BufferedWriter (Java 2 Platform SE 5.0) (original) (raw)

java.io

Class BufferedWriter

java.lang.Object extended by java.io.Writer java.io.BufferedWriter

All Implemented Interfaces:

public class BufferedWriter

Write text to a character-output stream, buffering characters so as to provide for the efficient writing of single characters, arrays, and strings.

The buffer size may be specified, or the default size may be accepted. The default is large enough for most purposes.

A newLine() method is provided, which uses the platform's own notion of line separator as defined by the system property line.separator. Not all platforms use the newline character ('\n') to terminate lines. Calling this method to terminate each output line is therefore preferred to writing a newline character directly.

In general, a Writer sends its output immediately to the underlying character or byte stream. Unless prompt output is required, it is advisable to wrap a BufferedWriter around any Writer whose write() operations may be costly, such as FileWriters and OutputStreamWriters. For example,

PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("foo.out")));

will buffer the PrintWriter's output to the file. Without buffering, each invocation of a print() method would cause characters to be converted into bytes that would then be written immediately to the file, which can be very inefficient.

Since:

JDK1.1

Field Summary

Fields inherited from class java.io.Writer
lock

Constructor Summary
BufferedWriter(Writer out) Create a buffered character-output stream that uses a default-sized output buffer.
[BufferedWriter](../../java/io/BufferedWriter.html#BufferedWriter%28java.io.Writer, int%29)(Writer out, int sz) Create a new buffered character-output stream that uses an output buffer of the given size.

Method Summary
void	close() Close the stream.
void	flush() Flush the stream.
void	newLine() Write a line separator.
void	[write](../../java/io/BufferedWriter.html#write%28char[], int, int%29)(char[] cbuf, int off, int len) Write a portion of an array of characters.
void	write(int c) Write a single character.
void	[write](../../java/io/BufferedWriter.html#write%28java.lang.String, int, int%29)(String s, int off, int len) Write a portion of a String.

Methods inherited from class java.io.Writer
append, append, [append](../../java/io/Writer.html#append%28java.lang.CharSequence, int, int%29), write, write

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, [wait](../../java/lang/Object.html#wait%28long, int%29)

Constructor Detail

BufferedWriter

public BufferedWriter(Writer out)

Create a buffered character-output stream that uses a default-sized output buffer.

Parameters:

out - A Writer

BufferedWriter

public BufferedWriter(Writer out, int sz)

Create a new buffered character-output stream that uses an output buffer of the given size.

Parameters:

out - A Writer

sz - Output-buffer size, a positive integer

Throws:

[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - If sz is <= 0

Method Detail

write

public void write(int c) throws IOException

Write a single character.

Overrides:

[write](../../java/io/Writer.html#write%28int%29) in class [Writer](../../java/io/Writer.html "class in java.io")

Parameters:

c - int specifying a character to be written.

Throws:

[IOException](../../java/io/IOException.html "class in java.io") - 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.

Ordinarily this method stores characters from the given array into this stream's buffer, flushing the buffer to the underlying stream as needed. If the requested length is at least as large as the buffer, however, then this method will flush the buffer and write the characters directly to the underlying stream. Thus redundantBufferedWriters will not copy data unnecessarily.

Specified by:

[write](../../java/io/Writer.html#write%28char[], int, int%29) in class [Writer](../../java/io/Writer.html "class in java.io")

Parameters:

cbuf - A character array

off - Offset from which to start reading characters

len - Number of characters to write

Throws:

[IOException](../../java/io/IOException.html "class in java.io") - If an I/O error occurs

write

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

Write a portion of a String.

If the value of the len parameter is negative then no characters are written. This is contrary to the specification of this method in the [superclass](../../java/io/Writer.html#write%28java.lang.String, int, int%29), which requires that an IndexOutOfBoundsException be thrown.

Overrides:

[write](../../java/io/Writer.html#write%28java.lang.String, int, int%29) in class [Writer](../../java/io/Writer.html "class in java.io")

Parameters:

s - String to be written

off - Offset from which to start reading characters

len - Number of characters to be written

Throws:

[IOException](../../java/io/IOException.html "class in java.io") - If an I/O error occurs

newLine

public void newLine() throws IOException

Write a line separator. The line separator string is defined by the system property line.separator, and is not necessarily a single newline ('\n') character.

Throws:

[IOException](../../java/io/IOException.html "class in java.io") - If an I/O error occurs

flush

public void flush() throws IOException

Flush the stream.

Specified by:

[flush](../../java/io/Flushable.html#flush%28%29) in interface [Flushable](../../java/io/Flushable.html "interface in java.io")

Specified by:

[flush](../../java/io/Writer.html#flush%28%29) in class [Writer](../../java/io/Writer.html "class in java.io")

Throws:

[IOException](../../java/io/IOException.html "class in java.io") - If an I/O error occurs

close

public void close() throws IOException

Close the stream.

Specified by:

[close](../../java/io/Closeable.html#close%28%29) in interface [Closeable](../../java/io/Closeable.html "interface in java.io")

Specified by:

[close](../../java/io/Writer.html#close%28%29) in class [Writer](../../java/io/Writer.html "class in java.io")

Throws:

[IOException](../../java/io/IOException.html "class in java.io") - If an I/O error occurs

Submit a bug or feature
For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.