public class BufferedInputStream
extends java.io.InputStream
BufferedInputStream adds functionality to another input stream-namely, the ability
to buffer the input and to support the mark and reset methods. When the
BufferedInputStream is created, an internal buffer array is created. As bytes from
the stream are read or skipped, the internal buffer is refilled as necessary from the contained
input stream, many bytes at a time. The mark operation remembers a point in the
input stream and the reset operation causes all the bytes read since the most recent
mark operation to be reread before new bytes are taken from the contained input
stream.| Modifier and Type | Field and Description |
|---|---|
protected byte[] |
buf
The internal buffer array where the data is stored.
|
protected int |
count
The index one greater than the index of the last valid byte in the buffer.
|
protected int |
marklimit
The maximum read ahead allowed after a call to the
mark method before subsequent
calls to the reset method fail. |
protected int |
markpos
The value of the
pos field at the time the last mark method was
called. |
protected int |
pos
The current position in the buffer.
|
| Constructor and Description |
|---|
BufferedInputStream(java.io.InputStream in)
Creates a
BufferedInputStream and saves its argument, the input stream in
, for later use. |
BufferedInputStream(java.io.InputStream in,
int size)
Creates a
BufferedInputStream with the specified buffer size, and saves its
argument, the input stream in, for later use. |
| Modifier and Type | Method and Description |
|---|---|
int |
available()
Returns an estimate of the number of bytes that can be read (or skipped over) from this input
stream without blocking by the next invocation of a method for this input stream.
|
void |
close()
Closes this input stream and releases any system resources associated with the stream.
|
void |
mark(int readlimit)
See the general contract of the
mark method of InputStream. |
boolean |
markSupported()
Tests if this input stream supports the
mark and reset methods. |
int |
read()
See the general contract of the
read method of InputStream. |
int |
read(byte[] b,
int off,
int len)
Reads bytes from this byte-input stream into the specified byte array, starting at the given
offset.
|
void |
reset()
See the general contract of the
reset method of InputStream. |
long |
skip(long n)
See the general contract of the
skip method of InputStream. |
protected volatile byte[] buf
protected int count
0 through buf.length; elements buf[0]
through buf[count-1]
contain buffered input data obtained from the underlying input stream.protected int pos
buf array.
This value is always in the range 0 through count. If it is less
than count, then buf[pos] is the next byte to be supplied as input;
if it is equal to count, then the next read or skip
operation will require more bytes to be read from the contained input stream.
BufferedInputStream.bufprotected int markpos
pos field at the time the last mark method was
called.
This value is always in the range -1 through pos. If there is no
marked position in the input stream, this field is -1. If there is a marked
position in the input stream, then buf[markpos] is the first byte to be supplied
as input after a reset operation. If markpos is not -1,
then all bytes from positions buf[markpos] through buf[pos-1] must
remain in the buffer array (though they may be moved to another place in the buffer array, with
suitable adjustments to the values of count, pos, and markpos
); they may not be discarded unless and until the difference between pos
and markpos exceeds marklimit.
BufferedInputStream.mark(int),
BufferedInputStream.posprotected int marklimit
mark method before subsequent
calls to the reset method fail. Whenever the difference between pos
and markpos exceeds marklimit, then the mark may be dropped by
setting markpos to -1.BufferedInputStream.mark(int),
BufferedInputStream.reset()public BufferedInputStream(java.io.InputStream in)
BufferedInputStream and saves its argument, the input stream in
, for later use. An internal buffer array is created and stored in buf.in - the underlying input stream.public BufferedInputStream(java.io.InputStream in,
int size)
BufferedInputStream with the specified buffer size, and saves its
argument, the input stream in, for later use. An internal buffer array of length
size is created and stored in buf.in - the underlying input stream.size - the buffer size.java.lang.IllegalArgumentException - if size <= 0.public int read()
throws java.io.IOException
read method of InputStream.read in class java.io.InputStream-1 if the end of the stream is reached.java.io.IOException - if this input stream has been closed by invoking its close() method, or an I/O error occurs.FilterInputStream.inpublic int read(byte[] b,
int off,
int len)
throws java.io.IOException
This method implements the general contract of the corresponding
method of the readInputStream
read method of the underlying stream. This iterated
read continues until one of the following conditions becomes true:
read method of the underlying stream returns -1, indicating
end-of-file, or
available method of the underlying stream returns zero, indicating that
further input requests would block.
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 bytes actually read.
Subclasses of this class are encouraged, but not required, to attempt to read as many bytes as possible in the same fashion.
read in class java.io.InputStreamb - destination buffer.off - offset at which to start storing bytes.len - maximum number of bytes to read.-1 if the end of the stream has been reached.java.io.IOException - if this input stream has been closed by invoking its close() method, or an I/O error occurs.public long skip(long n)
throws java.io.IOException
skip method of InputStream.skip in class java.io.InputStreamjava.io.IOException - if the stream does not support seek, or if this input stream has been closed by invoking its close() method, or an I/O error occurs.public int available()
throws java.io.IOException
This method returns the sum of the number of bytes remaining to be read in the buffer (
count - pos) and the result of calling the in.available().
available in class java.io.InputStreamjava.io.IOException - if this input stream has been closed by invoking its close() method, or an I/O error occurs.public void mark(int readlimit)
mark method of InputStream.mark in class java.io.InputStreamreadlimit - the maximum limit of bytes that can be read before the mark position becomes invalid.BufferedInputStream.reset()public void reset()
throws java.io.IOException
reset method of InputStream.
If markpos is -1 (no mark has been set or the mark has been
invalidated), an IOException is thrown. Otherwise, pos is set equal
to markpos.
reset in class java.io.InputStreamjava.io.IOException - if this stream has not been marked or, if the mark has been invalidated, or the stream has been closed by
invoking its close() method, or an I/O error occurs.BufferedInputStream.mark(int)public boolean markSupported()
mark and reset methods. The
markSupported method of BufferedInputStream returns true
.markSupported in class java.io.InputStreamboolean indicating if this stream type supports the mark and
reset methods.InputStream.mark(int),
InputStream.reset()public void close()
throws java.io.IOException
close in interface java.io.Closeableclose in interface java.lang.AutoCloseableclose in class java.io.InputStreamjava.io.IOException - if an I/O error occurs.