java.io

Class Writer

java.lang.Object

java.io.Writer

Direct Known Subclasses:

BufferedWriter, CharArrayWriter, FilterWriter, OutputStreamWriter, PipedWriter, PrintWriter, StringWriter

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

Version:

1.20, 00/05/03

Author:

Mark Reinhold

See Also:

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

Field Summary

Fields

Modifier and Type	Field and Description
protected Object	lock The object used to synchronize operations on this stream.

Constructor Summary

Constructors

Modifier	Constructor and Description
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

Methods

Modifier and Type	Method and Description
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

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