the label with the new line of text and replace the previous line. You are want create a multiline string and then set the label.

Code:

String str = ""; while ((line = input.readLine()) != null) { str += (line + "\n"); } label.setText(str);

I am not sure if this is what you were asking about, hope it helps.

If he replaces the label with a JTextArea he can just use the append(String str) method to make it multiline output.

randomx · 07-15-2004, 06:41 PM

Hi everybody...thanks for all your inputs...

I mixed a little bit of everything and this is the final WORKING code.

I'm posting it here. Maybe somebody might needed in the future. It's all about helping each other right?.

Code:

String cmdMem = "free -m -t -o" ;
      try {
        String lineMem ;
        String outputMem = "" ;
        Process procMem = Runtime.getRuntime ().exec ( cmdMem ) ;
        BufferedReader input =
            new BufferedReader
            ( new InputStreamReader ( procMem.getInputStream () ) ) ;
        while ( ( lineMem = input.readLine () ) != null ) {
          outputMem = ( lineMem + "\n" ) ;
          jTextAreaSystemResourcesOutput.append ( outputMem ) ;

        }

        input.close () ;
      }
      catch ( Exception err ) {
        err.printStackTrace () ;
      }