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Thread: adding get mothods to a class extending thread

  1. #1
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    Default adding get mothods to a class extending thread

    here is what i am trying to do...

    i have a class to run system commands which extending the Thread class.
    inside this class, a method called getOutput() that should return a string with the result.

    the commands run successfully with no problems. all i want to do is to get the output stream in a string...


    Thread t1 = new Command();
    t1.getOutput(); // --> Not working of course because it is not a method of the thread class

    Q: is that possible to do in another way... giving that the class extends Thread

    Thanks


  2. #2
    Super Moderator Json's Avatar
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    Default Re: adding get mothods to a class extending thread

    Hello,

    How are you executing these system commands?

    How are you actually feeding your results into the output variable?

    // Json

  3. #3
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    Default Re: adding get mothods to a class extending thread

    Hello Json, sorry i was away for the last couple of days...

    anyways, i have the following class, used to get the ls (unix command) of a file

    public class TestGetDate {
    String result;
    String file;
    Process p;
    BufferedReader stdInput;
    String s;
    String awk;
    String[] command;
    public TestGetDate(String file) throws IOException{
    super();
    this.file = file;

    p = Runtime.getRuntime().exec("ls -l " + file);
    stdInput = new BufferedReader(new InputStreamReader(p.getInputStream()));
    result = "";
    while (!procDone(p)) {
    while((s=stdInput.readLine()) !=null){


    result = result+s;
    }
    setOutput(result);

    }
    System.out.println(result);
    stdInput.close();

    }

    private boolean procDone(Process p) {
    try {
    int v = p.exitValue();
    return true;
    }
    catch(IllegalThreadStateException e) {
    return false;
    }
    }
    public void setOutput(String result){
    this.result = result;
    }
    public String getOutput(){
    return result;
    }

    }

    i want this class to run as a thread but when i do, i cannot run the getOutput() method.

    any ideas?

    Thanks anyway

  4. #4
    Super Moderator helloworld922's Avatar
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    Default Re: adding get mothods to a class extending thread

    I think it's because of how Java handles multi-threading... They have a very strict lock mechanism that prevents almost any chance of dual access, deadlocking, or an such other strange things associate with multi-threading. You can read Sun Java's Tutorial on Concurrency, but it's fairly hard to follow unless you have a fairly good knowledge of computer science and/or java.

  5. #5
    Senile Half-Wit Freaky Chris's Avatar
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    Default Re: adding get mothods to a class extending thread

    Make you class extend Thread. then instead of calling it using Thread t1 = new Command();

    You would do something like this, if command is the class you want to run as a thread, such as your TestGetDate class.

    Command c1 = new Command();
    c1.start();

    If I understood your problem correctly, then you can call c1.getOutput();

    Regards,
    Chri
    chris[at]javaprogrammingforums[dot]com

    Prifysgol Bangor University, North Wales

  6. The Following User Says Thank You to Freaky Chris For This Useful Post:

    aliaa2a (August 3rd, 2009)

  7. #6
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    Default Re: adding get mothods to a class extending thread

    Thanks Freaky Chris, it works like a charm.


  8. #7
    Senile Half-Wit Freaky Chris's Avatar
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    Default Re: adding get mothods to a class extending thread

    Excellent Glad I could help

    Chris
    Last edited by Freaky Chris; August 3rd, 2009 at 09:10 AM.
    chris[at]javaprogrammingforums[dot]com

    Prifysgol Bangor University, North Wales

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