java.io

Class BufferedReader

public class BufferedReader extends Reader

This subclass of FilterReader buffers input from an underlying implementation to provide a possibly more efficient read mechanism. It maintains the buffer and buffer state in instance variables that are available to subclasses. The default buffer size of 8192 chars can be overridden by the creator of the stream.

This class also implements mark/reset functionality. It is capable of remembering any number of input chars, to the limits of system memory or the size of Integer.MAX_VALUE

Constructor Summary
	BufferedReader(Reader in) Create a new `BufferedReader` that will read from the specified subordinate stream with a default buffer size of 8192 chars.
	BufferedReader(Reader in, int size) Create a new `BufferedReader` that will read from the specified subordinate stream with a buffer size that is specified by the caller.

Method Summary
void	close() This method closes the underlying stream and frees any associated resources.
void	mark(int readLimit) Mark a position in the input to which the stream can be "reset" by calling the `reset()` method.
boolean	markSupported() Returns `true` to indicate that this class supports mark/reset functionality.
int	read(char[] buf, int offset, int count) This method read chars from a stream and stores them into a caller supplied buffer.
int	read()
String	readLine() This method reads a single line of text from the input stream, returning it as a `String`.
boolean	ready() This method determines whether or not a stream is ready to be read.
void	reset() Reset the stream to the point where the `mark()` method was called.
long	skip(long count) This method skips the specified number of chars in the stream.

Constructor Detail

BufferedReader

public BufferedReader(Reader in)

Create a new BufferedReader that will read from the specified subordinate stream with a default buffer size of 8192 chars.

Parameters: in The subordinate stream to read from

BufferedReader

public BufferedReader(Reader in, int size)

Create a new BufferedReader that will read from the specified subordinate stream with a buffer size that is specified by the caller.

Parameters: in The subordinate stream to read from size The buffer size to use

Throws: IllegalArgumentException if size <= 0

Method Detail

close

public void close()

This method closes the underlying stream and frees any associated resources.

Throws: IOException If an error occurs

mark

public void mark(int readLimit)

Mark a position in the input to which the stream can be "reset" by calling the reset() method. The parameter readLimit is the number of chars that can be read from the stream after setting the mark before the mark becomes invalid. For example, if mark() is called with a read limit of 10, then when 11 chars of data are read from the stream before the reset() method is called, then the mark is invalid and the stream object instance is not required to remember the mark.

Note that the number of chars that can be remembered by this method can be greater than the size of the internal read buffer. It is also not dependent on the subordinate stream supporting mark/reset functionality.

Parameters: readLimit The number of chars that can be read before the mark becomes invalid

Throws: IOException If an error occurs IllegalArgumentException if readLimit is negative.

markSupported

public boolean markSupported()

Returns true to indicate that this class supports mark/reset functionality.

Returns: true

read

public int read(char[] buf, int offset, int count)

This method read chars from a stream and stores them into a caller supplied buffer. It starts storing the data at index offset into the buffer and attempts to read len chars. This method can return before reading the number of chars requested. The actual number of chars read is returned as an int. A -1 is returned to indicate the end of the stream.

This method will block until some data can be read.

Parameters: buf The array into which the chars read should be stored offset The offset into the array to start storing chars count The requested number of chars to read

Returns: The actual number of chars read, or -1 if end of stream.

Throws: IOException If an error occurs. IndexOutOfBoundsException If offset and count are not valid regarding buf.

read

public int read()

readLine

public String readLine()

This method reads a single line of text from the input stream, returning it as a String. A line is terminated by "\n", a "\r", or an "\r\n" sequence. The system dependent line separator is not used. The line termination characters are not returned in the resulting String.

Returns: The line of text read, or null if end of stream.

Throws: IOException If an error occurs

ready

public boolean ready()

This method determines whether or not a stream is ready to be read. If this method returns false then this stream could (but is not guaranteed to) block on the next read attempt.

Returns: true if this stream is ready to be read, false otherwise

Throws: IOException If an error occurs

reset

public void reset()

Reset the stream to the point where the mark() method was called. Any chars that were read after the mark point was set will be re-read during subsequent reads.

This method will throw an IOException if the number of chars read from the stream since the call to mark() exceeds the mark limit passed when establishing the mark.

Throws: IOException If an error occurs;

skip

public long skip(long count)

This method skips the specified number of chars in the stream. It returns the actual number of chars skipped, which may be less than the requested amount.

This method first discards chars in the buffer, then calls the skip method on the underlying stream to skip the remaining chars.

Parameters: count The requested number of chars to skip

Returns: The actual number of chars skipped.

Throws: IOException If an error occurs. IllegalArgumentException If count is negative.