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java.lang.Object
|
+----java.io.InputStream
|
+----java.io.FilterInputStream
|
+----java.io.BufferedInputStream
buf
count
marklimit
mark method before subsequent calls to the
reset method fail.
markpos
pos field at the time the last
mark method was called.
pos
BufferedInputStream(InputStream)
BufferedInputStream(InputStream, int)
available()
mark(int)
markSupported()
mark
and reset methods.
read()
read(byte[], int, int)
reset()
mark method was last called on this input stream.
skip(long)
n bytes of data from the
input stream.
buf
protected byte buf[]
count
protected int count
pos
protected int pos
buf array.
markpos
protected int markpos
pos field at the time the last
mark method was called. The value of this field is
-1 if there is no current mark.
marklimit
protected int marklimit
mark method before subsequent calls to the
reset method fail.
BufferedInputStream
public BufferedInputStream(InputStream in)
BufferedInputStream
public BufferedInputStream(InputStream in,
int size)
read
public synchronized int read() throws IOException
int in the range
0 to 255. If no byte is available
because the end of the stream has been reached, the value
-1 is returned. This method blocks until input data
is available, the end of the stream is detected, or an exception
is thrown.
The read method of BufferedInputStream
returns the next byte of data from its buffer if the buffer is not
empty. Otherwise, it refills the buffer from the underlying input
stream and returns the next character, if the underlying stream
has not returned an end-of-stream indicator.
-1 if the end of the
stream is reached.
read
public synchronized int read(byte b[],
int off,
int len) throws IOException
If this stream's buffer is not empty, bytes are copied from it into the array argument. Otherwise, the buffer is refilled from the underlying input stream and, unless the stream returns an end-of-stream indication, the array argument is filled with characters from the newly-filled buffer.
As an optimization, if the buffer is empty, the mark is not valid,
and len is at least as large as the buffer, then this
method will read directly from the underlying stream into the given
array. Thus redundant BufferedInputStreams will not copy
data unnecessarily.
-1 if the end of
the stream has been reached.
skip
public synchronized long skip(long n) throws IOException
n bytes of data from the
input stream. The skip method may, for a variety of
reasons, end up skipping over some smaller number of bytes,
possibly zero. The actual number of bytes skipped is returned.
The skip method of BufferedInputStream
compares the number of bytes it has available in its buffer,
k, where k = count - pos,
with n. If n ≤ k,
then the pos field is incremented by n.
Otherwise, the pos field is incremented to have the
value count, and the remaining bytes are skipped by
calling the skip method on the underlying input
stream, supplying the argument n - k.
available
public synchronized int available() throws IOException
The available method of
BufferedInputStream returns the sum of the the number
of bytes remaining to be read in the buffer
(count - pos)
and the result of calling the available method of the
underlying input stream.
mark
public synchronized void mark(int readlimit)
reset method repositions the stream at
the last marked position so that subsequent reads re-read the same
bytes.
The readlimit argument tells the input stream to
allow that many bytes to be read before the mark position gets
invalidated.
reset
public synchronized void reset() throws IOException
mark method was last called on this input stream.
If the stream has not been marked, or if the mark has been invalidated, an IOException is thrown. Stream marks are intended to be used in situations where you need to read ahead a little to see what's in the stream. Often this is most easily done by invoking some general parser. If the stream is of the type handled by the parser, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails. If an exception gets tossed within readlimit bytes, the parser will allow the outer code to reset the stream and to try another parser.
markSupported
public boolean markSupported()
mark
and reset methods. The markSupported
method of BufferedInputStream returns
true.
boolean indicating if this stream type supports
the mark and reset methods.
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