FileDocCategorySizeDatePackage
ProgressMonitorInputStream.javaAPI DocJava SE 5 API5088Fri Aug 26 14:57:58 BST 2005javax.swing

ProgressMonitorInputStream

public class ProgressMonitorInputStream extends FilterInputStream
Monitors the progress of reading from some InputStream. This ProgressMonitor is normally invoked in roughly this form: 
InputStream in = new BufferedInputStream(
new ProgressMonitorInputStream(
parentComponent,
"Reading " + fileName,
new FileInputStream(fileName)));

This creates a progress monitor to monitor the progress of reading the input stream. If it's taking a while, a ProgressDialog will be popped up to inform the user. If the user hits the Cancel button an InterruptedIOException will be thrown on the next read. All the right cleanup is done when the stream is closed.

For further documentation and examples see How to Monitor Progress, a section in The Java Tutorial.

see
ProgressMonitor
see
JOptionPane
author
James Gosling
version
1.19 12/19/03

Fields Summary
private ProgressMonitor
monitor
private int
nread
private int
size
Constructors Summary
public ProgressMonitorInputStream(Component parentComponent, Object message, InputStream in)
Constructs an object to monitor the progress of an input stream.

param
message Descriptive text to be placed in the dialog box if one is popped up.
param
parentComponent The component triggering the operation being monitored.
param
in The input stream to be monitored.



                                                                                           
      
                                       
                                        
        super(in);
        try {
            size = in.available();
        }
        catch(IOException ioe) {
            size = 0;
        }
        monitor = new ProgressMonitor(parentComponent, message, null, 0, size);
Methods Summary
public voidclose()
Overrides FilterInputStream.close to close the progress monitor as well as the stream.

        in.close();
        monitor.close();
public javax.swing.ProgressMonitorgetProgressMonitor()
Get the ProgressMonitor object being used by this stream. Normally this isn't needed unless you want to do something like change the descriptive text partway through reading the file.

return
the ProgressMonitor object used by this object

        return monitor;
public intread()
Overrides FilterInputStream.read to update the progress monitor after the read.

        int c = in.read();
        if (c >= 0) monitor.setProgress(++nread);
        if (monitor.isCanceled()) {
            InterruptedIOException exc =
                                    new InterruptedIOException("progress");
            exc.bytesTransferred = nread;
            throw exc;
        }
        return c;
public intread(byte[] b)
Overrides FilterInputStream.read to update the progress monitor after the read.

        int nr = in.read(b);
        if (nr > 0) monitor.setProgress(nread += nr);
        if (monitor.isCanceled()) {
            InterruptedIOException exc =
                                    new InterruptedIOException("progress");
            exc.bytesTransferred = nread;
            throw exc;
        }
        return nr;
public intread(byte[] b, int off, int len)
Overrides FilterInputStream.read to update the progress monitor after the read.

        int nr = in.read(b, off, len);
        if (nr > 0) monitor.setProgress(nread += nr);
        if (monitor.isCanceled()) {
            InterruptedIOException exc =
                                    new InterruptedIOException("progress");
            exc.bytesTransferred = nread;
            throw exc;
        }
        return nr;
public synchronized voidreset()
Overrides FilterInputStream.reset to reset the progress monitor as well as the stream.

        in.reset();
        nread = size - in.available();
        monitor.setProgress(nread);
public longskip(long n)
Overrides FilterInputStream.skip to update the progress monitor after the skip.

        long nr = in.skip(n);
        if (nr > 0) monitor.setProgress(nread += nr);
        return nr;