org.apache.commons.io.output
Class ThresholdingOutputStream
OutputStream
org.apache.commons.io.output.ThresholdingOutputStream
public abstract class ThresholdingOutputStream
extends OutputStream
An output stream which triggers an event when a specified number of bytes of
data have been written to it. The event can be used, for example, to throw
an exception if a maximum has been reached, or to switch the underlying
stream type when the threshold is exceeded.
This class overrides all
OutputStream
methods. However, these
overrides ultimately call the corresponding methods in the underlying output
stream implementation.
NOTE: This implementation may trigger the event
before the threshold
is actually reached, since it triggers when a pending write operation would
cause the threshold to be exceeded.
$Id: ThresholdingOutputStream.java 155419 2005-02-26 13:02:41Z dirkv $private int | threshold - The threshold at which the event will be triggered.
|
private boolean | thresholdExceeded - Whether or not the configured threshold has been exceeded.
|
private long | written - The number of bytes written to the output stream.
|
ThresholdingOutputStream(int threshold) - Constructs an instance of this class which will trigger an event at the
specified threshold.
|
protected void | checkThreshold(int count) - Checks to see if writing the specified number of bytes would cause the
configured threshold to be exceeded.
|
void | close() - Closes this output stream and releases any system resources associated
with this stream.
|
void | flush() - Flushes this output stream and forces any buffered output bytes to be
written out.
|
long | getByteCount() - Returns the number of bytes that have been written to this output stream.
|
protected abstract OutputStream | getStream() - Returns the underlying output stream, to which the corresponding
OutputStream methods in this class will ultimately delegate.
|
int | getThreshold() - Returns the threshold, in bytes, at which an event will be triggered.
|
boolean | isThresholdExceeded() - Determines whether or not the configured threshold has been exceeded for
this output stream.
|
protected abstract void | thresholdReached() - Indicates that the configured threshold has been reached, and that a
subclass should take whatever action necessary on this event.
|
void | write(b[] ) - Writes
b.length bytes from the specified byte array to this
output stream.
|
void | write(b[] , int off, int len) - Writes
len bytes from the specified byte array starting at
offset off to this output stream.
|
void | write(int b) - Writes the specified byte to this output stream.
|
threshold
private int threshold
The threshold at which the event will be triggered.
thresholdExceeded
private boolean thresholdExceeded
Whether or not the configured threshold has been exceeded.
written
private long written
The number of bytes written to the output stream.
ThresholdingOutputStream
public ThresholdingOutputStream(int threshold)
Constructs an instance of this class which will trigger an event at the
specified threshold.
threshold
- The number of bytes at which to trigger an event.
checkThreshold
protected void checkThreshold(int count)
throws IOException
Checks to see if writing the specified number of bytes would cause the
configured threshold to be exceeded. If so, triggers an event to allow
a concrete implementation to take action on this.
count
- The number of bytes about to be written to the underlying
output stream.
close
public void close()
throws IOException
Closes this output stream and releases any system resources associated
with this stream.
flush
public void flush()
throws IOException
Flushes this output stream and forces any buffered output bytes to be
written out.
getByteCount
public long getByteCount()
Returns the number of bytes that have been written to this output stream.
- The number of bytes written.
getStream
protected abstract OutputStream getStream()
throws IOException
Returns the underlying output stream, to which the corresponding
OutputStream
methods in this class will ultimately delegate.
- The underlying output stream.
getThreshold
public int getThreshold()
Returns the threshold, in bytes, at which an event will be triggered.
- The threshold point, in bytes.
isThresholdExceeded
public boolean isThresholdExceeded()
Determines whether or not the configured threshold has been exceeded for
this output stream.
true
if the threshold has been reached;
false
otherwise.
thresholdReached
protected abstract void thresholdReached()
throws IOException
Indicates that the configured threshold has been reached, and that a
subclass should take whatever action necessary on this event. This may
include changing the underlying output stream.
write
public void write(b[] )
throws IOException
Writes b.length
bytes from the specified byte array to this
output stream.
write
public void write(b[] ,
int off,
int len)
throws IOException
Writes len
bytes from the specified byte array starting at
offset off
to this output stream.
off
- The start offset in the byte array.len
- The number of bytes to write.
write
public void write(int b)
throws IOException
Writes the specified byte to this output stream.
b
- The byte to be written.