org.apache.commons.io.output
Class ProxyOutputStream

java.lang.Object
  extended by java.io.OutputStream
      extended by java.io.FilterOutputStream
          extended by 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


Copyright © 2002-2012 The Apache Software Foundation. All Rights Reserved.