org.apache.commons.io.output
Class ProxyOutputStream

java.lang.Object
  java.io.OutputStream
      java.io.FilterOutputStream
          org.apache.commons.io.output.ProxyOutputStream

All Implemented Interfaces:

Closeable, Flushable

Direct Known Subclasses:

CloseShieldOutputStream, CountingOutputStream, TaggedOutputStream, TeeOutputStream

public class ProxyOutputStream
extends FilterOutputStream

A Proxy stream which acts as expected, that is it passes the method calls on to the proxied stream and doesn't change which methods are being called. It is an alternative base class to FilterOutputStream to increase reusability.

See the protected methods for ways in which a subclass can easily decorate a stream with custom pre-, post- or error processing functionality.

Version:

$Id: ProxyOutputStream.java 1304052 2012-03-22 20:55:29Z ggregory $

Field Summary

Fields inherited from class java.io.FilterOutputStream

out

Constructor Summary

ProxyOutputStream(OutputStream proxy)
Constructs a new ProxyOutputStream.

Method Summary

protected void	afterWrite(int n) Invoked by the write methods after the proxied call has returned successfully.
protected void	beforeWrite(int n) Invoked by the write methods before the call is proxied.
void	close() Invokes the delegate's close() method.
void	flush() Invokes the delegate's flush() method.
protected void	handleIOException(IOException e) Handle any IOExceptions thrown.
void	write(byte[] bts) Invokes the delegate's write(byte[]) method.
void	write(byte[] bts, int st, int end) Invokes the delegate's write(byte[]) method.
void	write(int idx) Invokes the delegate's write(int) method.

Methods inherited from class java.lang.Object

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

Constructor Detail

ProxyOutputStream

public ProxyOutputStream(OutputStream proxy)

Constructs a new ProxyOutputStream.

Parameters:

proxy - the OutputStream to delegate to

Method Detail

write

public void write(int idx)
           throws IOException

Invokes the delegate's write(int) method.

Overrides:

write in class FilterOutputStream

Parameters:

idx - the byte to write

Throws:

IOException - if an I/O error occurs

write

public void write(byte[] bts)
           throws IOException

Invokes the delegate's write(byte[]) method.

Overrides:

write in class FilterOutputStream

Parameters:

bts - the bytes to write

Throws:

IOException - if an I/O error occurs

write

public void write(byte[] bts,
                  int st,
                  int end)
           throws IOException

Invokes the delegate's write(byte[]) method.

Overrides:

write in class FilterOutputStream

Parameters:

bts - the bytes to write

st - The start offset

end - The number of bytes to write

Throws:

IOException - if an I/O error occurs

flush

public void flush()
           throws IOException

Invokes the delegate's flush() method.

Specified by:

flush in interface Flushable

Overrides:

flush in class FilterOutputStream

Throws:

IOException - if an I/O error occurs

close

public void close()
           throws IOException

Invokes the delegate's close() method.

Specified by:

close in interface Closeable

Overrides:

close in class FilterOutputStream

Throws:

IOException - if an I/O error occurs

beforeWrite

protected void beforeWrite(int n)
                    throws IOException

Invoked by the write methods before the call is proxied. The number of bytes to be written (1 for the write(int) method, buffer length for write(byte[]), etc.) is given as an argument.

Subclasses can override this method to add common pre-processing functionality without having to override all the write methods. The default implementation does nothing.

Parameters:

n - number of bytes to be written

Throws:

IOException - if the pre-processing fails

Since:

2.0

afterWrite

protected void afterWrite(int n)
                   throws IOException

Invoked by the write methods after the proxied call has returned successfully. The number of bytes written (1 for the write(int) method, buffer length for write(byte[]), etc.) is given as an argument.

Subclasses can override this method to add common post-processing functionality without having to override all the write methods. The default implementation does nothing.

Parameters:

n - number of bytes written

Throws:

IOException - if the post-processing fails

Since:

2.0

handleIOException

protected void handleIOException(IOException e)
                          throws IOException

Handle any IOExceptions thrown.

This method provides a point to implement custom exception handling. The default behaviour is to re-throw the exception.

Parameters:

e - The IOException thrown

Throws:

IOException - if an I/O error occurs

Since:

2.0