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Class java.io.BufferedReader

java.lang.Object
   |
   +----java.io.Reader
           |
           +----java.io.BufferedReader

public class BufferedReader

extends Reader

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"));
 

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

See Also:

FileReader, InputStreamReader

BufferedReader(Reader)

Create a buffering character-input stream that uses a default-sized input buffer.

BufferedReader(Reader, int)

Create a buffering character-input stream that uses an input buffer of the specified size.

close()

Close the stream.

mark(int)

Mark the present position in the stream.

markSupported()

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

read()

Read a single character.

read(char[], int, int)

Read characters into a portion of an array.

readLine()

Read a line of text.

ready()

Tell whether this stream is ready to be read.

reset()

Reset the stream to the most recent mark.

skip(long)

Skip characters.

 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

 public BufferedReader(Reader in)

Create a buffering character-input stream that uses a default-sized input buffer.

Parameters:

in - A Reader

 public int read() throws IOException

Read a single character.

Throws: IOException

If an I/O error occurs

Overrides:

read in class Reader

 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

 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

 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

 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

 public boolean markSupported()

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

Overrides:

markSupported in class Reader

 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

 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

 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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