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Class java.io.BufferedReader 

java.lang.Object
   |
   +----java.io.Reader
           |
           +----java.io.BufferedReader
public class BufferedReader
extends Reader
Read text from a character-input stream, buffering characters so as to provide for the efficient reading of characters, arrays, and lines.

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

In general, each read request made of a Reader causes a corresponding read request to be made of the underlying character or byte stream. It is therefore advisable to wrap a BufferedReader around any Reader whose read() operations may be costly, such as FileReaders and InputStreamReaders. For example, 

 BufferedReader in
   = new BufferedReader(new FileReader("foo.in"));
will buffer the input from the specified file. Without buffering, each invocation of read() or readLine() could cause bytes to be read from the file, converted into characters, and then returned, which can be very inefficient.

Programs that use DataInputStreams for textual input can be localized by replacing each DataInputStream with an appropriate BufferedReader.

See Also:
FileReader, InputStreamReader

Constructor Index

o BufferedReader(Reader)
Create a buffering character-input stream that uses a default-sized input buffer.
o BufferedReader(Reader, int)
Create a buffering character-input stream that uses an input buffer of the specified size.

Method Index

o close()
Close the stream.
o mark(int)
Mark the present position in the stream.
o markSupported()
Tell whether this stream supports the mark() operation, which it does.
o read()
Read a single character.
o read(char[], int, int)
Read characters into a portion of an array.
o readLine()
Read a line of text.
o ready()
Tell whether this stream is ready to be read.
o reset()
Reset the stream to the most recent mark.
o skip(long)
Skip characters.

Constructors

o BufferedReader 
 public BufferedReader(Reader in,
                       int sz)
Create a buffering character-input stream that uses an input buffer of the specified size.

Parameters:
in - A Reader
sz - Input-buffer size
Throws: IllegalArgumentException
If sz is <= 0
o BufferedReader 
 public BufferedReader(Reader in)
Create a buffering character-input stream that uses a default-sized input buffer.

Parameters:
in - A Reader

Methods

o read 
 public int read() throws IOException
Read a single character.

Throws: IOException
If an I/O error occurs
Overrides:
read in class Reader
o read 
 public int read(char cbuf[],
                 int off,
                 int len) throws IOException
Read characters into a portion of an array.

Ordinarily this method takes characters from this stream's character buffer, filling it from the underlying stream as necessary. If, however, the buffer is empty, the mark is not valid, and the requested length is at least as large as the buffer, then this method will read characters directly from the underlying stream into the given array. Thus redundant BufferedReaders will not copy data unnecessarily.

Parameters:
cbuf - Destination buffer
off - Offset at which to start storing characters
len - Maximum number of characters to read
Returns:
The number of bytes read, or -1 if the end of the stream has been reached
Throws: IOException
If an I/O error occurs
Overrides:
read in class Reader
o readLine 
 public String readLine() throws IOException
Read a line of text. A line is considered to be terminated by any one of a line feed ('\n'), a carriage return ('\r'), or a carriage return followed immediately by a linefeed.

Returns:
A String containing the contents of the line, not including any line-termination characters, or null if the end of the stream has been reached
Throws: IOException
If an I/O error occurs
o skip 
 public long skip(long n) throws IOException
Skip characters.

Parameters:
n - The number of characters to skip
Returns:
The number of characters actually skipped
Throws: IOException
If an I/O error occurs
Overrides:
skip in class Reader
o ready 
 public boolean ready() throws IOException
Tell whether this stream is ready to be read. A buffered character stream is ready if the buffer is not empty, or if the underlying character stream is ready.

Throws: IOException
If an I/O error occurs
Overrides:
ready in class Reader
o markSupported 
 public boolean markSupported()
Tell whether this stream supports the mark() operation, which it does.

Overrides:
markSupported in class Reader
o mark 
 public void mark(int readAheadLimit) throws IOException
Mark the present position in the stream. Subsequent calls to reset() will attempt to reposition the stream to this point.

Parameters:
readAheadLimit - Limit on the number of characters that may be read while still preserving the mark. After reading this many characters, attempting to reset the stream may fail. A limit value larger than the size of the input buffer will cause a new buffer to be allocated whose size is no smaller than limit. Therefore large values should be used with care.
Throws: IllegalArgumentException
If readAheadLimit is < 0
Throws: IOException
If an I/O error occurs
Overrides:
mark in class Reader
o reset 
 public void reset() throws IOException
Reset the stream to the most recent mark.

Throws: IOException
If the stream has never been marked, or if the mark has been invalidated
Overrides:
reset in class Reader
o close 
 public void close() throws IOException
Close the stream.

Throws: IOException
If an I/O error occurs
Overrides:
close in class Reader 
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