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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* accompanied this code).
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package javax.swing;
import java.io.*;
import java.awt.Component;
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
/**
* Monitors the progress of reading from some InputStream. This ProgressMonitor
* is normally invoked in roughly this form:
* <pre>
* InputStream in = new BufferedInputStream(
* new ProgressMonitorInputStream(
* parentComponent,
* "Reading " + fileName,
* new FileInputStream(fileName)));
* </pre><p>
* 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.
*
*
* <p>
*
* For further documentation and examples see
* <a href="https://docs.oracle.com/javase/tutorial/uiswing/components/progress.html">How to Monitor Progress</a>,
* a section in <em>The Java Tutorial.</em>
*
* @see ProgressMonitor
* @see JOptionPane
* @author James Gosling
*/
public class ProgressMonitorInputStream extends FilterInputStream
{
private ProgressMonitor monitor;
private int nread = 0;
private int size = 0;
Constructs an object to monitor the progress of an input stream.
Params: - 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.
/**
* 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.
*/
public ProgressMonitorInputStream(Component parentComponent,
Object message,
InputStream in) {
super(in);
try {
size = in.available();
}
catch(IOException ioe) {
size = 0;
}
monitor = new ProgressMonitor(parentComponent, message, null, 0, size);
}
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
/**
* 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
*/
public ProgressMonitor getProgressMonitor() {
return monitor;
}
Overrides FilterInputStream.read
to update the progress monitor after the read.
/**
* Overrides <code>FilterInputStream.read</code>
* to update the progress monitor after the read.
*/
public int read() throws IOException {
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;
}
Overrides FilterInputStream.read
to update the progress monitor after the read.
/**
* Overrides <code>FilterInputStream.read</code>
* to update the progress monitor after the read.
*/
public int read(byte b[]) throws IOException {
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;
}
Overrides FilterInputStream.read
to update the progress monitor after the read.
/**
* Overrides <code>FilterInputStream.read</code>
* to update the progress monitor after the read.
*/
public int read(byte b[],
int off,
int len) throws IOException {
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;
}
Overrides FilterInputStream.skip
to update the progress monitor after the skip.
/**
* Overrides <code>FilterInputStream.skip</code>
* to update the progress monitor after the skip.
*/
public long skip(long n) throws IOException {
long nr = in.skip(n);
if (nr > 0) monitor.setProgress(nread += nr);
return nr;
}
Overrides FilterInputStream.close
to close the progress monitor as well as the stream.
/**
* Overrides <code>FilterInputStream.close</code>
* to close the progress monitor as well as the stream.
*/
public void close() throws IOException {
in.close();
monitor.close();
}
Overrides FilterInputStream.reset
to reset the progress monitor as well as the stream.
/**
* Overrides <code>FilterInputStream.reset</code>
* to reset the progress monitor as well as the stream.
*/
public synchronized void reset() throws IOException {
in.reset();
nread = size - in.available();
monitor.setProgress(nread);
}
}