Question

The application I am working on has a terribly slow loading web page. If I run the following code it works fine but only because of the call to sleep. If I don’t sleep then the InputStream is just a bunch of spaces, probably due to the application it is calling from. Is there any non-hack way around this?

public class PublishTool extends Thread {

  private URL publishUrl;

  private String filerLocation;

  public PublishTool() {
  }

  public PublishTool(String publishUrl, String filerLocation) throws NibException {

    try {
      this.publishUrl = new URL(publishUrl);
    } catch (MalformedURLException e) {
      throw new NibException("Publish Url :" + publishUrl + " is not valid. ");
    }

    this.filerLocation = filerLocation;

  }

  public void run() {

    File filerFile = new File(filerLocation);
    BufferedWriter writer = null;


    try {
      URLConnection conn = publishUrl.openConnection();
      BufferedReader reader = new BufferedReader(new InputStreamReader(new BufferedInputStream(conn.getInputStream())));

      writer = new BufferedWriter(new FileWriter(filerLocation));

      Thread.sleep(1000l);

      while (reader.ready()) {
        writer.write(reader.readLine() + "\n");
      }

    } catch (MalformedURLException e) {
      throw new IllegalStateException("Malformed URL for : " + publishUrl + " " + filerLocation, e);
    } catch (IOException e) {
      throw new IllegalStateException("IO Exception for  : " + publishUrl + " " + filerLocation, e);
    } catch (InterruptedException e) {
      throw new IllegalStateException("Thread was interrupted early... publishing might have failed.");
    } catch (NibException e) {
      throw new IllegalStateException("Publishing File Copy failed : " + filerLocation + ".bak" + " to " + filerLocation);
    } finally {
      try {
        writer.flush();
        writer.close();
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
  }

Answer 1

Don’t use reader.ready(). Just call readLine() and let readLine() block until the data’s ready. The end of the data will generally be signalled with a null line.

In case its helpful, a couple of code examples on my web site: reading from a URL.