java.io
Class OutputStreamWriter

java.lang.Object
  java.io.Writer
      java.io.OutputStreamWriter

Direct Known Subclasses:

FileWriter

public class OutputStreamWriter

extends Writer

An OutputStreamWriter is a bridge from character streams to byte streams: Characters written to it are encoded into bytes using a specified charset. The charset that it uses may be specified by name or may be given explicitly, or the platform's default charset may be accepted.

Each invocation of a write() method causes the encoding converter to be invoked on the given character(s). The resulting bytes are accumulated in a buffer before being written to the underlying output stream. The size of this buffer may be specified, but by default it is large enough for most purposes. Note that the characters passed to the write() methods are not buffered.

For top efficiency, consider wrapping an OutputStreamWriter within a BufferedWriter so as to avoid frequent converter invocations. For example:

 Writer out
   = new BufferedWriter(new OutputStreamWriter(System.out));
 

A surrogate pair is a character represented by a sequence of two char values: A high surrogate in the range '\uD800' to '\uDBFF' followed by a low surrogate in the range '\uDC00' to '\uDFFF'. If the character represented by a surrogate pair cannot be encoded by a given charset then a charset-dependent substitution sequence is written to the output stream.

A malformed surrogate element is a high surrogate that is not followed by a low surrogate or a low surrogate that is not preceeded by a high surrogate. It is illegal to attempt to write a character stream containing malformed surrogate elements. The behavior of an instance of this class when a malformed surrogate element is written is not specified.

Since:

JDK1.1

Author:

Mark Reinhold

See Also:

BufferedWriter, OutputStream, Charset

Field Summary

private sun.nio.cs.StreamEncoder

se

Fields inherited from class java.io.Writer

lock

Constructor Summary

OutputStreamWriter(OutputStream out)
Create an OutputStreamWriter that uses the default character encoding.

OutputStreamWriter(OutputStream out, Charset cs)
Create an OutputStreamWriter that uses the given charset.

OutputStreamWriter(OutputStream out, CharsetEncoder enc)
Create an OutputStreamWriter that uses the given charset encoder.

OutputStreamWriter(OutputStream out, String charsetName)
Create an OutputStreamWriter that uses the named charset.

Method Summary

void	close() Close the stream.
void	flush() Flush the stream.
(package private) void	flushBuffer() Flush the output buffer to the underlying byte stream, without flushing the byte stream itself.
String	getEncoding() Return the name of the character encoding being used by this stream.
void	write(char[] cbuf, int off, int len) Write a portion of an array of characters.
void	write(int c) Write a single character.
void	write(String str, int off, int len) Write a portion of a string.

Methods inherited from class java.io.Writer

write, write

Methods inherited from class java.lang.Object

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

Field Detail

se

private final sun.nio.cs.StreamEncoder se

Constructor Detail

OutputStreamWriter

public OutputStreamWriter(OutputStream out,
                          String charsetName)
                   throws UnsupportedEncodingException

Create an OutputStreamWriter that uses the named charset.

Parameters:

out - An OutputStream

charsetName - The name of a supported charset

Throws:

UnsupportedEncodingException - If the named encoding is not supported

OutputStreamWriter

public OutputStreamWriter(OutputStream out)

Create an OutputStreamWriter that uses the default character encoding.

Parameters:

out - An OutputStream

OutputStreamWriter

public OutputStreamWriter(OutputStream out,
                          Charset cs)

Create an OutputStreamWriter that uses the given charset.

Parameters:

out - An OutputStream

cs - A charset

Since:

1.4

OutputStreamWriter

public OutputStreamWriter(OutputStream out,
                          CharsetEncoder enc)

Create an OutputStreamWriter that uses the given charset encoder.

Parameters:

out - An OutputStream

enc - A charset encoder

Since:

1.4

Method Detail

getEncoding

public String getEncoding()

Return the name of the character encoding being used by this stream.

If the encoding has an historical name then that name is returned; otherwise the encoding's canonical name is returned.

If this instance was created with the OutputStreamWriter(OutputStream, String) constructor then the returned name, being unique for the encoding, may differ from the name passed to the constructor. This method may return null if the stream has been closed.

Returns:

The historical name of this encoding, or possibly null if the stream has been closed

See Also:

Charset

flushBuffer

void flushBuffer()
           throws IOException

Flush the output buffer to the underlying byte stream, without flushing the byte stream itself. This method is non-private only so that it may be invoked by PrintStream.

Throws:

IOException

write

public void write(int c)
           throws IOException

Write a single character.

Overrides:

write in class Writer

Parameters:

c - int specifying a character to be written.

Throws:

IOException - If an I/O error occurs

write

public void write(char[] cbuf,
                  int off,
                  int len)
           throws IOException

Write a portion of an array of characters.

Specified by:

write in class Writer

Parameters:

cbuf - Buffer of characters

off - Offset from which to start writing characters

len - Number of characters to write

Throws:

IOException - If an I/O error occurs

write

public void write(String str,
                  int off,
                  int len)
           throws IOException

Write a portion of a string.

Overrides:

write in class Writer

Parameters:

str - A String

off - Offset from which to start writing characters

len - Number of characters to write

Throws:

IOException - If an I/O error occurs

flush

public void flush()
           throws IOException

Flush the stream.

Specified by:

flush in class Writer

Throws:

IOException - If an I/O error occurs

close

public void close()
           throws IOException

Close the stream.

Specified by:

close in class Writer

Throws:

IOException - If an I/O error occurs