java.io

Class Writer

java.lang.Object

java.io.Writer

Direct Known Subclasses:

BufferedWriter, CharArrayWriter, EncodedStreamWriter, FilterWriter, OutputStreamWriter, PrintWriter, RegexWriter, StringWriter, TextWriter

public abstract class Writer
extends Object

This abstract class forms the base of the hierarchy of classes that write output as a stream of chars. It provides a common set of methods for writing chars to stream. Subclasses implement and/or extend these methods to write chars in a particular manner or to a particular destination such as a file on disk or network connection.

Author:

Aaron M. Renn (arenn@urbanophile.com), Per Bothner

Field Summary

Fields

Modifier and Type	Field and Description
protected Object	lock This is the object used to synchronize criticial code sections for thread safety.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Writer() This is the default no-argument constructor for this class.
protected	Writer(Object lock) This method initializes a Writer that will synchronize on the specified Object.

Method Summary

Modifier and Type	Method and Description
abstract void	close() This method closes the stream.
abstract void	flush() This method forces any data that may have been buffered to be written to the underlying output device.
void	write(char[] buf) This method all the writes char from the passed array to the output stream.
abstract void	write(char[] buf, int offset, int len) This method writes len char from the specified array buf starting at index offset into the array.
void	write(int b) This method writes a single char to the output stream.
void	write(String str) This method writes all the characters in a String to the output.
void	write(String str, int offset, int len) This method writes len chars from the String starting at position offset.

Methods inherited from class java.lang.Object

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

Field Detail

lock

protected Object lock

This is the object used to synchronize criticial code sections for thread safety. Subclasses should use this field instead of using synchronized methods or explicity synchronizations on this

Constructor Detail

Writer

protected Writer()

This is the default no-argument constructor for this class. This method will set up the class to synchronize criticial sections on itself.

Writer

protected Writer(Object lock)

This method initializes a Writer that will synchronize on the specified Object.

Parameters:

obj - The Object to use for synchronizing critical sections

Method Detail

flush

public abstract void flush()
                    throws IOException

This method forces any data that may have been buffered to be written to the underlying output device. Please note that the host environment might perform its own buffering unbeknowst to Java. In that case, a write made (for example, to a disk drive) might be cached in OS buffers instead of actually being written to disk.

Throws:

IOException - If an error occurs

close

public abstract void close()
                    throws IOException

This method closes the stream. Any internal or native resources associated with this stream are freed. Any subsequent attempt to access the stream might throw an exception.

This method in this class does nothing.

Throws:

IOException - If an error occurs

write

public void write(int b)
           throws IOException

This method writes a single char to the output stream.

Parameters:

b - The char to be written to the output stream, passed as an int

Throws:

IOException - If an error occurs

write

public void write(char[] buf)
           throws IOException

This method all the writes char from the passed array to the output stream. This method is equivalent to write(buf, 0, buf.length) which is exactly how it is implemented in this class.

Parameters:

buf - The array of char to write

Throws:

IOException - If an error occurs

write

public abstract void write(char[] buf,
                           int offset,
                           int len)
                    throws IOException

This method writes len char from the specified array buf starting at index offset into the array.

Subclasses must provide an implementation of this abstract method.

Parameters:

buf - The array of char to write from

offset - The index into the array to start writing from

len - The number of char to write

Throws:

IOException - If an error occurs

write

public void write(String str)
           throws IOException

This method writes all the characters in a String to the output.

Parameters:

str - The String whose chars are to be written.

IOException - If an error occurs

Throws:

IOException

write

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

This method writes len chars from the String starting at position offset.

Parameters:

str - The String that is to be written

offset - The character offset into the String to start writing from

len - The number of chars to write

Throws:

IOException - If an error occurs