org.apache.commons.io.output
Class ProxyWriter

java.lang.Object
  extended by java.io.Writer
      extended by java.io.FilterWriter
          extended by org.apache.commons.io.output.ProxyWriter
All Implemented Interfaces:
Closeable, Flushable, Appendable

public class ProxyWriter
extends FilterWriter

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 FilterWriter to increase reusability, because FilterWriter changes the methods being called, such as write(char[]) to write(char[], int, int) and write(String) to write(String, int, int).

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

Field Summary
 
Fields inherited from class java.io.FilterWriter
out
 
Fields inherited from class java.io.Writer
lock
 
Constructor Summary
ProxyWriter(Writer proxy)
          Constructs a new ProxyWriter.
 
Method Summary
protected  void afterWrite(int n)
          Invoked by the write methods after the proxied call has returned successfully.
 Writer append(char c)
          Invokes the delegate's append(char) method.
 Writer append(CharSequence csq)
          Invokes the delegate's append(CharSequence) method.
 Writer append(CharSequence csq, int start, int end)
          Invokes the delegate's append(CharSequence, int, int) method.
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(char[] chr)
          Invokes the delegate's write(char[]) method.
 void write(char[] chr, int st, int len)
          Invokes the delegate's write(char[], int, int) method.
 void write(int idx)
          Invokes the delegate's write(int) method.
 void write(String str)
          Invokes the delegate's write(String) method.
 void write(String str, int st, int len)
          Invokes the delegate's write(String) method.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ProxyWriter

public ProxyWriter(Writer proxy)
Constructs a new ProxyWriter.

Parameters:
proxy - the Writer to delegate to
Method Detail

append

public Writer append(char c)
              throws IOException
Invokes the delegate's append(char) method.

Specified by:
append in interface Appendable
Overrides:
append in class Writer
Parameters:
c - The character to write
Returns:
this writer
Throws:
IOException - if an I/O error occurs
Since:
2.0

append

public Writer append(CharSequence csq,
                     int start,
                     int end)
              throws IOException
Invokes the delegate's append(CharSequence, int, int) method.

Specified by:
append in interface Appendable
Overrides:
append in class Writer
Parameters:
csq - The character sequence to write
start - The index of the first character to write
end - The index of the first character to write (exclusive)
Returns:
this writer
Throws:
IOException - if an I/O error occurs
Since:
2.0

append

public Writer append(CharSequence csq)
              throws IOException
Invokes the delegate's append(CharSequence) method.

Specified by:
append in interface Appendable
Overrides:
append in class Writer
Parameters:
csq - The character sequence to write
Returns:
this writer
Throws:
IOException - if an I/O error occurs
Since:
2.0

write

public void write(int idx)
           throws IOException
Invokes the delegate's write(int) method.

Overrides:
write in class FilterWriter
Parameters:
idx - the character to write
Throws:
IOException - if an I/O error occurs

write

public void write(char[] chr)
           throws IOException
Invokes the delegate's write(char[]) method.

Overrides:
write in class Writer
Parameters:
chr - the characters to write
Throws:
IOException - if an I/O error occurs

write

public void write(char[] chr,
                  int st,
                  int len)
           throws IOException
Invokes the delegate's write(char[], int, int) method.

Overrides:
write in class FilterWriter
Parameters:
chr - the characters to write
st - The start offset
len - The number of characters to write
Throws:
IOException - if an I/O error occurs

write

public void write(String str)
           throws IOException
Invokes the delegate's write(String) method.

Overrides:
write in class Writer
Parameters:
str - the string to write
Throws:
IOException - if an I/O error occurs

write

public void write(String str,
                  int st,
                  int len)
           throws IOException
Invokes the delegate's write(String) method.

Overrides:
write in class FilterWriter
Parameters:
str - the string to write
st - The start offset
len - The number of characters 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 FilterWriter
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 FilterWriter
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 chars to be written (1 for the write(int) method, buffer length for write(char[]), 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 chars 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 chars written (1 for the write(int) method, buffer length for write(char[]), 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 chars 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


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