java.io
public class BufferedReader extends Reader
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 and Description |
---|
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. |
Modifier and Type | Method and Description |
---|---|
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()
Reads an char from the input stream and returns it
as an int in the range of 0-65535.
|
int |
read(char[] buf,
int offset,
int count)
This method read chars from a stream and stores them into a caller
supplied buffer.
|
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.
|
public BufferedReader(Reader in)
BufferedReader
that will read from the
specified subordinate stream with a default buffer size of 8192 chars.in
- The subordinate stream to read frompublic BufferedReader(Reader in, int size)
BufferedReader
that will read from the
specified subordinate stream with a buffer size that is specified by the
caller.in
- The subordinate stream to read fromsize
- The buffer size to useIllegalArgumentException
- if size <= 0public void close() throws IOException
close
in interface Closeable
close
in class Reader
IOException
- If an error occurspublic boolean markSupported()
true
to indicate that this class supports mark/reset
functionality.markSupported
in class Reader
true
public void mark(int readLimit) throws IOException
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.
mark
in class Reader
readLimit
- The number of chars that can be read before the mark
becomes invalidIOException
- If an error occursIllegalArgumentException
- if readLimit is negative.public void reset() throws IOException
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.
reset
in class Reader
IOException
- If an error occurs;public boolean ready() throws IOException
false
then this stream could (but is
not guaranteed to) block on the next read attempt.ready
in class Reader
true
if this stream is ready to be read,
false
otherwiseIOException
- If an error occurspublic int read(char[] buf, int offset, int count) throws IOException
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.
read
in class Reader
buf
- The array into which the chars read should be storedoffset
- The offset into the array to start storing charscount
- The requested number of chars to readIOException
- If an error occurs.IndexOutOfBoundsException
- If offset and count are not
valid regarding buf.public int read() throws IOException
Reader
This method will block until the char can be read.
read
in class Reader
IOException
- If an error occurspublic String readLine() throws IOException
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
.null
if end of stream.IOException
- If an error occurspublic long skip(long count) throws IOException
This method first discards chars in the buffer, then calls the
skip
method on the underlying stream to skip the
remaining chars.
skip
in class Reader
count
- The requested number of chars to skipIOException
- If an error occurs.IllegalArgumentException
- If count is negative.