ThresholdingOutputStream (Apache Commons IO 2.5 API)

java.lang.Object
- java.io.OutputStream
- - org.apache.commons.io.output.ThresholdingOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

Direct Known Subclasses:

DeferredFileOutputStream
```
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.

Version:

$Id: ThresholdingOutputStream.java 1687815 2015-06-26 17:18:56Z krosenvold $

Constructor Summary

Constructors
Constructor and Description

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

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

Method Summary

Methods
Modifier and Type	Method and Description
`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 void`	`resetByteCount()` Resets the byteCount to zero.
`protected void`	`setByteCount(long count)` Sets the byteCount to count.
`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(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
clone, equals, finalize, 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 IOException
```
    Writes the specified byte to this output stream.
    
    Specified by:
    
    write in class OutputStream
    
    Parameters:
    b - The byte to be written.
    
    Throws:
    
    IOException - if an error occurs.
  - write
```
public void write(byte[] b)
           throws IOException
```
    Writes b.length bytes from the specified byte array to this output stream.
    
    Overrides:
    
    write in class OutputStream
    
    Parameters:
    b - The array of bytes to be written.
    
    Throws:
    
    IOException - if an error occurs.
  - write
```
public void write(byte[] b,
         int off,
         int len)
           throws IOException
```
    Writes len bytes from the specified byte array starting at offset off to this output stream.
    
    Overrides:
    
    write in class 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:
    
    IOException - if an error occurs.
  - flush
```
public void flush()
           throws IOException
```
    Flushes this output stream and forces any buffered output bytes to be written out.
    
    Specified by:
    
    flush in interface Flushable
    
    Overrides:
    
    flush in class OutputStream
    
    Throws:
    
    IOException - if an error occurs.
  - close
```
public void close()
           throws IOException
```
    Closes this output stream and releases any system resources associated with this stream.
    
    Specified by:
    
    close in interface Closeable
    
    Specified by:
    
    close in interface AutoCloseable
    
    Overrides:
    
    close in class OutputStream
    
    Throws:
    
    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.
  - 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.
    
    Parameters:
    count - The number of bytes about to be written to the underlying output stream.
    
    Throws:
    
    IOException - if an error occurs.
  - resetByteCount
```
protected void resetByteCount()
```
    Resets the byteCount to zero. You can call this from thresholdReached() if you want the event to be triggered again.
  - setByteCount
```
protected void setByteCount(long count)
```
    Sets the byteCount to count. Usefull for re-opening an output stream that been previously written to.
    
    Parameters:
    count - The number of bytes that have already been written to the output stream
    Since:
    
    2.5
  - getStream
```
protected abstract OutputStream getStream()
                                   throws IOException
```
    Returns the underlying output stream, to which the corresponding OutputStream methods in this class will ultimately delegate.
    
    Returns:
    The underlying output stream.
    
    Throws:
    
    IOException - if an error occurs.
  - 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.
    
    Throws:
    
    IOException - if an error occurs.

Class ThresholdingOutputStream

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

ThresholdingOutputStream

Method Detail

write

write

write

flush

close

getThreshold

getByteCount

isThresholdExceeded

checkThreshold

resetByteCount

setByteCount

getStream

thresholdReached