com.jmobilecore.comm
Class BufferedInputStream

java.lang.Object
  java.io.InputStream
      java.io.ByteArrayInputStream
          com.jmobilecore.comm.BufferedInputStream

All Implemented Interfaces:

java.io.Closeable

public class BufferedInputStream
extends java.io.ByteArrayInputStream

The class is J2ME port of Sun's BufferedOutputStream which implements a buffered input stream. 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.

Author:

Greg Gridin

Field Summary

protected static int	DEFAULT_BUFFER_SIZE
protected java.io.InputStream	in The input stream.
protected int	marklimit The maximum read ahead allowed after a call to the mark method before subsequent calls to the reset method fail.

Fields inherited from class java.io.ByteArrayInputStream

buf, count, mark, pos

Constructor Summary

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.

Method Summary

int	available() Returns the number of bytes that can be read from this input stream without blocking.
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.

Methods inherited from class java.io.InputStream

read

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_BUFFER_SIZE

protected static int DEFAULT_BUFFER_SIZE

in

protected java.io.InputStream in

The input stream.

marklimit

protected int marklimit

The maximum read ahead allowed after a call to the 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.

See Also:

mark(int), reset()

Constructor Detail

BufferedInputStream

public BufferedInputStream(java.io.InputStream in)

Creates a BufferedInputStream and saves its argument, the input stream in, for later use. An internal buffer array is created and stored in buf.

Parameters:

in - the underlying input stream.

BufferedInputStream

public 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. An internal buffer array of length size is created and stored in buf.

Parameters:

in - the underlying input stream.

size - the buffer size.

Throws:

java.lang.IllegalArgumentException - if size <= 0.

Method Detail

available

public int available()

Returns the number of bytes that can be read from this input stream without blocking.

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.

Overrides:

available in class java.io.ByteArrayInputStream

Returns:

the number of bytes that can be read from this input stream without blocking.

See Also:

in

close

public void close()
           throws java.io.IOException

Closes this input stream and releases any system resources associated with the stream.

Specified by:

close in interface java.io.Closeable

Overrides:

close in class java.io.ByteArrayInputStream

Throws:

java.io.IOException - if an I/O error occurs.

mark

public void mark(int readlimit)

See the general contract of the mark method of InputStream.

Overrides:

mark in class java.io.ByteArrayInputStream

Parameters:

readlimit - the maximum limit of bytes that can be read before the mark position becomes invalid.

See Also:

reset()

markSupported

public boolean markSupported()

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

Overrides:

markSupported in class java.io.ByteArrayInputStream

Returns:

a boolean indicating if this stream type supports the mark and reset methods.

See Also:

InputStream.mark(int), InputStream.reset()

read

public int read()

See the general contract of the read method of InputStream.

Overrides:

read in class java.io.ByteArrayInputStream

Returns:

the next byte of data, or -1 if the end of the stream is reached.

See Also:

in

read

public 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.

This method implements the general contract of the corresponding read method of the InputStream class. As an additional convenience, it attempts to read as many bytes as possible by repeatedly invoking the read method of the underlying stream. This iterated read continues until one of the following conditions becomes true:

• The specified number of bytes have been read,

• The read method of the underlying stream returns -1, indicating end-of-file, or

• The 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.

Overrides:

read in class java.io.ByteArrayInputStream

Parameters:

b - destination buffer.

off - offset at which to start storing bytes.

len - maximum number of bytes to read.

Returns:

the number of bytes read, or -1 if the end of the stream has been reached.

reset

public void reset()

See the general contract of the 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.

Overrides:

reset in class java.io.ByteArrayInputStream

See Also:

mark(int)

skip

public long skip(long n)

See the general contract of the skip method of InputStream.

Overrides:

skip in class java.io.ByteArrayInputStream

Parameters:

n - the number of bytes to be skipped.

Returns:

the actual number of bytes skipped.