java.io
Class Writer

java.lang.Object
  java.io.Writer

All Implemented Interfaces:

Closeable, Flushable, Appendable

Direct Known Subclasses:

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

public abstract class Writer
extends Object
implements Appendable, Closeable, Flushable

Writer is an Abstract class for writing Character Streams. Subclasses of writer must implement the methods write(char[], int, int), close() and flush().

See Also:

Reader

Field Summary

protected Object	lock The object used to synchronize access to the writer.
(package private) static String	TOKEN_NULL

Constructor Summary

protected	Writer() Constructs a new character stream Writer using this as the Object to synchronize critical regions around.
protected	Writer(Object lock) Constructs a new character stream Writer using lock as the Object to synchronize critical regions around.

Method Summary

Writer	append(char c) Append a char cto the Writer.
Writer	append(CharSequence csq) Append a CharSequence csq to the Writer.
Writer	append(CharSequence csq, int start, int end) Append a subsequence of a CharSequence csq to the Writer.
abstract void	close() Close this Writer.
abstract void	flush() Flush this Writer.
void	write(char[] buf) Writes the entire character buffer buf to this Writer.
abstract void	write(char[] buf, int offset, int count) Writes count characters starting at offset in buf to this Writer.
void	write(int oneChar) Writes the specified character oneChar to this Writer.
void	write(String str) Writes the characters from the String str to this Writer.
void	write(String str, int offset, int count) Writes count number of characters starting at offset from the String str to this Writer.

Methods inherited from class java.lang.Object

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

Field Detail

TOKEN_NULL

static final String TOKEN_NULL

See Also:

Constant Field Values

lock

protected Object lock

The object used to synchronize access to the writer.

Constructor Detail

Writer

protected Writer()

Constructs a new character stream Writer using this as the Object to synchronize critical regions around.

Writer

protected Writer(Object lock)

Constructs a new character stream Writer using lock as the Object to synchronize critical regions around.

Parameters:

lock - the Object to synchronize critical regions around.

Method Detail

close

public abstract void close()
                    throws IOException

Close this Writer. This must be implemented by any concrete subclasses. The implementation should free any resources associated with the Writer.

Specified by:

close in interface Closeable

Throws:

IOException - If an error occurs attempting to close this Writer.

flush

public abstract void flush()
                    throws IOException

Flush this Writer. This must be implemented by any concrete subclasses. The implementation should ensure all buffered characters are written out.

Specified by:

flush in interface Flushable

Throws:

IOException - If an error occurs attempting to flush this Writer.

write

public void write(char[] buf)
           throws IOException

Writes the entire character buffer buf to this Writer.

Parameters:

buf - the non-null array containing characters to write.

Throws:

IOException - If this Writer has already been closed or some other IOException occurs.

write

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

Writes count characters starting at offset in buf to this Writer. This abstract method must be implemented by concrete subclasses.

Parameters:

buf - the non-null array containing characters to write.

offset - offset in buf to retrieve characters

count - maximum number of characters to write

Throws:

IOException - If this Writer has already been closed or some other IOException occurs.

ArrayIndexOutOfBoundsException - If offset or count are outside of bounds.

write

public void write(int oneChar)
           throws IOException

Writes the specified character oneChar to this Writer. This implementation writes the low order two bytes of oneChar to the Stream.

Parameters:

oneChar - The character to write

Throws:

IOException - If this Writer has already been closed or some other IOException occurs.

write

public void write(String str)
           throws IOException

Writes the characters from the String str to this Writer.

Parameters:

str - the non-null String containing the characters to write.

Throws:

IOException - If this Writer has already been closed or some other IOException occurs.

write

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

Writes count number of characters starting at offset from the String str to this Writer.

Parameters:

str - the non-null String containing the characters to write.

offset - the starting point to retrieve characters.

count - the number of characters to retrieve and write.

Throws:

IOException - If this Writer has already been closed or some other IOException occurs.

ArrayIndexOutOfBoundsException - If offset or count are outside of bounds.

append

public Writer append(char c)
              throws IOException

Append a char cto the Writer. The Writer.append(c) works the same as Writer.write(c).

Specified by:

append in interface Appendable

Parameters:

c - The character appended to the Writer.

Returns:

The Writer.

Throws:

IOException - If any IOException raises during the procedure.

append

public Writer append(CharSequence csq)
              throws IOException

Append a CharSequence csq to the Writer. The Writer.append(csq) works the same way as Writer.write(csq.toString()). If csq is null, then "null" will be substituted for csq.

Specified by:

append in interface Appendable

Parameters:

csq - The CharSequence appended to the Writer.

Returns:

The Writer.

Throws:

IOException - If any IOException raises during the procedure.

append

public Writer append(CharSequence csq,
                     int start,
                     int end)
              throws IOException

Append a subsequence of a CharSequence csq to the Writer. The first char and the last char of the subsequnce is specified by the parameter start and end. The Writer.append(csq) works the same way as Writer.write (csqcsq.subSequence(start,end).toString). If csq is null, then "null" will be substituted for csq.

Specified by:

append in interface Appendable

Parameters:

csq - The CharSequence appended to the Writaer.

start - The index of the first char in the CharSequence appended to the Writer.

end - The index of the char after the last one in the CharSequence appended to the Writer.

Returns:

The Writer.

Throws:

IndexOutOfBoundsException - If start is less than end, end is greater than the length of the CharSequence, or start or end is negative.

IOException - If any IOException raises during the procedure.