Monitoring file changes

Question

I'm trying to monitor the file content and adding any new line to JTextArea. I created thread, which monitor the file, but when the Scanner object reachs the end of file it stop working. I tried very simple method, which create new Scanner object and read the file from the begin, but it isn't good solution. It's the version which stop and do nothing :

public class TextAreaThread implements Runnable {

JTextArea text = null;
File file = null;
Scanner read = null;

public TextAreaThread(JTextArea text, File file) {
    this.text = text;
    this.file = file;
    try{
        read = new Scanner(file);
    }catch(FileNotFoundException e){
        JOptionPane.showMessageDialog(null,"Wrong file or file doesn't exist","Error",JOptionPane.ERROR_MESSAGE);
    }

}

public void run() { 

    while(true){
        while(read.hasNext())
                text.append(read.nextLine()+"\n");
        try {
            wait(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

    }

}


}

possible duplicate of [Java IO implementation of unix/linux "tail -f"](http://stackoverflow.com/questions/557844/java-io-implementation-of-unix-linux-tail-f) — NPE, Aug 01 '11 at 12:44

score 1 · Accepted Answer · answered Aug 01 '11 at 12:57

1

The wait method is not what you want here. Try Thread.sleep instead.

answered Aug 01 '11 at 12:57

Roland Illig

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Monitoring file changes

1 Answers1