Class ProgressMonitorInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

javax.swing.ProgressMonitorInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

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.

Since:

1.2

See Also:

• ProgressMonitor
• JOptionPane

Field Summary

Fields declared in class FilterInputStream

in

Modifier and Type	Field	Description
protected InputStream	in	The input stream to be filtered.

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
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 declared in class FilterInputStream

available, mark, markSupported

Modifier and Type	Method	Description
int	available()	Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream.
void	mark(int readlimit)	Marks the current position in this input stream.
boolean	markSupported()	Tests if this input stream supports the mark and reset methods.

Methods declared in class InputStream

nullInputStream, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo

Modifier and Type	Method	Description
static InputStream	nullInputStream()	Returns a new InputStream that reads no bytes.
byte[]	readAllBytes()	Reads all remaining bytes from the input stream.
int	readNBytes(byte[] b, int off, int len)	Reads the requested number of bytes from the input stream into the given byte array.
byte[]	readNBytes(int len)	Reads up to a specified number of bytes from the input stream.
void	skipNBytes(long n)	Skips over and discards exactly n bytes of data from this input stream.
long	transferTo(OutputStream out)	Reads all bytes from this input stream and writes the bytes to the given output stream in the order that they are read.

Methods declared in class Object

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

Modifier and Type	Method	Description
protected Object	clone()	Creates and returns a copy of this object.
boolean	equals(Object obj)	Indicates whether some other object is "equal to" this one.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. Finalization is deprecated and subject to removal in a future release.
final Class<?>	getClass()	Returns the runtime class of this Object.
int	hashCode()	Returns a hash code value for this object.
final void	notify()	Wakes up a single thread that is waiting on this object's monitor.
final void	notifyAll()	Wakes up all threads that are waiting on this object's monitor.
String	toString()	Returns a string representation of the object.
final void	wait()	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
final void	wait(long timeoutMillis)	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
final void	wait(long timeoutMillis, int nanos)	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Constructor Details

ProgressMonitorInputStream

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

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

Parameters:

parentComponent - The component triggering the operation being monitored.

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

in - The input stream to be monitored.

Method Details

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 in array b at which the data is written.

len - the maximum number of bytes to 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 in.skip(n) throws an IOException.

See Also:

• InputStream.skipNBytes(long)

close

public void close()
           throws IOException

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

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

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 this stream has not been marked or if the mark has been invalidated.

See Also:

• FilterInputStream.in
• FilterInputStream.mark(int)