org.apache.commons.io.output

Class ThresholdingOutputStream

java.lang.Object

java.io.OutputStream

org.apache.commons.io.output.ThresholdingOutputStream

All Implemented Interfaces:

java.io.Closeable, java.io.Flushable, java.lang.AutoCloseable

Direct Known Subclasses:

DeferredFileOutputStream

public abstract class ThresholdingOutputStream
extends java.io.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.

Constructor Summary

Constructors

Constructor and Description
ThresholdingOutputStream(int threshold) Constructs an instance of this class which will trigger an event at the specified threshold.

Method Summary

Modifier and Type	Method and Description
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.
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.
void	write(byte[] b) Writes b.length bytes from the specified byte array to this output stream.
void	write(byte[] 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.

Methods inherited from class java.lang.Object

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

Constructor Detail

ThresholdingOutputStream

public ThresholdingOutputStream(int threshold)

Constructs an instance of this class which will trigger an event at the specified threshold.

Parameters:

threshold - The number of bytes at which to trigger an event.

Method Detail

write

public void write(int b)
           throws java.io.IOException

Writes the specified byte to this output stream.

Specified by:

write in class java.io.OutputStream

Parameters:

b - The byte to be written.

Throws:

java.io.IOException - if an error occurs.

write

public void write(byte[] b)
           throws java.io.IOException

Writes b.length bytes from the specified byte array to this output stream.

Overrides:

write in class java.io.OutputStream

Parameters:

b - The array of bytes to be written.

Throws:

java.io.IOException - if an error occurs.

write

public void write(byte[] b,
                  int off,
                  int len)
           throws java.io.IOException

Writes len bytes from the specified byte array starting at offset off to this output stream.

Overrides:

write in class java.io.OutputStream

Parameters:

b - The byte array from which the data will be written.

off - The start offset in the byte array.

len - The number of bytes to write.

Throws:

java.io.IOException - if an error occurs.

flush

public void flush()
           throws java.io.IOException

Flushes this output stream and forces any buffered output bytes to be written out.

Specified by:

flush in interface java.io.Flushable

Overrides:

flush in class java.io.OutputStream

Throws:

java.io.IOException - if an error occurs.

close

public void close()
           throws java.io.IOException

Closes this output stream and releases any system resources associated with this stream.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Overrides:

close in class java.io.OutputStream

Throws:

java.io.IOException - if an error occurs.

getThreshold

public int getThreshold()

Returns the threshold, in bytes, at which an event will be triggered.

Returns:

The threshold point, in bytes.

getByteCount

public long getByteCount()

Returns the number of bytes that have been written to this output stream.

Returns:

The number of bytes written.

isThresholdExceeded

public boolean isThresholdExceeded()

Determines whether or not the configured threshold has been exceeded for this output stream.

Returns:

true if the threshold has been reached; false otherwise.