BufferedWriter - JRE Emulation | JRE Emulation
public class

BufferedWriter

extends Writer
java.lang.Object
   ↳ java.io.Writer
     ↳ java.io.BufferedWriter

Class Overview

Writes 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.

Summary

[Expand]
Inherited Fields
From class java.io.Writer
Public Constructors
BufferedWriter(Writer out)
Creates a buffered character-output stream that uses a default-sized output buffer.
BufferedWriter(Writer out, int sz)
Creates a new buffered character-output stream that uses an output buffer of the given size.
Public Methods
void close()
Closes the stream, flushing it first.
void flush()
Flushes the stream.
void newLine()
Writes a line separator.
void write(int c)
Writes a single character.
void write(String s, int off, int len)
Writes a portion of a String.
void write(char[] cbuf, int off, int len)
Writes a portion of an array of characters.
Inherited Methods
[Expand]
From class java.io.Writer
From class java.lang.Object
From interface java.lang.Appendable
From interface java.io.Closeable
From interface java.io.Flushable
From interface java.lang.AutoCloseable

Public Constructors

public BufferedWriter (Writer out)

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

Parameters
out A Writer

public BufferedWriter (Writer out, int sz)

Creates 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 If sz is <= 0

Public Methods

public void close ()

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

Throws
IOException

public void flush ()

Flushes the stream.

Throws
IOException If an I/O error occurs

public void newLine ()

Writes 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 If an I/O error occurs

public void write (int c)

Writes a single character.

Parameters
c int specifying a character to be written
Throws
IOException If an I/O error occurs

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

Writes 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 {@linkplain java.io.Writer#write(java.lang.String,int,int) superclass}, which requires that an IndexOutOfBoundsException be thrown.

Parameters
s String to be written
off Offset from which to start reading characters
len Number of characters to be written
Throws
IOException If an I/O error occurs

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

Writes 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 redundant BufferedWriters will not copy data unnecessarily.

Parameters
cbuf A character array
off Offset from which to start reading characters
len Number of characters to write
Throws
IOException If an I/O error occurs