Class BufferedInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

java.io.BufferedInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class BufferedInputStream
extends FilterInputStream

Reads from another stream through a buffer, so that many small reads become few large ones, and supports mark and reset.

Like most streams, it is for one thread at a time.

Field Summary

Fields

Modifier and Type	Field	Description
protected byte[]	buf	The buffer; null once the stream is closed, which every read checks.
protected int	count	How many bytes of buf are valid.
protected int	marklimit	How far past the mark a read may go before the mark is dropped.
protected int	markpos	The index in buf of the mark, or -1 when there is none.
protected int	pos	The index in buf of the next byte to read.

Fields inherited from class FilterInputStream

in

Constructor Summary

Constructors

Constructor	Description
BufferedInputStream(InputStream in)	Buffers in with an 8192 byte buffer.
BufferedInputStream(InputStream in, int size)	Buffers in with a buffer of size bytes.

Method Summary

Modifier and Type	Method	Description
int	available()	Returns the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller 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)	Marks the current position in this input stream.
boolean	markSupported()	Tests if this input stream supports the mark and reset methods.
int	read()	Reads the next byte of data from the input stream.
int	read(byte[] b, int off, int len)	Reads as the JDK does: on past the buffer while the stream underneath has bytes available without blocking, so a small buffer does not make every read a short one.
void	reset()	Repositions this stream to the position at the time the mark method was last called on this input stream.
long	skip(long n)	Skips over and discards n bytes of data from this input stream.

Methods inherited from class InputStream

read, readAllBytes, readNBytes, readNBytes, transferTo

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

buf

protected byte[] buf

The buffer; null once the stream is closed, which every read checks.

count

protected int count

How many bytes of buf are valid.

pos

protected int pos

The index in buf of the next byte to read.

markpos

protected int markpos

The index in buf of the mark, or -1 when there is none.

marklimit

protected int marklimit

How far past the mark a read may go before the mark is dropped.

Constructor Details

BufferedInputStream

public BufferedInputStream(InputStream in)

Buffers in with an 8192 byte buffer.

BufferedInputStream

public BufferedInputStream(InputStream in,
 int size)

Buffers in with a buffer of size bytes.

Throws

• IllegalArgumentException: when size is not positive

Method Details

read

public int read()
         throws IOException

Description copied from class: InputStream

Reads the next byte of data from the input stream. The value byte is returned as an 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. A subclass must provide an implementation of this method.

Overrides:

read in class FilterInputStream

Throws:

IOException

read

public int read(byte[] b,
 int off,
 int len)
         throws IOException

Reads as the JDK does: on past the buffer while the stream underneath has bytes available without blocking, so a small buffer does not make every read a short one.

Overrides:

read in class FilterInputStream

Throws:

IOException

skip

public long skip(long n)
          throws IOException

Description copied from class: InputStream

Skips over and discards n bytes of data from this input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. The actual number of bytes skipped is returned. If n is negative, no bytes are skipped. The skip method of InputStream creates a byte array and then repeatedly reads into it until n bytes have been read or the end of the stream has been reached. Subclasses are encouraged to provide a more efficient implementation of this method.

Overrides:

skip in class FilterInputStream

Throws:

IOException

available

public int available()
              throws IOException

Description copied from class: InputStream

Returns the number of bytes that can be read (or skipped over) from this input stream without blocking by the next caller of a method for this input stream. The next caller might be the same thread or another thread. The available method for class InputStream always returns 0. This method should be overridden by subclasses.

Overrides:

available in class FilterInputStream

Throws:

IOException

mark

public void mark(int readlimit)

Description copied from class: InputStream

Marks the current position in this input stream. A subsequent call to the reset method repositions this stream at the last marked position so that subsequent reads re-read the same bytes. The readlimit arguments tells this input stream to allow that many bytes to be read before the mark position gets invalidated. The general contract of mark is that, if the method markSupported returns true, the stream somehow remembers all the bytes read after the call to mark and stands ready to supply those same bytes again if and whenever the method reset is called. However, the stream is not required to remember any data at all if more than readlimit bytes are read from the stream before reset is called. The mark method of InputStream does nothing.

Overrides:

mark in class FilterInputStream

reset

public void reset()
           throws IOException

Description copied from class: InputStream

Repositions this stream to the position at the time the mark method was last called on this input stream. The general contract of reset is: If the method markSupported returns true, then: If the method mark has not been called since the stream was created, or the number of bytes read from the stream since mark was last called is larger than the argument to mark at that last call, then an IOException might be thrown. If such an IOException is not thrown, then the stream is reset to a state such that all the bytes read since the most recent call to mark (or since the start of the file, if mark has not been called) will be resupplied to subsequent callers of the read method, followed by any bytes that otherwise would have been the next input data as of the time of the call to reset. If the method markSupported returns false, then: The call to reset may throw an IOException. If an IOException is not thrown, then the stream is reset to a fixed state that depends on the particular type of the input stream and how it was created. The bytes that will be supplied to subsequent callers of the read method depend on the particular type of the input stream. The method reset for class InputStream does nothing and always throws an IOException.

Overrides:

reset in class FilterInputStream

Throws:

IOException

close

public void close()
           throws IOException

Description copied from class: InputStream

Closes this input stream and releases any system resources associated with the stream. The close method of InputStream does nothing.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class FilterInputStream

Throws:

IOException

markSupported

public boolean markSupported()

Description copied from class: InputStream

Tests if this input stream supports the mark and reset methods. The markSupported method of InputStream returns false.

Overrides:

markSupported in class FilterInputStream