javax.swing
Class ProgressMonitorInputStream

java.lang.Object
  java.io.InputStream
      java.io.FilterInputStream
          javax.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.

Author:

James Gosling

See Also:

ProgressMonitor, JOptionPane

Field Summary

private ProgressMonitor	monitor
private int	nread
private int	size

Fields inherited from class java.io.FilterInputStream

in

Fields inherited from class java.io.InputStream

Constructor Summary

ProgressMonitorInputStream(Component parentComponent, Object message, InputStream in)
Constructs an object to monitor the progress of an input stream.

Method Summary

void	close() Overrides FilterInputStream.close to close the progress monitor as well as the stream.
ProgressMonitor	getProgressMonitor() Get the ProgressMonitor object being used by this stream.
int	read() Overrides FilterInputStream.read to update the progress monitor after the read.
int	read(byte[] b) Overrides FilterInputStream.read to update the progress monitor after the read.
int	read(byte[] b, int off, int len) Overrides FilterInputStream.read to update the progress monitor after the read.
void	reset() Overrides FilterInputStream.reset to reset the progress monitor as well as the stream.
long	skip(long n) Overrides FilterInputStream.skip to update the progress monitor after the skip.

Methods inherited from class java.io.FilterInputStream

available, mark, markSupported

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

monitor

private ProgressMonitor monitor

nread

private int nread

size

private int size

Constructor Detail

ProgressMonitorInputStream

public ProgressMonitorInputStream(Component parentComponent,
                                  Object message,
                                  InputStream in)

Constructs an object to monitor the progress of an input stream.

Parameters:

message - Descriptive text to be placed in the dialog box if one is popped up.

parentComponent - The component triggering the operation being monitored.

in - The input stream to be monitored.

Method Detail

getProgressMonitor

public ProgressMonitor getProgressMonitor()

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.

Returns:

the ProgressMonitor object used by this object

read

public int read()
         throws IOException

Overrides FilterInputStream.read to update the progress monitor after the read.

Overrides:

read in class FilterInputStream

Returns:

the next byte of data, or -1 if the end of the stream is reached.

Throws:

IOException - if an I/O error occurs.

See Also:

FilterInputStream.in

read

public int read(byte[] b)
         throws IOException

Overrides FilterInputStream.read to update the progress monitor after the read.

Overrides:

read in class FilterInputStream

Parameters:

b - the buffer into which the data is read.

Returns:

the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

Throws:

IOException - if an I/O error occurs.

See Also:

FilterInputStream.read(byte[], int, int)

read

public int read(byte[] b,
                int off,
                int len)
         throws IOException

Overrides FilterInputStream.read to update the progress monitor after the read.

Overrides:

read in class FilterInputStream

Parameters:

b - the buffer into which the data is read.

off - the start offset of the data.

len - the maximum number of bytes read.

Returns:

the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

Throws:

IOException - if an I/O error occurs.

See Also:

FilterInputStream.in

skip

public long skip(long n)
          throws IOException

Overrides FilterInputStream.skip to update the progress monitor after the skip.

Overrides:

skip in class FilterInputStream

Parameters:

n - the number of bytes to be skipped.

Returns:

the actual number of bytes skipped.

Throws:

IOException - if an I/O error occurs.

close

public void close()
           throws IOException

Overrides FilterInputStream.close to close the progress monitor as well as the stream.

Overrides:

close in class FilterInputStream

Throws:

IOException - if an I/O error occurs.

See Also:

FilterInputStream.in

reset

public void reset()
           throws IOException

Overrides FilterInputStream.reset to reset the progress monitor as well as the stream.

Overrides:

reset in class FilterInputStream

Throws:

IOException - if the stream has not been marked or if the mark has been invalidated.

See Also:

FilterInputStream.in, FilterInputStream.mark(int)