Package org.apache.commons.io.output

# Class ProxyWriter

java.lang.Object
java.io.Writer
java.io.FilterWriter
org.apache.commons.io.output.ProxyWriter

All Implemented Interfaces:
  `Closeable`, `Flushable`, `Appendable`, `AutoCloseable`

Direct Known Subclasses:
  `CloseShieldWriter`, `FileWriterWithEncoding`, `TaggedWriter`

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)`.

- ## Field Summary

  ### Fields inherited from class java.io.FilterWriter

  `out`

  ### Fields inherited from class java.io.Writer

  `lock`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `ProxyWriter(Writer delegate)`
  Constructs a new ProxyWriter.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `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)`
  Handles any IOExceptions thrown.
  `void`
  `write(char[] cbuf)`
  Invokes the delegate's `write(char[])` method.
  `void`
  `write(char[] cbuf, int off, int len)`
  Invokes the delegate's `write(char[], int, int)` method.
  `void`
  `write(int c)`
  Invokes the delegate's `write(int)` method.
  `void`
  `write(String str)`
  Invokes the delegate's `write(String)` method.
  `void`
  `write(String str, int off, 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 Details

  - ### ProxyWriter

    public ProxyWriter(Writer delegate)
    Constructs a new ProxyWriter.
    Parameters:
      `delegate` - the Writer to delegate to

- ## Method Details

  - ### 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

  - ### 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) 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

  - ### 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

  - ### 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

  - ### close

    public void close() throws IOException
    Invokes the delegate's `close()` method.
    Specified by:
      `close` in interface `AutoCloseable`
    Specified by:
      `close` in interface `Closeable`
    Overrides:
      `close` in class `FilterWriter`
    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.

  - ### handleIOException

    protected void handleIOException(IOException e) throws IOException
    Handles any IOExceptions thrown.

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

    Parameters:
      `e` - The IOException thrown
    Throws:
      `IOException` - if an I/O error occurs.
    Since:
      2.0

  - ### write

    public void write(char[] cbuf) throws IOException
    Invokes the delegate's `write(char[])` method.
    Overrides:
      `write` in class `Writer`
    Parameters:
      `cbuf` - the characters to write
    Throws:
      `IOException` - if an I/O error occurs.

  - ### write

    public void write(char[] cbuf, int off, int len) throws IOException
    Invokes the delegate's `write(char[], int, int)` method.
    Overrides:
      `write` in class `FilterWriter`
    Parameters:
      `cbuf` - the characters to write
      `off` - The start offset
      `len` - The number of characters to write
    Throws:
      `IOException` - if an I/O error occurs.

  - ### write

    public void write(int c) throws IOException
    Invokes the delegate's `write(int)` method.
    Overrides:
      `write` in class `FilterWriter`
    Parameters:
      `c` - the character 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 off, int len) throws IOException
    Invokes the delegate's `write(String)` method.
    Overrides:
      `write` in class `FilterWriter`
    Parameters:
      `str` - the string to write
      `off` - The start offset
      `len` - The number of characters to write
    Throws:
      `IOException` - if an I/O error occurs.