javax.swing
Class ProgressMonitorInputStream

java.lang.Object
  extended byjava.io.InputStream
      extended byjava.io.FilterInputStream
          extended byjavax.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)