java.io
Class BufferedReader

java.lang.Object sample code for java.lang.Object definition code for java.lang.Object 
  extended by java.io.Reader sample code for java.io.Reader definition code for java.io.Reader 
      extended by java.io.BufferedReader
All Implemented Interfaces:
Closeable sample code for java.io.Closeable definition code for java.io.Closeable , Readable sample code for java.lang.Readable definition code for java.lang.Readable
Direct Known Subclasses:
LineNumberReader sample code for java.io.LineNumberReader definition code for java.io.LineNumberReader

public class BufferedReader
extends Reader sample code for java.io.Reader definition code for java.io.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.

Since:
JDK1.1
See Also:
FileReader sample code for java.io.FileReader definition code for java.io.FileReader , InputStreamReader sample code for java.io.InputStreamReader definition code for java.io.InputStreamReader

Field Summary
 
Fields inherited from class java.io.Reader sample code for java.io.Reader definition code for java.io.Reader
lock sample code for java.io.Reader.lock definition code for java.io.Reader.lock
 
Constructor Summary
BufferedReader sample code for java.io.BufferedReader.BufferedReader(java.io.Reader) definition code for java.io.BufferedReader.BufferedReader(java.io.Reader) (Reader sample code for java.io.Reader definition code for java.io.Reader  in)
          Create a buffering character-input stream that uses a default-sized input buffer.
BufferedReader sample code for java.io.BufferedReader.BufferedReader(java.io.Reader, int) definition code for java.io.BufferedReader.BufferedReader(java.io.Reader, int) (Reader sample code for java.io.Reader definition code for java.io.Reader  in, int sz)
          Create a buffering character-input stream that uses an input buffer of the specified size.
 
Method Summary
 void close sample code for java.io.BufferedReader.close() definition code for java.io.BufferedReader.close() ()
          Close the stream.
 void mark sample code for java.io.BufferedReader.mark(int) definition code for java.io.BufferedReader.mark(int) (int readAheadLimit)
          Mark the present position in the stream.
 boolean markSupported sample code for java.io.BufferedReader.markSupported() definition code for java.io.BufferedReader.markSupported() ()
          Tell whether this stream supports the mark() operation, which it does.
 int read sample code for java.io.BufferedReader.read() definition code for java.io.BufferedReader.read() ()
          Read a single character.
 int read sample code for java.io.BufferedReader.read(char[], int, int) definition code for java.io.BufferedReader.read(char[], int, int) (char[] cbuf, int off, int len)
          Read characters into a portion of an array.
 String sample code for java.lang.String definition code for java.lang.String readLine sample code for java.io.BufferedReader.readLine() definition code for java.io.BufferedReader.readLine() ()
          Read a line of text.
 boolean ready sample code for java.io.BufferedReader.ready() definition code for java.io.BufferedReader.ready() ()
          Tell whether this stream is ready to be read.
 void reset sample code for java.io.BufferedReader.reset() definition code for java.io.BufferedReader.reset() ()
          Reset the stream to the most recent mark.
 long skip sample code for java.io.BufferedReader.skip(long) definition code for java.io.BufferedReader.skip(long) (long n)
          Skip characters.
 
Methods inherited from class java.io.Reader sample code for java.io.Reader definition code for java.io.Reader
read sample code for java.io.Reader.read(char[]) definition code for java.io.Reader.read(char[]) , read sample code for java.io.Reader.read(java.nio.CharBuffer) definition code for java.io.Reader.read(java.nio.CharBuffer)
 
Methods inherited from class java.lang.Object sample code for java.lang.Object definition code for java.lang.Object
clone sample code for java.lang.Object.clone() definition code for java.lang.Object.clone() , equals sample code for java.lang.Object.equals(java.lang.Object) definition code for java.lang.Object.equals(java.lang.Object) , finalize sample code for java.lang.Object.finalize() definition code for java.lang.Object.finalize() , getClass sample code for java.lang.Object.getClass() definition code for java.lang.Object.getClass() , hashCode sample code for java.lang.Object.hashCode() definition code for java.lang.Object.hashCode() , notify sample code for java.lang.Object.notify() definition code for java.lang.Object.notify() , notifyAll sample code for java.lang.Object.notifyAll() definition code for java.lang.Object.notifyAll() , toString sample code for java.lang.Object.toString() definition code for java.lang.Object.toString() , wait sample code for java.lang.Object.wait() definition code for java.lang.Object.wait() , wait sample code for java.lang.Object.wait(long) definition code for java.lang.Object.wait(long) , wait sample code for java.lang.Object.wait(long, int) definition code for java.lang.Object.wait(long, int)
 

Constructor Detail

BufferedReader sample code for java.io.BufferedReader(java.io.Reader, int) definition code for java.io.BufferedReader(java.io.Reader, int)

public BufferedReader(Reader sample code for java.io.Reader definition code for java.io.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 sample code for java.lang.IllegalArgumentException definition code for java.lang.IllegalArgumentException - If sz is <= 0

BufferedReader sample code for java.io.BufferedReader(java.io.Reader) definition code for java.io.BufferedReader(java.io.Reader)

public BufferedReader(Reader sample code for java.io.Reader definition code for java.io.Reader  in)
Create a buffering character-input stream that uses a default-sized input buffer.

Parameters:
in - A Reader
Method Detail

read sample code for java.io.BufferedReader.read() definition code for java.io.BufferedReader.read()

public int read()
         throws IOException sample code for java.io.IOException definition code for java.io.IOException 
Read a single character.

Overrides:
read sample code for java.io.Reader.read() definition code for java.io.Reader.read() in class Reader sample code for java.io.Reader definition code for java.io.Reader
Returns:
The character read, as an integer in the range 0 to 65535 (0x00-0xffff), or -1 if the end of the stream has been reached
Throws:
IOException sample code for java.io.IOException definition code for java.io.IOException - If an I/O error occurs

read sample code for java.io.BufferedReader.read(char[], int, int) definition code for java.io.BufferedReader.read(char[], int, int)

public int read(char[] cbuf,
                int off,
                int len)
         throws IOException sample code for java.io.IOException definition code for java.io.IOException 
Read characters into a portion of an array.

This method implements the general contract of the corresponding read sample code for java.io.Reader.read(char[], int, int) definition code for java.io.Reader.read(char[], int, int) method of the Reader sample code for java.io.Reader definition code for java.io.Reader class. As an additional convenience, it attempts to read as many characters as possible by repeatedly invoking the read method of the underlying stream. This iterated read continues until one of the following conditions becomes true:

If the first read on the underlying stream returns -1 to indicate end-of-file then this method returns -1. Otherwise this method returns the number of characters actually read.

Subclasses of this class are encouraged, but not required, to attempt to read as many characters as possible in the same fashion.

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.

Specified by:
read sample code for java.io.Reader.read(char[], int, int) definition code for java.io.Reader.read(char[], int, int) in class Reader sample code for java.io.Reader definition code for java.io.Reader
Parameters:
cbuf - Destination buffer
off - Offset at which to start storing characters
len - Maximum number of characters to read
Returns:
The number of characters read, or -1 if the end of the stream has been reached
Throws:
IOException sample code for java.io.IOException definition code for java.io.IOException - If an I/O error occurs

readLine sample code for java.io.BufferedReader.readLine() definition code for java.io.BufferedReader.readLine()

public String sample code for java.lang.String definition code for java.lang.String  readLine()
                throws IOException sample code for java.io.IOException definition code for java.io.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 sample code for java.io.IOException definition code for java.io.IOException - If an I/O error occurs

skip sample code for java.io.BufferedReader.skip(long) definition code for java.io.BufferedReader.skip(long)

public long skip(long n)
          throws IOException sample code for java.io.IOException definition code for java.io.IOException 
Skip characters.

Overrides:
skip sample code for java.io.Reader.skip(long) definition code for java.io.Reader.skip(long) in class Reader sample code for java.io.Reader definition code for java.io.Reader
Parameters:
n - The number of characters to skip
Returns:
The number of characters actually skipped
Throws:
IllegalArgumentException sample code for java.lang.IllegalArgumentException definition code for java.lang.IllegalArgumentException - If n is negative.
IOException sample code for java.io.IOException definition code for java.io.IOException - If an I/O error occurs

ready sample code for java.io.BufferedReader.ready() definition code for java.io.BufferedReader.ready()

public boolean ready()
              throws IOException sample code for java.io.IOException definition code for java.io.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.

Overrides:
ready sample code for java.io.Reader.ready() definition code for java.io.Reader.ready() in class Reader sample code for java.io.Reader definition code for java.io.Reader
Returns:
True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.
Throws:
IOException sample code for java.io.IOException definition code for java.io.IOException - If an I/O error occurs

markSupported sample code for java.io.BufferedReader.markSupported() definition code for java.io.BufferedReader.markSupported()

public boolean markSupported()
Tell whether this stream supports the mark() operation, which it does.

Overrides:
markSupported sample code for java.io.Reader.markSupported() definition code for java.io.Reader.markSupported() in class Reader sample code for java.io.Reader definition code for java.io.Reader
Returns:
true if and only if this stream supports the mark operation.

mark sample code for java.io.BufferedReader.mark(int) definition code for java.io.BufferedReader.mark(int)

public void mark(int readAheadLimit)
          throws IOException sample code for java.io.IOException definition code for java.io.IOException 
Mark the present position in the stream. Subsequent calls to reset() will attempt to reposition the stream to this point.

Overrides:
mark sample code for java.io.Reader.mark(int) definition code for java.io.Reader.mark(int) in class Reader sample code for java.io.Reader definition code for java.io.Reader
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 sample code for java.lang.IllegalArgumentException definition code for java.lang.IllegalArgumentException - If readAheadLimit is < 0
IOException sample code for java.io.IOException definition code for java.io.IOException - If an I/O error occurs

reset sample code for java.io.BufferedReader.reset() definition code for java.io.BufferedReader.reset()

public void reset()
           throws IOException sample code for java.io.IOException definition code for java.io.IOException 
Reset the stream to the most recent mark.

Overrides:
reset sample code for java.io.Reader.reset() definition code for java.io.Reader.reset() in class Reader sample code for java.io.Reader definition code for java.io.Reader
Throws:
IOException sample code for java.io.IOException definition code for java.io.IOException - If the stream has never been marked, or if the mark has been invalidated

close sample code for java.io.BufferedReader.close() definition code for java.io.BufferedReader.close()

public void close()
           throws IOException sample code for java.io.IOException definition code for java.io.IOException 
Close the stream.

Specified by:
close sample code for java.io.Closeable.close() definition code for java.io.Closeable.close() in interface Closeable sample code for java.io.Closeable definition code for java.io.Closeable
Specified by:
close sample code for java.io.Reader.close() definition code for java.io.Reader.close() in class Reader sample code for java.io.Reader definition code for java.io.Reader
Throws:
IOException sample code for java.io.IOException definition code for java.io.IOException - If an I/O error occurs