java.io
Class Writer

java.lang.Object
  java.io.Writer

Direct Known Subclasses:

BufferedWriter, CharArrayWriter, FilterWriter, OutputStreamWriter, PipedWriter, PrintWriter, StringWriter, WriterToASCI, WriterToUTF8, WriterToUTF8Buffered

public abstract class Writer

extends Object

Abstract class for writing to character streams. The only methods that a subclass must implement are write(char[], int, int), flush(), and close(). Most subclasses, however, will override some of the methods defined here in order to provide higher efficiency, additional functionality, or both.

Since:

JDK1.1

Author:

Mark Reinhold

See Also:

Writer, BufferedWriter, CharArrayWriter, FilterWriter, OutputStreamWriter, FileWriter, PipedWriter, PrintWriter, StringWriter, Reader

Field Summary

protected Object	lock The object used to synchronize operations on this stream.
private char[]	writeBuffer Temporary buffer used to hold writes of strings and single characters
private int	writeBufferSize Size of writeBuffer, must be >= 1

Constructor Summary

protected	Writer() Create a new character-stream writer whose critical sections will synchronize on the writer itself.
protected	Writer(Object lock) Create a new character-stream writer whose critical sections will synchronize on the given object.

Method Summary

abstract void	close() Close the stream, flushing it first.
abstract void	flush() Flush the stream.
void	write(char[] cbuf) Write an array of characters.
abstract 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) Write a string.
void	write(String str, int off, int len) Write a portion of a string.

Methods inherited from class java.lang.Object

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

Field Detail

writeBuffer

private char[] writeBuffer

Temporary buffer used to hold writes of strings and single characters

writeBufferSize

private final int writeBufferSize

Size of writeBuffer, must be >= 1

See Also:

Constant Field Values

lock

protected Object lock

The object used to synchronize operations on this stream. For efficiency, a character-stream object may use an object other than itself to protect critical sections. A subclass should therefore use the object in this field rather than this or a synchronized method.

Constructor Detail

Writer

protected Writer()

Create a new character-stream writer whose critical sections will synchronize on the writer itself.

Writer

protected Writer(Object lock)

Create a new character-stream writer whose critical sections will synchronize on the given object.

Parameters:

lock - Object to synchronize on.

Method Detail

write

public void write(int c)
           throws IOException

Write a single character. The character to be written is contained in the 16 low-order bits of the given integer value; the 16 high-order bits are ignored.

Subclasses that intend to support efficient single-character output should override this method.

Parameters:

c - int specifying a character to be written.

Throws:

IOException - If an I/O error occurs

write

public void write(char[] cbuf)
           throws IOException

Write an array of characters.

Parameters:

cbuf - Array of characters to be written

Throws:

IOException - If an I/O error occurs

write

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

Write a portion of an array of characters.

Parameters:

cbuf - Array 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)
           throws IOException

Write a string.

Parameters:

str - String to be written

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.

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 abstract void flush()
                    throws IOException

Flush the stream. If the stream has saved any characters from the various write() methods in a buffer, write them immediately to their intended destination. Then, if that destination is another character or byte stream, flush it. Thus one flush() invocation will flush all the buffers in a chain of Writers and OutputStreams.

Throws:

IOException - If an I/O error occurs

close

public abstract void close()
                    throws IOException

Close the stream, flushing it first. Once a stream has been closed, further write() or flush() invocations will cause an IOException to be thrown. Closing a previously-closed stream, however, has no effect.

Throws:

IOException - If an I/O error occurs